title: Photoelectrochemical biosensor using enzyme-catalyzed in situ propagation of CdS quantum dots on graphene oxide.
abstract: An innovative photoelectrochemical (PEC) biosensor platform was designed based on the in situ generation of CdS quantum dots (QDs) on graphene oxide (GO) using an enzymatic reaction. Horseradish peroxidase catalyzed the reduction of sodium thiosulfate with hydrogen peroxide to generate H2S, which reacted with Cd(2+) to form CdS QDs. CdS QDs could be photoexcited to generate an elevated photocurrent as a readout signal. This strategy offered a "green" alternative to inconvenient presynthesis procedures for the fabrication of semiconducting nanoparticles. The nanomaterials and assembly procedures were characterized by microscopy and spectroscopy techniques. Combined with immune recognition and on the basis of the PEC activity of CdS QDs on GO, the strategy was successfully applied to a PEC assay to detect carcinoembryonic antigen and displayed a wide linear range from 2.5 ng mL(-1) to 50 μg mL(-1) and a detection limit of 0.72 ng mL(-1) at a signal-to-noise ratio of 3. The PEC biosensor showed satisfactory performance for clinical sample detection and was convenient for determining high concentrations of solute without dilution. This effort offers a new opportunity for the development of numerous rapid and convenient analytical techniques using the PEC method that may be applied in the design and preparation of various solar-energy-driven applications.
authors.affiliation: Jiangsu Collaborative Innovation Center of Biomedical Functional Materials and Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing, 210023 Jiangsu, People's Republic of China.
authors.forename: Xianxiang
authors.initials: X
authors.lastname: Zeng
authors.forename: Wenwen
authors.initials: W
authors.lastname: Tu
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Jianchun
authors.initials: J
authors.lastname: Bao
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Dai
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D019187:Cadmium Compounds / Q000737:chemistry*; D002272:Carcinoembryonic Antigen / Q000097:blood; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006108:Graphite / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000032:analysis; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry*; D055668:Photochemical Processes; D045663:Quantum Dots / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D002272:Carcinoembryonic Antigen; D004800:Enzymes, Immobilized; D013440:Sulfides; C034939:cadmium sulfide; D006108:Graphite; D006735:Horseradish Peroxidase; D006862:Hydrogen Sulfide
keywords: biosensing; enzyme catalysis; graphene oxide; photoelectrochemistry; quantum dots