Category: OSCAR

Spectroscopic characterization of newly designed fluorescent probes for biomedical research

Author(s): Amira Anwar

Mentor(s): Ozlem Dilek, Chemistry & Biochemistry

Abstract

The development of fluorescent probes is crucial for advancing cellular imaging and disease diagnostics, particularly in detecting oxidative stress, a key driver of cancer, neurodegenerative diseases, and fibrosis. A hallmark of oxidative stress is the carbonylation of biomolecules, which occurs when reactive oxygen species (ROS) modify proteins and other biomolecules, leading to cellular dysfunction. In this project, we designed and synthesized hydrazine-based small-molecule fluorophores to selectively target biological aldehydes, particularly those generated by lysyl oxidases (LOXs) during collagen oxidation. These aldehydes serve as important biomarkers of fibrosis and metastatic progression. The fluorophores react with aldehydes to form hydrazones, resulting in a fluorescence turn-on response that enables real-time monitoring of oxidative stress in cellular systems. To characterize probe performance, we analyzed their photophysical properties using UV-visible and fluorescence spectroscopy. Additionally, reaction kinetics were evaluated via UV-visible spectrophotometry, and structural validation was conducted using NMR and mass spectrometry. By refining probe design for enhanced fluorescence sensitivity and specificity, this work contributes to the development of next-generation imaging tools for studying disease mechanisms and advancing biomedical diagnostics.

Audio Transcript

Hi everyone, and thank you for checking out my presentation. I’ll be sharing my research on the spectroscopic characterization of newly designed fluorescent probes for biomedical research. These probes are designed to detect biologically relevant aldehydes—aldehydes are highly reactive molecules that can build up in the body during oxidative stress. This kind of cellular stress is involved in many major health conditions like cancer, fibrosis, and neurodegenerative diseases. By creating tools to visualize these aldehydes in real time, we hope to provide a better way to study early-stage disease and potentially improve how we diagnose and/or monitor these conditions. So, why is this important? Our bodies naturally produce molecules called reactive oxygen species, or ROS. But when there’s too much ROS and not enough defense, it leads to oxidative stress. This damages important parts of our cells—proteins, DNA, lipids, and nucleic acids. One of the results of this damage is something called carbonylation, an irreversible modification to proteins that disrupt its normal function which serves as a biomarker for disease progression. By detecting this early and accurately could give us new ways to track disease or catch it early—especially in conditions like cancer or metabolic disorders. Right here is an image of a normal cell being attacked by free radicals, elevated levels of ROS leads to oxidative stress. The role of LOX. A group of enzymes called lysyl oxidases, or LOX are important in building collagen, the main protein in connective tissues. But during that process, they produce aldehydes.These aldehydes, especially when overproduced, are closely tied to tissue damage and disease. So if we can track them, we can better understand what’s going on in the body during early disease stages.So this ia relaly good image on how LOX cross linking collagen occurs and potential way to image LOX. To tackle this, I designed a small molecule—called fluorescent probe—that glows when it detects aldehydes. The idea is simple: no aldehyde, no glow. But when an aldehyde is present, the probe reacts and lights up.This happens via click chem mechanism Shown right here. This kind of “turn-on” fluorescence lets us track where and when aldehydes are forming, even in real-time, which is incredibly useful for research and diagnostics. Here’s a detailed view of how it works: We start with an amine which converts into a hydrazine molecule—Molecule 5. This hydrazine reacts specifically with aldehydes. Once it does, the product becomes a fluorescent hydrazone molecule. We tested this with two model aldehydes: formaldehyde and butyraldehyde. And we saw that when the reaction happens, there’s a clear increase in fluorescence.To study the probe’s behavior, we used tools like UV-Vis and fluorescence spectroscopy. These techniques let us measure how much light the molecule absorbs and emits. Our data showed that after reacting with butyraldehyde, there was a strong increase in fluorescence. That confirmed the probe was working just as we hoped. We also wanted to know how fast this reaction happens and in what environments it works best.In our kinetic studies, we found that the probe reacted more quickly with butyraldehyde than with formaldehyde, and it performed better in methanol than in pbs which is similar to human body ph 7. Even better, the reaction happens in seconds, which is perfect for real-time tracking. Here’s a visual. In these three vials, you can see how the probe behaves: The first vial just has the probe in methanol—no fluorescence. The second has methanol, butyraldehyde and the probe—strong fluorescence. The third has methanol, formaldehyde and the probe—some fluorescence, but not as much.So, in summary, we’ve developed a fluorescent probe that’s small, fast-reacting, and selective for aldehydes. It gives a clear signal when aldehydes are present, which opens up exciting possibilities for detecting biologically relevant aldehydes, with an emphasis on those generated by lysyl oxidases (LOX). This tool could help researchers track disease progression or even assist in diagnostics in the future. Our next steps include:Testing the probe in live cells to see how it performs in biological systems. Making more versions of the probe, including ones that work in the near-infrared range for deeper imaging in tissues. And eventually, applying it in 3D printed tissue models or even live animal studies.Thank you so much for watching!

College of Humanities and Social Science OSCAR

Assessing Soil Organic Matter In a Legacy Wetland Mesocosm after the Colonization of Invasive Species

Author(s): Trinity Lavenhouse

Mentor(s): Changwoo Ahn, Environmental Science and Policy Department

Abstract

This study was conducted in Dr. Ahn’s wetland mesocosm on West Campus at George Mason University. Inside there are 40 wetland mesocosms that were created in 2012. The mesocosms were initially planted with 0 to 4 different native wetland species. Since COVID-19, maintenance halted which allowed the colonization of invasive species for the past three to five years. The goal of this study was to determine the amount of soil organic matter in each mesocosm after the colonization of invasive species. The hypothesis was that because there were more plants than there were previously, there will be a higher amount of soil organic matter in these mesocosms. The soil organic matter percentage was processed using the loss on ignition method. It was found that mesocosms that had sparsely spread, or no plants had the lowest soil organic matter while overgrown and dense mesocosms had the highest soil organic matter. After about 10 years, soil organic matter seemed to increase from a range of 2.36% to 2.59% to now a range of 4.15% to 6.21%. In the future a soil bulk density will be processed to analyze how soil porosity or compaction correlates with the soil organic matter found within the mesocosms. Also, plant identification will be conducted for all 40 mesocosms.

