Construction Of Photoelectrochemical Sensors Based On Organic Conjugated Semiconductor Materials And Tumor Markers

As one of the most advanced bioanalysis technologies,photoelectrochemical bioanalysis technology has been widely used due to its advantages of simple operation,fast response,low cost,low background,and high sensitivity.Up to now,photoelectrochemical bioanalysis technology has become a valuable tool for detecting the sensitivity and specificity of various biochemical species.The detection signal?electricity?and excitation source?light?of the photoelectrochemical biosensor are separated,resulting in a greatly reduced background signal during detection,making it more sensitive than traditional electrochemical methods.In the construction of biosensors,nanomaterials are used to improve the basic analysis characteristics of biosensors,such as response time,detection limit,sensitivity,selectivity,linear detection range,reproducibility and stability.In addition,when constructing a photoelectrochemical sensor,coupling a small-bandgap semiconductor with a large-bandgap semiconductor can effectively increase the absorption range of visible light,promote the separation of photocarriers,and suppress electron-hole recombination,thereby generating a strong photocurrent signal.In this paper,the inorganic semiconductor nanomaterials larger specific surface area and the advantages of high extinction coefficient and different organic semiconductor electron configuration,wide range of absorption and high absorption efficiency,combining the advantages of at the same time introduced a simple and efficient strategy of signal amplification,constructed for detecting different target biological sensors,and implements the sensitive detection of target.Mainly carried out research work in the following aspects:?1?A novel composite optoelectronic material g-C₃N₄/PFO?CN/PFO?was studied,combined with different signal amplification strategies,a sensitive and efficient DNA detection method for human type I T cell lymphovirus type I?HTLV-I?was designed.First,a simple?-?stacking method was used to synthesize the CN/PFO heterojunction structure,which provided a stable and strong photocurrent response for the created photoelectric biosensor.Second,?-Exo assisted target cycling and hybrid chain reaction?HCR?amplification were designed to increase sensitivity,while introducing alkaline phosphatase?ALP?at multiple biotin sites provided by double-stranded DNA to catalyze the dephosphorylation of phospho-L-ascorbic acid trisodium salts?AAP?to form large amounts of electron donor ascorbic acid?AA?.Based on the above principles,a sensitive and efficient photoelectrochemical sensor was constructed to achieve quantitative detection of HTLV-1 DNA.?2?A photochemical biosensor for template DNA detection was designed by combining co-sensitization and peroxidase catalysis.The TCPP/CdTe nanocomposite is used as a photosensitizer at the end of the hairpin structure to form a co-sensitized structure with the base material.At this time,the sensor system has a large photocurrent signal.When the target DNA is added and incubated,the hairpin structure will be opened,and then the change of the distance between the co-sensitivity reagents causes the co-sensitivity phenomenon to disappear,and the photoelectric signal decreases accordingly.At the same time,the G-quadruplex nucleic acid domain labeled in the hairpin structure will capture heme to form an enzyme that can catalyze the decomposition of hydrogen peroxide,and efficiently catalyze the decomposition of the electron donor in solution,causing the photocurrent signal to decrease again.This dual-signal photoelectrochemical biosensor realizes highly sensitive detection of specific DNA and has been successfully used in the determination of actual samples.