College of Materials and Chemistry & Chemical Engineering , Chengdu University of Technology , Chengdu 610059 , China.
Analytical & Testing Center , Sichuan University , 29 Wangjiang Road , Chengdu 610064 , China.
Anal Chem. 2019 Aug 6;91(15):9407-9412. doi: 10.1021/acs.analchem.9b01675. Epub 2019 Jul 18.
Singlet oxygen, generated from type-II photosensitization, has become increasingly popular in bioassay development in recent years. However, the transient nature of singlet oxygen in water (lifetime shorter than 4 μs) as well as its high activity make it easily inactivated by solvent molecules and other coexisting species, thus deteriorating use in the analytical sensitivity. Here, we proposed the use of a simple redox mediator for storing the energy of the transient singlet oxygen. To demonstrate such an idea, singlet oxygen generated from photosensitization of the double strand DNA-SYBR Green I (dsDNA-SG) complex was explored as a redox donor that can be modulated through formation and deformation of the dsDNA structure. After screening of a series of redox mediators with luminol chemiluminescence (CL) as the probe, ferrocyanide (KFe(CN)) was found to be the most efficient, resulting in ∼30-fold intensified luminol CL. By storing the oxidative capacity of singlet oxygen in ferrocyanide, the dsDNA-SG complex was evolved into a photosensitization-mediated chemiluminescence (PMCL) biosensing platform for DNA detection. Such a PMCL sensing platform allows label- and amplification-free detection of picomolar-scale DNA with a limit of detection (LOD) of 1.5 pM (0.45 fmol in absolute). The excellent sensitivity of PMCL sensing confirmed that such a facile storage approach to oxidative capacity would be appealing for singlet-oxygen-involved biosensing.
近年来，来自 II 型光致发光的单线态氧在生物测定开发中变得越来越受欢迎。然而，单线态氧在水中的瞬态性质（寿命短于 4 μs）及其高活性使其容易被溶剂分子和其他共存物质失活，从而降低了分析灵敏度的应用。在这里，我们提出了使用简单的氧化还原介体来储存瞬态单线态氧的能量。为了证明这种想法，我们探索了双链 DNA-SYBR Green I（dsDNA-SG）复合物的光致发光产生的单线态氧作为氧化还原供体，该供体可以通过 dsDNA 结构的形成和变形来调节。在使用鲁米诺化学发光（CL）作为探针筛选了一系列氧化还原介体之后，发现亚铁氰化钾（KFe(CN)）是最有效的，导致鲁米诺 CL 增强了约 30 倍。通过将单线态氧的氧化能力储存在亚铁氰化物中，dsDNA-SG 复合物演变成用于 DNA 检测的光致发光介导的化学发光（PMCL）生物传感平台。这种 PMCL 传感平台允许在没有标记和放大的情况下检测皮摩尔级别的 DNA，检测限（LOD）为 1.5 pM（绝对为 0.45 fmol）。PMCL 传感的优异灵敏度证实了这种氧化还原能力的简便存储方法对于涉及单线态氧的生物传感很有吸引力。