Audio Transcript

Hello, my name is Trinity Lavenhouse, and I am presenting my research on assessing soil organic matter in a legacy wetland mesocosm after the colonization of invasive species. My mentor is Dr. Changwoo Ahn.
So, to start off I am going to explain the importance of measuring soil organic matter! Soil organic matter is made up of decomposed plant and animal material. They contain quite a lot of organic compounds and are full of nutrients that help plants grow. So in general, it is important to measure the amount of soil organic matter that is present because it can indicate how healthy and fertile the soil is for plants to grow.
This study was conducted in Dr. Ahn’s wetland mesocosm on West campus in George Mason University. Inside there are 40 wetland mesocosms that were created in 2012. The mesocosms were initially planted with 0 to 4 different native wetland species. This picture is from 2014 after 2 growing seasons. Since COVID-19, maintenance halted. Unwanted plants weren’t removed and the water levels weren’t monitored like they use to be. This allowed the colonization of invasive species for the past three to five years. So, the goal of this study was to determine the amount of soil organic matter in each mesocosm after the colonization of invasive species. The hypothesis was that since there were more plants than there were previously, there will be a higher amount of soil organic matter in these mesocosms.
To take samples the mesocosms were split into 5 sections and one sample was taken from each section within the top 20 centimeters where organic matter is the most present, because soil organic matter decreases as you go further down. This was repeated for all 40 mesocosms. The soil organic matter percentage was processed using the loss on ignition method. To carry this out each sample was dried at 105°C for two days. After they were completely dry, they stayed in a desiccator to cool and were then crushed in with a mortar and pestle and sieved through a 2mm filter to get everything that is too big to go into the crucibles. The fine dirt was then placed in crucibles and fired at 360 Celsius for two hours and they were placed back into the desiccator to cool. Soil organic matter percentage is the percentage change of mass.
The results were all collected and all five of the samples were compiled and averaged represent the one mesocosm. It was found that mesocosms that had sparsely spread, or no plants had the lowest soil organic matter while overgrown and dense mesocosms had the highest soil organic matter. The standard error bars are large in mesocosms that had more plants or organic matter in a section than other sections. The mesocosms were then grouped by the initial number of species planted. There seems to be no significant difference across the board and the reason for that will be analyzed further.
In a previous study conducted by another person in this lab named Mary Means, they measured the total carbon content of all of the 34 planted mesocosms in 2014. Total carbon content is a is about 58% of soil organic matter so that conversion was used to estimate what the soil organic matter content was back in 2014. About ten years until now, later soil organic matter seemed to increase from a range of 2.36% to 2.59% to now a range of 4.15% to 6.21%. In the future a soil bulk density will be processed to analyze how soil porosity or compaction correlates with the soil organic matter found within the mesocosms. Also, plant identification will be conducted for all 40 mesocosms as when these samples were initially taken most of the plants were dead because it was the end of the winter.
Thank you for listening!

College of Engineering and Computing OSCAR

Comments to Communities: Modeling Online News-Related Discourse

Author(s): Reva Hirave

Mentor(s): Antonios Anastasopoulos, Computer Science

Abstract

This project presents the development of a lightweight, extensible tool designed to collect and aggregate user-generated commentary from online news platforms, including the New York Times, Fox News, and Reddit. By unifying disparate data formats into a standardized structure, this tool facilitates downstream tasks such as toxicity analysis, network modeling, and discourse comparison. To date, over 9,000 comments have been collected, and preliminary analysis using the Perspective API reveals cross-platform trends in toxicity and engagement. Additionally, early visualizations of user interaction networks explore the extent to which individuals engage outside their ideological or topical communities. Ultimately, this project aims to offer a command-line interface that enables customizable data harvesting across platforms, with filters for topic relevance, discussion tree structure, and other discourse features. This tool lays the groundwork for deeper investigations into online news discourse and community polarization.

Audio Transcript

Hi, I’m Reva, and this is Comments to Communities—a project about modeling how people talk about the news across online platforms.

The first rule of the internet: don’t forget the comments. Wreck-It Ralph wasn’t really wrong. Comment sections are chaotic, often toxic, and sometimes considered the worst parts of the internet. But they’re also where some of the most honest and unfiltered public discourse can happen. So instead of ignoring the comments, this project combs through thousands of them.

News sites and social media platforms host ideologically distinct communities. Commenters on The New York Times don’t necessarily talk anything like those on Fox News. Comments can reveal more than just interactions between strangers—they can reflect how online communities construct, challenge, or echo narratives around ongoing social issues.

But right now, existing tools for studying discourse fall short. They usually focus on one platform or treat comments as isolated utterances rather than parts of larger conversations. They also rarely combine toxicity metrics with network structure, which means they don’t fully capture complex social relationships.

This project addresses those gaps. These insights led us to two research questions:

How do different online communities talk about the news, and do they talk across ideological lines?

How can we measure the health of these discussions in ways that go beyond just likes or shares?

To answer these questions, we built a lightweight tool that scrapes and standardizes comments from three platforms: The New York Times, Fox News, and political subreddits. The tool unifies this data into a common format, adding metadata like reply structure and timestamps. This makes it easy to analyze both the content and the shape of these discussions—like who’s replying to whom, and how toxic the exchanges are.

So far, we’ve collected about 4,000 comments from The New York Times, another 4,000 from Reddit, and around 1,000 from Fox News. That’s just under 9,000 posts total, and while it’s not enough yet, it’s already yielded some compelling visualizations.

These are reply networks for Fox News, and you’ll also see one for The New York Times. Each node is a comment, and the size corresponds to the number of replies it received. Every edge—or line—represents a reply relationship. Nodes are color-coded by toxicity: green for less toxic and red for more toxic. These toxicity labels were generated using Google’s Perspective API.

These networks already hint at platform-specific dynamics and how polarized—or productive—these spaces can be. For example, if we look at the New York Times network, some circles are larger simply because they have more replies. One discussion concerns an op-ed about a former Kamala Harris skeptic, which is represented as the largest node in the middle. As expected, most comments have zero replies and cluster near the original post, but there are a few longer threads as well.

This opens up a range of further research questions, like: Do toxic comments produce toxic replies? Could we predict when a conversation will become toxic?

Why does any of this matter? Tools like this can help journalists, sociologists, and NLP researchers ask new kinds of questions—not just what people are saying, but how they’re saying it. If we want healthier discourse, we first need to understand how people talk. This project offers a step in that direction by making comment sections a little less mysterious and a lot more measurable.

This work builds on research from the 2024 Yellow Neck Workshop at Johns Hopkins and is supported by the OSCAR Program at George Mason University. I’d like to thank Dr. Antonis Anastasopoulos and the AI-Curated Democratic Discourse team from the JHU workshop.

Thank you so much for listening. Feel free to reach out if you want to explore the tool or just talk about the project. I’m available at arhavegu.edu.

Thank you again.

College of Humanities and Social Science OSCAR

Evaluating Perceptions of Basic Psychological Needs in Full-Time Employees

Author(s): Jessica Luther

Mentor(s): Lauren Kuykendall, Psychology

Abstract

The climate of the current workplace has changed drastically within the past few years, as a result of many jobs moving to remote work. Many employees have had to learn how to adjust to dealing with the physical separation of leadership, as well as balance their own basic psychological needs in a new environment. These three needs, autonomy, competence, and relatedness, are important workplace predictors that still need further exploration in the remote workplace. This study samples from both remote and in-person workers, providing a clear comparison of how the change in workplace setting impacts an employee’s perception of leader-member quality, as well as their basic psychological needs. We hypothesized that LMX would have a significant and positive impact on each basic psychological need. We also hypothesized that remote work will moderate the relationship between LMX and each basic psychological need, such that the positive relationship will be stronger for non-remote workers than remote workers. Participants consisted of 241 full-time employees, 123 in-person workers and 118 remote workers. Results show that while the correlation between LMX and each basic psychological need were significant, they were not statistically different between work locations. This has implications for how the basic psychological needs can be fulfilled in the remote environment, challenging the assumption that the in-person environment is better at fostering better leader relationships and significance of the impact on the employee.

