Sharpe Erica, Bradley Ryan, Frasco Thalia, Jayathilaka Dilhani, Marsh Amanda, Andreescu Silvana
Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699-5810.
Bastyr University California, 4106 Sorrento Valley Blvd. San Diego, CA 92121-1407.
Sens Actuators B Chem. 2014 Mar 31;193:552-562. doi: 10.1016/j.snb.2013.11.088.
We report a novel chemical sensing array based on metal oxide nanoparticles as a portable and inexpensive paper-based colorimetric method for polyphenol detection and field characterization of antioxidant containing samples. Multiple metal oxide nanoparticles with various polyphenol binding properties were used as active sensing materials to develop the sensor array and establish a database of polyphenol standards that include epigallocatechin gallate, gallic acid, resveratrol, and Trolox among others. Unique charge-transfer complexes are formed between each polyphenol and each metal oxide on the surface of individual sensors in the array, creating distinct optically detectable signals which have been quantified and logged into a reference database for polyphenol identification. The field-portable Pantone/X-Rite© CapSure® color reader was used to create this database and to facilitate rapid colorimetric analysis. The use of multiple metal-oxide sensors allows for cross-validation of results and increases accuracy of analysis. The database has enabled successful identification and quantification of antioxidant constituents within real botanical extractions including green tea. Formation of charge-transfer complexes is also correlated with antioxidant activity exhibiting electron transfer capabilities of each polyphenol. The antioxidant activity of each sample was calculated and validated against the oxygen radical absorbance capacity (ORAC) assay showing good comparability. The results indicate that this method can be successfully used for a more comprehensive analysis of antioxidant containing samples as compared to conventional methods. This technology can greatly simplify investigations into plant phenolics and make possible the on-site determination of antioxidant composition and activity in remote locations.
我们报道了一种基于金属氧化物纳米颗粒的新型化学传感阵列，作为一种便携且廉价的基于纸张的比色法，用于多酚检测以及含抗氧化剂样品的现场表征。具有各种多酚结合特性的多种金属氧化物纳米颗粒被用作活性传感材料，以开发传感器阵列并建立多酚标准数据库，其中包括表没食子儿茶素没食子酸酯、没食子酸、白藜芦醇和Trolox等。阵列中各个传感器表面的每种多酚与每种金属氧化物之间形成独特的电荷转移络合物，产生可光学检测的独特信号，这些信号已被量化并记录到用于多酚鉴定的参考数据库中。使用现场便携式的Pantone/X-Rite© CapSure® 颜色读取器来创建此数据库并促进快速比色分析。使用多个金属氧化物传感器可对结果进行交叉验证并提高分析准确性。该数据库已成功鉴定并量化了包括绿茶在内的真实植物提取物中的抗氧化成分。电荷转移络合物的形成也与抗氧化活性相关，显示出每种多酚的电子转移能力。计算了每个样品的抗氧化活性，并通过氧自由基吸收能力（ORAC）测定进行验证，结果显示出良好的可比性。结果表明，与传统方法相比，该方法可成功用于对含抗氧化剂样品进行更全面的分析。这项技术可以极大地简化对植物酚类物质的研究，并使在偏远地区现场测定抗氧化剂组成和活性成为可能。
