Label-free high-density protein arrays

Proteins play a significant role in almost all biological processes. A comprehensive understanding of cell biology requires devices for the analysis of a staggering number of protein isoforms and protein-protein interactions in a cell. We present a novel protein microarray, featuring peptide aptamers as protein detectors arrayed on gold electrodes with feature sizes an order-of-magnitude smaller than existing formats. We use a robust, label-free electronic sensing system and demonstrate specific protein recognition in whole cell lysates. The sensitivity equals or exceeds that of other devices and is within the clinically relevant range. The use of peptide aptamers selected in vivo to recognise specific protein isoforms, the electronic nature and scalability of the detection, and the scalability of the array fabrication combine to yield the potential for highly multiplexed devices with increasingly small detection areas and higher sensitivities that may ultimately allow simultaneous monitoring of hundreds of thousands of protein isoforms.