"Loading-type" Plasmonic Nanoparticles for Detection of Peroxynitrite in Living Cells.

To date, plasmon resonance energy transfer (PRET)-based analytical approaches still inevitably suffer from limitations, such as lack of appropriate acceptor-donor pairs and the extra requirements of active groups of acceptors, which place great obstacles in extending the application of such methods, especially in the area of living cell studies. Herein, we design and fabricate a kind of "loading-type" plasmonic nanomaterials constituting gold nanoparticles as donors of PRET coated with mesoporous silicon, in which organic small molecules (CHCN) as acceptors of PRET were loaded (Au@MSN-CHCN). This "loading-type" strategy could conveniently integrate acceptor-donor pairs into one nanoparticle, so as to achieve the goal of sensitive detection of biomolecules in a complex physiological microenvironment. Based on the change of PRET efficiency of Au@MSN-CHCN induced by the specific reaction between CHCN and peroxynitrite (ONOO-), ONOO-, which plays an irreplaceable role in a series of physiological and pathological processes, is sensitively and selectively detected. Furthermore, in situ imaging of exogenous and endogenous ONOO- in living cells was achieved even at a single nanoparticle level. This work provides a general approach to construct PRET probes for visualizing various biomolecules in living cells.