Dyeing to look inside cells

The direct visualization of a large number of different molecules inside cells could improve our understanding of many important processes, but remains challenging with existing methods. Lu Wei et al. show that stimulated Raman scattering measurements under electronic pre-resonance conditions makes it possible to image many different dye-labelled target molecules with very high selectivity and sensitivity in living cells. The team created a palette of new dyes that emit signals in the cell-silent Raman spectral window, making them readily observable, and report imaging of 16 different dye-labelled targets within live cells. Proof-of-principle experiments on neuronal co-cultures and brain tissues further underscore the potential of this super-multiplex optical imaging approach for untangling intricate interactions in complex biological systems.