Detection Of Thrombin By An Electrochemical Sensor Based On Metal-organic Coordination Compounds

Electrochemical biosensor technology has the advantages of simple operation,good selectivity,high sensitivity,low detection cost,etc.It has been widely used in biomedicine,environmental monitoring,food,medicine and other fields.The rapid detection of human body components using electrochemical biosensor technology is one of the most attractive research topics in current medicine.Metal-organic coordination compounds refer to complexes formed by metal ions and organic ligands through intermolecular forces such as coordination bonds and hydrogen bonds,including small-molecule coordination compounds and metal organic porous materials.It is different from ordinary organic polymers and inorganic polymers.Because it contains organic and inorganic components,it has both characteristics of organic compounds and inorganic compounds.At the same time,metal organic coordination compounds have a regulatable composition and excellent thermal stability,good charge selectivity,electrochemical stability and easy to modify features.Therefore,metal organic coordination materials have been rapidly developed in the field of electrochemistry and applied to various electrochemical detections.Among them,electroactive metal-organic coordination compounds have become advanced materials for electrochemical sensors as nanocarriers and redox mediators.At present,only a few articles have been reported.In this paper,two kinds of copper metal organic coordination compounds[Cu2(N3,N9-Ade)4(H2O)2·5H2O and Cu24(5-NH2-mBDC)24(DMF)12(H2O)]with amino groups have been synthesized according to references for the detection of thrombin as a signal source,the main use of metal organic coordination compounds to form electrochemical sensors,and further catalyzed oxidation of H2O2 to achieve further amplification of the signal in the buffer solution.The above two materials contain an independent-NH2,which can bind to the gold nanoparticles and thus can bind DNA.The DNA-binding material is applied to the detection of thrombin,and the purpose of detecting thrombin is achieved by electrochemically detecting the signal of the material.The main contents are as follows:1.Electrochemical biosensor for the detection of thrombin based on gold nanoparticles modified Cu2(N3,N9-Ade)4(H2O)2·5H2O(Cu-Ade)catalyzed hydrogen peroxide signal amplification,this is the first time that Cu-Ade has been combined with DNA to make an electrochemical biosensor to detect thrombin.In this paper,Cu-Ade with-NH2 was synthesized and characterized by X-ray diffraction(XRD),which confirmed the successful synthesis of Cu-Ade.The synthesized material was combined with gold nanoparticles because gold nanoparticles interact with-NH2 to produce AuNPs/Cu-Ade.Finally,AuNPs/Cu-Ade bound to NH2-DNA(S3)to generate S3/AuNPs/Cu-Ade.Based on Cu-Ade-free enzyme-catalyzed amplification,Cu-Ade was first bound to DNA to detect thrombin.Firstly,complementary sequence of aptamer(S1)is connected to the gold electrode.Next,the aptamers S2 of thombin and S1 are complementarily paired.Subsequently,a certain amount of thrombin is added to the electrode,and the added thrombin can swell the complementary paired aptamer.S1 was revealed.Finally,the dispersion of S3/AuNPs/Cu-Ade was dropped onto the gold electrode,and S3 was complemented with naked S1.The resulting electrode is used as the working electrode,and further signal amplification was achieved by sweeping the cyclic voltammetry of Cu-Ade in the electrolyte containing 1 mM H2O2 to oxidize H2O2.With this design,the thrombin biosensor showed a good linear range from 0.1 nM to 31.6 nM and a detection limit of 0.068 nM.This new method opens the way for better detection of thrombin proteins.2.Electrochemical biosensor for detecting thrombin based on gold nanoparticle modified Cu24(5-NH2-mBDC)24(DMF)12(H2O)12·(DMF)32(EtOH)6-(H2O)12(MOP-15)catalytic hydrogen peroxide signal amplification,this is the first time that MOP-15 has been combined with DNA to make an electrochemical biosensor to detect thrombin.In this paper,MOP-15 with-NH2 was synthesized according to the reference and characterized by X-ray diffraction(XRD),which proved the successful synthesis of MOP-15.The synthesized material was combined with gold nanoparticles because gold nanoparticles interact with-NH2 to produce AuNPs/MOP-15.Finally,AuNPs/MOP-15 bound to DNA to generate S3/AuNPs/MOP-15.Firstly,S1 is connected to the gold electrode.Next,the aptamers S2 of thrombin and S1 are complementarily paired.Subsequently,a certain amount of thrombin is added to the electrode,and the added thrombin can swell the complementary paired aptamer.S1 was revealed.Finally,the dispersion of S3/AuNPs/MOP-15 was dropped onto the gold electrode,and S3 was complemented with naked S1.The resulting electrode is used as the working electrode,and further signal amplification was achieved by sweeping the cyclic voltammetry of MOP-15 in the electrolyte containing 1.5 mM H2O2 to oxidize H2O2.With this design,the thrombin biosensor showed a good linear range from 0.1 nM to 100 nM and a detection limit of 0.048 nM.This new method opens the way for better detection of thrombin proteins.