title: Investigation of the influence of UV irradiation on collagen thin films by AFM imaging.
abstract: Collagen is the major fibrous extracellular matrix protein and due to its unique properties, it has been widely used as biomaterial, scaffold and cell-substrate. The aim of the paper was to use Atomic Force Microscopy (AFM) in order to investigate well-characterized collagen thin films after ultraviolet light (UV) irradiation. The films were also used as in vitro culturing substrates in order to investigate the UV-induced alterations to fibroblasts. A special attention was given in the alteration on collagen D-periodicity. For short irradiation times, spectroscopy (fluorescence/absorption) studies demonstrated that photodegradation took place and AFM imaging showed alterations in surface roughness. Also, it was highlighted that UV-irradiation had different effects when it was applied on collagen solution than on films. Concerning fibroblast culturing, it was shown that fibroblast behavior was affected after UV irradiation of both collagen solution and films. Furthermore, after a long irradiation time, collagen fibrils were deformed revealing that collagen fibrils are consisting of multiple shells and D-periodicity occurred on both outer and inner shells. The clarification of the effects of UV light on collagen and the induced modifications of cell behavior on UV-irradiated collagen-based surfaces will contribute to the better understanding of cell-matrix interactions in the nanoscale and will assist in the appropriate use of UV light for sterilizing and photo-cross-linking applications.
authors.affiliation: Biomedical Optics and Applied Biophysics Laboratory, Division of Electromagnetics, Electrooptics and Electronic Materials, School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou, Athens 15780 Greece. Electronic address: styliand@mail.ntua.gr.
authors.forename: Andreas
authors.initials: A
authors.lastname: Stylianou
authors.affiliation: Biomedical Optics and Applied Biophysics Laboratory, Division of Electromagnetics, Electrooptics and Electronic Materials, School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou, Athens 15780 Greece.
authors.forename: Dido
authors.initials: D
authors.lastname: Yova
authors.affiliation: Biomedical Optics and Applied Biophysics Laboratory, Division of Electromagnetics, Electrooptics and Electronic Materials, School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou, Athens 15780 Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Alexandratou
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D002460:Cell Line; D003094:Collagen / Q000737:chemistry* / Q000528:radiation effects*; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D001672:Biocompatible Materials; D003094:Collagen
keywords: Atomic Force Microscopy (AFM); Biomaterials; Collagen; Nanocharacterization; Thin films; Ultraviolet (UV)