Audio Transcript

Hi everyone! My name is Jessica Luther and this is my project, Evaluating Basic Psychological Needs in Full-Time Employees. This study was done with the help of Dr. Kuykendall, and represents my research conducted for the third semester of the Honors in Psychology program. Since COVID, there’s been more flexibility in allowing employees to have part-time and full-time positions working remotely. Prior research shows that perception of leader quality is a predictor for employee well-being which has been studied in both the in-person and remote environments. The perception of someone’s basic psychological needs has also been seen to change the remote environment, a result of whether it be not seeing people, or whether it be feelings of social isolation. Basic psychological need perception has also changed. Connecting these three topics, since COVID we have seen a lot of people moving to remote positions, and a lot of the recent research in remote work kind of reflects how leader quality or leadership styles are impacting employees, specifically, the outcomes such as autonomy, motivation, a lot of stress-related outcomes as well. So, for this study to provide a direct comparison between in-person and remote employees we looked at how leader member exchange, which is noted as LMX, or also known as the perception of leader quality, is moderated by remote work and how remote work changes the relationship that someone might have with their leader or the perception of the quality they have with their leader and how that impacts their three basic psychological needs, which are autonomy, competence, and relatedness. My hypotheses are split into two parts, you have hypotheses 1a through 1c. This deals with direct associations between LMX and autonomy, LMX and competence, and LMX and relatedness. Prior research shows LMX is positively related to autonym, competence and relatedness, so we assume the same thing for this study. Hypotheses 2a, 2b, and 2c are where my contribution to the research comes in. It suggests that remote work moderates this relationship so remote work will moderate the relationship between LMX and each basic psychological need, such that the positive relationship will be stronger for no-remote workers than remote workers. Basically, insinuating that we will see that autonomy, competence and relatedness are both significant and stronger for in-person employees rather than remote employees. So, my participants were 241 full-time employees, 51% worked in-person, 49% worked remotely. We did not include any hybrid workers or anyone who worked part-time just to have a more balanced sample of who we were sampling from so full-time in this case was defined as working 35 plus hours per week. 42.3% were male, 55.2% were female, and 2.5% identified as non-binary. They were excluded if they worked part-time, were hybrid workers, or resided somewhere other than the U.S.. So, the methodology for this was that they were recruited on Prolific, which is an anonymous survey taking website, and the survey itself took place on Qualtrics. The two instruments used were the LMX-7, which measures perceived leader-member quality, or leader-member exchange, and Self Determination Theory 21, or SDT-21 Basic Psychological Needs at Work Scale, which measures each basic psychological need through statements that were tested using a Likert scale. Participants, for their participation, were compensated 2.85%. So, for the results, we ran a correlational analysis between LMX and SDT, separating remote participants from in-person participants, so that we would be able to directly compare their results. We actually found that each component of self-determination theory, autonomy, competence, and relatedness, was significant with LMX in both groups. So Hypotheses 1a-1c were supported, which was expected because we’ve already seen this in prior research, However, Hypotheses 2a-2c were not supported. Even though each component was significant for in-person, through further testing we found that while everything was significant, they were significantly different so the correlations between LMX and SDT of in-person workers was not significantly different than LMX and SDT of remote workers. That suggests that these needs can be filled in both environments. The implications for this show how leadership perceptions might not really change based on environments, and even then, it’s not statistically significant between the two environments themselves, and actually remote work can still be a supporting environment, given that people have supportive leadership roles and supportive leaders that they can count on. One of the studies that I read noted that social isolation was a really really big concern, which could really damage someone’s feelings of relatedness. However, as seen in the table, relatedness was still significant in remote workers using LMX, so having that supportive leadership role really can help fill the need for relatedness. Further research should take into account what hybrid work or part time work might reveal because those are really samples as well. Knowing how different samples perceive different leadership styles is really important to understanding how leaders can support their employees and how leaders can really help fulfill some of these psychological needs. For my acknowledgements, I wanted to say that this couldn’t have been done without OSCAR funding, it was used to help compensate the participants for their participants, and I also wanted to thank Dr. Brielmaier, Dr. Zaccaro, and Dr. Z for all their help in my project as well. Thank you.

College of Science OSCAR

Synthesis and spectroscopic characterization of drug-fluorescent probe conjugates for live cell imaging

Author(s): Maryam Baig

Mentor(s): Ozlem Dilek, Chemistry and Biochemistry

Abstract

Recent advancements in technology and medicine have brought attention to fluorescent probes due to their non-invasive, highly sensitive capabilities in live cell imaging, especially in biomedical fields. These probes are particularly valuable for visualizing cellular signaling processes and tracking drug activities at the cellular level, making them essential tools for studying cell functions and drug delivery systems. In this study, we focus on the development and characterization of a coumarin-based fluorescent probe conjugated with omaveloxolone (OMA), a drug used to treat rare genetic disorders. The resulting drug-fluorophore conjugate provides a means to explore organelle-specific drug activation and monitor cellular signaling processes. The synthesis begins with the preparation of a fluorescent hydrazone compound, which is then conjugated to OMA to create the final drug-fluorophore construct. The conjugation process was monitored using kinetics and UV-vis spectroscopy, with detailed studies of reaction kinetics, including solvent choice and concentration, aimed at optimizing conditions for further investigations. The drug-fluorophore conjugate was characterized through thin-layer chromatography (TLC), nuclear magnetic resonance (NMR), and UV-vis spectroscopy. Various optimization steps were implemented to enhance the conjugate’s stability and efficiency, ensuring maximum fluorescence while preserving the biological activity of OMA. The fluorescent probe is designed to possess strong fluorescence and stability, making it ideal for cellular labeling when conjugated with the OMA drug. This conjugate is expected to demonstrate high fluorescence efficiency, stability within the cellular environment, low toxicity, and sufficient cell permeability. With the integration of fluorescent imaging technologies and molecular designs, drug visualization will have the potential to redefine our understanding of drug action in cellular systems, enabling the drug-conjugate dynamics in subcellular environment from new perspectives.

Audio Transcript

My name is Maryam Baig. I am a senior undergraduate at George Mason University, and I am presenting my project on the Synthesis and spectroscopic characterization of drug-fluorophore conjugates for live cell imaging. I had the opportunity to work on this project through Dr.Ozlem Dilek, who is part of the Department of Chemistry and Biochemistry located in the Institute for Advanced Biomedical Research at SciTech campus.

To provide a background for this project, I’d like to begin by explaining what fluorophores are. Fluorophores are chemical molecules that absorb Ultraviolet Visible light and project the emission in the form of light, and they help make up fluorescent probes. Fluorescent probes are molecular tools that allow scientists to visualize and observe live cell processes using highly sensitive, non-invasive and safe detection in biological cells. Omaveloxolone (OMA) is a drug being developed to treat Frederick’s ataxia, a rare and worsening disease that affects the nervous system. The fluorophore we are using for this project is a coumarin, and we have found that coumarin-based fluorophores have low inherent toxicity and can be readily internalized and washed out from cells, making them ideal for cell studies. In this project, we will focus on developing the fluorescently labeled OMA to monitor the delivery of fluorophore-OMA drug probes inside cells.

On this slide, we have two molecules that we will be using for our project. On the left side, you can see the OMA drug. It is a big molecule with multiple ketones present. Those are the double bonds with the oxygen molecules. On the right side, we have our CF3 coumarin. This is a published molecule and it is the coumarin that will we will be synthesizing and then conjugating with the OMA.

