title: Enhancement of silicon using micro-patterned surfaces of thin films.
abstract: Micro-textured biomaterials might enhance cytocompatibility of silicon-based micro-electro-mechanical system (bio-MEMS) dummies. Photolithography-physical vapour deposition was used to produce diamond-like carbon (DLC) or Ti squares and circles on silicon, and also their inverse replicas; then DLC and Ti were compared for their guiding potential, using a SaOS-2 cell model. Scanning electron microscopy at 48 hours indicated cells were well-spread on large-sized patterns (several cells on one pattern) and assumed the geometrical architecture of underlying features. Medium-sized patterns (slightly smaller than solitary indicator cells) were inhabited by singular cells, which stretched from one island to another, assuming longitudinal or branching morphologies. On small-sized patterns (much smaller than individual cells;rpar; cells covered large micro-textured areas, but cellular filopodia bypassed the bare silicon. Immunofluorescence and confocal laser scanning microscopy indicated that the actin cytoskeleton and vinculin-containing adhesion junctions were present on the patterned areas, but not on the bare silicon. Cell density/coverage disclosed a 3.4-3.7-fold preference for the biomaterial patterns over silicon substrate (p 0.001). Differences in the cellular response between materials were lost at 120 hours when cells were confluent. The working hypothesis was proven; enhancement by micro-patterning depends on the pattern size, shape and material and can be used to improve biocompatibility during the initial integration phase of the device.
authors.affiliation: Department of Medicine, Institute of Clinical Medicine, Helsinki University Central Hospital, Haartmaninkatu 8, FI-00029 HUS, Finland.
authors.forename: Emilia
authors.initials: E
authors.lastname: Kaivosoja
authors.forename: Sami
authors.initials: S
authors.lastname: Myllymaa
authors.forename: Vesa-Petteri
authors.initials: VP
authors.lastname: Kouri
authors.forename: Katja
authors.initials: K
authors.lastname: Myllymaa
authors.forename: Reijo
authors.initials: R
authors.lastname: Lappalainen
authors.forename: Yrjö T
authors.initials: YT
authors.lastname: Konttinen
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002448:Cell Adhesion / Q000502:physiology; D045744:Cell Line, Tumor; D048430:Cell Shape / Q000502:physiology; D020099:Coated Materials, Biocompatible; D003599:Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D008567:Membranes, Artificial; D055617:Micro-Electrical-Mechanical Systems / Q000379:methods* / Q000592:standards; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D011554:Pseudopodia / Q000502:physiology; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D008567:Membranes, Artificial; D012825:Silicon