OBJECTIVES: Recently, the use of biological synthesis of metal nanoparticles has attracted widespread attention. Researchers are trying to find a biological method to synthesize silver nanoparticles with little environmental pollution and easy preparation, and to explore the impact of preparation conditions on the synthesis of silver nanoparticles. This study aims to explore the biological synthesis of silver nanoparticles (AgNPs) with controllable size and good effect and to compare their biological activity with that of AgNPs prepared by chemical method. METHODS: In this study, AgNPs were prepared by biological method with water extract of Tricholomagambosum (WET) and cell-free supernatant of Lactobacillus crispatus (CFS) as reducing agent and protective agent, and silver nitrate solution as precursor. Meanwhile, AgNPs was synthesized by sodium citrate chemical method. The effects of temperature, pH, dosage of extraction solution and light conditions on the biosynthesis of WET-AgNPs and CFS-AgNPs were investigated, and their characteristic of the synthesized WET-AgNPs and CFS-AgNPs were analyzed. Finally, the antibacterial effect, toxicity and selectivity of the 3 different AgNPs were compared. RESULTS: AgNPs were synthesized successfully by the 3 methods with various characteristics. The AgNPs prepared by biological method (WET-AgNPs , CFS-AgNPs) were greatly affected by pH and temperature. The WET-AgNPs and CFS-AgNPs prepared by the biological methods had better antibacterial effect than the AgNPs by the chemical method (all P<0.01). Between them, the WET-AgNPs had a slightly higher antibacterial effect than the CFS-AgNPs. Compared with the AgNPs prepared by chemical method, the toxicity of the WET-AgNPs and CFS-AgNPs to normal cells was lower (both P<0.01), and the cell selectivity of the CFS-AgNPs was better when the concentration was 480 μg/mL. CONCLUSIONS AgNPs with biological activity can be synthesized from WET and CFS, which have different biological activity compared with the AgNPs prepared by biological method.
Humans ; Metal Nanoparticles ; Fatigue Syndrome, Chronic ; Silver/pharmacology* ; Anti-Bacterial Agents/pharmacology* ; Plant Extracts/pharmacology*

OBJECTIVE: To study the intervention effects of participatory training on the occupational health in polishing workers. METHODS: By the stratified random sampling method,930 front-line polishing workers were selected from 50 manufacturing enterprises in Guangzhou,467 workers in the intervention group and 463 workers in the control group. The intervention group adopted participatory training and the control group adopted the traditional training. We evaluated the changes of occupational health knowledge,attitude and practice( KAP) in workers of these two groups using the questionnaire table of occupational health KAP for polishing workers. Data of before intervention,immediately after intervention and 3 months after intervention were collected. RESULTS: The workers 'knowledge,attitude and practice scores at the time point of immediately after intervention were higher than those before intervention in the same group( P <0. 05). The workers' knowledge and practice scores of 3 months after intervention in intervention group were higher than those before intervention( P < 0. 05). The knowledge and practice scores of 3 months after intervention in the intervention group were higher than that in the control group( P < 0. 05). The evaluation scores on protection measure and warning signs of workers in the intervention group were lower than those in workers of control group 3 months after the intervention( P < 0. 05). Three months after the intervention,the workers in intervention group believed that the training was more effective than that in the control group in the following 6 aspects: improving the knowledge of occupational health,improving the ability of identifying risk factors, learning to use the personal protective equipment, helping other workmates,having confidence to make suggestions and introducing other workmates to participate in training( P < 0. 05).CONCLUSION: The participatory training is an effective intervention model in improving the workers ' awareness of occupational health KAP.