Synthetic non-classical luminescence generation by Enhanced Silica Nanophotonics based on Nano-Bio-FRET

C. SALINAS; M. V. AME; A. G. BRACAMONTE

RSC Advances

RSC

Lugar: London; Año: 2020 vol. 10 p. 20620 - 20637

2046-2069

Fluorescent Silica Nanoparticles (NPs-(SiO2-Fluo)) were synthesized based on the classical Störber method for cyanobacteria labelling. Modified mono-coloured SiO2 NPs with Fluorescein (Fl) and Rhodamine B (RhB) were obtained (NPs-(SiO2-Fl) and NPs-(SiO2-RhB)). Moreover, Multi-coloured SiO2 NPs by the incorporation of both emitters (NPs-(SiO2-RhB-Fl)) were tuned for optimal emissions and Biodetection of cyanobacteria (Cysbact.). The NPs-(SiO2?Fl) and NPs-(SiO2-RhB-Fl) were optimized to be detected by Laser Fluorescence Microscopy and by In Flow Cytometry with Laser excitation and Fluorescence detection. By TEM, homogeneous SiO2 NPs of 180.0 nm diameters were recorded. These sizes were slightly increased due to the covalent linking incorporation of the Fluorescent dye emitters to 210.0 nm sizes with Mono-coloured Fluorescent modified amined-organosilanes; while to 340.0 nm diameters with Multi-coloured dyes incorporation. These NPs-(SiO2-Fluo) showed variable emission depending of the dye emitter concentrations, quantum yields and applied Luminescent pathways. Thus, Mono-coloured NPs-(SiO2-Fl) and NPs-(SiO2-RhB) showed diminished emissions in comparison to Multi-coloured NPs-(SiO2-RhB-Fl). This enhancement was explained by Fluorescence Resonance Energy Transfer (FRET) between Fl as Fluorescent Energy Donor, and RhB as Energy acceptor produced within the Nanoarchitecture, produced just only in presence of both fluorophores with the appropriate Laser excitation of the Energy donor.The depositions of the Nano-emitters over cyanobacteria by non-covalent interactions were observed by TEM and Laser Fluorescence Microscopy. For Multi-coloured NPs-(SiO2-RhB-Fl) labelling it was observed Bio-FRET between the emission of the Nano-labellers and the natural fluorophores from the cyanobacteria that quenched the emission of the whole Nano-Biostructure in comparison to Mono-coloured NPs-(SiO2-Fl) labelling. This fact was explained and discussed by different Fluorescence Energy Transfer from the Nanolabellers towards different natural Chromophores coupling. In presence of the NPs-(SiO2-RhB-Fl) and NPs-(SiO2-RhB), the emission was coupled with the lower Quantum Yield Chromophores; while by the application of NPs-(SiO2-Fl) with higher Quantum Yield Chromophores. In this manner for Enhanced Luminescent Nanoplatforms tracking, the Multi-coloured NPs-(SiO2-RhB-Fl) showed improved properties; but higher Luminescent Bio-surfaces were generated with Mono-coloured NPs-(SiO2-Fl) that permitted faster cyanobacteria detection and counting by Laser Fluorescence Microscopy; and by In Flow Cytometry with Laser excitation and Fluorescence detection.