Examination of the effects of poly(N-vinylpyrrolidinone) hydrogels in direct and indirect contact with cells

Poly(N-vinylpyrrolidinone) (PNVP) has been used in various biomedical applications for many years. This study explores two PNVP hydrogels for their biocompatibility with skin cells and their ability to support the growth of skin cells in direct and indirect contact with the cells. Two crosslinked PNVP's were investigated, one crosslinked with ethylene glycol dimethacrylate (EGDMA) and the other crosslinked with diethylene glycol bisallylcarbonate (DEGBAC). The different crosslinkers lead to hydrogels with different mechanical and slightly different biological properties. While neither hydrogel proved to be a suitable substrate for culturing cells (based on fibroblasts and a range of other cells), indirect contact with both showed them to be biocompatible and even stimulatory to fibroblasts. The P(NVP-co-DEGBAC) hydrogel stimulated fibroblast viability more reliably than the P(NVP-co-EGDMA) hydrogel when in indirect contact with cells. This effect was shown to be independent of the presence of foetal calf serum in the culture media, and could not be explained by any hydrogel breakdown products during the course of these experiments. Rather the phenomenon was observed to be the result of a dynamic interaction between the hydrogels and the cells.