Yale scientists have created nanowire sensors coupled with simple microprocessor electronics that are both sensitive and specific enough to be used for point-of-care (POC) disease detection, according to a report in Nano Letters.
The sensors use activation of immune cells by highly specific antigens - signatures of bacteria, viruses or cancer cells - as the detector. When T cells are activated, they produce acid, and generate a tiny current in the nanowire electronics, signaling the presence of a specific antigen. The system can detect as few as 200 activated cells.
In earlier studies, these researchers demonstrated that the nanowires could detect generalized activation of this small number of T cells. The new report expands that work and shows the nanowires can identify activation from a single specific antigen even when there is substantial background "noise" from a general immune stimulation of other cells.
Describing the sensitivity of the system, senior author Tarek Fahmy, Yale assistant professor of biomedical engineering, said:. "Imagine I am the detector in a room where thousands of unrelated people are talking - and I whisper, 'Who knows me?' I am so sensitive that I can hear even a few people saying, 'I do' above the crowd noise. In the past, we could detect everyone talking - now we can hear the few above the many."
According to the authors, this level of sensitivity and specificity is unprecedented in a system that uses no dyes or radioactivity. Beyond its sensitivity, they say, the beauty of this detection system is in its speed - producing results in seconds - and its compatibility with existing CMOS electronics.