title: Enhanced Photoelectrochemical Proximity Assay for Highly Selective Protein Detection in Biological Matrixes.
abstract: This work proposes the first photoelectrochemical proximity assay (PECPA) method via the sensitization of CdTe quantum dots (QDs) on photoelectrochemical response of ITO/TiO2/CdS electrode for highly selective and sensitive detection of proteins. This detection was performed on a sensing interface formed via the hybridization of capture DNA immobilized on ITO/TiO2/CdS electrode with labeled antibody-DNA (DNA-Ab1). Upon the recognition of Ab1 to target protein, the immunocomplex of DNA-Ab1, target, and the detection antibody-DNA (DNA-Ab2) was formed, which led to the proximity hybridization of the DNA in DNA-Ab2, capture DNA, and signal DNA-CdTe QDs, and brought CdTe QDs to the ITO/TiO2/CdS electrode to produce a sensitized photocurrent. The photocurrent intensity increased with the increasing concentration of the specific target protein. Using insulin as a target, this sensitized method showed a detectable range of 10 fM to 10 nM and a detection limit of 3.0 fM without the need of a washing step. It possessed high selectivity and good accuracy for detection of proteins in biological matrixes. This method is extremely flexible and can be extended to varieties of protein targets.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, P.R. China.|School of Chemistry and Chemical Engineering, Shanxi University , Taiyuan 030006, P.R. China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210023, P.R. China.
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D019187:Cadmium Compounds / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D061925:Immobilized Nucleic Acids / Q000737:chemistry / Q000378:metabolism; D007118:Immunoassay; D007328:Insulin / Q000032:analysis*; D057230:Limit of Detection; D009693:Nucleic Acid Hybridization; D045663:Quantum Dots / Q000737:chemistry*; D013691:Tellurium / Q000737:chemistry; D017971:Tin Compounds / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
chemical_list: D000906:Antibodies; D019187:Cadmium Compounds; D061925:Immobilized Nucleic Acids; D007328:Insulin; D017971:Tin Compounds; C009495:titanium dioxide; C109984:indium tin oxide; D014025:Titanium; D013691:Tellurium; C028337:cadmium telluride