| At present,cancer is one of the most important factors leading to the increasing death rate in China.Early diagnosis and treatment are the most effective way to treat cancer.The detection of tumor markers is of great significance in diagnosis and prognosis.The photoelectrochemical?PEC?sensor based on nanomaterial has the advantages of low background signal and high sensitivity,which is widely used in tumor markers and other medical diagnosis fields.As one of the commonly used semiconductor nanomaterials,bismuth sulfide?Bi2S3?has good stability,high photoconductivity and strong light absorption performance,making it widely utilized in the fields of PEC,photocatalysis,lithium ion battery and medical diagnosis.In this paper,we have modified Bi2S3 by different methods to enhance PEC activity of the sensor,found suitable electronic donors and designed novel sensor construction strategies to build sensitive and novel PEC sensors,and further explored their application in tumor marker detection.1.A novel label-free photoelectrochemical sensor based on SnO2/NCQDs/Bi2S3composite for detection of NT-proBNPThe unique hierarchical mesoporous SnO2 microflower and nitrogen-doped carbon quantum dots?NCQDs?combine with Bi2S3 nanoparticles to construct a sensor with excellent photocurrent signal.NCQDs is utilized to modify Bi2S3 to enhance the PEC activity of the SnO2,and contributed to the in-situ growth of Bi2S3 nanoparticles on the surface of the SnO2 materials.Under the stimulation of visible light and ascorbic acid?AA?as an efficient electron donor,the NCQDs and Bi2S3 co-sensitized mesoporous SnO2 microflower?SnO2/NCQDs/Bi2S3?modified indium tin oxide?ITO?electrode exhibits an excellent photoelectric signal arriving at around 150?A,which enables the ultrasensitive detection of N-terminal forebrain natriuretic peptide?NT-proBNP?.When the concentration range is 0.01-50 ng/mL,the photocurrent signals decrease linearly with the logarithm of NT-proBNP concentration with a detection limit of 3.7 pg/mL?S/N=3?.Furthermore,the novel PEC sensor shows perfect selectivity,stability and reproducibility,which proves promising applications in the sensing and clinical diagnosis of cardiac disease.2.A photoelectrochemical sensor for SCCA detection based on BiOBr/Bi2S3heterostructures via self-sacrificial synthesis methodA novel PEC sensor based on BiOBr/Bi2S3 heterostructures is fabricated to detect squamous cell carcinoma antigen?SCCA?.Bi2S3 nanoparticles form on the BiOBr microflowers by the self-sacrificial synthesis method based on the facile reaction between BiOBr and S2-ions.The BiOBr/Bi2S3 heterostructures exhibit excellent PEC activity,when AA is employed as perfect electron donor.The photocurrent intensity of BiOBr/Bi2S3modified ITO electrode arrives at around 20?A,which is approximately 30 times than that of pure BiOBr.Dopamine forms easily polydopamine film via self-polymerization on the surface of BiOBr/Bi2S3 heterostructures to immobilize SCCA antibody.Under the optimal condition,the PEC sensor realizes the ultrasensitive determination of SCCA.With the SCCA concentration in the range of 0.001-75 ng/mL,the specific binding between SCCA and antibody lead to the linearly decrease of photocurrent signal with a low detection limit of 0.3pg/mL?S/N=3?.The facilely constructed PEC sensor has promising practical application in photocatalysis,analytical detection and biosensor,etc.3.A signal-off type photoelectrochemical sensor for the ultrasensitive detection of procalcitonin:Ru?bpy?32+and Bi2S3 co-sensitized ZnTiO3/TiO2 polyhedra as matrix and dual inhibition by SiO2/PDA-AuA signal-off type PEC sensor based on Ru?bpy?32+and Bi2S3 co-sensitized ZnTiO3/TiO2polyhedra as matrix and SiO2/PDA-Au as the label of second antibody is proposed for the sensitive detection of procalcitonin?PCT?.The hollow ZnTiO3/TiO2?ZTCHS?is prepared by hydrothermal method to enhance the utilization of visible light comparing with pure ZnTiO3or TiO2.The unique structure endows large specific surface areas and satisfying load capacity to ZTCHS.Ru?bpy?32+and Bi2S3 are utilized to co-sensitize ZTCHS to further strengthen the PEC performance of ZTCHS.It is interesting that the dual-inhibition effects of SiO2/PDA-Au further enhance the sensitivity of proposed PEC sensor.On the one hand,the steric hindrance of SiO2/PDA effectively restricts electron transfer.On the other hand,Au nanoparticles absorb visible light to compete with the matrix material.Based on the above aspects,the proposed signal-off type PEC sensor possesses a wide linear range?0.0001 ng/mL-100 ng/mL?and low detection limit?about 0.03 pg/mL,S/N=3?,demonstrating the promising application of PEC sensor in analysis fields.4.Cardiac troponin I photoelectrochemical sensor:{Mo368}as electrode donor for Bi2S3and Au co-sensitized FeOOH compositeA suitable electron donor,which guarantees the stability of the whole system,is considered as the driving force of the PEC sensor.Nowadays,searching appropriate electron donor is still one of the orientations to explore in the field of sensor.Na48[H496Mo368O1464S48]·ca.1000H2O(abbr.{Mo368}),as a type of polyoxometalate,has perfect morphology,definite size and unique electronic property.Due to the prominent water solubility,{Mo368}usually releases small cations and exists as large anions in the ultrapure water.The interesting property endows{Mo368}with excellent reducibility,which provides great feasibility to become an outstanding electron donor.In addition,FeOOH prepared through a simple operation owns high adsorption capacity,which ensures the fastness of other materials.Subsequently,the Bi2S3 and Au nanoparticles are utilized to co-sensitize FeOOH.The narrow band-gap and unique noble metal properties enhance the light-harvesting capability and photoelectric conversion efficiency.Combined with the specificity recognition of antigen and antibody,a novel PEC sensor is constructed with a wide detection range of?1.00 pg/mL-100 ng/mL?and low detection limit?0.76 pg/mL?,which achieves the sensitive detection of cardiac troponin I in early diagnosis of cardiovascular disease. |
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