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We describe a straightforward approach to the immobilization of various proteins by micro-contact printing, which can be used to pattern cells on substrates. Optical response and topography of protein on patterned surface are studied. Scanning near field optical microscopy (SNOM) and atomic force microscopy (AFM) were utilized together for detecting fluorescence and imaging topography of patterned protein respectively. After immobilization of the proteins into adhesive shape of line and space, it was found that cells adhere to and spread selectively on the patterned protein. In microarrays experiments, a serious limitation is the unreliability of low signal intensities data and the lack of reproducibility for the resulting ration between samples and controls. To improve the sensitivity of the fluorescence detection of fluorescein isothiocyanate in protein array, we used SNOM for detecting low signal intensity. It is convenient to measure fluorescence signal from the patterned protein allowing us to monitor the small protein of fluorescence. The finding illustrates the importance of microcontact printing as a method for positioning proteins at surfaces, and demonstrate the scope of controlled surface chemistry to direct cell adhesion. |