Browsing by Author "Kira, Atsushi"

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Induction of Cell-Cell Connections by Using in situ Laser Lithography on a Perfluoroalkyl-Coated Cultivation Platform
(2011-03-21)
Okano, Kazunori
;
Yu, David
;
Matsui, Ai
;
Maezawa, Yasuyo
;
Hosokawa, Yoichiroh
This article describes a novel laser-directed microfabrication method carried out in aqueous solution for the organization of cell networks on a platform. A femtosecond (fs) laser was applied to a platform culturing PC12, HeLa, or normal human astrocyte (NHA) cells to manipulate them and to facilitate mutual connections. By applying an fs-laser-induced impulsive force, cells were detached from their original location on the plate, and translocated onto microfabricated cell-adhesive domains that were surrounded with a cell-repellent perfluoroalkyl (R(f)) polymer. Then the fs-laser pulse-train was applied to the Rf polymer surface to modify the cell-repellent surface, and to make cell-adhesive channels of several mm in width between each cell-adhesive domain. PC12 cells elongated along the channels and made contact with others cells. HeLa and NHA cells also migrated along the channels and connected to the other cells. Surface analysis by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that the Rf polymer was partially decomposed. The method presented here could contribute not only to the study of developing networks of neuronal, glial, and capillary cells, but also to the quantitative analysis of nerve function.
Micropatterning of perfluoroalkyl self-assembled monolayers for arraying proteins and cells on chips
(2009-06-15)
Kira, Atsushi
;
Okano, Kazunori
;
Hosokawa, Yoichiroh
;
Naito, Akira
;
Fuwa, Koh
Organosilane self-assembled monolayers (SAMs) with perfluoroalkyl groups (R(f)) on glass surfaces were used for arraying proteins and cells on chips. Quartz crystal microbalance measurements confirmed the inhibition of protein adsorption on R(f)-SAM-modified surfaces and showed efficient adsorption on hydroxyl-, carboxyl-, and amino group-modified surfaces. The characteristics of R(f)-modified surfaces were evaluated using solvent contact angle measurement and Fourier transform infrared (FTIR) spectroscopy. The R(f) surface was highly water-and oil-resistant, as inferred from the contact angles of water, oleic acid, and hexadecane. Specific peaks of IR spectra were detected in the region from 1160 to 1360 cm(-1). Etching with dry plasma completely exfoliated the R(f)-SAM, exposing the underlying intact glass surface. Modi. cation conditions were optimized using contact angle and FTIR measurements. After dry plasma processing, the contact angles of all solvents became undetectable, and the IR peaks disappeared. Micrometer scale protein and cell patterns can be fabricated using the proposed method. Protein adsorption on micropatterned R(f)-SAM-modified chips was evaluated using fluorescence analysis; protein adsorption was easily controlled by patterning R(f)-SAM. PC12 and HeLa cells grew well on micropatterned R(f)-SAM-modified chips. Micropatterning of R(f)-SAM by dry plasma treatment with photolithography is useful for the spatial arrangement of proteins and cells. (C) 2009 Elsevier B. V. All rights reserved.