Philip

Developing my own interest in Composite Materials: My hobby evolved from making a small towing glider to a radio control nitro fuel airplane. To me, it would be very exciting to make a lighter and sturdier airplane with high-performance materials. The questions and ideas on high-performance materials had been a long-standing question to me. Through high schools and college years, I figured out that attempts to find a unique solution for the composite material question require multiple years of training and broader knowledge of engineering and materials science. In my senior years in college, I had a chance to test my idea on composite materials. As an exchange student at Virginia Commonwealth University, Richmond, VA in 2002, I was able to join a composite material project which was aimed to characterize electrical properties of polyimide-SWNT (single-wall nanotube) composites for aerospace device and biomedical sensor applications. It was a simple characterization of electrical properties of the composite with respect to change of physicochemical properties of the composite. I prepared my senior thesis out of this project and it was an excellent opportunity to assess what trainings I need to have to reach the goals of creating a fancy composite material.

Shifting gears to Biomaterials for Tissue Engineering: Then, my conclusion was to go to grad school to work on composite materials. When I searched graduate programs in multiple engineering disciplines including Chemical Engineering and Materials Science and Engineering, I actually found that a significant number of researches was on biomedical and energy technology. I consulted many people and my mind was being attracted more to a relatively new area (then) called Tissue Engineering. The motto was that we can engineer materials and deliver cells to replace damaged or lost organs! This was not exactly the goal I had pursued, but it was more exciting, more challenging and broader impact than the aerospace composite materials that I wanted to design. With this excitement and challenge, I joined the Collier laboratory in 2005. I started gaining deeper and better understanding in engineering biomaterials. This training period made me forward-think to deliver engineered tissues for curing patients suffering from damaged or lost tissues. I used polypeptide self-assembling biomaterials to accelerate endothelial growth to coat synthetic vascular grafts (supported by AHA predoctoral fellowship). However, I just saw another step missing toward engineering tissues. With engineered materials, that is cool to instruct cells. However, we need different types of cells to make a better replacement. I wanted to delve into creating tissues using stem cell, which would be an incredible source for regenerating tissues. I imagined that developing engineered biomaterials with more systematic approaches can change methods of creating tissue with stem cells. I saw an opportunity with mathematical guidance in tissue regeneration.

Moving forward to Regenerative Medicine: The induced pluripotent stem cell (iPS cell) technology have allowed us to explore more options to regenerate damaged or lost tissues/organs. The stem cell community established at the University of Wisconsin-Madison was pretty impressive and the Ogle laboratory at UW-Madison (which was moved to the University of Minnesota-Twin Cities in 2013) was highly interested in developing 3D extracellular matrix (ECM)-inspired biomaterials for directing stem cell differentiation. Since our engineered tissue will be created in entirely different microenvironments when compared to in vivo, we need different methods with systematic, unbiased approaches rather than simply mimicking in vivo microenvironments. The latter would be too complex to follow or we may not be able to recreate a perfect copy of such microenvironments. I was able to find a specific combination of ECM proteins to direct iPS cell differentiation to cardiomyocytes (supported by AHA postdoc fellowship) by mathematical formalism. The systematic, unbiased approaches worked, but we still could not solve one of the challenging problems in the field. That is how to mature differentiating stem cells into cardiomyocytes. After I joined the Department of Biological Engineering at Louisiana State University as an Assistant Professor in 2016, I continue this development to find specific signals from ECMs to integrins to accelerate maturation of cardiac progenitor cells. Specific formulations of ECM and basement membrane proteins at the costamere will guide appropriate myofibrillogenesis and this could be a key mechanism to attain mature, adult-like cardiomyocytes from stem or progenitor cells. To better understand proteins associated with this earlier myofibrillogenesis, we use a proteomics approach to identify ECM-integrin engagement in many different 3D engineered microenvironments. We also hypothesized that metabolomic profiles of differentiating stem cells into mature cardiomyocytes will reveal unique molecular signatures in the 3D engineered microenvironments.