title: Photopatterning Proteins and Cells in Aqueous Environment Using TiO2 Photocatalysis.
abstract: Organic contaminants adsorbed on the surface of titanium dioxide (TiO2) can be decomposed by photocatalysis under ultraviolet (UV) light. Here we describe a novel protocol employing the TiO2 photocatalysis to locally alter cell affinity of the substrate surface. For this experiment, a thin TiO2 film was sputter-coated on a glass coverslip, and the TiO2 surface was subsequently modified with an organosilane monolayer derived from octadecyltrichlorosilane (OTS), which inhibits cell adhesion. The sample was immersed in a cell culture medium, and focused UV light was irradiated to an octagonal region. When a neuronal cell line PC12 cells were plated on the sample, cells adhered only on the UV-irradiated area. We further show that this surface modification can also be performed in situ, i.e., even when cells are growing on the substrate. Proper modification of the surface required an extracellular matrix protein collagen to be present in the medium at the time of UV irradiation. The technique presented here can potentially be employed in patterning multiple cell types for constructing coculture systems or to arbitrarily manipulate cells under culture.
authors.affiliation: Frontier Research Institute for Interdisciplinary Sciences, Tohoku University; CREST, Japan Science and Technology Agency; h-yamamoto@bme.tohoku.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: School of Fundamental Science and Engineering, Waseda University.
authors.forename: Takanori
authors.initials: T
authors.lastname: Demura
authors.affiliation: School of Fundamental Science and Engineering, Waseda University.
authors.forename: Kohei
authors.initials: K
authors.lastname: Sekine
authors.affiliation: School of Fundamental Science and Engineering, Waseda University.
authors.forename: Sho
authors.initials: S
authors.lastname: Kono
authors.affiliation: CREST, Japan Science and Technology Agency; Research Institute of Electrical Communication, Tohoku University.
authors.forename: Michio
authors.initials: M
authors.lastname: Niwano
authors.affiliation: CREST, Japan Science and Technology Agency; Graduate School of Biomedical Engineering, Tohoku University.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Hirano-Iwata
authors.affiliation: Faculty of Science and Engineering, Waseda University.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tanii
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D002384:Catalysis; D002448:Cell Adhesion / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D009474:Neurons / Q000166:cytology*; D016716:PC12 Cells; D055668:Photochemical Processes; D051381:Rats; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D054457:Tissue Scaffolds; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D016326:Extracellular Matrix Proteins; D012821:Silanes; D014867:Water; C061189:octadecyltrichlorosilane; C009495:titanium dioxide; D014025:Titanium