Yin Yiyuan B, Conrad Christian L, Heck Kimberly N, Lejarza Fernando, Wong Michael S
ACS Appl Mater Interfaces. 2019 May 15;11(19):17491-17500. doi: 10.1021/acsami.9b04699. Epub 2019 May 2.
Luminescent gold nanoclusters (Au NCs) are a promising probe material for selective chemical sensing. However, low luminescent intensity and an incomplete understanding of the mechanistic origin of the luminescence limit their practical implementation. We induced glutathione-capped Au NCs to aggregate within silica-coated microcapsular structures using polymer-salt aggregate self-assembly chemistry. The encapsulated NCs have a 5× luminescence enhancement compared to free Au NCs and can detect Cr(VI) at concentrations as low as 6 ppb (=0.12 μM CrO) through luminescence quenching, compared to free Au NCs, which have a limit of detection (LOD) of 52 ppb (=1 μM CrO). The LOD is 16× lower than the United States Environmental Protection Agency maximum contaminant level for total chromium (Cr(III) + Cr(VI), 100 ppb) in drinking water. No pH adjustment is needed using the encapsulated Au NCs, unlike the case for free Au NCs. The luminescent microcapsule material can sense Cr(VI) in simulated drinking water with a ∼20-30 ppb LOD, serving as a possible basis for a practical Cr(VI) sensor.
发光金纳米团簇（Au NCs）是一种用于选择性化学传感的有前景的探针材料。然而，低发光强度以及对发光机制起源的不完全理解限制了它们的实际应用。我们利用聚合物 - 盐聚集体自组装化学方法，诱导谷胱甘肽包覆的Au NCs在二氧化硅包覆的微囊结构内聚集。与游离的Au NCs相比，封装后的NCs发光增强了5倍，并且通过发光猝灭能够检测低至6 ppb（= 0.12 μM CrO）的Cr(VI)，而游离的Au NCs的检测限（LOD）为52 ppb（= 1 μM CrO）。该检测限比美国环境保护局规定的饮用水中总铬（Cr(III) + Cr(VI)，100 ppb）的最大污染物水平低16倍。与游离的Au NCs不同，使用封装的Au NCs无需调节pH值。这种发光微囊材料能够在模拟饮用水中以约20 - 30 ppb的检测限检测Cr(VI)，为实用的Cr(VI)传感器提供了可能的基础。
