Tiny disease detector is like a lab on a chip

The antigen-specific T-cells of the immune system are so called because they respond to particular infections. Antigens—protein fragments from viruses, bacteria or other microorganisms—are displayed to circulating T-cells on the surface of antigen-presenting cells. If a T-cell’s receptors recognize and bind to an antigen, the T-cell is activated, prompting the rapid proliferation of additional T-cells that precisely target the same invader.

Monitoring this process is important for understanding the immune response in many contexts, including autoimmune diseases and cancer. However, current measurement techniques are time-consuming and labor-intensive and require sophisticated laboratory equipment.

In the October 2008 issue of Nano Letters, a team led by Tarek Fahmy, Ph.D., assistant professor of biomedical engineering at Yale, describes a simple nanoscale measurement system that can detect the activation of as few as 200 antigen-specific T-cells in seconds.

The new device could power highly sensitive instruments that immediately determine which strain of flu, tuberculosis or E. coli a patient has, or detect the presence of minute amounts of residual disease after chemotherapy or antiviral treatment.