title: Directing neuronal cell growth on implant material surfaces by microstructuring.
abstract: For best hearing sensation, electrodes of auditory prosthesis must have an optimal electrical contact to the respective neuronal cells. To improve the electrode-nerve interface, microstructuring of implant surfaces could guide neuronal cells toward the electrode contact. To this end, femtosecond laser ablation was used to generate linear microgrooves on the two currently relevant cochlear implant materials, silicone elastomer and platinum. Silicone surfaces were structured by two different methods, either directly, by laser ablation or indirectly, by imprinting using laser-microstructured molds. The influence of surface structuring on neurite outgrowth was investigated utilizing a neuronal-like cell line and primary auditory neurons. The pheochromocytoma cell line PC-12 and primary spiral ganglion cells were cultured on microstructured auditory implant materials. The orientation of neurite outgrowth relative to the microgrooves was determined. Both cell types showed a preferred orientation in parallel to the microstructures on both, platinum and on molded silicone elastomer. Interestingly, microstructures generated by direct laser ablation of silicone did not influence the orientation of either cell type. This shows that differences in the manufacturing procedures can affect the ability of microstructured implant surfaces to guide the growth of neurites. This is of particular importance for clinical applications, since the molding technique represents a reproducible, economic, and commercially feasible manufacturing procedure for the microstructured silicone surfaces of medical implants.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Reich
authors.forename: Elena
authors.initials: E
authors.lastname: Fadeeva
authors.forename: Athanasia
authors.initials: A
authors.lastname: Warnecke
authors.forename: Gerrit
authors.initials: G
authors.lastname: Paasche
authors.forename: Peter
authors.initials: P
authors.lastname: Müller
authors.forename: Boris
authors.initials: B
authors.lastname: Chichkov
authors.forename: Timo
authors.initials: T
authors.lastname: Stöver
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenarz
authors.forename: Günter
authors.initials: G
authors.lastname: Reuter
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D002478:Cells, Cultured; D003054:Cochlear Implants; D004566:Electrodes; D005724:Ganglia / Q000378:metabolism; D006309:Hearing; D007834:Lasers; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning / Q000379:methods; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D016716:PC12 Cells; D010984:Platinum / Q000737:chemistry; D051381:Rats; D012828:Silicones / Q000737:chemistry; D013136:Spiral Ganglion / Q000378:metabolism; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D012828:Silicones; D010984:Platinum