Construction And Application Of Ionic Iridium Complex Sensitized Photoelectrochemical Sensors

In the current environment where the level of medical care is rapidly improving,cancer is still a disease with a relatively high fatality rate.Therefore,the detection of cancer markers is different in the early screening,early diagnosis,curative effect monitoring and postoperative prognosis of cancer.Ordinary meaning.Photoelectrochemical sensing is a novel quantitative analysis method,which has the advantages of fast,simple,sensitive,and wide detection range.The application of photoelectrochemical sensors to the detection of cancer markers is a very promising research topic.In this paper,iridium complexes[Ir(4epbt)₂(phen)]⁺(PF₆^-),[Ir(4epbt)₂(dipy)]⁺(PF₆^-)quantum dots CdTe,CdTe Se,and optimized photoelectric sensitization effect between iridium complexes and corresponding quantum dots,and prepared superparamagnetic Fe₃O₄,Fe₃O₄@Si O₂,and finally constructed a good selectivity and high sensitivity The photoelectrochemical biosensor realizes the detection of microRNA-10b and microRNA-21 in complex actual samples.The main tasks are as follows:(1)Using o-aminothiophenol as raw material,an iridium complex with N^N ligand(1,10-phenanthroline)and N^N ligand(bipyridine)was designed and synthesized.The product was synthesized during the experiment,and the structure of the product was characterized by IR,¹HNMR,and ¹³CNMR.The photoelectric performance of the photoelectric signal sensitization between[Ir(4epbt)₂(phen)]⁺(PF₆^-)and CdTe quantum dots was studied and optimized by the photoelectrochemical workstation.Under the condition of-0.05 V bias potential,[Ir(4epbt)₂(phen)]⁺(PF₆^-)can amplify the signal of CdTe quantum dots by 5.5 times.Under the condition of 0.1 V bias potential,[Ir(4epbt)₂(dipy)]⁺(PF₆^-)can The signal of CdTe Sequantum dots was amplified by 3.8 times,and an excellent sensitization effect was achieved.(2)Developed a photoelectrochemical biosensor with close to zero background noise for ultra-sensitive microRNA-10b detection based on DNA tetrahedron(TET)as a nanocarrier to effectively immobilize CdTe quantum dots,CdTe QDs-[Ir(4epbt)₂(phen)]⁺(PF₆^-)(CdTe QDs-Ir)is used as a signal probe.And through entropy-driven DNA amplification and superparamagnetic Fe₃O₄@Si O₂ particles,the selectivity and sensitivity are further improved.The photoelectrochemical biosensor has a low detection limit of 0.34 amol L^-1 for miRNA-10b in a wide linear range from1 amol L^-1 to 100 fmol L^-1.(3)A triple signal amplification based on cascade entropy drive and iridium complex sensitized CdSeTe was constructed for the ultra-sensitive detection of miRNA-21.Firstly,the target miRNA-21 is converted into a large amount of output DNA(S)by entropy drive,and then the DNA(S)is introduced into the next amplification system by magnetic separation.In this amplification system,a large number of quantum dots are connected.The DNA strand AP1 and DNA strand AP2 of CdSeTe grow into a trigeminal tree structure through base complementary pairing,and a DNA trigeminal tree structure with abundant cutting sites is obtained.At this time,[Ir(4epbt)₂(dipy)]⁺(PF₆^-)is inserted into the double strand of DNA to obtain a photoelectrochemical sensor with excellent performance.This triple signal amplification photoelectrochemical sensor quantitatively detects miRNA-21 in a wide linear range from 10 amol L^-1 to 1 pmol L^-1,and shows a low detection limit of 3.6 amol L^-1.