| Electrochemical biosensors are devices that convert the concentration of biological substances into electrical signals.In recent years,they have received extensive attention in the fields of clinical,medical and environmental fields.MicroRNA is a non-coding RNA molecule,which plays an important role in biological growth and development,proliferation and differentiation,organ development and so on.Protein is an essential component of living organisms,participating in various physiological reactions in the body,regulating its activities and promoting metabolism.Therefore,the use of electrochemical biosensing platforms for rapid and sensitive detection of these biomolecules has great research value.We combined oligonucleotides with two-dimensional nanomaterials to construct electrochemical biosensors for sensitive and specific detection of proteins and microRNAs.The main research contents are as follows:?1?Sulfur-doped graphene was prepared and used as a electrode modified material.Two hairpin RNA strands?HP1 and HP2?were designed.Firstly,HP1 was immobilized on the surface of electrode.Then HP2 and streptavidin-labeled alkaline phosphatase?SA-ALP?were applied on the electrode surface.When the target protein was present,the electrochemical signal degreased,and a new method for detecting thrombin was established accordingly.The new method showed a linear range of1×10-11-2×10-10 mol/L and a detection limit of 2.76×10-12 mol/L.?2?Nitrogen-phosphorus co-doped graphene oxide was synthesized and used as electrode modified material.The thrombin electrochemical sensor was constructed with tetrahedral DNA probe and rolling circle amplification technology?RCA?.The developed sensor had the characteristics of high stability and selectivity.The linear range was 1×10-13-1×10-7 mol/L,and the detection limitwas 3.53×10-14 mol/L?S/N=3?.The method can be used for reall sample detection.?3?MoSe2 nanospheres were synthesized by using SiO2 nanospheres as template.The gold nanoparticles were immobilized on the MoSe2 nanospheres modified electrode and then a novel electrochemical sensor was fabricated based on hybridization chain reaction for sensitive detection of microRNA.The linear range of new method was 1×10-16-1×10-10 mol/L with a detection limit of 0.016 fmol/L.The developed method showed the advantages of high sensitivity,good selectivity and good reproducibility,and could be used for real sample detection. |
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