On-Demand Retrieval and Evaluation of MSCs Encapsulated in Enzymatically-Degradable PEG-Based Hydrogels

摘要

Matrix metalloproteinases (MMPs) are enzymes expressed by a variety of cell types to remodel their extracellular matrix. The inclusion of MMP-sensitive sequences in poly(ethylene glycol) (PEG)-based hydrogel systems allows for localized hydrogel degradation, enabling behaviors such as cell spreading and migration. Furthermore, cells can be recovered from gels post-culture through exogenous addition of enzymes like collagenase. Thus, this system may be used to differentiate stem cells in these gels via exposure to external stimuli, followed by on-demand cell recovery for delivery to injury sites. As a first step, we investigated the possible effects of cell spreading on stem cell markers by encapsulating human mesenchymal stem cells (hMSCs) in MMP-cleavable PEG using two different peptides known to exhibit different degradation kinetics. Through 7d, we analyzed cell morphology and the expression of putative MSC cell surface markers using flow cytometry following enzymatic gel degradation.