In order to grow or spread, cancer cells break down surrounding tissue using specialized enzymes called proteases. The Bhatia Lab designs tiny sensors to measure protease activity in highly specific locations. This image shows the probes (magenta) homed in on epithelial cells (green) in the colon, where proteases are hard at work.

Turning this technology on tumors will provide clinicians with a highly sensitive tool to detect cancer cells and assess their response to treatment. As a diagnostic platform, these nanosensors offer new strategies for visualizing the biology of disease.