Amine functionalized TiO2–carbon nanotube composite: synthesis, characterization and application to glucose biosensing

12/2011; 1(4):189-195. DOI: 10.1007/s13204-011-0025-0

ABSTRACT The synthesis of amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2-TiO2-CNTs) using sol–gel method was investigated. The synthesized nanocomposite was characterized with XRD, FTIR spectroscopy,
BET test and SEM imaging. The results demonstrated a unique nanostructure with no destruction of the CNTs’ shape. In addition,
the presence of amine groups on the composite surface was confirmed by FTIR. This nanocomposite was used for one-step immobilization
of glucose oxidase (GOx) to sense glucose. The result of cyclic voltammetry showed a pair of well-defined and quasi-reversible
peaks for direct electron transfer of GOx in the absence of glucose. Also, the result of electrochemical impedance spectroscopy
indicated that GOx was successfully immobilized on the surface of NH2-TiO2-CNTs. Furthermore, good amperometric response showed that immobilized GOx on the NH2-TiO2-CNTs exhibits exceptional bioelectrocatalytic activity toward glucose oxidation.

KeywordsCarbon nanotube–TiO2
–Glucose oxidase–Bioelectrocatalysis

Download full-text


Available from: Hedayatollah Ghourchian, Aug 21, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel optical sensor based on TiO2 nanoparticles for Valine detection has been developed. In the presented work, commercial TiO2 nanoparticles (Sigma Aldrich, particle size 32 nm) were used as sensor templates. The sensitive layer was formed by a porphyrin coating on a TiO2 nanostructured surface. As a result, an amorphous layer between the TiO2 nanostructure and porphyrin was formed. Photoluminescence (PL) spectra were measured in the range of 370-900 nm before and after porphyrin application. Porphyrin adsorption led to a decrease of the main TiO2 peak at 510 nm and the emergence of an additional peak of high intensity at 700 nm. Absorption spectra (optical density vs. wavelenght, measured from 300 to 1100 nm) showed IR shift Sorret band of prophiryn after deposition on metal oxide. Adsorption of amino acid quenched PL emission, related to porphyrin and increased the intensity of the TiO2 emission. The interaction between the sensor surface and the amino acid leads to the formation of new complexes on the surface and results in a reduction of the optical activity of porphyrin. Sensitivity of the sensor to different concentrations of Valine was calculated. The developed sensor can determine the concentration of Valine in the range of 0.04 to 0.16 mg/ml.
    Proceedings of SPIE - The International Society for Optical Engineering 11/2013; 9032. DOI:10.1117/12.2044464 · 0.20 Impact Factor