title: Low-potential photoelectrochemical biosensing using porphyrin-functionalized TiO₂ nanoparticles.
abstract: A novel photoelectrochemical biosensing platform for the detection of biomolecules at relatively low applied potentials was constructed using porphyrin-functionalized TiO₂ nanoparticles. The functional TiO₂ nanoparticles were prepared by dentate binding of TiO₂ with sulfonic groups of water-soluble [meso-tetrakis(4-sulfonatophenyl)porphyrin] iron(III) monochloride (FeTPPS) and characterized by transmission electron microscopy; contact angle measurement; and Raman, X-ray photoelectron, and ultraviolet-visible absorption spectroscopies. The functional nanoparticles showed good dispersion in water and on indium tin oxide (ITO) surface. The resulting FeTPPS-TiO₂-modified ITO electrode showed a photocurrent response at +0.2 V to a light excitation at 380 nm, which could be further sensitized through an oxidation process of biomolecules by the hole-injected FeTPPS. Using glutathione as a model, a methodology for sensitive photoelectrochemical biosensing at low potential was thus developed. Under optimal conditions, the proposed photoelectrochemical method could detect glutathione ranging from 0.05 to 2.4 mmol L⁻¹ with a detection limit of 0.03 mmol L⁻¹ at a signal-to-noise ratio of 3. The photoelectrochemical biosensor had an excellent specificity against anticancer drugs and could be successfully applied to the detection of reduced glutathione in gluthion injection, showing a promising application in photoelectrochemical biosensing.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science (Ministry of Education of China), Department of Chemistry, Nanjing University, Nanjing 210093, P. R. China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Tu
authors.forename: Yitong
authors.initials: Y
authors.lastname: Dong
authors.forename: Jianping
authors.initials: J
authors.lastname: Lei
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D005978:Glutathione / Q000032:analysis / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010777:Photochemistry / Q000379:methods*; D011166:Porphyrins / Q000032:analysis* / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D011166:Porphyrins; C009495:titanium dioxide; D014025:Titanium; D005978:Glutathione