Department of Chemistry, North-Eastern Hill University, Permanent Campus, Shillong, India.
Nanotechnology. 2011 Jun 17;22(24):245502. doi: 10.1088/0957-4484/22/24/245502. Epub 2011 Apr 20.
We have used fluorescent ZnS nanoparticles as a probe for the determination of adenine. A typical 2 × 10(-7) M concentration of adenine quenches 39.3% of the ZnS fluorescence. The decrease in ZnS fluorescence as a function of adenine concentration was found to be linear in the concentration range 5 × 10(-9)-2 × 10(-7) M. The limit of detection (LOD) of adenine by this method is 3 nM. Among the DNA bases, only adenine quenched the fluorescence of ZnS nanoparticles in the submicromolar concentration range, thus adding selectivity to the method. The amino group of adenine was important in determining the quenching efficiency. Steady-state fluorescence experiments suggest that one molecule of adenine is sufficient to quench the emission arising from a cluster of ZnS consisting of about 20 molecules. Time-resolved fluorescence measurements indicate that the adenine molecules block the sites on the surface of ZnS responsible for emission with the longest lifetime component. This method may be applied for the determination of adenine in biological samples since the measurements have been carried out at pH 7.
我们使用荧光 ZnS 纳米粒子作为腺嘌呤的探针。典型的 2×10(-7) M 浓度的腺嘌呤猝灭 39.3%的 ZnS 荧光。ZnS 荧光随腺嘌呤浓度的变化呈线性关系，浓度范围为 5×10(-9)-2×10(-7) M。该方法检测腺嘌呤的检出限（LOD）为 3 nM。在 DNA 碱基中，只有腺嘌呤在亚微摩尔浓度范围内猝灭了 ZnS 纳米粒子的荧光，从而增加了方法的选择性。腺嘌呤的氨基在确定猝灭效率方面很重要。稳态荧光实验表明，一个腺嘌呤分子足以猝灭由大约 20 个分子组成的 ZnS 簇发出的发射。时间分辨荧光测量表明，腺嘌呤分子阻断了 ZnS 表面上负责发射最长寿命成分的位点。由于该测量是在 pH 7 下进行的，因此该方法可用于生物样品中腺嘌呤的测定。