On this slide we have the synthesis procedure of our starting material, which is an amine, into the CF3 hydrazine that we will be using to conjugate to the OMA. As you can see, we will be adding an NH2 group, which is in amine group, to the existing amine.

To begin, we started by doing a thin layer chromatography between the drug, the dye and the conjugate after we had made the three. We diluted our samples in methanol, and then our TLC chamber solutions included various ratios of solvents that allowed us to visualize the mobility and composition of molecules on the TLC plates.

These are images from our TLC experiment. The samples on the left on the TLC plates are the CF3 dye, while the samples on the right are the product. As you can see, we observed a slight difference in shift between the lowest dots on the TLC samples. This indicates that we may have something new in our product.

From here we moved onto kinetics experiments, and after doing absorbance and emission data collection and nuclear magnetic resonance tests, we were able to make some conclusion. The data from the absorbance and emission graphs show that the drug-dye conjugate is fluorescent. Our NMR comparison between the CF3, the purified conjugate, and the OMA drug also gave us interesting results which we will see in the further slides.

This slide shows a comparison of the absorbance and emission data graphs that we collected for the conjugate to help us understand the composition of our molecule. As stated in the legend at the bottom of the slide, we can see that the CF3 is shown in red, the OMA is shown in blue, and the conjugate is shown in green. And if we look at the graphs, we can see that the red and green lines were very similar while the blue line was not as high. Because the red and green lines are so similar, we came to question if the dye may be overpowering the drug.

To see a more detailed and more accurate composition of the molecules we had worked with we conducted NMRs for each of the molecules. The purpose of an NMR is to analyze the magnetic properties of atomic nuclei to study the structure, the dynamics and interactions of the molecule. The area outlined here by black lines is where we will zoom in for the next slide.

Enlarging that small area shows us these multiple peaks that appear between the three samples. The yellow highlight indicates peaks that belong to the OMA drug. The blue highlighted peaks indicate the CF3 molecule, and the darker blue highlighted peaks indicate that we may still have some starting material remaining in our conjugate.

Based on the results of our NMR and the other test that we conducted we plan to move forward by trying to figure out where the CF3 is attaching on the OMA drug and how we can predict an NMR for it. Because of the dark blue highlight peaks that were present in our NMR on the previous slide, we decided to re-crystallize the CF3 coumarin to purify it further before we make another conjugate, and to try and get rid of those extra peaks. Finally, we plan to expand our range of molecules that can be conjugated with the OMA drug to see which one will be most efficient. We did a quick experiment in vials using small samples of different types of small molecules which you can see in this bottom image here and you can see were able to fluoresce. We plan to go forward with molecules numbers 2, 5, and 8, and study them further to see if they will be able to conjugate with the OMA drug.

Lastly, I’d like to acknowledge and thank Dr.Ozlem Dilek, Eva-Maria Rudler, and the rest of the Dilek team for their support and guidance throughout this project along with the GMU Department of Chemistry and Biochemistry. Additionally, I would like to express my gratitude to Dr.Karen Lee and the OSCAR team for giving me this unique research opportunity. Thank you for listening to my presentation.

College of Engineering and Computing OSCAR

DNA-origami-based biomimetic interfaces for T-cell activation

Author(s): Benjamin Safa

Mentor(s): Remi Veneziano, Bioengineering

Abstract

DNA Origami Nanoparticles, also referred to as DNA-NPs, are nanostructures that take advantage of the Watson-Crick complementary base pairing rules to create precise DNA nanostructures with precise and customizable size and shape within the 10-nanometer to 100-nanometer size range. DNA-NPs provide a highly programmable interface for function as nanocarriers of proteins and are highly biocompatible, allowing them to be administered in vivo as they can be broken down by natural enzymes within the body (such as DNAse). DNA-NPs have also shown significant promise in the realm of T-cell activation, acting as nanocarriers for conjugated tumor antigens and antibodies, allowing for the activation of T-cells and recognition of target antigens (such as those overexpressed in tumor cells). Here, we aim to determine favorable nanoscale organizations of simple DNA-NP motifs—specifically ligand stoichiometry, protein orientation, and position—to determine the efficacy of different T-cell signaling pathways in CD8+ T-cell expansion and proliferation. Building on previous work done under previous URSPs, the previous wheel motif will be utilized in order to move forward with assembling such interfaces. Various protein conjugation methods will be tested with motif—mainly copper free click chemistry techniques, such as DBCO-azide, maleimide-thiol, and NHS/NH2 —and conjugation efficiency will be tested through the use of surface plasmon resonance experiments. Motifs will then be tested with fluorophores/mock proteins (i.e., streptavidin) to verify the nanoscale control of antigen presentation using the DNA Origami technique, most likely through the use of atomic force microscopy (AFM) and fluorescence resonance energy transfer (FRET) experiments. After validating optimal conjugation methods with the motifs, interfaces will be produced with attached cytokines and tested by our collaborator in vitro with CD8+ T-cells.

Audio Transcript

Unknown Speaker 0:01
Ben, hi everyone. My name is Ben Safa, and my project is DNA origami based biomedic interfaces for T cell activation.

Unknown Speaker 0:11
So a key problem in adoptive cell therapy, which is a form of cancer immunotherapy,

Unknown Speaker 0:17
is basically the immunosuppressive environment of the tumor microenvironment and the related cell exhaustion adopted. U cell therapy is a form of cancer where we extract white blood cells from patients, modify them, and then re administer them. And these white blood cells are susceptible to a variety of things, but the main problem that we’re focusing on is cell exhaustion, which causes limited responses across cancers.

Unknown Speaker 0:51
The need for a memory type is integral to solving this problem of cell exhaustion, and

Unknown Speaker 0:59
there have been different types of platforms created for this, but DNA origami is something that may provide a very efficient, scalable platform and very precise platform to solving this problem. DNA origami is basically

Unknown Speaker 1:15
DNA nanostructures that are created through a long, single strand scaffold and several short staple strands that help fold the structure into any arbitrary shape.

Unknown Speaker 1:25
This research thus attempts to create such interfaces,

Unknown Speaker 1:31
namely 2d

Unknown Speaker 1:33
structures to enrich memory like qualities in T cells, in the context of improving adoptive cell therapy and fusion products.

Unknown Speaker 1:43
So the methods we employed for this were one design and two synthesis. We started with a target geometry, in this case a wheel, and used the software predicts to generate scaffold and staple sequences, and we used we ordered those Safa scaffold and scaffold sequences from

Unknown Speaker 2:05
a manufacturer and added different types of

Unknown Speaker 2:10
synthesized the scaffold, first using DNA polymerase and different types of materials such as DNTPs, and added the staple strands to get our final structure.

