Immobilization of Bioactive Peptides on Benzocyclobutene (BCB) Surface Grafted- Dextran for Neural Implant Applications

In vitro cell adhesion and neurite growth on dextran-coated Benzocyclobutene (BCB) films, covalently grafted with bioactive peptides are investigated. For cell/tissue adhesive surfaces, synthetic peptide GRGDSP was employed. GRADSP was used as an inactive control for nonspecific peptide-induced cell adhesion. For surface coatings with neurite growth-promoting activity, the laminin-based peptide SRARKQAASIKVAVSADR was utilized. Three cell lines were utilized in these studies. The cell cultures investigated in this study were 3T3 fibroblasts, neuronal-like PC 12 cells, and a glial-like (glioblastoma) T98-G cell line. Chemical composition of all modified surfaces was verified by X-ray photoelectron spectroscopy (XPS). Our non-toxic aqueous methods to graft cell adhesion peptides on dextran monolayer surfaces, effectively limited non-specific cell adhesion and neurite growth in the presence of cultured cells. Microscopic visualization and imaging of these surfaces showed that dextran coatings promoted essentially no adhesion of all cell lines tested. Surface-grafted cell adhesion RGD peptides stimulated fibroblast and glial cell adhesion with minimal neuronal PC12_cell attachment and spreading in vitro. In contrast, surface-grafted inactive RAD peptide sequences did not promote significant cell interaction of all cell types indicating that peptide-grafted surfaces did not promote non-specific cell adhesion. Surface-grafted high affinity IKVAV peptides promoted cell type-dependent interactions. The IKVAV-grafted surfaces also promoted neurite growth on all substrates.