Traces of biomolecules such as DNA can be detected with a new “dynamic” technique based on the observation of association and dissociation events of gold nanoparticles. If the desired DNA sequence is present, it can reversibly bind two nanoparticles together. This can be detected in real time through a change in light scattering. As reported in the journal Angewandte Chemie, this method differentiates true signals from noise and can detect deviations of individual bases.