内源性电场调控抗菌离子传输以提高植入材料抗菌性能

Endogenous electric field as a bridge for antibacterial ion transport from implant to bacteria

组织植入材料相关感染是临床治疗的一大顽疾,基于抗菌离子释放系统的抗菌植入材料是经济高效的抗生素治疗替代手段.但过量释放的抗菌离子在杀灭细菌的同时也可能引起生物毒性.因此,如何提高释放离子的抗菌效率是急需解决的根本问题.本研究设计了一种负载低剂量抗菌离子的铁电植入材料,该植入材料表面电势可在不改变自身成份的前提下通过外源电场极化进行调控.研究发现上述铁电植入材料释放的抗菌离子将在植入材料自身与带电细菌之间形成的内源性电场作用下定向输运到达细菌.研究结果表明在12 h内,高表面电势植入材料向细菌输运的离子量达到低表面电势植入材料输运量的2.4倍,从而使抗菌效率从65%提高到100%,并展现出较低的细胞毒性.本研究表明植入材料与生命体间的内源性电场在介导物质传输中发挥重要作用,为设计高性能抗菌生物材料提供了一个新的视角.

Tissue implant-related infections are among the most serious complications after surgical implantation,including orthopedics and dentistry.Implants with antibacterial ion release systems are efficient and economical antibiotic substitutes to fight against bacterial infections.However,the excessive amount of released antibacterial ions may cause biological toxicity while killing bacteria.This raises a fundamental issue on how to properly control the amounts of ions and their efficacy.Here,we develop low-dose antibacterial ions-incorporated ferroelectric implants(copper-doped potassium sodium niobate,K0.5Na0.5NbO3-Cu,KNNCu)whose surface potential can be tuned via external polarization.The released Cu2+ions can be targeted to bacteria via endogenous electric field(EEF)between KNNCu implants and negatively charged bacteria.Intriguingly,the antibacterial efficacy of the implants is determined by the amount of Cu^2+ions that reaches bacteria,instead of the total amount of released Cu2+ions.The amount of Cu2+ions reaching bacteria from the high-surface-potential implant is 2.4 times that from the lowsurface-potential implant within 12 h,resulting in the increased antibacterial ratio from about 65%to 100%,while remaining low cell toxicity.This work provides insights into the specific role of the EEF in guiding mass transport between charged materials and living organisms,and a new perspective for the design of high-performance antibacterial biomaterials.