Electrochemical Biosensing Method For MicroRNA Based On Bivalent Recognition In The Nanochannels

Electrochemical biosensing can convert specific interactions between biological molecules into highly sensitive electrochemical signal,which has become a hot topic in the field of electroanalysis.In this paper,three new electrochemical detection methods based on dual-interface electrochemical biosensing platform were established for mi RNA-21 and let-7a by using the nanochannels as the recognition interface and electrode as the detection interface,respectively.The study not only provides new principles for electrochemical biosensing,but also expands the application range of MoS₂ nanosheets.The paper is divided into four chapters,and the author’s main research includes the following three aspects:1.A novel electrochemical biosensing method based on the sensitivity enhancement strategy of the bivalent recognition-induced nanoparticles in nanochannels was established by monitoring the change of MB concentration with electrochemical-treated MoS₂ nanosheets modified electrode.The method for mi RNA-21 detection exhibited a linear range of 0.1fmol·L^-1 to 1 nmol·L^-1 with the detection limit of 0.03 fmol·L^-1 and could be used for the detection of mi RNA-21 in the serum.2.A novel ratiometric electrochemical biosensing method based on spherical DNAzyme（s DNAzyme）-catalyzed deposition at both inner and outer surfaces of nanochannels was established by monitoring the ratio of peak current of MB and Fc(I_MB/I_Fc)with the electrode modified with the ultrasonic-prepared Fc-MoS₂ nanocomposites.The method for let-7a detection exhibited a linear range of 0.05 fmol·L^-1 to 10 pmol·L^-1 with the detection limit of0.01 fmol·L^-1 and could be successfully applied to the detection of let-7a in serum and cancer cells.3.A novel electrochemical biosensing method based on the intermolecular G-quadruplex on the outer surface of MoS₂ hybrid nanochannels was established by monitoring the change of K₃[Fe（CN）₆]concentration with a glassy carbon electrode.The method for let-7a detection exhibited a linear range of 0.1 pmol·L^-1 to 10 nmol·L^-1 with the detection limit of 0.06pmol·L^-1 and could be used for the detection of let-7a in the serum.