Phthalates Promote Dissemination of Antibiotic Resistance Genes: An Overlooked Environmental Risk.

Plastics-microorganism interactions have aroused growing environmental and ecological concerns. However, previous studies concentrated mainly on the direct interactions and paid little attention to the ecotoxicology effects of phthalates (PAEs), a common plastic additive that is continuously released and accumulates in the environment. Here, we provide insights into the impacts of PAEs on the dissemination of antibiotic resistance genes (ARGs) among environmental microorganisms. Dimethyl phthalate (DMP, a model PAE) at environmentally relevant concentrations (2-50 µg/L) significantly boosted the plasmid-mediated conjugation transfer of ARGs among intrageneric, intergeneric, and wastewater microbiota by up to 3.82, 4.96, and 4.77 times, respectively. The experimental and molecular dynamics simulation results unveil a strong interaction between the DMP molecules and phosphatidylcholine bilayer of the cell membrane, which lowers the membrane lipid fluidity and increases the membrane permeability to favor transfer of ARGs. In addition, the increased reactive oxygen species generation and conjugation-associated gene overexpression under DMP stress also contribute to the increased gene transfer. This study provides fundamental knowledge of the PAE-bacteria interactions to broaden our understanding of the environmental and ecological risks of plastics, especially in niches with colonized microbes, and to guide the control of ARG environmental spreading.

Injectable hydrogel encapsulating Cu2MnS2 nanoplates for photothermal therapy against breast cancer.

BACKGROUND: In order to explore the possibility of treating breast cancer by local photo-therapy, a photothermal agents loaded in situ hydrogel was established. In detail, The Cu2MnS2 nanoplates were prepared by one-pot synthesis and, the thermosensitive Pluronic F127 was used as the hydrogel matrix. The Cu2MnS2 nanoplates and the hydrogel were characterized by morphous, particle size, serum stability, photothermal performance upon repeated 808 nm laser irradiation as well as the rheology features. The therapeutic effects of the Cu2MnS2 nanoplates and the hydrogel were evaluated qualitatively and quantitatively in 4T1 mouse breast cancer cells. The retention, photothermal efficacy, therapeutic effects and systemic toxicity of the hydrogel were assessed in tumor bearing mouse model. RESULTS: The Cu2MnS2 nanoplates with a diameter of about 35 nm exhibited satisfying serum stability, photo-heat conversion ability and repeated laser exposure stability. The hydrogel encapsulation did not negatively influence the above features of the photothermal agent. The nanoplates loaded in situ hydrogel shows a phase transition at body temperature and, as a result, a long retention in vivo. CONCLUSIONS: The photothermal agent embedded hydrogel played a promising photothermal therapeutic effects in tumor bearing mouse model with low systemic toxicity after peritumoral administration.