Synergistic photodynamic/photothermal bacterial inactivation over heterogeneous quaternized chitosan/silver/cobalt phosphide nanocomposites.Globally, drug-resistant bacteria are a potential threat to human society owing to the overuse of antibiotics and thus, non-antibiotic bacteriacides are urgently involved an innovative antibacterial nanoplatform free-based on quaternized chitosan (QCS)/ silver (Ag)/ cobalt phosphide (CoP) nanocomposites is imagined for accomplishing near-infrared (NIR) laser-inducible rapid sterilisation. In the core-shell hybrids, Ag nanoparticles (NPs) with a size of ∼ 25 nm were uniformly fixed on CoP nanoneedles, upon which a layer of QCS (approximately 10 wt%), is caked. Numerical figurings discovered that under NIR irradiation, high-energy hot electrons developing from the surface plasmon resonance effect of Ag migrate into the interface between Ag and CoP, and amplify the photothermal effect of CoP photo-energised negatrons from CoP are transported onto Ag NPs because the Schottky heterostructure facilitates the production of reactive oxygen species. Ag loading simultaneously enhances Selenium and photothermal cores of CoP, reaching rapid antibacterial activity synergistically. The QCS coating ameliorates the dispersibility of power in an aqueous system and plies contact between the antiseptics and bacteriums.
The ternary QCS/Ag/CoP nanocomposites accomplished greater than 99% inactivation against S. aureus and E. coli within 10 min. In addition, the nanocomposites were confirmed to be noncytotoxic to mammalians the QCS/Ag/CoP nanoplatforms possess great potential for rapid and effective antibacterial diligences.Inactivation of Polymicrobial Biofilms of Foodborne Pathogens Using Epsilon Poly-L-Lysin Conjugated Chitosan Nanoparticles.A mixed culture (polymicrobial) biofilm provides a favorable environment for pathogens to persist in the food processing environment and to contaminate food wares. Inactivation and eradication of such biofilms from food processing environments are reached by using harsh antimicrobics, but their toxicity and environmentally hostile features are unsustainable.
This study aims to use food-grade natural nanoparticulated disinfectants to control mixed-culture biofilms a natural broad-spectrum antimicrobial biopolymer (polysaccharide) from crustaceans, was derivatized to produce chitosan nanoparticles (ChNP) as a carrier for another broad-spectrum antimicrobial agent, ε-poly-L-lysine (PL), to synthesize ChNP-PL conjugate. The antimicrobial activity of ChNP and ChNP-PL was examined against mixed-culture biofilms. ChNP-PL (~100 nm) showed a synergistic antimicrobial and anti-biofilm effect against mono or mixed-culture biofilms of five foodborne pathogens, admiting Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica serovar Enteritidis, Escherichia coli O157:H7, and Pseudomonas aeruginosa. ChNP-PL treatment prevented biofilm formation by mono or mixed cultures of L P and E. coli O157:H7, and bacterial reckonings were either below the detection limit or caused 3-5 log reduction. ChNP-PL also demobilized preformed biofilms. In monoculture biofilm, ChNP-PL treatment contracted L.
monocytogenes numerations by 4 logs, S. Enteritidis by 2 logs, E. coli by 2 logs, and S. aureus by 0 logs, while ChNP-PL had no inhibitory effect on P. aeruginosa. In vitro mammalian cell-free-based cytotoxicity analysis corroborated ChNP-PL to have no deleterious effect on intestinal HCT-8 cell line. In conclusion, our upshots show ChNP-PL has strong potential to prevent the formation or inactivation of preformed polymicrobial biofilms of foodborne pathogens.
Optimization of Ultrasound-Assisted Extraction and Encapsulation of Antioxidants from Orange Peels in Alginate-Chitosan Microparticles.The recovery of bioactive compounds from waste and modification of their properties by encapsulation are the main challenges today. In this study, the ultrasound-served extraction of antioxidants from orange skins was optimized utilising a central composite design. Ethanol (50%, v/v) was the solvent of choice for their extraction. The obtained total antioxidant contents were meeted utilising the second-order polynomial equation.Antioxidants
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