Based On Nucleic Acid Isothermal Cycle And Gold Nanoparticle Signal Amplification Strategy, A Tumor Marker Light Signal Sensor Was Constructed

Cancer is one of the diseases that seriously endangers human health and has a high mortality rate in today’s society.The Studies have shown that the cure rate is closely related to early diagnosis and treatment.Tumor markers,as an important type of cancer diagnosis method,have attracting more attentions for their changes at the lesions prior to that of in morphocytology.However,the existing conventional diagnostic methods have problems of low specificity and poor sensitivity for tumor marker analysis.Therefore,it is urgent to develop new,efficient and sensitive methods for detection of tumor markers.In this paper,basing on fluorescence,dark field imaging and electrochemiluminescence technique,we have constructed three kinds of biosensig systems for the detection of tumor markers such as platelet-derived growth factor BB（PDGF-BB）,carcinoembryonic antigen（CEA）and Ramos cells.1.A smart aptamer sensing method was developed for high sensitive and selective PDGF-BB assay through target protein induced DNA molecules conformation changes.Combining nucleic acids isothermal recycling amplification strategies and highly-specific of aptamer recognition unit,the designed aptamer sensors shows a simple but powerful approach without multiple washing steps as well as precious implement.This strategy offers a simple,specific and efficient platform to quantify the target protein in low concentrate and is expected to be applied for other kinds of cancer-related proteins in a convenient way.2.we proposed a dual-potential electrochemiluminescence sensor for Ramos cell detection on the basis of two kinds of ECL-responding molecular and the ECL intensity increment of CdS with the surface plasmon resonance of Au.In this approach,AuNPs was deposited on FTO under cyclic voltammetry to bound with DNA1 through Au-S bound.After the hybridization of DNA1 and DNA2-functional Au-luminol,intensive ECL of luminol was detected in the presence of coreactant H₂O₂ at 4.5 V（vs SCE）.When the electrode was treated with Ramos-cell-containing solution,amount of DNA2-functionalized Au-luminol would separate from FTO,accompanying the decrease of luminol-generating ECL and the exposure of single strand DNA1.Finally,with the help of DNA3-Au-DNA4 and Au-DNA4,DNA5-modified CdS was attached to FTO for the formation of surperstructure.The reticulate structure could produce a new ECL signal of CdS at-1.25 V（vs SCE）.The selectivity and specificity of this dual-potential ECL sensor showed well performance and indicated great promise in averting false positive results in bioanalysis.3.we have demonstrated an antigen-induced AuNP dimers strategy for ultrasensitive detection of CEA on the basis of enumerating scattering light spots of AuNP dimers with dark-field microscope.The humanoid immunocomplex-triggered AuNP dimerization could effectively adjust the distance between nanoparticles and then enhance the plasmon coupling effect,resulting in the red-shift of scattering light which is distinguish in dark-filed microscope.With more sophisticated design,this strategy can be extended to analyze other kinds of biomolecular markers individually or simultaneously,and this method has a certain perspective and practicality in the quantitative analysis of clinical tumor markers.