Construction Of Quantum Dots And Gold Nanoparticles-Based Methods For Biomarkers Detection In Vitro

In recent years,with the rapid development of nanotechnology and in vitro diagnostic techniques,preparation of multifunctional immune probe using nanomaterial,such as,quantum dots and gold nanoparticles,has become a hotspot in the field of in vitro diagnostics.With the emergence of nanoparticles of excellent physical and chemical properties,such as,quantum dots and gold nanoparticles,and it is expected to make a breakthrough in the field of disease detection,which is helpful to solve the shortcomings of traditional immunoassay technology.Therefore,in view of the existing problems in the diagnosis of diseases,such as complex operation,long detection time,lack of detection sensitivity and so on,we propose a quantum dot based immunochromatographic assay and an enzymeantibody dual labeled gold nanoparticles probes based fluorescent enzyme linked immunosorbent assay?FELISA?in this paper for rapid,sensitive and quantitative detection of biomarkers in organisms.Firstly,the core shell structure of CdSe quantum dots?QDs?were prepared,and the mainly factors that affect the optical properties of quantum dots were explored to realize the controllable synthesis.The QDs were modified with amphiphilic polymer PMAO,and the properties of QDs before and after modification were also investigated,the QDs fluorescent probes QDs-Ab₂ were prepared by activating the carboxyl group of QDs with EDC to couple with the free amino groups of antibody.The QDs-based immunofluorescence strips?QDs-IFS?were constructed,optimized the test strips with exploring the reaction conditions,and the performance of QDs-IFS was evaluated,and then the QDs-IFS was applied to the patient's serum.Secondly,gold nanoparticles?AuNPs?were prepared by sodium citrate,and the AuNPs labeled HAT immune probes were prepared by electrostatic adsorption.Optimization of the AuNP probes was carried out in terms of the particle size of gold nanoparticles,the ratio and dosage of proteins,and the concentration of probes were also discussed.A new type of fluorescent ELISA was developed with detection of AFP and HBsAg,and the fluorescent ELISA was applied to the serum of the patients.The experimental results showed that the prepared CdSe QDs were with high fluorescence quantum yield,uniform particle size and high crystallinity.The optical properties of QDs were well maintained,QDs-IFS has good specificity and sensitivity and excellent stability,and good results with preliminary detection of the serum of patients were obtained,showed great potential of the QDs-IFS in biomarker rapid quantitative detection.AuNPs were with uniform morphology,and the AuNP labeled HAT immune probes have immune enzymatic activity of antibody and the immune activity of thrombin,combined with Rhodamine₁₁₀ substrate,a new type of fluorescence ELISA was built up with good specificity and superhigh sensitivity,the detection sensitivity of AFP and HBsAg were 10^-8 ng/mL and 5*10^-4 IU/mL with good prospects in the field of biomarkers detection.