Construction Of Photoelectric Sensor Based On Inorganic Nanomaterials And Its Application In Tumor Detection

Long non-coding RNAs（lncRNAs）are a new type of regulatory RNAs with a length of more than 200 nucleotides and almost no protein coding ability.They participate in the biological process of gene silencing or activation through various mechanisms（e.g.,epigenetic pathways,chromatin modification,direct interaction with DNA,RNA or protein）.Researchers continue to discover that novel lncRNAs are used as tumor suppressor genes or oncogenes in the pathogenesis of cancers（such as colorectal cancer,breast cancer,and gastric cancer）.Overexpression and underexpression of lncRNA may be closely related to the occurrence of cancer.Therefore,lncRNA can be used as a biomarker for clinical diagnosis.Detection of lncRNA is of great significance for prevention,treatment and identification of disease prognosis.However,there are few reported methods for the detection of lncRNAs,so it is necessary to develop a method with high sensitivity,high accuracy,low cost and simple operation.When photoelectric materials are excited by light,they will generate and transmit electrons,thereby converting light signals into electrical signals.Since the excitation signal and the detection signal are different types of signals,the interference of the background signal on the detection can be effectively reduced,thereby improving the sensitivity of the detection method.Photoelectric chemistry（PEC）sensors based on photoelectric materials have attracted extensive attention in the field of biological analysis due to their unique advantages such as high sensitivity,low background signal,easy miniaturization,low cost and simple operation.The photoelectric activity of the photoelectric material modified on the electrode surface is crucial to the performance of the photoelectric sensor.Common photoelectric materials include inorganic semiconductor materials,organic semiconductor materials,and composite materials.For a single material,the high electron-hole recombination rate leads to low photoelectric conversion efficiency,and the coupling of two materials with different photoelectric activities can promote charge separation,thereby improving the photoelectric conversion efficiency.Based on this,we constructed a photoelectrochemical sensor using composite materials as photoelectric conversion materials to detect lncRNA related to colorectal cancer.The research content of the paper is as follows:The first chapter is the introduction.Firstly,the significance of lncRNA is introduced.Then,the research status of common nucleic acid detection methods and lncRNA detection methods are introduced.Finally,the photoelectrochemical sensors related to this paper are introduced,including the working mechanism of the photoelectrochemical sensors,the classification and application of the photoelectrochemical sensors.In the second chapter,a photoelectrochemical sensor using Mo:Bi VO₄ as the photoelectric conversion material was constructed to detect three kinds of lncRNA（L1,UCA1 and AF079515）related to colorectal cancer.Firstly,Mo:Bi VO₄ was successfully prepared and characterized by morphology,crystal form,optical properties and photoelectric properties.Then,the Mo:Bi VO₄electrode was modified with probe-L1,probe-UCA1 and probe-AF079515,respectively.Through the principle of base complementary pairing,the probes could successfully capture the corresponding lncRNAs.Due to the insulative properties of lncRNAs,the quantitative analysis of lncRNAs was performed according to the photocurrent intensity.The sensor detects three types of colorectal cancer-related lncRNAs respectively,improving the accuracy of tumor detection.In addition,the sensor has the advantages of high sensitivity,good stability,low cost and easy operation.The third chapter is the preparation of 1D/2D Cd S-Ti₃C₂T_x Mxene composite materials for photoelectrochemical sensors.Firstly,one-dimensional Cd S nanowires and Ti₃C₂T_x nanosheet were prepared and characterized by Zeta potential,morphology and crystal form to prove that the materials have been successfully prepared.Then we prepared Cd S nanowires and Ti₃C₂T_xcomposites,and analyzed their morphology,crystal form and optical properties to prove that the composite materials were successfully synthesized.Finally,we tested its photoelectric properties.Finally,we tested its photoelectric properties.The synthesis procedure of this material is simple and has good photoelectric properties...