Study On The Construction And Properties Of Antibacterial Polylactic Acid-based Composite Fibers Reinforced By Metal Nanoparticles

Human bone is an active tissue,but when it is damaged in a large area,it cannot repair itself,so it is necessary to find suitable materials for bone transplantation,and artificial bone materials have attracted much attention.Electrospun polylactic acid(PLLA)fibers have been widely used in drug delivery,diagnosis and bone tissue repair due to their excellent degradability and non-toxic degradation products.However,PLLA has poor biological activity and hydrophilicity,and lacks osteogenic activity and antimicrobial properties.In order to improve the osteogenesis and antibacterial properties of PLLA,we modified the PLLA base to improve its performance,including the following three aspects:(1)The long-term antibacterial PLLA-based silver(Ag)composites were prepared by the combination of electrospinning technology and pulsed electrochemical deposition.Based on the strong adhesion of polydopamine(PDA),the electrochemically driven chitosan(CS)was used to regulate silver ion(Ag~+)on the surface of PLLA substrate,and the PLLA-based@PDA@CS/Ag composite material was successfully prepared.The results showed that the silver nanoparticles were uniformly distributed and had good physiological stability,which could achieve long-lasting antibacterial properties.(2)In order to further improve the ability of bone formation,PLLA-based composite materials containing strontium hydroxy-apatite(Sr HA)and copper(Cu)were constructed by combining electrospinning technology and pulsed electrochemical deposition technology.Based on the dual regulation of PPy,the uniform distribution of Sr HA and Cu was realized.The results show that the composite has excellent osteogenic properties and good physiological stability,which can achieve the dual purpose of lasting antibacterial and enhancing osteogenic activity.(3)In order to achieve rapid sterilization,improve the hydrophilicity and reduce the complexity of the system,the electro-spinning technology and immersion technology were combined to construct the PDA-modified PLLA base-loaded Cu composite.Based on the adhesion and reduction of PDA,combined with the properties of Cu and external light stimulation,the material can achieve the purpose of rapid sterilization.The results showed that the nanoparticles on the surface of PLLA@PDA/Cu fibers were uniformly distributed,with small size,improved hydrophilicity,rapid sterilization ability,excellent osteogenic activity and excellent biological activity.