利用去氧核醣核酸保護之奈米金探針與側流層析技術應用於視覺辨識之快速可攜式汞離子偵測器

Abstract

汞離子及甲基汞是已知會經由生物累積過程進入人體，並對中樞神經、腦部造成傷害的重金屬離子。因此發展針對河川、大型水體的簡易檢測方法在環境檢測中是非常重要的。近年來在實驗室已經利用奈米金粒子之獨特光學性質，發展出數種高靈敏性、快速分析的汞離子偵測器。然而，這些偵測方式仍須仰賴繁複的操作步驟、藥品、紫外光–可見光分光儀及螢光光譜儀等儀器的輔助以達到定量分析之目的，因此我們開發出一套嶄新且簡易操作的汞離子濃度偵測技術：藉由包覆富含胸腺嘧啶的去氧核醣核酸序列的奈米金探針，即使在鹽類水溶液中仍保有良好分散性之技術，結合側流層析法達到不須仰賴複雜儀器及專業知識即可操作之系統來偵測水溶液中的汞離子。利用奈米金探針分別滯留在硝化纖維薄膜上之檢測區所產生帶狀紅色區域作為視覺辨識的訊號來源。相較於其他方法，此設計之拋棄式感測器兼具有低成本、方便使用，以及快速、靈敏、污染物定量之工具等優點，在未來汞離子分析的環保議題中將會被廣泛應用。

The most common organic source of mercury, methyl mercury, is able to accumulate in the human body through the food chain by microbial biomethylation in aquatic sediments from water-soluble mercuric ion (Hg2+) and cause serious and permanent damage to the brain with both acute and chronic toxicity. The conveniently routine detection of Hg2+ is central to the environmental monitoring of rivers and large bodies of water and for evaluating the safety of aquatically derived food supplies. Recent progress in the laboratory has been in a result of improvements in rapid analytical techniques and detection limits for sensing Hg2+ by using the unique optical property of gold nanoparticles (AuNPs).[ , ] While these AuNPs-based colorimetric sensors have taken an important step towards real-time sensing and have been detectable by naked eyes, they still require laboratory type operations such as precise transfer and mixing of multiple solutions. Therefore, with the combination of the AuNP-based visual test with lateral flow assay (LFA),[ ] a rapid, cost-effective, highly sensitive, and reproducible technique was developed for the field detection of Hg2+ in environmental waters. In this study, we designed poly-thymine DNA modified AuNP probes that could protect AuNPs from aggregating even in the salinity solutions and employ LFA to detect the Hg2+ without complicated instrumentations and technical expertise. The captured AuNP probes on test zone and control zone of the sensor produced the characteristic red bands, enabling visual discrimination of Hg2+ concentrations. The demand of Hg2+ analysis in environmental applications requires parallel analytical strategies; such a method with simplicity and rapidity will find wide use in the future.