Synthesis Of Copper Sulfide Nanomaterials And Its Applications In Antibacterial And Cancer Cell Detection

Copper sulfide nanomaterials have excellent near-infrared absorption ability,good biocompatibility and enzyme-like activity,which have broad application prospects in the field of biomedicine.In this paper,copper sulfide nanoparticles(CuS NPs)were synthesized by a simple chemical precipitation method,and CuS-PDA nanoparticles were obtained by surface modification of CuS NPs with polydopamine(PDA).The catechol groups on the surface of the PDA were used to react with the amino groups on folic acid(FA)in Michael addition/Schiff base reaction.CuS-PDA-FA nanoparticles were obtained by coupling FA to the surface of CuS-PDA.Transmission electron microscopy(TEM)images showed that CuS-PDA was homogeneous nanoparticles.X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)proved that the nanoparticles were indeed CuS-PDA.Fourier transform infrared spectroscopy(FT-IR)results appeared the characteristic peak of FA,which proved the CuS-PDA-FA was synthesized successfully,and the existence of FA did not affect the morphology and properties of CuS-PDA.UV-visible near-infrared(UV-vis-NIR)absorption spectra indicated that CuS-PDA had stronger absorption capacity of near-infrared light compared with CuS NPs.CuS-PDA has photothermal and photothermal stability,which gives respectively the anti-bacteria rate was 99.06%and 98.85%to Escherichia coli and Staphylococcus aureus under near infrared irradiation at 808 nm.The obvious indentations and damage of bacterial cell membrane were displayed by scanning electron microscope(SEM)images.The relative ROS level and malondialdehyde content were significantly increased,which also proved that the integrity of cell membrane was destroyed.The anti-bacterial mechanism may be the synergistic effect of photoheat and photodynamics,which destroys bacterial structure and leads to bacterial death.CuS-PDA-FA has excellent peroxidase-like activity and the optimum p H was 4.0,the optimum temperature was 30℃.The catalytic kinetics curves of CuS-PDA-FA showed that it was consistent with the typical Michaelis-Menten equation.Moreover,the K_mvalue of CuS-PDA-FA for substrate TMB was 0.33 and less than horseradish peroxidase(HRP),indicating that the affinity of CuS-PDA-FA for TMB was stronger than that of HRP.The excellent biocompatibility of CuS-PDA-FA was proved by MTT colorimetric assay.The specific combination of FA with the FA receptor on the surface of He La cells enabled CuS-PDA-FA to anchor on the cells.The blue product ox TMB was produced after the chromogenic substrates hydrogen peroxide and TMB were added,,which can transform the catalytic process into color signal and the minimum detection quantity was 2500 cells.Based on the near-infrared absorption characteristics and enzyme-like activity of copper sulfide,the synthesis route using water as solvent was selected to avoid the potential toxicity brought by toxic organic surfactants.It was applied in antibacterial and the detection of cancer cells,providing a new idea for the development of effective antibacterial strategies and early diagnosis methods of cancer.