Lin Xiaofeng, Lin Wensheng, Yang Meijia, Chen Jiayao, Yu Dingshan, Hong Wei, Chen Xudong
Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education of China, Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films, School of Chemistry, Sun Yat-sen University Guangzhou 510275 P. R. China
RSC Adv. 2018 Nov 9;8(66):37729-37734. doi: 10.1039/c8ra07043a. eCollection 2018 Nov 7.
The chain reaction amplification mechanism (CRAM) has been extensively studied, but it has not been effectively developed at the molecular scale and still needs to consume amounts of monomers to show the macroscopic phenomenon needed for detection. Herein, rationally-designed silica-coated silver nanoparticles with acrylic acid-functionalization were used as a plasmonic nanosensor to realize highly sensitive and fast colorimetric glucose detection with less monomer consumption, which effectively integrated CRAM with the localized surface plasmon resonance effect, developing CRAM at the molecular scale. The glucose detection mechanism of the proposed sensor was based on free-radical polymerization by biocatalytic initiation, which would induce the aggregation of Ag NPs, leading to a decrease in the plasmon resonance intensity. As a result, the detection limit could reach 2.06 × 10 M, 10 times lower than that of a commercial glucose assay kit with a limit of 1.1 × 10 M. Moreover, FDTD simulation further confirmed that the intensity of the extinction gradually decreased with an increase in the degree of aggregation of Ag NPs. The approach could be used for high selectivity toward glucose detection and would be suitable for other practical applications of the detection of low concentrations of glucose.
链反应扩增机制（CRAM）已得到广泛研究，但在分子尺度上尚未得到有效发展，且仍需消耗大量单体才能呈现出检测所需的宏观现象。在此，将合理设计的丙烯酸官能化二氧化硅包覆银纳米颗粒用作等离子体纳米传感器，以实现高灵敏度、快速比色法葡萄糖检测，同时减少单体消耗，这有效地将CRAM与局域表面等离子体共振效应相结合，在分子尺度上发展了CRAM。所提出传感器的葡萄糖检测机制基于生物催化引发的自由基聚合，这会诱导银纳米颗粒聚集，导致等离子体共振强度降低。结果，检测限可达2.06×10⁻⁷M，比商业葡萄糖检测试剂盒的1.1×10⁻⁶M的检测限低10倍。此外，FDTD模拟进一步证实，随着银纳米颗粒聚集程度增加，消光强度逐渐降低。该方法可用于对葡萄糖检测具有高选择性，并且适用于其他低浓度葡萄糖检测的实际应用。
