Detection And Analysis Of Biomolecules Based On Room-temperature Phosphorescence Of Mn-ZnS Quantum Dots

Research on biomolecules allows us to understand the pathogenesis of some diseases from the perspective of genes.Designing molecular probes assists the in-vivo detection of trace-level biomolecules,theoretically underlies the occurrence of diverse diseases,and provides theoretical guidance for effective dose control in clinical medicine.Nano-molecular probes are featured by water solubility,photochemical stability,and large specific surface area,and thus improve the detection performance of traditional biomolecular probes.Besides these advantages,room-temperature phosphorescence(RTP)quantum dots(QDs)nanoprobes also avoid the interferences from the background fluorescence or scattering light of biological fluids.Thus,RTP QDs nanoprobes are more precise in detection of biological samples.In this study,by utilizing the optical properties of RTP QDs,we used nanoprobes to detect some major biomolecules(DNA,cytochrome C,chitosan oligosaccharide).The main contents are listed below.(1)Nanohybrids were formed from 3-mercaptopropionic acid(MPA)-coated Mn-doped ZnS quantum dots(QDs)and methylene blue(MB)via electrostatic interaction,and then used into detection of trace DNA.The principle of detection is as follows: MB binds with Mn-doped ZnS QDs via electrostatic interaction,and then quenches the RTP of the QDs through photoinduced electron-transfer(PIET).After the addition of DNA,MB binds with DNA through intercalation and electrostatic interaction,and desorbs from the surfaces of Mn-doped ZnS QDs,which recovers the RTP of the QDs.On this basis,a DNA detection method based on the properties of RTP was set up.This method shows detection range of0.2-20 mg/L,and a detection limit of 0.113 mg/L.Since this method is based on the RTP of QDs,it is not interfered by the background fluorescence or scattering light in vivo,and thus,avoids complex sample pretreatment.Thus,this method is very feasible for detection of traceDNA in biofluids.(2)The MPA-capped of Mn-doped ZnS QDs(QDs)were prepared using water phase synthesis.Based on the room temperature phosphorescence properties of QDs,we estabilished a sensitive and rapid method of detecting Cytochrome C(Cyt C).The detection method utilizes the electron transfer process between QDs and Cyt C,so that the RTP of QDs is quenched to detect the content of Cyt C.In phosphate buffer solution with pH 7.4,Cyt C enabled to quench the phosphorescence of Mn-doped ZnS QDs at 590 nm through electrostatic interaction.The quenching phosphorescence intensity had a good linear relationship with the concentration of Cyt C,the detection range from 0.1 to 10 ?M(correlation coefficient R=0.990)and from 10 to 40 ?M(correlation coefficient R=0.991),and a detection limit of 0.062 ?M was obtained.The method is very feasible for detection of trace Cyt C.(3)A new method for the accurate and efficient detection of chitosan oligosaccharide content was established by electrostatic interaction between the MPA-capped of Mn-doped ZnS QDs and chitosan oligosaccharide(COS).The detection method utilizes the interaction between QDs and chitosan oligosaccharide(COS),so that the RTP of QDs is enhanced to detect the content of COS.In phosphate buffer solution with pH 7.4,COS enabled to enhance the phosphorescence of Mn-doped ZnS QDs at 590 nm.The enhancing phosphorescence intensity had a good linear relationship with the concentration of COS,the detection range from 0.06 to 10 ?g/mL(correlation coefficient R=0.988),and a detection limit of 0.028?g/mL was obtained.The method is very feasible for detection of trace COS.Generally,by using the RTP properties of ODs,we used novel nanoprobes to detect the concentrations of some important biomolecules(DNA,cytochrome C,chitosan oligosaccharide).This study will theoretically underlie the research on molecular biology and the occurrence of diverse diseases.