| Poly(lactic acid)(PLA)is a bio-based synthetic polyester material known for its excellent biodegradability and biocompatibility.It is widely recognized as one of the most promising environmentally friendly bio-based and biodegradable materials,accounting for 70% of the biodegradable materials market.With extensive research,PLA-based antimicrobial materials have gained increasing attention.Its wide availability of raw materials can help reduce dependence on non-renewable resources like petroleum.The self-degradation of polylactic acid is mainly in the form of hydrolysis,and the degradation products will continue to catalyze the degradation of polylactic acid,which can be completely degraded into carbon dioxide and water under natural conditions.In the field of textiles,PLA fibers are considered as fully biodegradable bio-based synthetic fibers and have gained increasingly widely used.However,there are differernt viewpoints and controversies regarding the antimicrobial performance of PLA.Some articles suggest that PLA exhibits poor antimicrobial properties,while other research results indicate that PLA possesses favorable inherent antimicrobial activity.Therefore,this point is still worth further investigation and exploration.Additionally,the harm of fiber microplasticization has gained increasing attention.As a fully biodegradable and environmentally friendly synthetic fiber material,there is limited research on the potential harmlessness of PLA microplastics in the human lungs.This study investigates the antimicrobial performance of pure PLA textiles and the potential impact of PLA microplastics on the human respiratory system.Firstly,the antimicrobial properties of PLA fibers were examined,and the underlying reasons for the antimicrobial activity of PLA were analyzed.Subsequently,experiments were designed to explore the effects of PLA microplastics on the human lungs.Through experimental research,the antibacterial properties of polylactic acid and the research results on the impact of PLA microplastics on human lungs were obtained.During the investigation of the antimicrobial properties of poly(lactic acid)(PLA),the antimicrobial performance of mesh fabrics with PLA fibers on the front side and pure cotton fibers on the reverse side was assessed using the K-B method specified in industry standard FZ/T73023-2006.Furthermore,the antibacterial activities of textile products including pillowcases made of pure cotton fabric,pillows with PLA fiber filling,and PLA fiber wadding with polyester fabric as the lining were evaluated using the oscillation method outlined in GB/T20944.3-2008,with pure cotton fabric serving as the control group.Through experimental test results and data analysis,the antibacterial properties of PLA textiles were obtained,and the antibacterial principle of PLA was analyzed.The results on the antimicrobial properties of PLA fibers demonstrated their significant antibacterial activities.The antibacterial rates against Escherichia coli,Staphylococcus aureus,Candida albicans,and Klebsiella pneumoniae were found to be 85%,98%,90%,and 97%,respectively.These data indicated that PLA textile products exhibited a favorable inhibitory effect on bacteria.The antibacterial mechanism and reason may be that polylactic acid fibers will precipitate lactic acid during use,and a weak acidic environment can be formed on the surface.In the experiment on the potential harmlessness of PLA microplastics to the human lungs,the main method was to simulate the in vitro lung environment and investigate whether polylactic acid microplastics had adverse effects on simulated alveolar surfactant solutions and simulated lung fluids.The commonly used polyester was selected as a control group.Under simulated lung conditions,the activity of alveolar surfactant on the microplastic surfaces and the surface tension of alveolar surfactant solutions were examined and analyzed for both PLA and polyester microplastics.The study also explored the presence of reactive oxygen species(ROS)in the simulated lung fluids,as well as the underlying reasons for ROS generation.The results of the experimental study on the harmlessness of PLA microplastics to the human body indicated that PLA microplastics had minimal impact on the activity of simulated alveolar surfactant and the surface tension of alveolar surfactant solutions.PLA exhibited good degradation capability in simulated lung fluids.The interaction between PLA microplastics and active substances in simulated lung fluids could generate hydroxyl radicals,however,polylactic acid microplastics do not have biological persistence,and the effect of polylactic acid on human lungs is far less than that of polyester microplastics.The above research results demonstrated that the use of PLA fibers could significantly reduce the microplastic hazard associated with conventional synthetic fibers.Moreover,PLA fibers possessed excellent antibacterial properties and represent a more biocompatible and healthier green fiber material for human use. |
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