Unknown Speaker 2:22
Then after that, what we hope to do is attach any type of protein you want. Likely this will be different types of stimulatory ligands, such as 41 BB. This is common

Unknown Speaker 2:35
stimulatory ligand for memory for T cells. We also could attach stuff like fluorophores to track our interfaces and different types of

Unknown Speaker 2:48
beads to characterize these structures,

Unknown Speaker 2:55
so the results that we experienced

Unknown Speaker 2:59
are detailed. So at the top here we have our scaffold synthesis. So we started with a template, primers and additives. So these are DNTPs, which allow us to make the scaffold, and we have a faint Ben at the bottom, which is our single strand DNA, which you want to isolate, as well as our double strand at the top,

Unknown Speaker 3:27
the single strand DNA here is has been purified through centrifugation, and after that, we folded it with our structures, with Our staple strands, and did a variety of different characterization on this at the bottom here, you’ll see a dynamic light scattering graph on the left, then a atomic force microscopy graph image, and then a gel electrophoresis image on the left. Our DLs graph shows the diameter of our particles, and we measured it to be around 58 nanometers, and we got something around that value. So that means it’s consistent. Our AFM images showed that there were some defects in our structure, so that would require us to go back to the staple sequence design, which is what we did and what we’re currently working on. And our gel electrophoresis showed that we were able to successfully purify our structures.

Unknown Speaker 4:27
So

Unknown Speaker 4:29
over the course of the spring, basically what we’ve done is verify the folding of our structures and modify our staple sequences such that we are able to get a structure that does not have the defects that you see in these AFM images. We’ve also proceeded to add overhangs, and we are going to be trying conjugation protocols over this coming summer. Thank you. Applause.

College of Humanities and Social Science OSCAR

Predictors of Young Adults’ Physical Activity and Sedentary Behavior

Author(s): Matthew Burdick

Mentor(s): Jerome Short, Psychology

Abstract

Although cardiorespiratory fitness and muscular strength are the strongest predictors of lifespan examined in epidemiologic and experimental research, over 75% of adults in the United States fail to meet national physical activity (PA) guidelines and many live sedentary lifestyles. Identifying predictors of PA and sedentary behavior (SB) may inform public health interventions. This study uses questionnaire and activity monitor data to identify predictors of PA/SB for young adults. Young adults are an underexamined population within the PA/SB literature and research on this topic has yielded inconsistent findings. Participants (n = 216) were about 20 years old, predominantly female (n = 149), and owned a smart watch. The study transpired over 29 days with a pretest and two posttests. We examined 6 predictors: perceived stress, anxiety, depression, somatic pain, meaning in life, and gratitude. Sitting time was significantly negatively correlated with meaning in life, moderate PA, vigorous PA, and exercise satisfaction. Moderate PA and exercise satisfaction were unique predictors of sitting time. Perceived stress and somatic pain were negatively correlated with vigorous PA and steps per week. Sitting was negatively correlated with days of walking. Exercise satisfaction was a unique predictor of vigorous PA and daily steps. We found bidirectional relationship between perceived stress and vigorous PA that was mediated by exercise satisfaction. Our findings indicate that interventions should focus on lowering sitting time and raising exercise satisfaction to promote young adults’ adherence to CDC PA recommendations. The relationship between psychological factors and PA might be largely explained by exercise satisfaction.

Audio Transcript

Hello everyone. So exercise. We all know fundamentally that exercise is probably good for us. It might make us lose some weight. It might help us be more energetic throughout the day. It even might make us live longer. So why is it so hard for us to exercise? So. Research shows that cardio respiratory fitness, and muscular strength are the strongest predictors of lifespan in the research.

So this beats cancer risk. This beats smoking risk. This beats type two diabetes. If you can run fast and hard and you can lift heavy, you will likely live for a long time. Despite this, over 75% of adults in the United States fail to meet the national guidelines. So why is this the case? So our question was, what are the mental and physical factors that predict exercise and sitting behavior, especially in young adults?

And the way we attacked this question was we recruited over 200 Mason students who with a mean age of 20 years old, and we required them to wear smartwatch smart watches throughout a 29 day period. And now throughout that period we analyze their sort of different psychological and physical variables through questionnaire data.

And after that study we were able to run data analysis using SPSS.

So what predictors or did we examine in this study? So we examined sort of two classes of predictors that we hypothesized to be either protective or harmful to physical activity. So protective. We have meaning in life. So the sense that someone feels that they can engage purposefully in their day-to-day lives, sort of the antithesis to nihilism.

And now you have gratitude is gratitude can be a state and a trait so people can feel grateful. All of the time. Or they can have moments where they feel gr grateful, which is more of the trait like gratitude. Um, this questionnaire measures both the state and the trait, but it basically means how grateful are you or like how much gratitude do you have for your current situation despite all the negatives.

So it’s sort of like almost an optimistic worldview. We also have several risk factors, so perceived stress. Anxiety, somatic symptoms and depression. Somatic symptoms meaning bodily pain and aches.

So what do we hypothesize?

First things first, we hypothesize that the risk factors, so remember, that’s your perceived stress, anxiety, depression, and body pain. We predicted that that would be. Um, related to less exercise and more sitting. So for example, someone who is very anxious, we expect them to exercise less and sit more. And this is in line with the research.

Um, uh, alternatively, we think that the protective factors, so those are our median life and gratitude will be related to more exercise and less sitting. Finally, we predict that all these factors to both risk and protective factors will uniquely predict exercise in sitting. So that means that out of all the variables that we assessed in our study, we would think that the, all our protective and risk factors accountant for unique variants in our outcomes.

So what we observe. Our relationship between our predictors and outcomes is primarily attributed to our factors instead of some other confounding third variable. So what do we find? So first we found some pretty interesting information about our samples activity. So again, we have about 200 Mason students over 18 years old.

With a mean age of 20 years old, and we found that GMU students surpass Americans in meeting C to C guidelines. So that means that you can see in our figure here that almost 54% of American, or sorry, 54% of GMU students meet or exceed the national guidelines of activity. So the CD. C recommends that people, especially adults, more specifically.

Participate in at least 150 minutes. So two and a half hours of moderate intensity exercise per week, or the equivalent of vigorous activity. And so we found that in our sample over almost 54% of our students met or exceeded these guidelines. Whereas nationally, only 25% of American adults meet those guidelines.

So we’re almost twice as compliant. Compared to the average American, but this can be somewhat misleading because as you can see on our bottom bar here, the sedentary bar, almost 20% of GE students in our sample had zero minutes, zero minutes of activity per week. And so that was a cause for concern.

We found that meaning in life was negatively related to sitting time. So people who perceive that they have a purposeful engagement in their life, that they can traverse the day-to-day events of their life and feel like it has purpose. Those people tended to sit less throughout this 29 day period.

We also found that people who were physically active, especially within the moderate physical activity category, um, this uniquely predicted sitting time up to 29 days after baseline. So basically this was our big longitudinal finding that people who were. Especially active at day one of our study tended to sit less up to almost a month after baseline.

Additionally, we found that perceived stress and somatic pain were negatively related to vigorous activity and daily steps. So people who reported being more stressed and having more bodily pain, typically exercised less and walked less.

So exploratory analysis revealed some interesting results. So especially before examining the relationship between stress and vigorous activity. As you can recall, before we found that stress was negatively related to physical activity, but uh, exploratory analysis revealed that stress was not a unique predictor of vigorous activity, meaning that.

There’s something else accounting for that variance. And what we found was exercise satisfaction accounted for that variance in a bi-directional, fully mediated model. So what does that mean? It means that perceived stress has no relationship, uh, has at least no unique relationship with vigorous activity.

But when you include exercise satisfaction. It has a mediaing relationship so that, so in our first model here in Model A, we found that people who were stressed reported less exercise satisfaction and exercise satisfaction. Being a strong predictor of vigorous activity would increase vigorous activity.

