Ultraluminescent gold Core-shell nanoparticles applied to individual bacterial detection based on Metal-Enhanced Fluorescence Nanoimaging

DANIELA GONTERO; ALICIA V. VEGLIA; DENIS BOUDREAU; A. GUILLERMO BRACAMONTE

JOURNAL OF NANOPHOTONICS

SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS

Año: 2018 vol. 12 p. 1 - 12

1934-2608

Gold Core-shell nanoparticles were synthesized based on metallic cores, variable silica shell spacers covered with modified fluorescent silica layers. Ultraluminescent properties were obtained based on Metal-Enhanced Fluorescence (MEF). Different silica spacers were synthesized in order to optimize the MEF enhancement factor (MEFEF). An optimal MEFEF was determined equal to 9.5 for shorter silica spacers (d-SiO2-=10 nm). These nanoparticles were deposed on Escherichia coli bacteria at different concentration levels for Bioimaging generation over their surface. The best luminescent nanoparticles were deposed on intermediate and high bacteria concentration. In presence of intermediate bacteria concentration, the ultraluminescent nanoparticles adsorbed showed a (35-45) % of increase compared with individual nanoparticles. In order to modify the surface of individual bacteria, diluted samples of bacteria were used, in which a 20 % decrease in fluorescence emission was measured. In the presence of higher bacteria concentrations, less clear and bright images were obtained.At diluted ultraluminescent nanoparticle concentrations, a decrease in brightness and image detail was observed; and in the absence of nanoparticle deposition, no image was recorded. Accordingly, these ultraluminescent gold Core-shell nanoparticles have shown to be useful as platforms for biodetection and tracking applications.