Raman tags in the cell-silent region as biological probes

Recently, Raman tags in the cell-silent region have gained prominence for imaging of small bioactive molecules in living cells. The tiny size of the Raman tag ensures that the properties of the target molecule is minimally perturbed while its distinct Raman signal in the spectrally silent region of the cell gives it high specificity and strong chemical contrast. Here, we discuss newly-developed cell-silent Raman tags that further expand the potential uses of these tags in biological studies. The development of a mitochondrion-targeting Raman probe and the structure-based imaging of a bioactive molecule in live cells are presented.