Photoinduced Antibacterial Activity and Cytotoxicity of CdS Stabilized on Mesoporous Aluminosilicates and Silicates

Abstract

Inactivation of bacteria under the influence of visible light in presence of nanostructured materials is an alternative approach to overcome the serious problem of the growing resistance of pathogenic bacteria to antibiotics. Cadmium sulfide quantum dots are superefficient photocatalytic material suitable for visible light transformation. In this work, CdS nanoparticles with size of less than 10 nm (QDs) were synthesized on the surface of natural and synthetic mesoporous aluminosilicates and silicates (halloysite nanotubes, MCM-41, MCM-41/Halloysite, SBA-15). Materials containing 5–7 wt.% of CdS were characterized and tested as agents for photocatalytic bacteria degradation of Gram-positive S. aureus and Gram-negative E. coli with multiple antibiotic resistance. Eukaryotic cell viability tests were also conducted on the model cancer cells A 459. We found that the carrier affects prokaryotic and eukaryotic toxicity of CdS quantum dots. CdS/MCM-41/HNTs were assumed to be less toxic to eukaryotic cells and possess the most prominent photocatalytic antibacterial efficiency. Under visible light irradiation, it induced 100% bacterial growth inhibition at the concentration of 125 μg/mL and the bacteriostatic effect at the concentration of 63 μg/mL. CdS/MCM-41/HNTs showed 100% E. coli growth inhibition in the concentration of 1000 μg/mL under visible light irradiation.

Clays and Wound Healing

“…Those toxicities evaluations about wound healing materials should be carried out following those clinical medical orientations, which are different from oral usage, intravenous usage, external usage, etc., and that enable those standardized evaluation activities to be carried out in the micro/nano-biological studies. The evaluation of toxicities is related to influencing factors about mineral-based wound healing materials in literature [87][88][89][90][91], including mineral size distribution, mineral trace elements, human skin-associated cell lines, micro/nano-biological interactions, etc. Besides, some side effects were correlated with the excess dosages and silica sand.…”

Halloysite-Based Magnetic Nanostructures for Diverse Applications: A Review

“…Direct injections of HNTs may lead to thrombosis, and inhalation of HNTs may cause oxidative stress, an inflammatory response, and autophagy, resulting in subchronic toxicity in mice. Despite these concerns, further exploration of alternative routes for HNT-based drug delivery are yet to be explored. − …”