American Chemical Society
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Carbon–SiO2 Hybrid Nanoparticles with Enhanced Radical Stabilization and Biocide Activity

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journal contribution
posted on 2023-11-13, 15:08 authored by Fotini Fragou, Areti Zindrou, Yiannis Deligiannakis, Maria Louloudi
Nanocarbon and nanosilica are widely-used nanomaterials of significant industrial interest. Herein, a library of {carbon–SiO2} hybrid nanoparticles, with controlled nanocarbon content and sp3/sp2 profile, was engineered by a flame spray pyrolysis (FSP) process in one step. Their structure–function relationship was evaluated by studying their radical-generation and radical-stabilization activities, using electron paramagnetic resonance spectroscopy in tandem with their biocide activity toward marine bacteria Aliivibrio fischeri. The surface properties of the C–SiO2 hybrids were studied by Raman spectroscopy and surface-charge analysis by zeta potential measurements. Raman spectroscopy indicates that the FSP process, as designed and used herein, allows the progressive incorporation of nanocarbon moieties into the SiO2 nanostructure, which may lead to distortion of the siloxane matrix. Concurrently, the C–SiO2 hybrids’ surface charge profile reveals a trend correlated with the acute biocide activity toward Aliiv. fischeri. Interestingly, we find no correlation between the stable radical population and the nanohybrids’ biocide activity. Within this context, we discuss the role of surface charge, radical properties, and SiO2 lattice distortions by the nanocarbon, all of them parametrized via FSP process protocols. Thus, the present study’s findings provide critical insight into the structure–biocide activity relationship of carbon–SiO2 hybrid nanoparticles. Technology-wise, the present work exemplifies a scalable FSP process for the industrial production of applied nanomaterials, such as C–SiO2 nanostructures.