title: Highly efficient visual detection of trace copper(II) and protein by the quantum photoelectric effect.
abstract: This work presented a photocurrent response mechanism of quantum dots (QDs) under illumination with the concept of a quantum photoelectric effect. Upon irradiation, the photoelectron could directly escape from QDs. By using nitro blue tetrazolium (NBT) to capture the photoelectron, a new visual system was proposed due to the formation of an insoluble reduction product, purple formazan, which could be used to visualize the quantum photoelectric effect. The interaction of copper(II) with QDs could form trapping sites to interfere with the quantum confinement and thus blocked the escape of photoelectron, leading to a "signal off" visual method for sensitive copper(II) detection. Meanwhile, by using QDs as a signal tag to label antibody, a "signal on" visual method was also proposed for immunoassay of corresponding protein. With meso-2,3-dimercaptosuccinic-capped CdTe QDs and carcino-embryonic antigen as models, the proposed visual detection methods showed high sensitivity, low detection limit, and wide detectable concentration ranges. The visualization of quantum photoelectric effect could be simply extended for the detection of other targets. This work opens a new visual detection way and provides a highly efficient tool for bioanalysis.
authors: State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University , Nanjing 210093, China.
authors: Peng
authors: P
authors: Wang
authors: Jianping
authors: J
authors: Lei
authors: Mengqi
authors: M
authors: Su
authors: Yueting
authors: Y
authors: Liu
authors: Qing
authors: Q
authors: Hao
authors: Huangxian
authors: H
authors: Ju
mesh_terms: D002272:Carcinoembryonic Antigen / Q000032:analysis*; D003300:Copper / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods*; D057230:Limit of Detection; D009580:Nitroblue Tetrazolium / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D014796:Visual Perception
chemical_list: D002272:Carcinoembryonic Antigen; D009580:Nitroblue Tetrazolium; D003300:Copper