【摘要】 目的 研究纳米银体外抗H3N2流感病毒的作用，并初步探索其作用机制。 方法 在H3N2流感病毒吸附细胞后加入纳米银和吸附前用纳米银预处理犬肾细胞（MDCK），在体外用细胞病变效应（cytopathic effect，CPE）观察法和3-（4，5-二甲基-2-噻唑）-2，5-二苯基溴化四唑（3-（4，5-dimethylthiazol-2-yl）-2，5-diphenyltetrazolium bromide，MTT）测值法，分析纳米银对H3N2流感病毒感染MDCK细胞的预防作用、直接灭活作用以及对流感病毒子代病毒体生成的抑制作用，运用RT-PCR法研究纳米银对H3N2流感病毒HA基因复制的干扰作用。 结果 纳米银能明显杀伤H3N2流感病毒，50、25 μg/mL的纳米银溶液与H3N2流感病毒充分作用2 h后感染MDCK细胞，细胞存活率分别为94.38%和92.17%，纳米银能有效抑制流感病毒对MDCK细胞的侵入和侵入后病毒的继续增殖，25 μg/mL纳米银溶液通过上述两种方式处理细胞，细胞存活率分别为85.39%和83.28%，与病毒对照组相比，差异均有统计学意义（Plt;0.001）；400、200 μg/mL纳米银溶液分别与流感病毒H3N2充分混合作用15、30、60、120 min后，病毒液的HA基因均未能成功扩增，纯病毒液和溶剂对照组在1 700 bp处均出现明显条带。 结论 通过3种不同的给药方式，纳米银在体外均能明显抑制流感病毒对细胞的感染，纳米银抑制流感病毒的机制可能是通过干扰H3N2流感病毒和吸附、穿入和基因的复制，从而抑制子代病毒体的生成。【Abstract】 Objective To explore the anti-viral effects of silver-nanoparticles (silver-nps) on H3N2 influenza virus in vitro and to evaluate its mechanism. Methods Silver-nps was added to canine kidney cells (MDCK) before and after the cells was adsorpted by H3N2 influenza virus. Cytopathic effect (CPE) assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to analyze the preventive effect, directly off deactivation, and the inhibit formation of progeny virions of silver-nps on H3N2 viruses. The interference of HA gene replication was observed by the RT-PCR assay. Results The survival rate of MDCK cells was 94.38% and 92.17% after 50 and 25 μg/mL silver-nps were mixed with 100 TCID50 H3N2 virus in 2 hours, and the survival rate of MDCK cells was 85.39% and 83.28% before and after the cells was adsorpted by H3N2 influenza virus when 25 μg/mL silver-nps was added to the cells (all compared to virus control, Plt;0.001), which showed that silver-nps could inactivate H3N2 virus, prevente them invasing to the cells and reproducting when H3N2 entered the cell remarkedly. The HA gene was not amplified successfully when 50 and 25 μg/mL silver-nps were mixed with 100TCID50 H3N2 virus in 15, 30, 60, and 120 minutes later, but both pure virus solution and solvent control group appeared a significant bright band in the 1 700 bp area. Conclusion Under three different administration modes, silver-nps has an obvious effect against H3N2 in vitro, which could interfere the HA gene replication and inhibit the formation of H3N2 progeny virions.
ObjectiveTo research on the types of pathogenic bacteria in wound infection and analyze the effectiveness of long-term use of nano-silver dressing in the treatment of pressure ulcers, in order to provide references for the management of pressure ulcer wound. MethodsFifty-five patients (60 wounds) with stage Ⅲ-Ⅳ pressure ulcer wound treated in all departments between September 2011 and August 2015 were chosen to be our study subjects. Under overall intervention, all the wounds were assessed by the same method, cleansed and debrided, after which nano-silver antimicrobial dressing was used to intervene until the wound healed or the end of 8 weeks. The wounds which were not healed were treated with wet dressing therapy until wound healing. The detection rate of pathogenic bacteria before intervention and 2, 4 and 8 weeks after intervention, change of pressure ulcer healing score and the rate of wound healing were observed. ResultsBefore the intervention, 12 kinds of pathogenic bacteria were detected, including mainly Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and coagulase negative Staphylococci. The detection rate of pathogenic bacteria was 92.73% (51/55). With the use of nano-silver dressing during different time periods, the detection rate of pathogenic bacteria and the total score of pressure ulcer were lowered by varying degrees (P<0.01). Four and 8 weeks after intervention, wound bed improved significantly and the detection rate of pathogenic bacteria decreased faster. The healing rate during the intervention period was 23.64% (13/55). ConclusionThe incidence of pressure ulcer wound infection is high. The use of nano-silver wound dressing can effectively remove pathogenic bacteria and promote wound healing.
We prepared silver nanoparticles/polyethyleneimine-reduction graphene oxide (AgNP/rGO-PEI) composite materials, and evaluated their quality performance in our center. Firstly, we prepared AgNP/rGO-PEI, and then analysed its stability, antibacterial activity, and cellular toxicity by comparing the AgNP/rGO-PEI with the silver nanoparticles (PVP/AgNP) modified by polyvinylpyrrolidone. We found in the study that silver nanoparticles (AgNP) distributed relatively uniformly in AgNP/rGO-PEI surface, silver nanoparticles mass fraction was 4.5%, and particle size was 6-13 nm. In dark or in low illumination light intensity of 3 000 lx meter environment (lux) for 10 days, PVP/AgNP aggregation was more obvious, but the AgNP/rGO-PEI had good dispersibility and its aggregation was not obvious; AgNP/rGO-PEI had a more excellent antibacterial activity, biological compatibility and relatively low biological toxicity. It was concluded that AgNP/rGO-PEI composite materials had reliable quality and good performance, and would have broad application prospects in the future.
In order to solve the problem of high cytotoxicity in vitro of nano-silver antibacterial gel, and the problem of large nano-silver particle size and size distribution, this study prepared nano-silver antibacterial gel with better biocompatibility and good antibacterial effect by using physical cross-linking method and using poloxamer as dispersant when prepared nano-silver. In this study, nano-silver was prepared by photo-initiator method and by adding poloxamer as a dispersant, and then UV-visible absorption spectrum test and scanning electron microscopy (SEM) test were carried out using prepared nano-silver mixture and particles after drying respectively. The gel was prepared through adjusting its pH value by using sodium bicarbonate, and then pH value test, SEM test for cross-section of gel, swelling ratio test, viscosity test, inhibition zone test and in vitro cytotoxicity test were carried out. The test results showed that the maximum absorption wavelength of prepared nano-silver, using poloxamer as dispersant and ultra-pure water as solvent, was 414 nm, and the average nano-silver size was about 60 nm. The prepared nano-silver using poloxamer as dispersant had smaller particle diameter and narrower particle size distribution than those using PVP as dispersant. Similarly, the prepared nano-silver using ultra-pure water as solvent also had smaller particle diameter and narrower particle size distribution than those using distilled water as solvent. The pH value of the prepared gel was between 5.8~6.1. The dried gel section had many holes. The water absorption of gel was fine and the viscosity of gel was fit to coat on the gauze. In addition, the prepared gel with nano-silver had greater ability to inhibit Escherichia coli and Staphyloccocus aureus at the concentrations of 24, 18 and 12 μg/mL. And the biocompatibility of the prepared gel with nano-silver was good when the concentration below 24 μg/mL. Based on the above features, the nano-silver antibacterial gel could be used in the treatment of burn or other wounds.