A Guillermo Bracamonte

National University of Cordoba (UNC), Argentine

Title: Tuning high electromagnetic fields from the Nanoscale towards the far field for Nanophotonics and Biophotonics applications: core-shell and hybrid Nanocomposites

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Biography

A.Guillermo Bracamonte, PhD in Chemical Sci., holds an assistant professor position at UNC and research position at CONICET (Commission of Research in Science, Argentina). During his research career, he held postdoctoral positions at COPL, Laval University (Quebec), and University of Victoria (British Columbia), Canada. He was research visitor at University of Regensburg, Germany (Bayern), Germany; and researcher at the NASA Astrobiology Institute, and University of Akron (Ohio) United States. Then, he began his own Research Group, in collaboration with other International Researchers, within Nanophotonics, Biophotonics and Nanomedicine.

Abstract

In this presentation is discussed about the design and synthesis of subwavelength Silica nanoparticles and hybrids Silica nanocomposites, and gold Core-shell nanoparticles for Enhanced Fluorescence based on Metal Enhanced Fluorescence (MEF). Thus, the tuning of Plasmonics was afforded to the development of controlled Ultraluminescent properties. These Nanoparticles are of high interest for Nanotechnology, Biophotonics, and Nanomedicine applications. It was optimized Luminescent SiO2 NPs and Ultra-Luminescent Au@SiO2 based on MEF. The fluorophore was Rhodamine B (RhB), well known as emitter and photon counter. The MEF, it is an effect produced by the excitation of a strong electromagnetic field in the near field that have effect on the occupation of the excited state affecting as well the kinetic constants of fluorescent lifetime decays. In order to study the MEF phenomena it was tuned and assayed variable gold cores sizes on the Luminescence of Au@SiO2-RhB nanoarchitecture. It was evaluated the MEF Enhancement Factors (MEFEF) by dissolving the gold cores. Analysis of single nanoparticles and nanocomposites in presence of Au@SiO2-RhB, MEFEF of 20-40 and 10 with 40 and 20 nm respectively by Laser Fluorescence Microscopy NanoImaging. These enhancements were accompanied with shortening of Fluorescence Lifetime decays attributed to MEF phenomena. Core-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, and Unicellular microorganisms with smaller core sizes. In this context, as well it should be contemplated the Optical activity of Biostructures for Bioimaging applications. 

Moreover it was discussed about the Bioconjugation of these Nanoparticles as well as the incorporation or chemical surface modifications with other types of organic molecular spacers for potential Nanophotonics applications as well.