This paper presents a CMOS image sensor with a 32 x 32 pixel array for cell capture, detection, and quantification. Pixels measuring 15 pm x 15 mu m have a modified structure, suitable for post-CMOS electroless gold plating, which enables surface activation for cell capture without the need for any intermediate layer. This structure also increases the detection probability of captured cells, even when cells are much smaller than the pixel, owing to a special light mask implemented on pixels. Cells as small as 3 pm in diameter can be detected with this pixel structure. The proof of concept for surface activation of the gold coated sensor pixels was demonstrated by capturing and imaging MCF-7 breast cancer cells on the modified sensor surface. Accordingly, electroless gold coating of the Al pixels was achieved and the gold coated surface of the CMOS image sensor was activated with thiol-modified antibodies that can capture MCF-7 cells. Cells were then optically detected under green LED illumination. (C) 2013 Elsevier B.V. All rights reserved.