title: Nanofabrication for micropatterned cell arrays by combining electron beam-irradiated polymer grafting and localized laser ablation.
abstract: Most methods reported for cell-surface patterning are generally based on photolithography and use of silicon or glass substrates with processing analogous to semiconductor manufacturing. Herein, we report a novel method to prepare patterned plastic surfaces to achieve cell arrays by combining homogeneous polymer grafting by electron beam irradiation and localized laser ablation of the grafted polymer. Poly(N-isopropylacrylamide) (PIPAAm) was covalently grafted to surfaces of tissue culture-grade polystyrene dishes. Subsequent ultraviolet ArF excimer laser exposure to limited square areas (sides of 30 or 50 microm) produced patterned ablative photodecomposition of only the surface region (approximately 100-nm depth). Three-dimensional surface profiles showed that these ablated surfaces were as smooth and flat as the original tissue culture-grade polystyrene surfaces. Time-of-flight secondary ion mass spectrometry analysis revealed that the ablated domains exposed basal polystyrene and were surrounded with PIPAAm-grafted chemistry. Before cell seeding, fibronectin was adsorbed selectively onto ablated domains at 20 degrees C, a condition in which the non-ablated grafted PIPAAm matrix remains highly hydrated. Hepatocytes seeded specifically adhered onto the ablated domains adsorbed with fibronectin. Because PIPAAm, inhibits cell adhesion and migration even at 37 degrees C when the grafted density is > 3 microg/cm2, all the cells were confined within the ablated domains. A 100-cell domain array was achieved by this method. This surface modification technique can be utilized for fabrication of cell-based biosensors as well as tissue-engineered constructs.
authors.affiliation: Institute of Advanced Biomedical Engineering and Technology, Tokyo Women's Medical University, Japan. myamato@abmes.twmu.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamato
authors.forename: Chie
authors.initials: C
authors.lastname: Konno
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Koike
authors.forename: Yuki
authors.initials: Y
authors.lastname: Isoi
authors.forename: Tasuya
authors.initials: T
authors.lastname: Shimizu
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Kimiko
authors.initials: K
authors.lastname: Makino
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D002478:Cells, Cultured; D005353:Fibronectins / Q000737:chemistry; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism; D007834:Lasers; D036103:Nanotechnology; D051381:Rats; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D005353:Fibronectins; C052970:poly-N-isopropylacrylamide