Peptide Functionalized Gold Nanoparticles as a Stimuli Responsive Contrast Medium in Multiphoton Microscopy.

There is a need for biochemical contrast mediators with high signal-to-noise ratios enabling noninvasive biomedical sensing, for example, for neural sensing and protein-protein interactions, in addition to cancer diagnostics. The translational challenge is to develop a biocompatible approach ensuring high biochemical contrast while avoiding a raise of the background signal. We here present a concept where gold nanoparticles (AuNPs) can be utilized as a stimuli responsive contrast medium by chemically triggering their ability to exhibit multiphoton-induced luminescence (MIL) when performing multiphoton laser scanning microscopy (MPM).