AVS 50th International Symposium
    Applied Surface Science Tuesday Sessions
       Session AS+BI-TuA

Paper AS+BI-TuA1
Spatially Defined Immobilization of Biomolecules on Microstructured Polymer Substrate*

Tuesday, November 4, 2003, 2:00 pm, Room 324/325

Session: Biomaterials Characterization
Presenter: A. Hozumi, National Institute of Advanced Industrial Science and Technology, Japan
Authors: A. Hozumi, National Institute of Advanced Industrial Science and Technology, Japan
N. Shirahata, National Institute of Advanced Industrial Science and Technology, Japan
S. Asakura, Waseda University, Japan
A. Fuwa, Waseda University, Japan
Y. Yokogawa, National Institute of Advanced Industrial Science and Technology, Japan
T. Kameyama, National Institute of Advanced Industrial Science and Technology, Japan
Correspondent: Click to Email
　The spatial arrangement of biomolecules on solid surfaces with artificial control in the micro~nanometer scale has attracted attention in biotechnical and biomedical applications. Here we report a simple method by which a number of biomolecules can be immobilized onto positions spatially defined in micrometer-scale. Our approach demonstrated here is based on the photodecomposition and hydrophilization of polymeric material using vacuum ultraviolet (VUV) light of 172 nm radiated from a Xe@sub 2@@super *@ excimer lamp. Each poly (methyl methacrylate) (PMMA) substrate was irradiated for 30 min at 10@super 3@ Pa with VUV light through a photomask contacting the PMMA surface. As confirmed by atomic force microscopy, after VUV-irradiation, microwell arrays composed of about 2 nm in diameter and 350 nm in depth were successfully formed on the PMMA substrates. Next, using such microstructured PMMA substrates, we demonstrated spatial arrangement of biomolecules. The microstructured sample was immersed into a solution containing antibodies labeled with fluorescence for 30 min. The antibodies were selectively adsorbed on the microwells in which the surfaces were photooxidized, while the surrounding regions where they were not unirradiated regions remained free of adsorption, as evidenced by fluorescence microscopy. This specific adsorption was probably due to the differences in chemical properties between the VUV-irradiated and unirradiated regions, as well as due to the geometrically effect. Indeed, according to water-contact angle measurements and X-ray photoelectron spectroscopy analysis, the VUV-irradiated PMMA surface became highly hydrophilic with its water-contact angle changing from 80Åã to 25Åã due to the formation of polar-functional groups, such as C=O and O-C=O, on the surface. Such chemically and geometrically defined microwells are expected to serve as spatially arranged active sites for the immobilization of a wide variety of biomolecules. ).