Segura Biomaterials Lab
Principal Investigator: Dr. Tatiana Segura
Mentor: Dr. Shangjing Xin
Project #1: Microporous Annealed Particles for Stroke Recovery
I am studying the effect of adding various proteins and cell components to microporous annealed particles and their effect on improving brain regeneration through both angiogenesis and synaptogenesis.
Stroke is the leading cause of death in America. After stroke, the brain can be damaged, leaving dead cells and tissue at the stroke location. To help the stroke site or other wound sites regenerate, porous biomaterials are a promising candidate that offers a scaffold upon which the cells can grow. However, ways to integrate porous scaffolds are often invasive and caustic. Microporous annealed particles (MAP) are an emerging class of biomaterials where the gel can be injected into the wound site alongside the crosslinker allowing it to form a porous network in situ, adapting to the wound cavity in a less invasive manner. The aim of this project is to use these MAP gels to improve the regeneration of stroke sites in mice.
We were able to achieve improvements in vasculature infiltration into the stroke infarct and demonstrate behavior improvements in mice treated with MAP scaffolds conjugated to activated astrocyte exosomes. This work was presented at the Annual BMES 2022 conference.
BME Teaching Lab
Mentor: Dr. Cameron Kim
Project #2: Developing an Antisense Oligonucleotide for Alzheimer’s Disease
Aug 2021-April 2023
Alzheimer’s disease (AD) affects over 6.2 million people in the U.S. and is the leading cause of dementia. Current treatments target the aggregation of amyloid β plaques and tau proteins but fail to address disease progression. Therefore, there is a need for a therapeutic to address the underlying biology of AD and alleviate cognitive decline. Neuroinflammation has emerged as a key feature in AD and provides a new way to target the disease.
As a continuation of a yearlong BME 490L/590L: Senior Biotech Design project, our team worked to develop strategies to deliver siRNA into microglia cells, which are brain-resident immune cells. Specifically, we focused on viral and non-viral methods for the downregulation of complement protein receptor C3aR. C3aR is an important receptor because it is involved in amyloid β innate immune activation, which is an under-targeted therapeutic area, and knocking it out in mice has led to improvements in tau pathology. Through our work in the 2022-2023 school year, we have created an AAV2-shRNA capsid and demonstrated successful viral transduction of BV2 murine microglial cells with AAV2. The highest efficiency we achieved was a transduction rate of 55% of the cells as well as a total 63.3% knockdown of C3aR expression. We were also able to successfully label both transferrin and RAGE aptamers for crossing the blood-brain barrier and targeting microglia cells respectively; however, the cells got contaminated before we were able to test the aptamers in vitro. We presented posteres in both the 2022 Duke Design Fair and the 2023 Visible Thinking conference.
Overall, through this project, we all grew as independent and collaborative researchers. As a team, we were able to gain skills in many scientific techniques including flow cytometry, gel electrophoresis, and bioconjugation. Although, having an open-ended question led us to a lot of issues and troubleshooting, we were able to develop resiliency and overcome issues as a team by motivating one another. We found this experience to be an invigorating one that has helped us prepare for our future research endeavors.
Arya Biological and Soft Materials Modeling Lab
Principal Investigator: Dr. Gaurav Arya
Project #3: Modeling Bottlebrush Surface Adsorption
May 2020 – Aug 2021
Designed coarse-grain molecular dynamics (MD) model to imitate the adsorption of bottlebrush polymers onto a surface to optimize grafting-to polymer brush density for better lubricative and antifouling properties
Fig. 1: Biotin-headed bottlebrush polymers adsorbing onto fixed streptavidin beads.
Functionalizing a surface with polymers can endow it with many unique properties such as lubrication, protein resistance, and biocompatibility. Currently, grafting-from techniques can yield high polymer density but often use harsh chemicals which are not suitable for use in situ. The alternative is the grafting-to approach, which uses preformed polymers and allows them to adsorb onto a surface. This allows for a less harsh approach to adding polymers onto a surface such as a knee joint to provide lubrication relief for patients with osteoarthritis. However, this approach is limited in that the kinetics of the adsorption process are not well understood. This project aimed to replicate a previously experimentally tested grafting-to, biotin-streptavidin-based system to study how these bottlebrush polymers adsorbed onto a surface and what conformations they adapted. Using an MD model, I was able to simulate bottlebrushes at a variety of densities, lengths, and widths during different conditions. The information from this project could help scientists optimize and tailor polymer-based therapeutics to be as effective as possible.