Preparation Of Graphdiyne-based Quantum Dots And Its Application In Detection

Graphdiyne quantum dots is a new type of low-dimensional semiconductor carbon materials.It has the advantages of high stability,excellent biocompatibility,excellent optical properties,good electrical conductivity and low cytotoxicity of traditional carbon-based quantum dots.Compared with graphene-based quantum dots,it has high?-electron conjugation,and thus make it has high research value and application potential.In this paper,based on graphdiyne(GDY),two kinds of graphdiyne-based quantum dots were prepared by simple methods:graphdiyne oxide quantum dots(GDYO-QDs)and nitrogen doped graphdiyne quantum dots(N-GDQDs).These two kinds of quantum dots are used in the construction of biosensors to achieve the accurate detection of Fe³⁺,ascorbic acid(AA),dopamine(DA)and glutathione(GSH).The main research contents are as follows:1.GDYO-QDs were obtained by hydrothermal and ultrasonic treatment.The particle size of GDYO-QDs is relatively uniform.The GDYO-QDs has excellent fluorescence properties and the quantum yield is 14.6%.Based on the good fluorescence properties of GDYO-QDs,the fluorescence sensing mechanism for the detection of Fe³⁺and AA was investigated.Fe³⁺quenches the quantum dots through the synergistic effect of internal filter effect(IFE)and photoinduced electron transfer(PET).Due to the reducibility of AA,it can promote the fluorescence recovery of Fe³⁺/GDYO-QDs solution.The GDYO-QDs-based fluorescence sensor has been successfully applied to the detection of Fe³⁺and AA in real biological serum samples,exhibiting good practical application.2.N-GDQDs were prepared by hydrothermal method using urea as nitrogen source.The flurescence properties of N-GDQDs have been greatly improved by introducing nitrogen,and the quantum yield is 48.6%.The electrochemical properties of N-GDQDs was studied,it was found that N-GDQDs has strong electron transport ability and good conductivity.Based on the excellent flurescence and electrochemical properties of N-GDQDs,a novel dual-mode(electrochemical-fluorescence)sensor was constructed to detect DA.In addition,the recovery experiments in the real biological serum samples showed that the detection method has a good potential for clinical application.3.The enzyme properties of N-GDQDs were investigated.The experimental model of 3,3',5,5'-tetramethylbenzidine(TMB)and H₂O₂ was used to verify that N-GDQDs have excellent peroxidase-like activity.The steady-state kinetics showed that N-GDQDs have a fast catalytic rate.Based on N-GDQDs-TMB-H₂O₂ solution system,a GSH visual sensor was established and applied to the detection of GSH in urine and serum samples successfully.Compared with the commercial GSH detection kit,the sensor has high practical application value.