Size Matters: Biosensors behave oddly when very small

Physicists have built tiny instruments sensitive enough to detect single molecules of DNA, and the construction of these sensors generally follows a simple rule: the smaller the better. However, this rule might have a limit, a new study finds.

Scientists have used microsensors to detect lone viruses, and some researchers have proposed using them to screen for HIV and cancer-indicating proteins (SN: 10/13/01, p. 237: Available to subscribers at Detecting cancer risk with a chip). The common assumption is that even smaller sensors could detect such particles more p