Surface Plasmon Enhanced Fluorescence of Glycine-Dimer-Functionalized Silver Nanoparticles

Abstract

We present experimental results on the fluorescence of glycine-dimers-functionalized silver nanoparticles. Silver nanoparticles were synthesized by using a solid state thermal reduction of silver nitrate in a glycine matrix yielding polydisperse silver nanoparticles. For particles of average core diameter of 23 nm the fluorescence quantum yield was determined to be 5.2+/−0.1 % and depended non-monotonically on the size of the nanoparticles. The fluorescence emission of the glycine dimers was enhanced by the strong local electric field due to the surface plasmon resonance in silver nanoparticles. The application of small fluorescent silver nanoparticles of average diameters 5 +/− 4 nm as imaging markers for yeast cells was demonstrated. The nanoparticles were able to penetrate yeast cell membranes and accumulate inside the vesicles within the cell. The luminescence was observed after 12 h of incubation inside the nuclei of about 10% of the cells suggesting that silver nanoparticles penetrated into the nuclei of the cells.