In this paper, we report a method of printing uniform protein lines on glass slides by using UV-treated flat PDMS stamps. Unlike traditional microcontact printing (mu CP) which requires microstructured PDMS stamps, this mu CP method only requires a flat PDMS stamp, an UV lamp and a number of straight needles. Our results show that lines of bovine serum albumin (BSA), immunoglobin (IgG), anti-biotin, anti-human IgG and anti-mouse IgG can be printed evenly on glass slides by using this mu CP method. We also demonstrate that the printed protein lines are suitable for applications such as microfluidic immunoassays. (C) 2010 Elsevier Inc. All rights reserved.