Preparation Of Graphdiyne Based Nanoenzymes And Their Peroxidase Properties

Peroxidase is a kind of important substance that maintains normal physiological activities of living organisms.However,most natural enzymes are proteins with high price.Under conditions of high temperature,strong acid or strong alkali,their structure is unstable and easy to be inactivated.Morever,it is difficult to prepare and extract.Based on the understanding of the structure and catalytic mechanism of natural enzymes,it is of great significance to synthesize mimic enzymes with low price and active center to replace natural enzymes.Graphdiyne,a promising two-dimensional carbon material,this papermainly studied three different supported peroxidase-like nanozymes which were synthesized by facile methods:single element doped graphdiyne（x-GDY）,boron and nitrogen co-doped graphdiyne（BN-GDY）and graphdiyne decorated Mn O₂（Mn O₂/GDY）nanozymes,and then explored their catalytic properties through some different application such as colon cancer therapy,antibacterial and degradation of organic pollutants.The main contentsare as follows:1.The simulated reaction of peroxidase（POD）catalyzed by nonmetal doped graphdiyne（GDY）prepared by hydrothermal method was studied and two doped GDY（B-GDY and N-GDY）with best performance were screened out.Moreover,ML tools were used to predict the maximum energy barrier or maximum energy consuming step of various models based on a portion of the calculation data,which effectively decreased the calculation cost.In addition,six nonmetallic atom doped GDYs with different expected properties were synthesized,and their experimental kinetic parameters verified the prediction results.The degradation of methylene blue（MB）was used as a model to investigate the performance of six simulated enzymes for degradation of organic pollutants.2.BN-GDY nanosheet was prepared by a facile hydrothermal process,and the peroxidase-like activity of BN-GDY was evaluated by TMB-H₂O₂ as the model.The catalytic mechanism of BN-GDY nanozyme was studied by Michaelis-Menten equation,electron paramagnetic resonance（EPR）and density functional theory（DFT）.The difference of catalytic activity between GDY and BN-GDY was explained from thermodynamics point of view.Based on BN-GDY,a therapeutic strategy for colon cancer with ferroptosis-apoptosis mechanism was constructed.The feasibility and mechanism of BN-GDY as a metel free anticancer agent in the treatment of colon cancer were investigated.3.Mn O₂/GDY was prepared by ultrasound-assisted electrostatic self-assembly method.TMB-H₂O₂ was used as the model to evaluate the catalytic activity of the enzyme,the mechanism of enhancing the catalytic activity of Mn O₂ was explored.The peroxidase-like performance of Mn O₂/GDY was investigated in depth using a combination of DFT calculations and experiments.A classical sterilization model was established and Mn O₂/GDY was evaluated to have a rapid,efficient and broad-spectrum sterilization effect.