Photoelectrochemical Sensors Based On Functional Nanomaterials And Their Applications In Biological Detection

Early detection and treatment of diseases are of great significance for the healthy development of human beings.Therefore,biomarkers have been widely concerned by researchers as an important indicator for early diagnosis and prevention of diseases.Highly sensitive and highly selective detection methods occupy an important position in the practical application stage of biomarker analysis.In recent years,great progress has been shown based on the above studies.Furthermore,in order to further meet the requirements for the detection of trace target analytes,it is necessary to focus on the development of biomolecule detection methods with high selection,high sensitivity,and wide detection range.This paper is based on the design and development of functional optoelectronic nanomaterials,combined with signal amplification technology to build a high-performance photoelectrochemical?PEC?biosensing platform for achieving highly sensitive detection of biomarkers.The main research contents are as follows:?1?As a digestive enzyme,trypsin is the key to pancreatic exocrine regulation,and is considered as one of the most important biomarkers in clinical diagnosis.This work develops a convenient PEC sensing platform for quantitative detection of trypsin based on molybdenum disulfide nanosheets and titanium dioxide nanorod composites?MoS₂-TiO₂?.Due to the protein's insulation,apoferritin?APO?is immobilized on the surface of Mo S₂-Ti O₂/indium tin oxide electrode and affects the photocurrent response.When trypsin is present,it can decompose APO and restore the PEC signal to achieve the purpose of detecting trypsin.The linear range of the biosensor is 1-1000 ng·mL^-1,the detection limit is as low as 0.82 ng·m L^-1,and the practical application in serum samples has been successfully verified.?2?Bleomycin?BLM?is a class of antibiotics derived from natural glycopeptides and is widely used as an anticancer drug for various cancers.However,improper use of BLM can lead to some serious consequences in clinical applications.Here,a PEC biosensor is constructed based on a tungsten sulfide nanorod array grown on a titanium mesh?WS₂ NA/TM?and gold nanoparticles?Au NPs?as a composite material of PEC,combined with nanoenzyme-catalyzed bioprecipitation technology for sensitive detection of BLM.DNA₁?P1?and DNA₂?P2?are immobilized on Au/WS₂ and nanoenzyme silver nanoparticles/zinc-based metal organic framework?Ag/Zn MOF?,respectively.The Ag/Zn MOF-P2/BSA/P1-Au/WS₂ probes are prepared by a hybridization reaction between two DNAs.When BLM is present,BLM with Fe²⁺as a cofactor can specifically recognize and cleave the 5'-GC-3'active site of P2,which recover the photocurrent.The biosensor has a linear correlation in the range of BLM concentration from0.5 n M to 500 n M,and the detection limit is as low as 0.18 n M,which can realize highly sensitive detection of BLM.In addition,the recovery of BLM in human serum is better.?3?Prostate specific antigen?PSA?is very important for the early screening and diagnosis of related diseases.Therefore,it is urgent to develop a convenient and sensitive testing method to detect the activity of PSA.In this work,the cadmium sulfide nanorod array and cuprous oxide nanoparticle composites?CdS-Cu₂O NAs/TM?are used as photoactive materials to construct a PEC aptamer sensor for efficient and sensitive detection of PSA.The PSA is captured by the aptamer fixed on the surface of the material and reacts with holes,which enhances the photocurrent.The sensor shows excellent performance for PSA detection,with a linear range of0.1-100 ng·mL^-1 and a detection limit as low as 0.026 ng·m L^-1.The results of actual sample analysis are also satisfactory,proving that the sensor has broad application prospects.?4?Vascular endothelial growth factor 165(VEGF₁₆₅)overexpression or down-regulation is related to pathological blood vessels.Therefore,it is urgent to develop a highly sensitive and highly selective method to detect VEGF₁₆₅ for the early diagnosis of related cancers.Using Cu?OH?₂ as a precursor,the Cu₂O@Cu-MOF nanobelt arrays are successfully grown on copper mesh by using a one-step hydrothermal method.The PEC aptamer sensor is constructed based on the above nanoarray materials combined with rolling circle amplification and enzymatic biocatalytic precipitation technology to detect VEGF₁₆₅.The proposed PEC aptasensor demonstrated good performance with a linear range from 10 to 1×10⁸ fM and a detection limit down to 2.3 fM.The successfully constructed aptamer sensor not only provides a new path for sensitive determination of targets,but also extends the application of semiconductor@MOFs array materials in the field of PEC sensing.