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  • Visible light induced photo...
    Wang, Wenjing; Bao, Lei; Lei, Jianping; Tu, Wenwen; Ju, Huangxian

    Analytica chimica acta, 09/2012, Letnik: 744
    Journal Article

    Display omitted ► The near-infrared QDs are synthesized in an aqueous solution. ► QDs-based biosensor exhibits visible-light induced cathodic photocurrent. ► The oxygen dependency of the photocurrent is verified. ► A photoelectrochemical strategy is established by coupling with enzymatic reaction. ► Photoelectrochemical sensor shows high upper detection limit, acceptable stability and accuracy. A visible light induced photoelectrochemical biosensing platform based on oxygen-sensitive near-infrared quantum dots (NIR QDs) was developed for detection of glucose. The NIR QDs were synthesized in an aqueous solution, and characterized with scanning electron microscopy and X-ray photoelectron spectroscopy. The as-prepared NIR QDs were employed to construct oxygen-sensitive photoelectrochemical biosensor on a fluorine-doped tin oxide (FTO) electrode. The oxygen dependency of the photocurrent was investigated at as-prepared electrode, which demonstrated the signal of photocurrent is suppressed with the decreasing of oxygen. Coupling with the consumption of oxygen during enzymatic reaction, a photoelectrochemical strategy was proposed for the detection of substrate. Using glucose oxidase (GOx) as a model enzyme, that is, GOx was covalently attached to the surface of CdTe QDs, the resulting biosensor showed the sensitive response to glucose. Under the irradiation of visible light of a wavelength at 505nm, the proposed photoelectrochemical method could detect glucose ranging from 0.1mM to 11mM with a detection limit of 0.04mM. The photoelectrochemical biosensor showed a good performance with high upper detection limit, acceptable stability and accuracy, providing an alternative method for monitoring biomolecules and extending the application of near-infrared QDs.