title: In vitro assessment of bioactive coatings for neural implant applications.
abstract: Recent efforts in our laboratory have focused on developing methods for immobilizing bioactive peptides to low cell-adhesive dextran monolayer coatings and promoting biospecific cell adhesion for biomaterial implant applications. In the current study, this dextran-based bioactive coating technology was developed for silicon, polyimide, and gold, the base materials utilized to fabricate our prototype neural implants. Chemical composition of all modified surfaces was verified by X-ray photoelectron spectroscopy (XPS). We observed that surface-immobilized dextran supported very little cell adhesion in vitro (24-h incubation with serum-supplemented medium) on all base materials. Inactive nonadhesion-promoting Gly-Arg-Ala-Asp-Ser-Pro peptides immobilized on dextran-coated materials promoted adhesion and spreading at low levels not significantly different from dextran-coated substrates. Arg-Gly-Asp (RGD) peptide-grafted surfaces were observed to promote substantial fibroblast and glial cell adhesion with minimal PC12 (neuronal cell) adhesion. In contrast, dextran-coated materials with surface-grafted laminin-based, neurite-promoting Ile-Lys-Val-Ala-Val (IKVAV) peptide promoted substantial neuron cell adhesion and minimal fibroblast and glial cell adhesion. It was concluded that neuron-selective substrates are feasible using dextran-based surface chemistry strategies. The chemical surface modifications could be utilized to establish a stable neural tissue-implant interface for long-term performance of neural prosthetic devices.
authors.affiliation: Department of Bioengineering, Arizona State University, P.O. Box 879709, Tempe, Arizona 85287-9709, USA. smassia@asu.edu
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Massia
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Holecko
authors.forename: Gholam R
authors.initials: GR
authors.lastname: Ehteshami
mesh_terms: D000595:Amino Acid Sequence; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D003911:Dextrans; D009474:Neurons; D009842:Oligopeptides; D019736:Prostheses and Implants; D012825:Silicon; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D003911:Dextrans; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid; D012825:Silicon