Penn State University

PHD Student, Materials Science and Engineering at University of Pennsylvania

Dallas, Texas, United States

University of Pennsylvania

PHD Student, Materials Science and Engineering

Thesis AbstractSurface-Enhanced Raman Spectroscopy (SERS) biosensors have astounding levels of sensitivity as they amplify the intensity of Raman scattering. Prior research even shows these biosensors reaching sensitivities capable of detecting a single non-absorbing molecule in solution. However, these are typically made using expensive and time-consuming techniques, such as electron-beam lithography. My research aims to greatly reduce the manufacturing costs of SERS biosensors by introducing a new nano-sphere lithography technique. These new sensors are made by depositing a Self-Assembled Monolayer (SAM) of Polystyrene spheres on the surface of a silicon wafer and then heat treating them, so that individual spheres will melt into neighboring spheres. This melting into neighboring spheres will create an nonuniform density profile, which then allows for different parts of the substrate to be etched at different rates. With careful control of heating and plasma-etching parameters it is possible to construct both a nano-triangle and nano-honeycomb polystyrene template.  Finally, chromium/gold would be deposited on this template and the spheres removed, to create a P6mm pattern of nano-triangles which form the basis for the biosensor.

Penn State University (Wong Lab for Nature Inspired Engineering)

Undergraduate Researcher

Project AbstractProtein-protein interactions, the driving force for all cell activity, regulate a multitude of biological processes ranging from stem cell differentiation to gene expression. Drugs, hormones, and other stimulants are commonly used to perturb protein interactions. However they offer poor spatiotemporal resolution. Optogenetic methods seek to develop a platform which allows precise control of protein-protein interactions via the use of light-sensitive proteins. One of the most commonly used photosensory proteins, Arabidopsis thaliana Cryptochrome2 (CRY2), can undergo both light induced homo-oligomerization and hetero-dimerization with its binding partner CIB1, which can confound results and analysis. Therefor it is crucial to effectively modulate CRY2 oligomerization, particularly during hetero-dimerization. This work seeks to determine how fluorescence tags and bulky fusion proteins may modulate homo-oligomerization. We found that GFP fused CRY2 oligomerizes less than the mCherry fused counterpart. Furthermore, we found that CRY2 oligomerization can be significantly inhibited by the tdTomato fused CIB1 during hetero-dimerization; tdTomato is a bulky fluorescence protein which provides steric hindrance towards oligomerization.

Stanford University (Cui Lab)

Project AbstractCurrent Alpha-fetoprotein (AFP) sensing technologies such as ELISA require a lot of equipment, time, and skill. Still, it would be less sensitive then our proposed graphene biosensors, which in theory could detect a single AFP. Graphene’s unique material properties and sensitivity to the surrounding environment are exploited in our sensor for the detection of AFP. A U-shaped gold electrode containing a small gap for the sensing area would then be patterned using photolithography. The gap would be closed by covering the bare substrate with our few-layer-graphene (FLG) structure. We tune the thickness, and thus the properties, of graphene through a unique layer-by-layer self-assembly process which uses graphene solution and polyelectrolytes. The graphene sensing area is further prepared with poly-l-lysine and then functionalized with anti-AFP. Also, due to the fact that the ability to detect AFP is heavily limited by the signal-noise ratio, we redesigned the basic interface between gold and graphene in multiple ways to achieve a better signal-noise ratio in our sensors. The sensors that were fabricated were successful in detecting alpha-fetoprotein even in concentrations as low as 1 pg/ml.  Lastly, the redesigned gold/graphene interface showed promising results and seems to have only been limited by our fabrication procedure.

University of Minnesota

I interned at Boeing’s Defense, Space, and Security division in Houston. This was my opportunity for me to explore industry as a career path, and a chance to prepare for the Astronaut Program, which is a long-term professional goal. I had the unique opportunity to work two projects: optimizing verification process for International Space Station payloads and developing spacewalk safety procedure. Furthermore, due to my enthusiasm for space research and exploration, I received a part-time internship at the Lunar and Planetary Institute. This experience taught me how to work in large groups, coordinate in collaborative multidisciplinary assignments, and juggle various projects. I even honed my presentation skills through an hour-long closing talk, which was also my first professional presentation.

Victor Acero