Millions of mesenchymal stem cells (MSCs) per kilogram of patient body weight are generally required for clinical applications, underscoring a pressing need for scalable culture systems. To reduce the time and cost associated with the expansion of MSCs, microcarriers that provide a surface for cell adhesion and are subsequently kept in suspension in a bioreactor were developed. Microcarrier culture systems can produce hundreds of millions of cells and show promise for scale-up to meet industrial lot size requirements with lower media and resource requirements than traditional cell culture. We previously validated the synthetic copolymer (polyethylene glycol methyl ether methacrylate-ran-vinyl azlactone-ran-glycidyl methacrylate; PVG, Figure 1A) based on polyethyleneglycol in 2D, spin-coated films onto flat substrates as a chemically defined template for cell culture. When functionalized with the cell adhesive peptide sequence RGD this chemically defined surface is suitable for MSC adhesion and expansion. We present a novel method for the creation of chemically defined, customizable microcarriers via covalent anchoring of the PVG copolymer to the surface of PS microcarriers and its characterization by spectroscopy. These PVG-coated microcarriers reduce protein adsorption and prevent the adhesion of cells until they are functionalized with RGD peptide. MSCs cultured on these coated microcarriers adhere, expand, and retain their ability to differentiate, indicating maintenance of the stem cell phenotype. We envision these microcarriers that use customizable polymer coatings to lower the currently intractable cost associated with cell expansion and achieve efficient, xeno-free expansion of functional therapeutic cells. Figure 1: A) Schematic of coating process/polymer chemistry. Polystyrene microcarriers are coated in (ii) poly-L-lysine (PLL) and (iii) polyethylene glycol methyl ether methacrylate-ran-vinyl azlactone-ran-glycidyl methacrylate; P(PEGMEMA-r-VDM-r-GMA); PVG. Desired peptides can be applied to this coating, in this example a peptide functionalized with (iv) Arg-Gly-Asp (RGD) and (v) a scrambled version of the peptide. (B) cells adhered to functionalized microcarriers

Chemically defined microcarriers for the expansion of mesenchymal stem cells

255th National Meeting (2018)

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