In Flow Metal Enhanced Fluorescence for Biolabelling and Biodetection

A. G. BRACAMONTE*; A. V. VEGLIA; D. GONTERO

Photochemical & Photobiological Sciences (PPS), RSC

RSC

Lugar: London; Año: 2020 vol. 1 p. 1 - 5

1474-9092

Determination of Escherichia Coli Bacteria by In Flow Cytometry with Laser excitation and fluorescence detection applying Ultraluminescent Core-shell nanoparticles based on Metal Enhanced Fluorescence (MEF) was developed. The Core-shell nanoparticles are composed by a 40 nm core modified with a silica spacer grafted with Rhodamine B (RhB). The electromagnetic field in the near field of the core surface enhanced the fluorescence of RhB by Plasmonic and fluorophore reporter coupling. The hydrophilic silica spacer permitted the non-covalent interaction with the polar Escherichia Coli Bacteria surface and by this manner Ultraluminescent Bacteria Bio-labelling was developed. By Laser Fluorescence Microscopy was recorded clear, well defined and bright Bacteria Imaging based on the non-covalent deposition of the Ultraluminescent Nano-emitters. Using these Nano-labellers, it was possible to detect by In flow Cytometry labelled Escherichia Coli Bacteria. Higher values of Side scattered light (SSC) and Forward scattered light (FSC), as well as number of event detection were observed for labelled Bacteria compared to non-labelled. The sensitivity of the methodology was evaluated by varying the Bacteria concentration and acceptable analytical figures of merit were determined. Applying this methodology it was possible to quantify Escherichia Coli bacteria from a synthetic real sample of fortified water. Similar results were obtained by Bacteria counting with Laser Fluorescence Microscopy and by a Cell-Bacteria counter as well.