Experimental photophysical characterization of fluorophores in the vicinity of gold nanoparticles

We propose an experimental-based tool for dealing with fluorescence modulation close to nanoparticles for application in studies of fluorophores in the vicinity of gold nanoparticles (AuNPs), typically addressed via theoretical models. We performed a photophysical characterization of fluorophores in the vicinity of AuNPs, showing that correct Phi(F) determination suffers from a local pH effect, and address the observed radiative enhancement. Our approach is based on the experimental assurance that the reference fluorophores are in the same optical conditions as those of the AuNP-fluorophore conjugates. We demonstrate the relevance for introducing corrections for the inner filter effect and the reabsorption of the emitted light caused by AuNPs. The proposed approach could circumvent the need for theoretical based corrections and allow for more accurate determination of fluorescence emission in the vicinity of gold nanoparticles.