Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University , Chengdu, Sichuan 610064, P. R. China.
College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology , Chengdu, Sichuan 610059, P. R. China.
Anal Chem. 2017 Dec 19;89(24):13269-13274. doi: 10.1021/acs.analchem.7b03327. Epub 2017 Dec 5.
The interest in label-free bioassays is increasing rapidly because of their simple procedure and direct information on the interaction between the target molecule and the sensing unit. One of the major obstacles in the application of label-free biosensors is the difficulty to produce stable and reproducible optical, electric, electrochemical, or magnetic properties for the sensitive detection of the target molecules. In this work, we demonstrated a label-free DNA assay, by directly measuring the intrinsic Cu and Cu stable isotopes inside the double-strand DNA-templated Cu nanoparticles. The experimental conditions, including detection of copper by elemental mass spectrometry, the copper nanoparticles formation parameters, the hybrid chain reaction parameters, and analytical performance, were investigated in detail. The Cu signal intensity possesses a linear relation with the concentration of target DNA over the range of 20-1000 pM with a detection limit of 4 pM (3σ). The detection limit of this method is among the most sensitive label-free techniques and also comparable to the lanthanides and Au nanoparticles labeled assays by elemental mass spectrometric detection. The proposed label-free bioassay is simple and sensitive and eliminated the need for optical, electric, electrochemical, or magnetic properties of the sensing unit. To our best knowledge, this is the first report of the label-free bioassay by metal stable isotope detection.
由于其简单的程序和对目标分子与传感单元之间相互作用的直接信息，无标记生物测定法的兴趣正在迅速增加。无标记生物传感器应用的主要障碍之一是难以产生稳定且可重复的光学、电学、电化学或磁性能，以对目标分子进行敏感检测。在这项工作中，我们通过直接测量双链 DNA 模板化 Cu 纳米粒子内的固有 Cu 和 Cu 稳定同位素，展示了一种无标记的 DNA 测定法。详细研究了包括元素质谱法检测铜、铜纳米粒子形成参数、杂交链反应参数和分析性能在内的实验条件。Cu 信号强度与目标 DNA 的浓度在 20-1000 pM 范围内呈线性关系，检测限为 4 pM（3σ）。该方法的检测限属于最灵敏的无标记技术之列，与元素质谱检测的镧系元素和 Au 纳米粒子标记测定法相当。所提出的无标记生物测定法简单灵敏，并且消除了对传感单元的光学、电学、电化学或磁性能的需求。据我们所知，这是首次通过金属稳定同位素检测报告无标记生物测定法。
