Photoelectrochemical sensing of glucose based on quantum dot and enzyme nanocomposites

A simple procedure for constructing the photoelectrochemical biosensor based on TiO2/CdSe@CdS QD nanocomposite modified electrode was developed. The TiO2/CdSe@CdS QD nanocomposite modified electrode was obtained by alternately depositing water-soluble CdSe@CdS QD and a mixture of [cobalt(o-phen)3]2+/3+ and poly(ethyleneimine) (PEI) over mesoscopic TiO2 films. The obtained TiO2/CdSe@CdS QD nanocomposite modified electrode exhibits much higher and stable photocurrent intensity than that of the photoelectrochemical biosensors reported so far. After the TiO2/CdSe@CdS QD nanocomposite modified electrode was coated with glucose oxidase, the photocurrent intensity was enhanced towards the addition of glucose. Thus, a photoelectrochemical biosensor for the detection of glucose was developed by monitoring the changes in the photocurrent intensity. Moreover, the proposed biosensor possessed good reproducibility and storage stability. Combining TiO2/CdSe@CdS nanocomposite and other biomolecules could be extended readily for sensing other biorecognition events.