title: Enlargement of gold nanoparticles on the surface of a self-assembled monolayer modified electrode: a mode in biosensor design.
abstract: Gold nanoparticle (Au-NP) seeds were adsorbed onto the surface of a self-assembled monolayer (SAM)-modified electrode. With the treatment of this modified electrode by Au-NPs growth solution containing different concentrations of H2O2 or cholesterol along with cholesterol oxidase (ChOx), the Au-NP seeds on the electrode surface were enlarged in varying degrees. As a result, the peak currents in corresponding cyclic voltammograms were inversely proportional to the concentration of H2O2 or cholesterol. ChOx was also further modified onto the surface of Au/SAM/Au-NP electrode to prepare Au/SAM/Au-NP/ChOx electrode. Using the enzyme-modified electrode to detect cholesterol, which also utilized the enlargement of the NPs, an extraordinary low detection limit of 5 x 10(-9) M was achieved and two linear dependence ranges of 7.5 x 10(-8)-1 x 10(-6) and 1 x 10(-6)-5 x 10(-5) M were obtained. Consequently, new kinds of H2O2 and cholesterol biosensors could be fabricated.
authors.affiliation: Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P. R. China.
authors.forename: Nandi
authors.initials: N
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yu
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D006046:Gold