Ultraluminescent gold core-shell nanoparticles applied to individual bacterial detection based on metal-enhanced fluorescence nanoimaging

GONTERO, DANIELA; VEGLIA, ALICIA V.; BOUDREAU, DENIS; BRACAMONTE, ANGEL GUILLERMO

JOURNAL OF NANOPHOTONICS

SPIE-SOC PHOTOPTICAL INSTRUMENTATION ENGINEERS

Año: 2018 vol. 12 p. 125051 - 1250512

1934-2608

Gold core-shell nanoparticles were synthesizedbased on metallic cores, variablesilica shell spacers covered withmodified fluorescent silica layers. Ultraluminescent propertieswere obtained based on metal-enhancedfluorescence (MEF). Different silica spacers were synthesizedto optimize the MEF enhancement factor (MEFEF). An optimal MEFEF was determinedequal to 9.5 for shorter silica spacers(d−SiO2-= 10 nm). These nanoparticles were deposed onEscherichia coli bacteria atdifferent concentration levels for Bioimaging generation over theirsurfaces. The best luminescentnanoparticles were deposed on intermediate and higher bacteriaconcentrations. In the presence ofintermediate bacteria concentrations, the ultraluminescentnanoparticles adsorbed showed anincrease of 35% to 45% compared with individual nanoparticles.To modify the surface of individualbacteria, diluted samples of bacteria were used inwhich a 20% decrease in fluorescenceemission was measured. In the presence of higher bacteriaconcentrations, fewer clear and brightimages were obtained. At diluted ultraluminescent nanoparticleconcentrations, a decrease in brightnessand image detail was observed; and in theabsence of nanoparticle deposition, noimage was recorded. Accordingly, these ultraluminescentgold core-shell nanoparticles have been shown tobe useful as platforms for biodetection andtracking applications.