So basically, people who were stressed had less as facts from exercising, and so were less likely to exercise. Additionally, this was bidirectional. So if you flip it on its head, it is also true. So vigorous activity has no unique predictive relationship with perceived stress, but when you add exercise satisfaction, vigorous activity can, is, can be associated with a lot of exercise satisfaction.

And in doing so since exercise satisfaction is, is, um, associated with less perceived stress. It can vigor activity, could then could lead to less perceived stress. I should state that this is cross-sectional data, so we’re not making a causal claim, but we did find a fully mediated cross-sectional model with these variables, some things to take away with you.

So median life is negatively related to setting time. So. If you can find a way to increase your perception of life being purposeful to you, that things aren’t meaningless, that your actions matter. If you can increase that, you may be able to sit less and improve your physical health. Um, being active, especially moderately active, decreases your risk of sitting for chronically amount, chronic amounts of time.

Uh, stress may reduce exercise satisfaction, which in turn would reduce your, um, vigorous physical activity and vigorous activity may raise exercise satisfaction. And finally, satisfaction is weigh in more vigorous activity. Thank you for listening. Have a good day.

College of Science OSCAR

A Non-Invasive Buffer Based Alternative to DNA Extraction from Teeth

Author(s): Fatima Durrani

Mentor(s): Joseph DiZinno, Forensics

Abstract

In forensic and anthropological contexts, DNA extraction from teeth is critical in cases where individuals must be identified from mass disaster sites, crime scenes, or ancient skeletal remains. Traditionally, the standard method adopted by the FBI and forensic laboratories is an invasive one, involving the drilling, crushing, or creating a powder of the tooth to access DNA within the dentin. This approach is impractical, since the tooth is a piece of evidence and can be important for analysis in the future. My study aims to provide a non-destructive alternative. I followed a protocol proposed by Monalisa Heng and Éadaoin Harney, using a guanidine-based buffer to extract DNA without damaging the tooth. Cleaned third molars were placed in the buffer, leeching DNA out of the cementum. This buffer proved successful, extracting DNA suitable for analysis, demonstrating that non-invasive extraction is a feasible alternative to destructive techniques. Additional research should be done in the future, including DNA sequencing to assess the quality and completeness of the genetic material. In addition, sodium or potassium acetate buffers could also be tested for comparative studies of non-invasive DNA extraction

Audio Transcript

Hello everyone, my name is Fatima Durani. I am a biology major and a forensic science minor. Or rather I have a minor in forensic science I conducted my research under the guidance of Dr. Madden in the biology department. I am a predental student as you can probably tell from my research so let’s get straight into it. My research focus is on a non-invasive buffer-based method of DNA extraction from teeth you’re probably asking Fatima why the heck are you doing research on teeth so some up when it comes to ancient remains or mass disasters where corpses are decay beyond identification, forensic scientist Take the teeth of these corpses extract DNA from these teeth and identify individuals, however All these scenarios have one thing in common can be used as evidence fortunately, the standard protocol to extracting DNA from these teeth is to destroy the truth. Now this visual I included actually is a minimally invasive method where the tooth is drilled and the DNA is extracted that way once it’s placed in the buffer however, in many cases, the entire tooth is destroyed and into a powder. And DNA extracted that way this is impractical when you’re looking as teeth as a source of evidence for future analysis So a solution to this issue is a buffer-based extraction protocol, which is what my research focuses on I used a buffer proposed by Mona, Lisa, Hank and Dr. Harney So this buffer includes guineas HCL which help DNA extract from the tooth while preserving the pH in the integrity of the DNA so as you can see here, I included a visual that shows you that the pulp in the Denton this pink flesh inside the tooth contain most of the DNA in the in invasive protocol which includes crushing the tooth aims to extract DNA from this area however, DNA is also included in the cement in the enamel, which is the outer portion of the tooth The invasive method that I will use that the invasive method that I will use using the buffer plants to extract DNA from this cement in the enamel, especially around the root right here, so the invasive protocol includes powder rising. The tooth placing get a protein is buffer and then quantify it using PCR. The noninvasive method includes emerging in a buffer created right here and then purifying the DNA quantify it using PCR and then and then both results or both DNA extractions from both methods will be analyze and analyze using gel electrophoresis This is just me. I gonna be so loud because teeth can contain diseases so I worked under a hood. This is the invasive method that I used crushing the juice to extract the DNA. This is the buffer and the that was placed in the buffer and this was me just cleaning the truth with. To remove any debris or blood so ask for the results in the conclusions the gel for the noninvasive method actually showed a successful amount of DNA these bands represent DNA at the 450 base pair Portion Well, one well one was the negative control which was just a buffer and two was the positive control which was a swab of my cheek and then the remaining well not including the ladder were the third molars that were placed in the buffer and DNA was extracted that way Invasive method actually was supposed to be a control method that had a positive result however, as you can see deep, something went wrong. There is no bands like the invasive method and there are two but they’re very faint so the likely reasoning behind this was. When I placed the powder in the button the Chex buffer I placed too much tooth powder, which let you contamination. Some future improvements to the study. Include adding DNA sequencing to check for contamination. Using degraded samples to allow my buffer to be implemented in anthropological settings and testing other buffers such as sodium and potassium acetate, which are stronger and more likely to extract more DNA from the acknowledgments. I’d like to know who is my mentor Doctor Who ordered all of materials necessary for this project and Dr. Madden for providing the lab and the resources I needed to conduct my research. As for the work protocol, buffer were inspired by Mona Lisa Hayes study on the development of non-invasive DNA extraction method. Definitely check her study and research out. It’s very interesting. She worked on dog teeth thank you guys so much for listening to my little research. Blurb have a nice day.

College of Humanities and Social Science College of Science OSCAR

Pharmacological Characterization of Chimeric NMDA Receptors in Xenopus

Author(s): Diborah Gutema

Mentor(s): Theodore Dumas, Department of Psychology, Interdisciplinary Program in Neuroscience

Abstract

NMDA receptors (NMDARs) play a critical role in synaptic plasticity and cognitive function by mediating both ionotropic and non-ionotropic signaling. During postnatal development, NMDA receptors undergo a subunit shift from GluN2B to GluN2A, a transition associated with synaptic maturation and the emergence of mature cognitive function. While previous research has explored the physiological and behavioral consequences of this transition, the specific mechanisms driving these changes remain unclear. In particular, the relative contributions of ionotropic and non-ionotropic signaling have not been fully defined. Ionotropic signaling involves calcium influx through the receptor channel upon ligand binding, while non-ionotropic signaling refers to intracellular signaling cascades initiated by conformational changes in the receptor that occur independently of ion flow. This study aims to dissect these signaling pathways by utilizing chimeric GluN2 subunits engineered to separate ionotropic and non-ionotropic functions. Chimeric constructs are currently being subcloned into Xenopus laevis–compatible vectors for functional expression in oocytes. This work has involved preparation of the pGEMHE-membrane-EGFP backbone through bacterial culture and plasmid isolation via alkaline lysis mini prep, followed by gel electrophoresis and spectrophotometric analysis to assess plasmid integrity and purity. Restriction digests were performed to linearize the plasmid and confirm backbone identity. In parallel, GluN2A, GluN2B, and chimeric constructs have been cultured from glycerol stocks and are currently undergoing PCR amplification with construct-specific primers. Following amplification, the inserts will be digested, purified, and ligated into the vector. Preliminary results confirm successful plasmid preparation, and insert amplification and ligation are ongoing. Once subcloning is complete, the constructs will be injected into Xenopus laevis oocytes, followed by two-electrode voltage clamp (TEVC) recordings to measure receptor responses to varying concentrations of glutamate and glycine, as well as pharmacological modulators of NMDA receptors. Statistical analyses using two-way ANOVA will compare current amplitudes across receptor type (GluN2A, GluN2B, ABc, BAc) and treatment condition (agonist/modulator concentration), with the goal of identifying distinct electrophysiological profiles associated with each subunit composition. This study will characterize how differences in GluN2 subunit composition and intracellular domain identity affect NMDA receptor-mediated signaling in an isolated system.

