Yang Wang,Jie Tang,Xiaoyu Luo,Xiaoya Hu,Chun Yang,Qin Xu
In this work, a kojic acid electrochemical sensor, based on a non-covalent molecularly imprinted polymer (MIP) modified electrode, had been fabricated in the lab-on-valve system. The sensitive layer was synthesized by cyclic voltammetry using o -phenylenediamine as the functional monomer and kojic acid as the template. The template molecules were then removed from the modified electrode surface by washing with NaOH solution. Differential pulse voltammetry method using ferricyanide as probe was applied as the analytical technique, after extraction of kojic acid on the electrode. Chemical and flow parameters associated with the extraction process were investigated. The response recorded with the imprinted sensor exhibited a response in a range of 0.01–0.2 μmol L −1 with a detection limit of 3 nmol L −1 . The interference studies showed that the MIP modified electrode had excellent selectivity. Furthermore, the proposed MIP electrode exhibited good sensitivity and low sample/reagent consumption, and the sensor could be applied to the determination kojic acid in cosmetics samples.
Summary The development of effective natural antibacterial agents is important due to the insecurity of synthetic antimicrobial agents and consumer preferences. In this study, kojic acid (KA) and tea polyphenols (TP) were found to exhibit synergistic inhibitory effect against Escherichia coli O157:H7 with a fractional inhibitory concentration index of 0.25. KA combined with TP at 25% of their minimum inhibitory concentrations (MICs) completely inactivated E. coli O157:H7 within 4 h. Subsequently, propidium iodide uptake tests, genomic DNA interaction analysis, molecular docking, field emission scanning electron microscopy and biofilm formation assay were conducted to understand the synergistic antibacterial mechanism of KA-TP. The results demonstrated that KA-TP attacked the cell membrane cooperatively, thus disturbing membrane integrity and cell structure, and KA could bind to the genomic DNA to affect the biofilm formation of E. coli O157:H7. Moreover, the contamination of E. coli O157:H7 on raw salmon fillets was eliminated to varying degrees after soaking treatments with KA and/or TP for 30 min. The depuration effect was further enhanced when KA combined with TP, and more than 2-log reduction of E. coli O157:H7 was obtained under the treatment of KA-TP at 2 MIC, suggesting that KA-TP may serve as a natural compound disinfectant for ready-to-eat aquatic products.
危险品化学品经营许可证（带存储）