Preparation Of CdTe Quantum Dots And Its Application In Detecting SrMV In Sugarcane

Nanotechnology is recognized as one of the most promising research fields in the 21st century.As a kind of semiconductor crystal with nanometer scale,quantum dot has been confirmed by a large number of studies and have broad application prospects in various applications.Sugarcane,as the most important sugar crop in the world,will be harmed by virus in the growth process.Sr MV is a kind of virus that causes sugarcane mosaic symptoms all over the world.Sr MV will lead to the degradation of sugarcane’s species and the decline of its yield and quality.Therefore,it is of great significance to detect sugarcane virus in time for effective prevention and control of sugarcane virus.At present,the main methods of virus detection are enzyme linked immuno sorbent assay and polymerase chain reaction,but they are time-consuming and expensive.Quantum dot based biosensors have recently been used in life sciences to detect human pathogenic viruses,fungi and harmful food-borne bacteria,but only a few are used to detect plant viruses.In this paper,two kinds of quantum dots were synthesized and characterized-Cd Te QDs and C QDs.Experimental results show that the synthesized Cd Te QDs and C QDs are both water-soluble,and the surface contains a large number of carboxyl and hydroxyl functional groups.Secondly,a biosensor was constructed using these two quantum dots to detect bovine serum albumin（BSA）.The biological donor part of the sensor consists of Cd Te QDs and specific antibodies against BSA（Ig G）.When Ig G-Cd Te QDs and BSA-C QDs came close,the donor-acceptor complex Ig G-Cd Te QDs+BSA-C QDs was generated based on the interaction of antigen-antibody molecules,which lead to a significant decrease in the fluorescence emission intensity of Cd Te QDs,and when a certain concentration of BSA was added,the emission intensity of Cd Te QDs at?_max 550 nm will be restored,so the homologous antigen BSA in solution can be detected.Further experimental results show that when BSA is added to the composite system,the fluorescence intensity of Cd Te QDs recovers,and the corresponding equation is y=2985.6ln（x）-4715.1,and its correlation coefficient R²=0.9499.Finally,the coat protein of Sr MV named p ET30a-Sr MV-CP was induced to express,then the corresponding antibody was prepared to connect with the synthetic quantum dots,and a biosensor for detecting Sr MV was constructed.The bio-receptor part of the sensor consists of specific antibodies against Sr MV-CP,which can detect the presence of the homologous antigen Sr MV in the solution.In the reaction,the donor-acceptor complex Sr MV Ab-Cd Te QDs+Sr MV CP-C QDs is generated based on the antigen-antibody molecule.Sr MV Ab-Cd Te QDs（donor）and Sr MV CP-C QDs（acceptor）came close,resulting in a significant decrease in the fluorescence emission intensity of Cd Te QDs.The attachment of antibody-antigen molecules is accomplished through several non-covalent interactions,this type of binding is not stable.In different antibody-antigen complexes,the antigen part can be replaced by free antigen molecules in solution.Therefore,adding free antigen to the solution to replace Sr MV CP-C QDs with free Sr MV CP will increase the fluorescence intensity of Sr MV CP-C QDs.The results of the standard addition experiment showed that the recovery rate was93%-103%,indicating that this analytical method can be used for the quantitative detection of Sr MV in sugarcane.The constructed biosensor was used to detect Sr MV in sugarcane,and the detection results were compared with the ELISA results,the detection results of the two methods were consistent.Nano-biosensors can detect samples within minutes,which is time-saving and simple compared to other methods.Therefore,this method is very advantageous in large-scale screening.