Determination of size and mass-and number-based concentration of biogenic SeNPs synthesized by lactic acid bacteria by using a multimethod approach

MORENO-MARTIN, GUSTAVO; PESCUMA, MICAELA; PÉREZ-CORONA, TERESA; MOZZI, FERNANDA; MADRID, YOLANDA

ANALYTICA CHIMICA ACTA

ELSEVIER SCIENCE BV

Año: 2017 vol. 992 p. 34 - 41

0003-2670

Seleniumnanoparticles (SeNPs) were synthesized by a green technology using lactic acidbacteria (LAB, Lactobacillus acidophilus, L. delbrueckii subsp. bulgaricus andL. reuteri). The exposure of aqueous sodium selenite to LAB led to thesynthesis of SeNPs. Characterization of SeNPs by transmission electronmicroscopy with energy dispersive X-ray spectrum (EDXS) analysis revealed thepresence of stable, predominantly monodispersed and spherical SeNPs of anaverage size of 146 ± 71 nm. Additionally, SeNPs hydrodynamic size wasdetermined by dispersive light scattering (DLS) and nanoparticle tracking analysis(NTA). For this purpose, a methodology based on the use of surfactants in basicmedium was developed for isolating SeNPs from the bacterial pellet. Thehydrodynamic size values provided by DLS and NTA were 258 ± 4 and 187 ± 56 nm,respectively. NTA measurements of number-based concentration reported values ofð4:67±0:30Þx 109 SeNPs mL 1 with a relative standard deviation lower than 5% (n¼ 3). The quantitative results obtained by NTA were supported by theoreticalcalculations. Asymmetrical flow field flow fractionation (AF4) on line coupledto the inductively couple plasma mass spectrometry (ICP-MS) and off-linecoupled to DLS was further employed to characterize biogenic SeNPs. Thedistribution of the particle size for the Se-containing peak provide an averagesize of (247 ± 14) nm. The data obtained by independent techniques were in goodagreement and the developed methodology