Study On Interfacial Engineering Of Graphene Oxide Electrode By Perylene-containing Polyhexamethylene Guanidine Hydrochloride And Its Application For Bacterial Detection Based On Electrochemistry

Bacterial infection has been a major threat to human life and public health.Rapid and sensitive detection of pathogenic bacteria and inhibition of bacterial growth are important for preventing infection and improving survival.Most of the traditional sensors have problems such as complicated operation,time-consuming detection and high cost.Impedance-based electrochemical sensors using carbon electrodes have been explored for bacterial detection.However,the pristine carbon surface is inefficient in attracting and killing bacterial cells,which affects the detection performance of sensors like this.Therefore,we use polymer antibacterial agent to modify the surface of graphene oxide electrodes to design an electrode that can detect bacteria easily with simple preparation,low cost,fast speed and high sensitivity.First,we synthesized a novel type of polymer antibacterial agent,denoted as PBI-PHMG,using polyhexamethylene guanidine hydrochloride（PHMG）and3,4,9,10-pyridinetetracarboxylic dianhydride（PDA）as raw materials.Its synthesis conditions were optimized,and its molecular structure,physical and chemical properties,and antibacterial activity were characterized.Next,graphene oxide（GO）was coated on porous Ni electrode to form GO electrode by chemical vapor deposition（CVD）using shellac biopolymer as a carbon source.Then,the PBI-PHMG was conjugated with the GO on the surface of porous Ni by the collectively strong pi-pi interactions between the large aromatic structures contained in the PBI-PHMG and GO,forming a stable GO/PBI-PHMG（PPG）electrode.As the positively charged guanidinium group in the PBI-PHMG structure has a strong accumulation and killing effect on negatively charged bacteria,the PPG electrode exhibits high sensitivity to bacteria at lower concentrations(<40 CFU m L^-1).The limit of detection（LOD）for Gram-negative Escherichia coli（E.coli）and Gram-positive Staphylococcus aureus（S.aureus）was as low as 2 CFU m L^-1.At the same time,the electrode can quickly detect bacteria by incubating with bacteria for 30 minutes.The facile preparation,short detection time and high sensitivity of the PPG electrodes are promising for practical applications in the fields of biology,medicine and food safety.