Tracking metal enhanced fluorescence from Eschericcia coli nano-bio-assemblies within colloidal dispersions by static and 3D spectra emissions

Abstract

It was studied the interactions of single Ultraluminescent 40 nm gold Core shell Nanoparticles (d40 Au@SiO2-Fl) with Eschericcia Coli bacteria (Esc. Col). By this manner, it was tracked from initial Nano-Bio-assembly formation (Au@SiO2-Fl-Esc. Col) towards inter-Nano-Biostructure interactions. In order to do that it was determined association constants between d40 Au@SiO2-Fl and Biostructures by 3D Fluorescence, fluorescence spectroscopy measurements. The association constant was related with non-covalent Nano-Biostructure interactions of 45 ± 2 biostructure-1; accompanied with a Quantum Yield ratio between the Bio-assembly and Nano-labeller of 3.6 ± 0.1 times, with the maximal concentration of bacteria addition. This phenomenon of interaction was tracked from the bulk of the colloidal dispersion. And, from these individual interactions, it was possible to generate Bioimaging by Laser Fluorescence Microscopy in real time of the dynamic of Bio-assembly formation as well as the by inter-Nano-Biostructures. These data leaded to the correlation of 3D Fluorescence spectroscopy within different bacteria concentrations. The recorded spectra showed increased values of intensities that fitted to a linear equation as model of the experimental data records. About analytical performances, it could be noted that optimized sensitivity by 3D Fluorescence was unless 65% higher than by static Fluorescence. Moreover, it should be mentioned that two distributions of emissions were recorded that correlated with Plasmonics coupling with natural emitters within the UV and MEF Nanolabeller emissions. Thus, optimizing conditions, LODs of 0.3x10 3 bacterium*mL−1 were determined. Moreover, by In Flow Cytometry was recorded different sensitivity values depending of the Laser excitation applied. These phenomena were explained by the development of different Nano-Bio-emitters species. In addition, in order to validate the methodology, it was quantified Biostructures from fortified aqueous samples. By 3D Fluorescence it was determined recoveries of (97 ± 8)x103, and (93 ± 5)x103 from upper and lower distributions of emissions recorded in 3D Fluorescence topographies. The reproducibility in all cases was by %CV of 98–99 %; therefore the proposed Bioassays showed interesting insights in Nano-Biotechnology with impact in varied Research fields. In this way, it was showed and discussed about Bio-analytical applications for Eschericcia Coli detection and quantification within colloidal dispersion with relative simple, accessible and portable fluorescence spectroscopy set ups. Therefore, it was given insights for accessible Nano-Biodetection based on Ultra-sensitive MEF Nanoplatforms for Bio-labeling using standard spectroscopic and compared by In Flow Citometry analysis as well.