Temperature‐Responsive Injectable Hydrogels Containing Gelatin and Cell Adhesion Peptides for Adipose‐Derived Stem Cell Delivery

ABSTRACT Research on injectable polymers (IPs) has been actively conducted in recent decades for biomedical applications. Temperature‐responsive IPs are especially effective because they can be gelled by injecting them into a living organism without external contamination. Adipose‐derived stem cells (AdSCs) can be easily harvested in a minimally invasive manner and differentiated into various cell lineages. Versatile therapeutic applications have been developed through the secretion of various cytokines from AdSCs. In this study, we prepared IP hydrogels comprising a temperature‐responsive polymer with reactive succinimide groups (tri‐PCG‐OSu), a biomacromolecule (gelatin) as a crosslinker, and Pluronic with RGDS peptide (PL‐RGDS) as a cell adhesion factor to extend the duration of the gel state and improve cell engraftment in the IP hydrogels for AdSC delivery. The combined use of gelatin and cell adhesion peptides in the polymer matrix improved the fraction of living cells encapsulated in the IP hydrogels and increased the expression levels of angiogenic factors in AdSCs cultured within them. We also presume that a certain number of cells in the IP hydrogels could be differentiated into adipocytes using the differentiation‐inducing medium. These results suggest that our temperature‐responsive IP system could be used as a cell delivery material for regenerative medicine.