Fabricating and Optimizing Iron Nanorods for Controlled Navigation and Drug Delivery in Extracellular Matrices

Author(s): Christopher Veatch

Mentor(s): Jeffrey Moran, Mechanical Engineering

Abstract

Many types of cancer or fibrosis are impervious to common drug delivery techniques. In theory, tiny carriers known as nanoparticles can be loaded with drugs and, if they are able to reach the disease site, deliver medication only where it is needed. A common disadvantage of nanoparticle-based drug delivery is the lack of control of where the particles end up after being introduced to the body; the vast majority never reach their intended targets. As a solution to this problem, we hypothesize that if magnetic nanorods are introduced into the vicinity of a disease site (such as a tumor), and a magnetic field is applied, the nanorods will penetrate through the tissue and reach the disease site more effectively. Throughout the course of the semester, I devised a procedure and ordered the necessary parts for the fabrication of magnetic iron nanorods using a process called templated electrodeposition. Numerous vendors experienced delays because of COVID-19-related supply chain issues, but we eventually were able to obtain all the necessary chemicals, supplies, and equipment required for fabrication. Upon completion of this semester, the lab is now fully prepared to fabricate magnetic nanorods out of both iron and nickel for use in experiments in the spring.

Video Transcript

Hello everyone, my name is Christopher Veatch and I will be presenting my project, Fabricating and Optimizing Iron Nanorods for Controlled Navigation and Drug Delivery in Extracellular Matrices, which was supervised by Dr. Jeffrey Moran of the GMU mechanical engineering department. 

It is known that nanoparticle drug therapy holds great promise in treating a variety of diseases such as cancer and fibrosis but in its current state, it is both unreliable and inefficient. The purpose of this project was then to create an apparatus for the fabrication of biocompatible magnetic nanorods that can be actively propelled through extracellular matrix reliably and efficiently to their target destination. To fulfill the requirements of being both magnetic and biocompatible, iron was chosen to be the material to be fabricated into nanorods. 

Prepared for you here is a drawing of the fabrication procedure. What we start with is a positively charged counter electrode and a negatively charged working electron made out of gold and a plating solution which is water containing positively charged iron ions. Attached to the gold working electrode is a porous membrane that has many pores and each of the pores are going to be the size of the rods that we are going to create. An electrical current is going to be sent through the apparatus and the positively charged iron ions are going to be attracted to the negatively charged gold working electrode and they will be sent down and as soon as they hit the gold working electrode, they are going to gain electrons which will turn them into a solid metallic iron. The length of the rods is going to be directly dependent on how long we leave the apparatus on. Once the ions are turned into metallic iron, we are going to remove the gold layer with sandpaper and we are going to dissolve the membrane with sodium hydroxide and then we are left with freely suspended iron nanorods. 

Here is a pictorial rendition of how the apparatus will actually be assembled. The red line you see in the working electron on the right is the gold working electrode and the electrolyte is the plating solution which is water containing positively charged iron ions.

This is the holder that was on the right-hand side of the schematic I just showed you. 

This along with a counter electrode will be immersed vertically inside of a beaker such as this one filled with plating solution. The white space that you see here is where the membrane is going to go. The threaded metal top here on this rod is what is going to facilitate the electrical connection between the gold underside of the membrane and the power supply such as this one using an alligator clip. This is what the membranes are going to look like. The gold coating is on this side you can tell because it is a little bit shinier and this gold coating is going to act as the working electrode. Although these are only 13 mm in diameter, each one of these membranes contains over 13 billion cylindrical pores. That means that over the course of an afternoon, in a single experiment, we can fabricate over 13 billion rods.

So, let’s take another look at that schematic. Hopefully it is now easier to visualize that the item shown on the right is the holder that I was showing you and that the gold on the membrane will act as the working electrode inside of it.

This is an image taken on a scanning electron microscope of what the iron nanorods would look like when they are fabricated. With the membranes shown in this video, nanorods with a diameter of 40 nanometers will be produced. To put this scale in perspective, the average human hair is between 80,000 and 100,000 nanometers wide!

Upon the conclusion of this semester, our goal of creating an efficient procedure to fabricate iron nanorods and acquiring the necessary components and materials to begin fabrication has been accomplished. The goal moving forward will be to grow nanorods from a variety of different metals for a variety of different medical and industrial applications.  

Thank you to everyone who has viewed my virtual presentation and I would like to extend a special thanks to Dr. Mair from Weinberg Medical Physics, Shrishti Singh, and the team at InRedox. Also thanks to the George Mason office of student-scholarship, creative activities, and research who made this project possible.

6 replies on “Fabricating and Optimizing Iron Nanorods for Controlled Navigation and Drug Delivery in Extracellular Matrices”

Hi Chris. This is the first time I have really understood how nanorods are made. Well done. How tightly can you control the length of the rods? It’s about duration of current applied, but how precise is the control? Nice job on the video.

Thanks for the question Dr. Lee. There is a direct relationship between the duration of current applied to the length of the rod and this in theory will be precise to only a few nanometers of variation. The lab has discussed projects in the future that would test this precision.

Interesting project Chris! I really liked your drawing of the whole process. I am a very visual learner so it really helped me understand how the electron deposition process works, great job!

Fantastic presentation! I felt I perfectly understood the process behind making the rods which is very tough to do. Now that you can make the rods, what are the next steps? How can we optimize them to deliver certain drugs?

Thanks for the response. Moving forward the rods will now be synthesized and tested in an imitation extracellular matrix to see how well they flow. Through this testing, we will be able to see which sizes can best navigate through ECM and therefore deliver drugs.

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