Research On The Graphene Complex For Bacterial Detection And Antibacterial

Bacterial infection has become one of the serious problems that threaten human health in the world.Therefore,the research of new multifunctional antibacterial materials has become the focus of the attention of scientists.Photothermal therapy（PTT）is an advanced antibacterial method to treat against bacteria that usually can lead to thermal ablation of microorganisms and cells by using near infrared（NIR）light to transform optical energy into heat.Graphene oxide（GO）,as a derivative of graphene,is regarded as a potential excellent antibacterial material with good antibacterial ability,excellent water solubility and stability.Besides,GO has good near-infrared light absorption characteristics and thermal conductivity,which can be used for photothermal conversion.The abundant oxygen-containing groups on the surface of GO provide active sites that can be modified.This paper focuses on the surface modification of GO,prepares and characterizes new GO composites,and applies them to the selective killing of bacteria by combining its antibacterial property and PTT.The main research contents are as follows:（1）This topic designed and prepared a GO-based multifunctional composite material（GO-PEG-NH₂）by functionalizing the surface of GO to achieve the selective capture,separation and photothermal killing of bacteria.The structure and properties of GO-PEG-NH₂ composites were characterized by various test methods.The test results show that GO-PEG-NH₂ composites have a sheet-like structure,exhibit good biocompatibility,stability and excellent photothermal conversion ability.The temperature of GO-PEG-NH₂ aqueous solution（50μg/m L）can reach 55°C under irradiation of 808 nm laser for 5 min.The selective capture ability of GO-PEG-NH₂composites to bacteria was verified by confocal laser scanning microscope（CLSM）andζpotential experiments,owing to the poly（ethylene glycol）（PEG）chains and positively charged amino groups,GO-PEG-NH₂ can specifically recognize and capture bacteria in the presence of cells.Finally,the plate counting method was used to verify the antibacterial ability of the GO-PEG-NH₂ composite.It was able to efficiently kill bacteria under the irradiation of 808 nm laser and the antibacterial efficiency reached 99%.（2）The GO-PEG-PLL composite modified by PEG and poly-L-lysine（PLL）was designed and prepared.Its morphology and structure were characterized by atomic force microscope（AFM）,and its photothermal effect was characterized by NIR laser.The antibacterial ability of GO-PEG-PLL composite was evaluated by the plate counting method.The results show:The introduction of PEG avoids the agglomeration of PLL and GO,GO-PEG-PLL composite has better dispersion and stability.The synergistic effect of PLL and GO antibacterial properties make them have enhanced antibacterial properties.After 12 h of incubation with E.coli,the antibacterial efficiency reached 94%.Besides,the GO-PEG-PLL composite has excellent light-to-heat conversion ability.It was able to efficiently kill bacteria under the irradiation of808 nm laser for 5 min and the antibacterial efficiency reached 99%.GO-PEG-PLL composite material has good antibacterial ability.Photothermal ablation can further eliminate residual bacteria.Combining the antibacterial ability of GO-PEG-PLL composite material with PTT improves the antibacterial efficiency and overcomes the shortcomings of low antibacterial efficiency.