College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, PR China.
Anal Chim Acta. 2013 Apr 15;772:81-6. doi: 10.1016/j.aca.2013.02.025. Epub 2013 Feb 24.
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.
贵金属纳米团簇的构建和应用受到了持续关注。通过整合酶活性和荧光用于潜在应用，酶封端的金属团簇更受青睐。本工作展示了一种葡萄糖氧化酶（一种用于葡萄糖的酶）功能化的金纳米团簇探针用于检测葡萄糖。在生理条件下，通过蚀刻反应成功制备了这种生物缀合物，其中四羟甲基鏻保护的金纳米颗粒和硫辛酸修饰的葡萄糖氧化酶分别作为前体和蚀刻剂。这些生物缀合物具有独特的荧光光谱（λ（发射最大值）=650nm，λ（激发最大值）=507nm），量子产率可接受（约 7%）。此外，共轭的葡萄糖氧化酶仍然保持活性，并催化葡萄糖和溶解氧的反应生成 H2O2，定量猝灭了金纳米团簇的荧光，为葡萄糖检测奠定了基础。获得了 2.0×10(-6)-140×10(-6)M 的线性范围和 0.7×10(-6)M（S/N=3）的检测限。同样，通过这种通用的合成方法也制备了另一种辣根过氧化物酶/金纳米团簇生物缀合物。这种酶/金属团簇生物缀合物代表了一类有前途的细胞器或细胞内生物靶标生物传感器。
