Premium
Photoelectrochemistry of Free‐Base‐Porphyrin‐Functionalized Zinc Oxide Nanoparticles and Their Applications in Biosensing
Author(s) -
Tu Wenwen,
Lei Jianping,
Wang Peng,
Ju Huangxian
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201100577
Subject(s) - photocurrent , photoelectrochemistry , nanoparticle , indium tin oxide , materials science , biosensor , photochemistry , porphyrin , photoconductivity , electrode , chemistry , nanotechnology , electrochemistry , optoelectronics , thin film
The photoelectrochemical properties of free‐base‐porphyrin‐functionalized zinc oxide nanoparticles were studied. A universal photoelectrochemical biosensing platform was constructed on indium tin oxide (ITO) by using the functional nanohybrid. The nanohybrid was synthesized by means of dentate binding of ZnO nanoparticles with carboxylic groups of 4,4′,4′′,4′′′‐(21 H ,23 H ‐porphine‐5,10,15,20‐tetrayl)tetrakis(benzoic acid) (TCPP), and characterized with scanning electron microscopy, contact angle measurement, and spectral techniques. The nanohybrid‐coated ITO electrode showed an efficient photocurrent response under irradiation at a wavelength of 360 nm, which could be greatly improved upon addition of cysteine by its oxidation at +0.3 V. The possible mechanism was that cysteine acts as a sacrificial electron donor to scavenge the photogenerated holes that locate on the excited state of TCPP, which then injects the photoexcitation electrons into the conduction band of ZnO nanoparticles, thereby transferring photoinduced electrons to the ITO electrode. Based on this enhanced photocurrent signal, a novel method for photoelectrochemical detection of cysteine was developed with a linear range of 0.6 to 157 μmol L −1 in physiological media. The detection limit was 0.2 μmol L −1 at a signal‐to‐noise ratio of 3. The novel strategy of cysteine analysis could provide an alternative method for monitoring biomolecules and extend the application of porphyrin‐functionalized semiconductor nanoparticles.