Mobile microscopic sensors for high resolution in vivo diagnostics

Molecular electronics and nanoscale chemical sensors could allow the construction microscopic sensors capable of detecting patterns of chemicals in a fluid. Information from a large number of such devices flowing passively in the bloodstream allows estimates of the properties of tiny chemical sources in a macroscopic tissue volume. We use estimates of plausible device capabilities to evaluate their performance for typical chemicals released into the blood by tissues in response to localized injury or infection. We find that the devices can readily discriminate a single cell-sized chemical source from the background chemical concentration, providing high-resolution sensing in both time and space. By contrast, such a chemical source would be difficult to distinguish from background when diluted throughout the blood volume as obtained with a blood sample.