Vancomycin Derived Nanomaterials For Biosensing And Antibacterial Applications

Infections caused by drug-resistant bacteria have become one of the most serious problems threatening public health.The emergence of drug-resistant bacteria due to antibiotic overuse renders the conventional single antibiotic therapy less efficient.Besides,the development of dense bacterial biofilm limited the penetration of antibiotic drugs,reducing their therapeutic efficacy,which makes bacterial infections more difficult to treat.The long-term or overload dosage of a single antibacterial procedure is viewed as the major culprit to the development of antibiotic resistance and therefore superbugs may have arouse.Therefore,the integration of two distinct bactericides into one compact platform provides a promising strategy to realize a combinational antimicrobial therapy.Through this combinational therapy,the efficiency of antibiotic against bacteria could be significantly improved by reducing drug dosage based on its synergistic effect and these combinational drugs could efficiently inactive bacteria from two distinct fronts with less opportunity for imparting drug resistance to some extent.Besides combination therapy,it is an alternative option to develop novel bactericides with different antibacterial mechanisms from traditional antibiotics.Among these novel bactericides,those which inactivate bacteria based on reactive oxygen species(ROS)including photodynamic and nanozyme agents have spurred wide attention.Antimicrobial photodynamic therapy(a PDT),which generates ROS upon light irradiation for bacterial inactivation has been considered as a promising solution due to its negligible drug resistance,minimal invasiveness and spatiotemporal controllability.Nanozyme with wide-spectrum antibacterial activity,minimal side effects and negligible drug resistance has rapidly become the new generation of antibiotic.Herein,we constructed two antibacterial nanoplatforms based on the antibiotic vancomycin,which take advantage of combinational therapy and ROS treatment,respectively,in order to solve the issue of drug-resistant bacteria.The research work is carried out based on the following two aspects:(1)Based on combinational therapy,we utilized polydopamine nanoparticles(PDA NPs)with excellent biocompatibility as ideal matrices to accommodate vancomycin and silver nanoparticles(Ag NPs),achieving a compact nanoplatform where these two distinct antibacterial agents were strongly integrated.This facile and rational design bypassed the chemical combination which may involve sophisticated covalent modification and physical integration of those two bactericides which usually suffers from instability.In the meantime,the obtained antibacterial nanoplatform exhibited significant killing efficiency against both Escherichia coli(E.coli,a typical type of Gram-negative bacteria)and Staphylococcus aureus(S.aureus,a typical type of Gram-positive bacteria)with lowed dosage of antibiotics to reduce the possibility of drug resistance.Furthermore,this nanoplatform also exhibited remarkable antibacterial effects and significant wound-healing promotion without any toxicity to major organs as demonstrated in the in vivo infected wound mice model.(2)Based on ROS therapy,we synthesized a novel carbon dots through hydrothermal treatment of vancomycin.This obtained vancomycin carbon dots(Van-CDs)with extraordinary hydrogen peroxide(H2O2)nanozyme activity could efficiently convert H2O2 into highly toxic·OH and could produce singlet oxygen(~1O2)upon 660 nm light irradiation due to their photodynamic properties for augmented bacterial inactivation.Besides,the existence of multiple vancomycin residual functional groups on the surface on Van-CDs could realize the potential bacteria targeting to achieve better antibacterial performance.Results demonstrated this novel Van-CDs could not only efficiently wipe out planktonic bacteria but also remove dense bacteria biofilm,holding great potential for diabetic foot infection therapy.Finally,this Van-CDs nanoplatform with brilliant hydrogen peroxide nanozyme activity could realize such biosensing application as glucose detection as well.