Nanobiotechnologists are developing devices that can measure specific enzymes and proteins. These devices are expected to detect single enzyme or protein molecules accurately, providing highly sensitive biosensing applications. A recent study by Strano and co-workers shows that single-walled carbon nanotubes (SWNTs) hold great promise as implantable biosensors. Although most researchers have focused on substrate-oriented biosensors, Strano and colleagues have shown that the inherent fluorescent properties of suspended individual SWNTs can be used for solution-phase beta-D-glucose sensing.