title: Sterilization of collagen scaffolds designed for peripheral nerve regeneration: Effect on microstructure, degradation and cellular colonization.
abstract: In this study we investigated the impact of three different sterilization methods, dry heat (DHS), ethylene oxide (EtO) and electron beam radiation (β), on the properties of cylindrical collagen scaffolds with longitudinally oriented pore channels, specifically designed for peripheral nerve regeneration. Scanning electron microscopy, mechanical testing, quantification of primary amines, differential scanning calorimetry and enzymatic degradation were performed to analyze possible structural and chemical changes induced by the sterilization. Moreover, in vitro proliferation and infiltration of the rat Schwann cell line RSC96 within the scaffolds was evaluated, up to 10days of culture. No major differences in morphology and compressive stiffness were observed among scaffolds sterilized by the different methods, as all samples showed approximately the same structure and stiffness as the unsterilized control. Proliferation, infiltration, distribution and morphology of RSC96 cells within the scaffolds were also comparable throughout the duration of the cell culture study, regardless of the sterilization treatment. However, we found a slight increase of chemical crosslinking upon sterilization (EtO<DHS<β), together with an enhanced resistance to denaturation of the EtO treated scaffolds and a significantly accelerated enzymatic degradation of the β sterilized scaffolds. The results demonstrated that β irradiation impaired the scaffold properties to a greater extent, whereas EtO exposure appeared as the most suitable method for the sterilization of the proposed scaffolds.
authors.affiliation: Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy; Dhitech Scarl - Distretto Tecnologico High Tech, Via per Monteroni, 73100 Lecce, Italy.
authors.forename: Graziana
authors.initials: G
authors.lastname: Monaco
authors.affiliation: Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy.
authors.forename: Rahmatullah
authors.initials: R
authors.lastname: Cholas
authors.affiliation: Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Salvatore
authors.affiliation: Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy. Electronic address: marta.madaghiele@unisalento.it.
authors.forename: Marta
authors.initials: M
authors.lastname: Madaghiele
authors.affiliation: Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sannino
mesh_terms: D000818:Animals; D002460:Cell Line; D003094:Collagen / Q000737:chemistry*; D009416:Nerve Regeneration; D010525:Peripheral Nerves / Q000378:metabolism*; D051381:Rats; D012583:Schwann Cells / Q000378:metabolism*; D013242:Sterilization / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D003094:Collagen
keywords: Collagen scaffolds; Ethylene oxide; Nerve regeneration; Radiation; Sterilization