Abstract
Polypeptide coating improves fibroblast adhesion to hyaluronan
Hyaluronic acid (hyaluronan, HyA) is a matrix component implicated in cell adhesion, growth and repair. HyA salts are soluble in water and inhibit cell adhesion, limiting their use in tissue engineering of artifical matrices. Polypeptide coatings are frequently used to enhance cell attachment to insoluble plastic surfaces via cell surface receptors. This paper describes polypeptide resurfacing of HyA strands to limit dissolution and improve cell adhesion. HyA strands 120 µm in diameter were extruded into absolute ethanol, crosslinked with glutaraldehyde and then resurfaced with either polypeptides (poly-D-lysine, poly-L-lysine) or amino acids (glycine, glutamine). Modified HyA specimens were inoculated with rat connective tissue fibroblasts and after 7 days in vitro evaluated by histological and immunohistochemical methods. Five specimens were implanted subcutaneously in rats for an additional 14 day trial in vivo. Results showed that: (1) both polylysine coatings enhanced fibroblast attachment compared to uncoated and amino acid-coated HyA, (2) glutaraldehyde crosslinking alone improved HyA dissolution time in vitro, whereas polylysine and amino acid coatings created an insoluble shell that further extended the lifetime of HyA strands, and (3) modified HyA has good biocompatibility (low cytotoxicity) both in vitro and in vivo. This outcome suggests that polypeptide resurfacing to control stability and cell interaction may expand the range of in vitro and clinical uses of HyA.