Audio Transcript

Hello all. I am Diborah Gutema and this is my video presentation for my project, Pharmacological Characterization of Chimeric NMDA Receptors in Xenopus laevis Oocytes.

NMDA receptors are ion channels located on neurons that allow calcium ions to enter the cell when activated by the neurotransmitter glutamate. This calcium signaling, known as ionotropic signaling, is critical for synaptic plasticity, learning, and memory. NMDA receptors can also engage in non-ionotropic signaling, where conformational changes in the receptor trigger internal signaling pathways without ion movement. Each receptor is composed of two GluN1 subunits and two GluN2 subunits. A developmental shift occurs where GluN2B subunits are gradually replaced by GluN2A, a transition essential for synapse maturation. Understanding how these subunits contribute to ion flow and conformational signaling is the focus of our project.

To investigate how different regions of NMDA receptor subunits contribute to signaling, we are working with chimeric GluN2 constructs developed by Dr. Dumas’s lab. These chimeras are engineered by swapping specific intracellular domains between the GluN2A and GluN2B subunits. In doing so, we can separate the functional contributions of individual regions, such as the intracellular tail, to ion flow and to non-ionotropic signaling. By studying receptors with these controlled domain swaps, we aim to determine which portions of the subunit structure are responsible for differences in calcium permeability, activation properties, and downstream signaling. This semester, we focused on preparing the DNA constructs necessary for expressing these receptors in Xenopus laevis oocytes for future functional testing.

The overall goal of this project is to express wild-type and chimeric NMDA receptors in Xenopus laevis oocytes and compare their ionotropic signaling properties using two-electrode voltage clamp recordings. By analyzing how domain swaps between GluN2A and GluN2B affect receptor function, we aim to better understand the molecular basis of NMDA receptor signaling. This semester, we focused on preparing high-quality plasmid DNA, optimizing restriction digests, and initiating PCR amplification of the GluN2 receptor inserts to prepare for future subcloning and expression studies.

First, upon receiving the plasmid pGEMHE-membrane-mEGFP, we transferred a sample from the backstab into a 3 mL bacterial culture, which was incubated overnight at 37 degrees Celsius for 16 to 24 hours. The plasmid includes a Xenopus laevis promoter sequence, which enables later expression in oocytes. Following incubation, we isolated and purified the plasmid DNA from the bacterial culture using a alkaline lysis mini prep protocol. To ensure the integrity and purity of the plasmid, we assessed DNA quality using agarose gel electrophoresis to check for intact plasmid structure and spectrophotometry to measure the 260/280 absorbance ratio.

Next, we performed restriction digests to prepare the plasmid for future subcloning. We used the enzyme NheI to linearize the plasmid and carried out diagnostic digests to prepare for the later excision of the GFP segment originally present in the vector.

In parallel, we grew bacterial cultures containing the DNA for GluN2A, GluN2B, ABc, and BAc constructs. Using these templates, we initiated PCR amplification with construct-specific primers to selectively amplify the inserts. PCR amplification is currently ongoing. Once complete, we will purify the amplified products and verify insert size by gel electrophoresis before moving on to the next phase of subcloning.

After the inserts are fully amplified and purified, we will digest them with restriction enzymes to create compatible ends with the plasmid vector. We will then use a DNA ligase enzyme to join the inserts and vector together, creating new plasmids that carry either the wild-type or chimeric NMDA receptor sequences. Some ligation reactions will be performed in-house, while others may be sent for commercial cloning depending on efficiency. Sequence verification will follow to confirm successful ligation.

Following sequence confirmation, we will synthesize capped RNA transcripts from the recombinant plasmids using in vitro transcription. These RNA molecules will then be injected into individual Xenopus laevis oocytes, allowing the cells to produce functional NMDA receptors for electrophysiological testing.

Two to three days after RNA injection, we will perform two-electrode voltage clamp recordings, a technique that holds the membrane potential constant while measuring ionic currents. By applying glutamate and glycine, we will evaluate receptor function based on current amplitudes, activation and deactivation kinetics, and dose-response characteristics. Comparing wild-type and chimeric receptors will help us determine how specific subunit regions influence NMDA receptor ionotropic signaling.

This semester, we focused on growing bacterial cultures, isolating and purifying plasmid DNA, troubleshooting purification and digestion protocols, and beginning PCR amplification of the NMDA receptor inserts. These steps are critical for setting up RNA synthesis, oocyte injection, and functional testing. Moving forward, we aim to complete subcloning, synthesize RNA, and characterize receptor function using TEVC recordings.

I’d like to take a moment to thank those who have been instrumental in this project.

Dr. Herin who has been an invaluable mentor in electrophysiology and molecular biology.

Dr. Dumas who has provided expert guidance on receptor signaling and chimeric constructs.

Hannah Zikria-Hagemeier who was essential in training me on plasmid preparation.

Finally, I’d like to thank the rest of the PBNJ Lab for their collective support through guidance and resources, which has been key to my growth as a researcher.

Thank you all for your help and support!

College of Engineering and Computing OSCAR

Developing an Affordable Open-Source Bionic Hand

Author(s): Robert Haas

Mentor(s): Nathaila Peixoto, Electrical and Computer Engineering

Abstract

This project explores the feasibility of developing an affordable, open-source, bionic prosthetic hand to develop an alternative to be used in applications where traditional prosthetics are not an option. Developing a functional prototype based on proportions taken from a human hand provided a solid foundation for the rest of the project. The initial prototype served as a testbed, allowing me to test different methods of control. Such as input from an electromyography amplifier and accelerometer module, that when processed by an Arduino microcontroller can be used to control servos that open and close the hand. The project aims to provide a functional prototype, design schematics, and CAD models as reference material. To be used by others in the pursuit of developing and delivering non-traditional prosthetics options.

Audio Transcript

INTRO:
Welcome to a brief overview of my Undergraduate Student Research Project, Developing an Affordable Open-source Prosthetic Hand.

BACKGROUND:
The initial prototype I designed was part of a group project for my introduction to engineering class. It was controlled by a mobile app that connected to a microcontroller via Bluetooth module. This prototype had several shortcomings, most notably the single motor set up didn’t deliver enough power to close the hand properly. This issue was compounded by the hand’s lack of flexibility.

SECOND PROTOTYPE:
When developing the second prototype, I mitigated these problems with additional motors on the back of the hand and included a horizontal joint in the upper half of the palm, allowing the hand to flex.

