Poly(ethylene glycol) hydrogel system supports preadipocyte viability, adhesion, and proliferation

The ultimate goal of this research is to develop an injectable cell-scaffold system capable of permitting adipogenesis to abrogate soft tissue deficiencies resulting from trauma, tumor resection, and congenital abnormalities. The present work compares the efficacy of photopolymerizable poly(ethylene glycol) and specific derivatives as a scaffold for preadipocyte (adipocyte precursor cell) viability, adhesion, and proliferation. Four variations of a poly(ethylene glycol) scaffold are prepared and examined. The first scaffold consists of poly(ethylene glycol) diacrylate, which is not susceptible to hydrolysis or enzymatic degradation. Preadipocyte death is observed over 1 week in this hydrogel configuration. Adhesion sites, specifically the laminin-binding peptide sequence YIGSR, were incorporated into the second scaffold to promote cellular adhesion as a prerequisite for preadipocyte proliferation. Preadipocytes remain viable in this scaffold system, but do not proliferate in this nondegradable hydrogel. The third scaffold system studied consists of poly(ethylene glycol) modified with the peptide sequence LGPA to permit polymer degradation by cell-secreted collagenase. No adhesion peptide is incorporated into this scaffold system. Cellular proliferation is initially observed, followed by cell death. The previous three scaffold configurations do not permit preadipocyte adhesion and proliferation. In contrast, the fourth system studied, poly(ethylene glycol) modified to incorporate both LGPA and YIGSR, permits preadipocyte adherence and proliferation subsequent to polymer degradation. Our results indicate that a scaffold system containing specific degradation sites and cell adhesion ligands permits cells to adhere and proliferate, thus providing a potential cell-scaffold system for adipogenesis.