Wabash Blogs Summers in Science

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Dan Albrecht: Etching Silicon Chips in Cutting Edge Research

Dan Albrecht — This summer I am working on nanotechnology research focused on porous silicon biochips.

Silicon is one of the most technologically important materials; it’s utilized extensively in microelectronics fabrication and silicon chips are found in just about everything, from X-Boxes and personal computers to dishwashers and car engines.

However, when silicon is etched with hydrofluoric acid to create porous silicon (silicon with a surface of numerous tiny pores), new characteristics arise. Porous silicon can emit light, making it potentially useful as a biosensor inside the body and its large surface area allows the tiny pores to be coated with any variety of molecules that could be used in medical diagnostics or disease treatment.

There is one drawback in that the tiny pores degrade easily once the silicon has been etched, but recent studies have shown that the attachment of organic molecules to the chips prevent degradation while still preserving the porous characteristics. There are several different chemical reactions used to attach organic molecules to silicon chips and exploring these lie at the heart of my project.

Under the mentorship of Dr. Lon Porter in the Wabash Chemistry Department, I am etching silicon chips and functionalizing them via three different chemical reactions. Each involves a different mechanism: one uses a carbocation catalyst, another employs a Lewis Acid catalyst, and a thermal reaction that only requires heat.

After the reaction is complete, I put the chips in simulated stomach and intestinal fluid to see how the chips would degrade if ingested by a potential patient. Although all three reactions reportedly yield the same product, we see a difference in the degree of chip stability that results from these reactions. In addition, I am also experimenting with three different sets of organic functional groups: hexane (six carbons long), dodecene (twelve carbons long), and octodecene (eighteen carbons long), to see how the varying carbon chain lengths prevent oxidative degradation of the porous silicon.

This project is quite a departure from traditional labs in my science classes. Being able to research, set up, and carry out my own project gives me a feeling of significance and independence I hadn't felt before in the lab. Before the beginning of the Fall semester, the Porter Lab is adding a new microwave reactor that will allow us to react chips using a beefed-up version of the same microwave ovens used in the kitchen. I plan to extend my research with Dr. Porter into the Fall semester and hope to continue into either medical school or grad school after my senior year here at Wabash.

I feel like my background in science from Wabash allowed me to jump into the research setting with ease and gave me the capacity to pick up new laboratory techniques that will be helpful as I continue with my research in the future.This internship has been an excellent opportunity and I only wish I'd done it last summer, too.