Sub-wavelength Ultraluminescent hybrids Sílica nanoparticles for BioImaging applications based on Metal Enhanced Fluorescence

ALICIA VEGLIA; CARINA SALINAS; DENIS BOUDREAU; WILLIAM ROBINSON; A. GUILLERMO BRACAMONTE

La Falda, Córdoba

Congreso; 5to Congreso Argentino de Microscopia SAMIC; 2018

IntroductionIn order to obtain detailed images and highly resolution from Nanoscale for Bioimaging generation it is need it to overcome the resolution limit of optical microscopes. This challenge was overcame by the last Nobel Prix in chemistry 2014 obtained by E. Betzig, S. W. Hell, W. E. Moerner by a switch on/off molecular Fluorescence. For enhanced resolution, It is of our interest the Metal Enhanced Fluorescence (MEF) phenomena related with effects produced by the excitation of a strong electromagnetic field in the near field of metallic nanoparticles, and Enhanced Plasmonics (EP) phenomena for Ultraluminescent NanoImaging and Bioimaging applications. ObjectiveDesign and synthesis of subwavelength Silica nanoparticles and hybrids Silica nanocomposites as gold Core-shell nanoparticles for Enhanced Fluorescence based on MEF for Biophotonics applications by Laser Fluorescence Microscopy.Material and methodsSilica nanoparticles (SiO2 NPs) and gold Core-shell nanoparticles (Au@SiO2) were synthesized by the sol-gel method and by a modified Störber method respectively. Gold nanoparticles were synthesized by the classical Turkevich method. ResultsIt was optimized Luminescent SiO2 NPs and Ultra-Luminescent Au@SiO2 based on MEF, with Rhodamine B (RhB) as fluorescent dye (See Figure 1). It was tuned and assayed variable gold cores sizes (5 nm, 20 nm and 40 nm) on the Luminescence of Au@SiO2-RhB nanoarchitecture (See Figure 1.b; c and d). Figure 1: Synthesis of NanoparticlesIt was evaluated the MEF Enhancement Factors (MEFEF) by dissolving the gold cores, and at the best for 40 nm cores it was recorded values of 20-40 by Laser Fluorescence Microscopy. For 5 nm gold cores variable numbers of cores were encapsulated (See Figure 1.b). Applications in Biophotonics for Single Molecule Detection (SMD) and Bioimaging for Escherichia Coli Bacteria detection were evaluated. While, the SiO2-RhB nanoparticles were applied for Ciano-bacteria detection.ConclusionsCore-shell nanoparticles with 40 nm cores showed the strongest hot-Ultraluminescent-spots and higher Ultraluminescent bacteria surface coverage, while for 20 nm and 5 nm cores weaker intensities were measured compared to 40 nm. However, it was determined higher Nano-resolution with intermedium intensities accompanied with enhanced detail of Bacteria Bioimaging with smaller core sizes.