Nanoparticles and nanowires

Another boon to bioanalysis looks set come from the attaching of nanoparticles to molecules of interest. Nanoparticles small enough to behave as quantum dots can be made to emit light at varying frequencies. If you can get particles that emit at different frequencies to attach to different molecules, you can spectroscopically determine the presence of many different molecules at the same time in a single sample.

Several companies have been created to commercialize this and other variations on nanoparticle bioanalysis. One variation with similar applications, i.e. offering improved parallelism, uses instead nanowires that have distinctive stripes on them, like a bar code.
Others are exploiting the sensitivity of the electrical properties of nanowires (and even nanotubes) to develop highly sensitive biodetectors that could reveal the presence of a single molecule of substance. Quantum dots offer the same capability, for example by being stimulated to emit a photon in the presence of a certain molecule. Recent developments in single-photon detection and emission bear on this space too.