FINGER DEVELOPMENT: 20 sec (show pictures of finger prototypes and them video of them flexing)
When designing the fingers, I developed multiple prototypes to test different tolerances for the hinge joints. I used dual pivoting joints for the fingers to increase flexibility and extended the supports on the back of each of the links to prevent them from flexing backwards.

MATERIALS
I tested multiple materials for this project including PLA+, PETG, and Resin. Resin provided the highest level of detail with resin. However, the most practical option was PETG. It’s stronger and more heat resistant then PLA+, and unlike resin it can be printed on a standard FDM printer.

CONTROL METHODS
I experimented with multiple control methods, using an off the shelf electromyography amplifier, also known as EMG, and custom-built amplifier. I was able to control the hand using the input from an accelerometer module. When the module detects a tilt the motors wind mono filament line closing the hand. When the module is tilted back the motors spin the opposite direction, unwinding the line and opening the hand. One area for improvement is with the EMG amplifier. I was unable to control the hand using input from the EMG amplifier.

CONCLUSION
There are some improvements that can be made to the project. Specifically, further testing of the EMG component as well as exploring other methods of control, to provide diverse control options to potential users. Additionally, certain components of the hand such as the cable guides and elastic retainers could be redesigned to print as one piece. This would also reduce and optimize the materials needed to construct it. I would also like to integrate a Bluetooth component to the hand, to allow the user to configure specific gesture presets through an app.

College of Humanities and Social Science College of Science OSCAR

Secretory Mitophagy Exports p53: A new pro-tumor survival mechanism.

Author(s): Layla Hasanzadah

Mentor(s): Purva Gade, Center for Applied Proteomics & Molecular Medicine

Abstract

Mitochondrial dysfunction is associated with many life-threatening illnesses, from Parkinson’s disease to malignant cancers. Cells remove damaged, aged, or stressed mitochondria through a process called mitophagy. Our team is investigating a potential pro-tumor survival mechanism cancer cells enact with the help of mitophagy initiation and subsequent export. Mitophagy initiation is sensed by the molecule PINK1, triggering the isolation and packaging of the damaged mitochondrial segment for degradation through the lysosome. Cancer cell mitophagy is triggered by elevated oxidative stress and mitochondrial DNA damage caused by hypoxia, chemotherapy, radiotherapy, and immunotherapy. In our recent study, we discovered a secretory form of mitophagy in which damaged mitochondrial segments are packaged and exported outside of the cell within PINK1+ extracellular vesicles (EV). Additionally, we found that these PINK1+ EVs export tumor suppressors (TS) phospho-P53 and Merlin along with mitochondrial segments outside the tumor cell. It has been discovered that p53 is phosphorylated by PINK1, ultimately enhancing mitophagy. We also found that Merlin, an unappreciated TS associated with neurofibromatosis, interacts with p53 through the MDM2 mediator. We hypothesize that secretory mitophagy export of TS and other mitophagy-related proteins is an adaptive mechanism of cancer cells to withstand oxidative stress and avoid apoptosis. The export of TS p53 and Merlin were analyzed in 4T1 & IOMM-Lee cells. We isolated EVs via differential ultracentrifugation followed by immunoprecipitation of purified EV samples with PINK1 and phospho-p53 to identify protein-protein interactions. Western blotting and mass spectrometry were performed to validate immunoprecipitation results and PINK1 and p53 interaction. Understanding the role of EV-mediated export of TS in secretory mitophagy can reveal novel mechanisms aiding cancer cells’ survival under oxidative stress caused by chemotherapy or other treatments, offering potential therapeutic targets for various cancers.

Audio Transcript

Mitochondrial dysfunction is associated with many life-threatening illnesses, from Parkinson’s disease to malignant cancers. Cells remove damaged, aged, or stressed mitochondria through a process called mitophagy. Mitochondria are known as the powerhouse of the cell for a reason: they help produce the majority of the energy needed to power our cells. In Parkinson’s disease, scientists have found that the process of mitophagy is impaired, leading to an accumulation of dysfunctional mitochondria within cells. On the other hand, in cancer cells, mitophagy plays a more complex role and may even be enhanced. As evidenced by my research, our lab at the Center for Applied Proteomics and Molecular Medicine found that the process may serve as a kind of survival mechanism used by cancer cells in the face of oxidative stress caused by chemotherapy or radiation.
Mitophagy initiation is sensed by the molecule PINK-1, triggering the isolation and packaging of the damaged mitochondrial segment for degradation through the lysosome. Our team discovered a secretory form of mitophagy in which mitochondrial segments are packaged and exported outside of the cell within extracellular vesicles (EVs) derived from the interstitial fluid of breast cancer tumors. Moreover, it has been discovered that the tumor suppressor molecule p53 interacts and becomes phosphorylated by PINK-1, ultimately enhancing mitophagy and carcinogenesis. Pancreatic cancer (PC) p53 mutations are associated with tumor aggressiveness. Decreased levels of intercellular p53 leads to increased genetic instability, higher tumor growth rate, and survival. Pancreatic cancer is the 3rd most fatal cancer in the U.S. due to high rates of metastasis and late diagnoses. Understanding and targeting this imbalance may result in new forms of personalized medicine for PC patients.
In terms of materials and methods, I cultured PANC-1 and BXPC-3 cell lines and incubated them for 5 days, then applied a drug called CCCP to each flask. CCCP induces oxidative stress to mimic the conditions experienced by cancer cells undergoing treatment like chemotherapy or radiation. Afterwards, I confirmed that I had protein in my sample, and used various stages of ultracentrifugation to isolate the extracellular vesicles produced by these cells. The vesicles came in 3 sizes: 2K (the largest), 10K, and 100K (the smallest). To analyze the proteins within my samples, I used Western Blotting and mass spectrometry, and used the ExoView R200 to examine and categorize the EVs used in the experiment.

Here you can see some images of me working in the lab: doing cell culture, running Western Blots, and observing my pancreatic cancer cells.

My project produced some very interesting results. I compared the relative concentrations of p53, the tumor suppressor protein, and PINK-1, the mitophagy-associated signalling molecule, and found that there is a very high and positive correlation between the export of PINK-1 p-p53 via EVs when oxidative stress is induced, indicating that p53 is degraded and exported alongside PINK-1 in EVs.Exported p53 may aid tumor progression and constitute a novel diagnostic method of non-invasively determining the mitochondrial health and p53 status within PC. PC EVs positive for phospho-p53 represent a novel diagnostic biomarker indicative of tumor stress. Targeting EV pathways in combination with oxidative stress could be a novel method of treating PC. Our lab is currently investigating if secretory mitophagy & EV export of tumor suppressors is common among other kinds of cancer, as well.

We recently published a paper on the topic of secretory mitophagy, but again, we hope to connect secretory mitophagy to the export of other tumor suppressors in future studies.

I wanted to thank my mentors and colleagues at the Center for Applied Proteomics and Molecular Medicine for their continued guidance and support, including the following people: Purva Gade, my direct mentor, Dr. Lance Liotta, Dr. Marissa Howard, Sofie Strompf, Angela Rojas, and Thomas Philipson.

I would also like to thank the GMU OSCAR URSP program and Dr. Karen Lee, as I received funding and guidance from OSCAR throughout the past semester.

Thank you very much for listening to my presentation!

College of Visual and Performing Arts OSCAR