In spite of tremendous efforts dedicated to addressing bacterial infections and biofilm formation, the post-antibiotic ear continues to witness a gap between the established materials and an easily accessible yet biocompatible antibacterial reagent. Here we show carbon dots (CDs) synthesized via a single hydrothermal process can afford promising antibacterial activity that can be further enhanced by exposure to light. By using citric acid and polyethyleneimine as the precursors, the photoluminescence CDs can be produced within one-pot, one-step hydrothermal reaction in only 2 h. The CDs demonstrate robust antibacterial property against both Gram-positive and Gram-negative bacteria and, notably, a considerable enhancement of antibacterial effect can be observed upon photo-irradiation. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) when exposed to light, leading to an augmented reactive oxygen species level. The approach for disruption of biofilms and inhibition of biofilm formation by using the CDs has also been established. Our findings present a potential solution to combat antibacterial resistance, and offer a path to reduce dependence on traditional antibiotics.

Background: There is an urgent need for risk assessment and mechanism exploration of fish allergens to provide a theoretical basis and methodological reference for food safety. PV is a major marine food allergen that can cause allergic reactions in fish allergic patients. This study aims to break through the previous model of evaluating the sensitivity of food allergens on single effector cells but to construct a coupling cell co-culture system for the process of dendritic cell maturation and T cell differentiation during sensitization. Methods: A new type of highly effective allergen sensitization evaluation model was proposed based on the effect of PV-induced differentiation of dendritic cells and T cells on the sensitization process. Results: Flow cytometry, ELISA, proteomics and transcriptomics approaches revealed that PV could promote the maturation of dendritic cells, mainly by inducing BMDC to express MHC Ⅱ, CD86, and other phenotypic molecules, while promoting cytokines/chemokines IL-6, IFN-γ, IL-23, and IL-12p70, whereas inhibiting TNF-α expression. It could strengthen the synthesis process of biological protein of DC cells and improve the expression level of genes such as the migration ability of DC cells in vivo. Finally, PV could induce T cells to shift to Th2 differentiation by inducing the increase of IL-4 level, which leads to allergic behavior. Conclusions: Therefore, the new allergen sensitization evaluation coupled with the cell co-culture system, in combination with the changes of the above markers could be used for quick and efficient determination of the potential sensitization possibility and sensitization intensity of fish allergens.

Phage display technology is commonly applied for high-throughput screening of single-domain antibodies (sdAbs), and the problem of non-specific adsorption caused by carrier proteins is often faced during the biopanning of single-domain antibodies against haptens. Therefore, an enrofloxacin (ENR)-functionalized cryogels was prepared for application in the biopanning of ENR-specific phages, which was prepared by the ethylenediamine (EDA) and carbodiimide methods. To improve the efficiency of biopanning, double blocking, a wash solution flow rate of 1 ml/min and phage pre-incubation were applied to the biopanning process through single-factor experiments. The results of flat colony counting showed that the phage output of AG-ENR cryogels was 15 times higher than the phage output of AG cryogels for the same input amount. And 7 complete sequences of ENR-specific shark sdAbs were obtained by monoclonal phage ELISA and sequence alignment. All these results indicated that AG-ENR cryogels can improve the efficiency of hapten-specific phages biopanning and this study provided a novel and efficient method for phage biopanning for single-domain antibody to haptens.