title: Glucose oxidase-functionalized fluorescent gold nanoclusters as probes for glucose.
abstract: Creation and application of noble metal nanoclusters have received continuous attention. By integrating enzyme activity and fluorescence for potential applications, enzyme-capped metal clusters are more desirable. This work demonstrated a glucose oxidase (an enzyme for glucose)-functionalized gold cluster as probe for glucose. Under physiological conditions, such bioconjugate was successfully prepared by an etching reaction, where tetrakis (hydroxylmethyl) phosphonium-protected gold nanoparticle and thioctic acid-modified glucose oxidase were used as precursor and etchant, respectively. These bioconjugates showed unique fluorescence spectra (λ(em max)=650 nm, λ(ex max)=507 nm) with an acceptable quantum yield (ca. 7%). Moreover, the conjugated glucose oxidase remained active and catalyzed reaction of glucose and dissolved O2 to produce H2O2, which quenched quantitatively the fluorescence of gold clusters and laid a foundation of glucose detection. A linear range of 2.0×10(-6)-140×10(-6)M and a detection limit of 0.7×10(-6)M (S/N=3) were obtained. Also, another horseradish peroxidase/gold cluster bioconjugate was produced by such general synthesis method. Such enzyme/metal cluster bioconjugates represented a promising class of biosensors for biologically important targets in organelles or cells.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, PR China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xia
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Long
authors.forename: Jianxiu
authors.initials: J
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques; D001786:Blood Glucose / Q000032:analysis; D005453:Fluorescence; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000737:chemistry*; D006046:Gold; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D001786:Blood Glucose; D006046:Gold; D005949:Glucose Oxidase; D005947:Glucose