Preparation of Immobilized ε-Polylysine PET Nonwoven Fabrics and Antibacterial Activity Evaluation

A novel antibacterial material （L-PET） was prepared by immobilizing ε-polylysine on polyethylene terephthalate （PET） nonwoven fabrics. Surface modifications of the fabric were performed by using a chemical modification procedure where carboxyl groups were prepared on the PET surface, a coupling agent was grafted, and the ε-polylysine was immobilized. Scanning electron microscopy （SEM） was used to analyze the surface morphology of the fabrics, while the toluidine blue method and X-ray photoelectron spectroscopy （XPS） were used to evaluate the grafting densities. The antibacterial activities of the L-PET were investigated by using the shaking-flask method. The electron micrographs showed that the surface of the blank PET and the modified fabrics did not change. The results of XPS analysis confirmed that ε-polylysine was successfully grafted onto the surface of PET. The results of the antibacterial experiments showed that L-PET fabrics had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, and that L-PET fabrics were stable in storage for at least two years.

Production of nitrite-free frankfurter-type sausages by combiningε-polylysine with beetroot extracts:An assessment of microbial,physicochemical,and sensory properties

The current study investigated the utilization ofε-polylysine(ε-PL)and beetroot extract(BE)as suitable nitrite substitutes in frankfurter-type sausages packaged in vacuum polyethylene bags.The sample’s technological,safety,antimicrobial,and organoleptic attributes were analyzed during 30 days of storage at 4℃.Compared with controls,the sausages containingϵ-PL with BE had no significant differences in the water activity and proximate composition.The results showed that the T5 and T4 samples had the highest residual nitrite and total phenolic contents at day 45.Incorporatingε-PL and BE into frankfurter-type sausages prevented the increase of pH and maintained samples’pink color and texture consistency during storage.T3 and T4 samples could effectively delay the growth of total viable count,coliform,Clostridium perfringens,mold,and yeasts within acceptable limitations during refrigerated storage.

Antibacterial characteristics and mechanisms of some herbal extracts and ϵ-polylysine against two spoilage bacterial

This study aimed to evaluate the antibacterial effects of ε-polylysine (ε-PL) and plant extracts of Thymus vulgaris, Zataria multiflora, and Salvia verticillata against the spoilage bacterium Pseudomonas aeruginosa and Pectobacterium carotovorum . Chemical compounds contained in the plants extracts were detected using HPLC and H NMR assays. To determine the antimicrobial effects, the minimum inhibitory concentration (MIC) was calculated. Scanning electron microscopy (SEM) was used to evaluate the mode of action of plant extracts and ε-polylysine on bacteria. Bacterial membrane electrical conductivity was also measured to investigate the effect of treatments on electrolyte leakage. Based on HPLC results, rosmarinic acid, caffeic acid, gallic acid, and chlorogenic acid were identified as major chemical ingredients of the extracts. Based on HPLC results, chlorogenic acid in the T. vulgaris, Z. multiflora, and S. verticillata extracts with the values of 3.209, 3.163, and 1.455 mg/L, respectively, was the dominant compound. Gallic acid, carvacrol, and p -cymene were detected in the H NMR assay as predominant secondary metabolites. The results of SEM revealed that plant extracts and ε-polylysine caused deformity of bacterial membranes. Minimum inhibitory concentration values for T. vulgaris, ε-polylysine, Z. multiflora, and S. verticillata were determined to be 0.78, 1.56, 6.25, and 25 mg/L;respectively. The electrical conductivity of bacterial cell membranes followed a dose-dependent trend. The highest electrical conductivity was observed in T. vulgaris treatment, followed by ε-polylysine and Z. multiflora .

Enhanced production of cytidine 5'-monophosphate using biocatalysis of di-enzymes immobilized on amino-functionalized sepharose

Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.

A targeted nanoplatform co-delivery of pooled siRNA and doxorubicin for reversing of multidrug resistance in breast cancer

Multi-drug resistance(MDR)has become the largest obstacle to the success of cancer patients receiving traditional chemotherapeutics or novel targeted drugs.Here,we developed a targeted nanoplatform based on biodegradable boronic acid modifiedε-polylysine to co-deliver P-gp siRNA,Bcl-2 siRNA,and doxorubicin for overcoming the challenge.The targeted nanoplatform showed a robust suppressing efficiency for the invasion,proliferation,and colony formation of adriamycin(ADR)resistant breast cancer cell line(MCF-7/ADR)cells in vitro.The ATP responsiveness of the nanoplatform was also proved in the research.In the in vivo antitumor experiment,the targeted nanoplatform showed a significant inhibition of tumor growth with good biocompatibility.The goal of this study is to develop a novel and facile strategy to prepare a highly efficient and safe gene and drug delivery system for MDR breast cancer based on biocompatibleε-polylysine polymers.