Hydrophilic and salt responsive polymers promote depletion aggregation of bacteria

Chemotherapeutics-Loaded Poly(Dopamine) Core-Shell Nanoparticles for Breast Cancer Treatment

Chemophotothermal therapy is an emerging treatment of metastatic and drug-resistant cancer anomalies. Among various photothermal agents tested, poly(dopamine) provides an excellent biocompatible alternative that can be used to develop novel drug delivery carriers for cancer treatment. This study explores the synthesis of starch-encapsulated, poly(dopamine)-coated core-shell nanoparticles in a one-pot synthesis approach and by surfactant-free approach. The nanoparticles produced are embellished with polymeric stealth coatings and are tested for their physiologic stability, photothermal properties, and drug delivery in metastatic triple-negative breast cancer cell (TNBC) lines. Our results indicate that stealth polymer-coated nanoparticles exhibit superior colloidal stability under physiologic conditions, and are excellent photothermal agents, as determined by the increase in temperature of solution in the presence of nanoparticles, upon laser irradiation. The chemotherapeutic drug-loaded nanoparticles also showed concentration-dependent toxicities in TNBC and in a brain metastatic cell line. SIGNIFICANCE STATEMENT: This study develops, for the first time, biocompatible core-shell nanoparticles in a template-free approach that can serve as a drug delivery carrier and as photothermal agents for cancer treatment.

Enhanced Cryopreservation Efficacies of Ice Recrystallization Inhibiting Nanogels

Development of new cryopreservation technologies holds significant potential to revolutionize the fields of cell culture, tissue engineering, assisted reproduction, and transfusion medicine. The current gold standard small-cell permeating cryopreservation agents (CPAs) demonstrate promising cryopreservation efficacies but are cytotoxic and immunogenic at the concentrations required for cryopreservation applications. In comparison, new cell impermeable CPAs of nanodimensions demonstrate outstanding potential to overcome the drawbacks of existing CPAs. In this study, we report the synthesis of vitamin B5 analogous methacrylamide (B5AMA)-incorporated nanogels as a potential solution to address the commonly observed limitations of existing CPAs. The stimuli-responsive poly(B5AMA) nanogels prepared by radical polymerization demonstrated significant ice recrystallization inhibition efficacies and showed either superior or comparable cryopreservation efficacies compared to the traditional cryoprotectant DMSO/glycerol in both eukaryotic and prokaryotic cells.

Mechanistic insight of lysozyme transport through the outer bacteria membrane with dendronized silver nanoparticles for peptidoglycan degradation

Drug resistance has become a global problem, prompting the entire scientific world to seek alternative methods of dealing with resistant pathogens. Among the many alternatives to antibiotics, two appear to be the most promising: membrane permeabilizers and enzymes that destroy bacterial cell walls. Therefore, in this study, we provide insight into the mechanism of lysozyme transport strategies using two types of carbosilane dendronized silver nanoparticles (DendAgNPs), non-polyethylene glycol (PEG)-modified (DendAgNPs) and PEGylated (PEG-DendAgNPs), for outer membrane permeabilization and peptidoglycan degradation. Remarkably, studies have shown that DendAgNPs can build up on the surface of a bacterial cell, destroying the outer membrane, and thereby allowing lysozymes to penetrate inside the bacteria and destroy the cell wall. PEG-DendAgNPs, on the other hand, have a completely different mechanism of action. PEG chains containing a complex lysozyme resulted in bacterial aggregation and an increase in the local enzyme concentration near the bacterial membrane, thereby inhibiting bacterial growth. This is due to the accumulation of the enzyme in one place on the surface of the bacteria and penetration into it through slight damage of the membrane due to interactions of NPs with the membrane. The results of this study will help propel more effective antimicrobial protein nanocarriers.

The aggregation of Aspergillus spores and the impact on their inactivation by chlorine-based disinfectants

The formation of fungal biofilm goes through some different states, including monodisperse state, aggregated state, germinated state, hyphal and biofilm. The aggregation of spores is a primary step of fungal biofilm development in aquatic systems. Previous studies on the inactivation of fungi were mostly performed in the monodisperse state of fungal spores and biofilm state, however, the inactivation of aggregated fungal spores is still unclear. In this study, the aggregated characteristics of fungal spores (Aspergillus fumigatus and Aspergillus flavus) at different pH values were firstly studied, and the inactivation efficiency of fungal spores at different aggregation degree by chlorine-based disinfectants was also clarified. The results showed that the aggregation degree of Aspergillus fumigatus was the highest at pH 9.0 while it was the lowest at pH 5.0. Aggregation between fungal spores was mainly mediated by occasional adhesin-adhesin interactions and electrostatic interactions. Compared with monodisperse spores, fungal spores were more resistant to chlorine-based disinfectants with the increase of spore aggregation degree. The inactivation rate constants of Aspergillus fumigatus at 30% and 63% aggregation degree were 1.5- and 4-folds lower than that of monodisperse spores, respectively. The lower proportion of membrane damage and higher intracellular reactive oxygen species level for aggregated spores than monodisperse spores was observed according to the flow cytometric results after chlorine-based disinfectants treatment. The reasons for the lower inactivation efficiency of aggregated spores are as following: the protection of outer layer spores and signals between aggregates lead to the increase of resistance for aggregated spores. This study is meaningful for the control of the fungal spores at different states in water.