Summary
The dynamics of living cells can be studied by live-cell fluorescence microscopy. However, this often requires the use of excessive light energy to obtain good signal-to-noise ratio, which can then photobleach the fluorochromes used, and more worrisome, lead to photo-toxicity. Thus, strategies that can reduce the amount and/or exposure to excitation light would improve live-cell microscopy. Upon light excitation, noble metal nanoparticles such as silver (AgNP) generate plasmons, which can amplify the excitation of fluorophores that are proximal to the surface of the nanoparticle. These can also couple to the oscillating dipole of nearby radiating fluorophores, which modifies the rate of emission and enhances their fluorescence. Here, we show that AgNP fed to cells to accumulate within lysosomes enhanced the fluorescence of lysosome-targeted BODIPY-cholesterol and DQ-BSA. Moreover, AgNP increased the fluorescence of GFP fused to the cytosolic tail of LAMP1, showing that metal enhanced fluorescence occurs across the lysosomal membrane. Importantly, by using AgNP, we could track lysosome motility with reduced laser power without damaging and altering lysosome dynamics. Overall, AgNP-enhanced fluorescence may be a useful tool to study the dynamics of the endo-lysosomal pathway while minimizing photo-toxicity.
Competing Interest Statement
The authors have declared no competing interest.
