具有可生物降解、细胞相容、抗菌及生物膜控制的壳聚糖磺基甜菜碱衍生物薄膜生物材料的研究

The purpose of this research was to develop a chitosan sulfobetaine(CS-SNCC)film via the solutioncasting method as a biodegradable antibacterial material for biomedical applications.Chitosan and monochloro-triazine sulfobetaine were used as the raw materials for CS-SNCC preparation,and Fourier-transform infrared(FTIR),ultraviolet–visible(UV-Vis),energy-dispersive X-ray(EDX),and Xray photoelectron spectroscopy(XPS)spectra were used to characterize and analyze the structure of the synthesized CS-SNCC.Furthermore,the swelling property,thermal stability,biodegradability,cytocompatibility,and antibacterial properties of the CS-SNCC film were comprehensively investigated and compared with those of the chitosan film.The results for the film’s enzymatic biodegradation behavior show that the CS-SNCC film undergoes a weight loss of 45.54%after 21 days of incubation.In addition,the CS-SNCC film effectively resists bacterial adhesion,prevents the formation of bacteria biofilms,and exhibits high antibacterial activity,with inactivation rates of 93.43%for Escherichia coli and 91.00%for Staphylococcus aureus.Moreover,the CS-SNCC film shows good cellular activity and cytocompatibility according to the cytotoxicity results.Therefore,the prepared biodegradable,cytocompatible,antibacterial,and biofilm-controlling CS-SNCC film has potential for biomedical applications.

Effects of Different Broth Enrichment upon Phage Magnetoelastic Biosensor for Fast Detecting Low <i>Salmonella</i>Counts on Problematic Produce

According to the FDA Bacteriological Analytical Manual (BAM) for Salmonella identification in produce, two pre-enrichment steps with 48 hours of incubation are the golden procedures. Lactose broth is recommended for the first pre-enrichment step medium for leafy greens, and the universal pre-enrichment (UP) broth is for tomatoes. However, the suggested broths were evaluated to have the maximum performance using the culture-dependent methods, and may not be applied to other methods, such as biosensor detection platform. A wireless bacteriophage magnetoelastic (ME) biosensor has been recently developed for real-time or rapid detection of food-borne pathogens in various foods. This affinity-based biosensor utilizes a phage oligonucleotide as the probe to capture target bacteria. In this study, the efficiencies of different pre-enrichment media for early detection of low Salmonella on spinach leaves and tomatoes use ME biosensors to shorten detection time. Four broths of modified peptone water, Lennox broth (LB), lactose broth, and UP broth were selected in this study. Various pre-enrichment times for ME biosensor detection were investigated. After spiking 4 cfu/g Salmonella on the tomatoes surfaces, the phage biosensor was able to detect Salmonella within 5 hours of pre-enrichment comparing to 24 hours in the FDA procedures. For Salmonella spiked spinach leaves, the same medium showed Salmonella positive within 7 hours. This study demonstrated that LB broth is the best medium to shorten pre-enrichment time to pass Salmonella number detection thresholds for ME biosensor detection in spinach and tomatoes when comparing to FDA procedures.