PART 1: NON-TECHNICAL Over the past three decades, a variety of fundamental scientific discoveries have identified cells that can be used in medical research and therapy. However, in order to be effectively used, these cells must be manufactured efficiently, controllably, and reproducibly. Culturing and expanding cells while enhancing their desired function is essential for biomanufacturing, and critical for ultimate use of cells to understand and treat human disease. This proposal focuses on biomanufacturing two important cell types, namely human mesenchymal stem cells (hMSCs) that have been used in over 500 human clinical trials, and endothelial cells (ECs) that form human blood vessels. Developing a better in vitro understanding and control over regulation of hMSC and EC behaviors such as adhesion, proliferation, and differentiation may facilitate their efficient manufacturing and increased success as cell therapies. This research program will lead to understanding of cell behaviour, and to more effective manufacturing of therapeutic cells, by developing biomaterials to mimic parts of the native extracellular matrix (ECM). These biomaterials in the form of polymer coatings will aid in answering key fundamental questions in cell biology and provide an efficient, well-defined platform for cell biomanufacturing. The resulting polymer-coated "microcarriers" for 3D cell expansion can be delivered to cell biologists and bioengineers, who can then customize them to probe key biological questions. Hands-on exhibits developed on Stem Cells and Tissue Engineering through this research will be disseminated nationally by the PI's and the graduate students. The research program will serve to inspire and involve undergraduate students in polymer science and engineering research, by working with graduate student mentors.
PART 2: TECHNICAL SUMMARY This research program will study the synthesis of polymer coatings to answer key fundamental questions in cell biology using 2D coatings, and to develop polymer-coated microcarriers that provide an efficient, well-defined platform for cell biomanufacturing. These key fundamental goals include: i) understanding the influence of local and global coating compositions on cellular behaviors; ii) understanding the role of substrate-mediated growth factor (GF) sequestering on GF-dependent cell expansion; and iii) exploring the influence of controlled, divalent presentation of receptor-binding peptides on receptor activation and associated cell behavior. These studies will result in the design of an efficient copolymer coating and ligation chemistry to present receptor-coreceptor clusters with controlled spacing to study their influence on GF signaling and associated cell behaviors. To quantitatively characterize the functionality of the surface, this research will develop Time of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS) in conjunction with X-ray photoelectron spectroscopy (XPS), and assess the local and global heterogeneities in surface composition. The outcome of this research will be the synthesis of chemically defined microcarriers via a copolymer chemistry that is customizable to different cell types and culture media with relevant bio-inspired peptides that regulate cell adhesion and GF sequestering. We envision a new class of microcarriers that use customizable polymer coatings, lower the currently intractable cost of media formulations, and achieve efficient, xeno-free expansion of functional therapeutic cells. The ability to tailor microcarriers to support adhesion and receptor activation of specific cell types without using complex and expensive media would be transformative in biomanufacturing, which is a rapidly growing segment of health care in cell and tissue therapy.