Qingdao University

Xiaowen Jiang

Hui Jin

Rijun Gui

Yujiao Sun

Zejun Sun

A method for preparing a ratiometric electrochemical miR3123 aptasensor based on a copper-based metal-organic framework (Cu-MOF) composite doped with black phosphorus nanosheets (BPNSs) and thionine (TH) is provided. TH/Cu-MOF is prepared by reacting TH with Cu-MOF precursor, and BPNSs/TH/Cu-MOF is prepared by drop coating the BPNSs and drop coated onto an electrode. A ferrocene (Fc)-labeled single-stranded DNA aptamer is adsorbed on the BPNSs to prepare aptamer-BPNSs/TH/Cu-MOF. Target molecule miR3123 is bonded with the single-stranded DNA aptamer Fc-DNA, Fc-DNA is forced to escape from the BPNSs. Electrochemical signals of Fc are, therefore, weakened while TH signals are slightly affected. The ratiometric electrochemical miR3123 aptasensor is constructed by fitting a linear relationship between peak current intensity ratios I/Iand concentrations of the miR3123.

Method for preparing ratiometric electrochemical miR3123 aptasensor based on metal-organic framework composite

A method for preparing a nanohybrid used for ratiometric fluorescence and ratiometric electrochemical sensing simultaneously is provided. Surface-aminated (&#x2014;NH) SiOnanospheres encapsulating an electroactive material A or B are prepared and conjugated with surface-carboxylated (&#x2014;COOH) carbon dots (CDs) or gold nanoclusters (AuNCs) to prepare a conjugate, and the conjugate is conjugated with a DNA aptamer terminated with &#x2014;NH. Ions or biomolecules are added to two types of DNA-conjugate dispersions, and ratiometric florescence sensing is realized by fitting the linear relationship between ratiometric fluorescent peak intensity I/Iand a specific ion concentration or a specific biomolecule concentration. A-SiO@CDs-DNA is attached to the surface of a gold electrode based on a DNA terminal &#x2014;SH and Au&#x2014;S bonding; B&#x2014;SiO@AuNCs-DNA and ions or biomolecules are added, and ratiometric electrochemical sensing is realized by fitting the linear relationship between the specific ion concentration or the specific biomolecule concentration and the ratiometric current peak intensity I/I.

Method for preparing nanohybrid used for ratiometric fluorescence and ratiometric electrochemical sensing simultaneously

A method for preparing an upconversion-luminescence flexible hybrid membrane for visual detection of tumor markers is provided. Metal ion doped black phosphorus quantum dots (M-BPQDs) are prepared by adopting ultrasonic and solvothermal processes; mesoporous SiOgrows on the surfaces of the M-BPQDs and amination modification is performed; the M-BPQDs are connected with carboxylated single-stranded DNA1; receptor molecules enter pores; single-stranded DNA2 aptamers and the DNA1 are combined due to base complementation to encapsulate receptors in the pores; and an M-BPQDs probe is prepared. DNA1 terminal-SH and a composite membrane are formed by assembling polymethyl methacrylate-polyimide-gold nanoparticles in a layer-by-layer manner bound by Au&#x2014;S bonds, and the membrane and the probe are connected to construct the flexible hybrid membrane. The new flexible hybrid membrane is simple and inexpensive to prepare and is highly sensitive.

Method for preparing upconversion-luminescence flexible hybrid membrane for visual detection of tumor marker

A method for preparing a ratiometric fluorescent probe for cymoxanil based on a double-emission quantum dot-silver nanoparticle complex, wherein, the double-emission carbon quantum dots and the silver nanoparticles are prepared, and the inner filter effect occurring between the double-emission carbon quantum dots and the dispersed silver nanoparticles causes the blue fluorescence quenching of the carbon quantum dots. However, the specific binding of cymoxanil to silver nanoparticles causes the silver nanoparticles to accumulate, and then the inner filter effect occurring between the double-emission carbon quantum dots and the dispersed silver nanoparticles causes the green fluorescence quenching of carbon quantum dots. In this regard, the linear relationship between the intensity ratio of two fluorescent emission peaks of carbon quantum dots and the molar concentration of cymoxanil is established, and the ratiometric fluorescent probe for cymoxanil is constructed.

Method for preparing ratiometric fluorescent probe for cymoxanil based on double-emission quantun dot-silver nanoparticle complex

A method for preparing a ratiometric electrochemical aptasensor for vanillin based on an aptamer-gold nanoparticle-ferrocene-Ketjenblack-ZIF-8 nanocomposite modified electrode includes, dripping ZIF-8 nanocomposite doped with ferrocene and Ketjenblack on the surface of the bare glassy carbon electrode, and immersing this modified electrode in the chloroauric acid solution. The cyclic voltammetry is employed to scan and electrodeposit gold nanoparticles to obtain the gold nanoparticle-deposited ZIF-8 nanocomposite. The aptamer of vanillin is attached to gold nanoparticles via Au&#x2014;S bonds to construct an aptamer-coupled nanocomposite sensing platform. Then, the electrochemical curves in the presence of different vanillin concentrations are measured, the linear relationship between the ratios of the current peak intensities of ferrocene and vanillin and the molar concentrations of vanillin is fitted, and the ratiometric electrochemical aptasensor for vanillin is constructed.

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Qingdao, China

Xiaowen Jiang