胶体金
材料科学
微流控
拉曼散射
纳米颗粒
拉曼光谱
纳米技术
水溶液
下降(电信)
乳状液
毛细管作用
分子
化学工程
化学
复合材料
有机化学
工程类
物理
光学
电信
计算机科学
作者
Yeong Hwa Kim,Dong Jae Kim,Sangmin Lee,Dong‐Ho Kim,Sung‐Gyu Park,Shin‐Hyun Kim
出处
期刊:Small
[Wiley]
日期:2019-11-28
卷期号:15 (52)
被引量:40
标识
DOI:10.1002/smll.201905076
摘要
Surface-enhanced Raman scattering (SERS) is one of the most promising methods to detect small molecules for point-of-care analysis as it is rapid, nondestructive, label-free, and applicable for aqueous samples. Here, microgels containing highly concentrated yet evenly dispersed gold nanoparticles are designed to provide SERS substrates that simultaneously achieve contamination-free metal surfaces and high signal enhancement and reproducibility. With capillary microfluidic devices, water-in-oil-in-water (W/O/W) double-emulsion drops are prepared to contain gold nanoparticles and hydrogel precursors in innermost drop. Under hypertonic condition, water is selectively pumped out from the innermost drops. Therefore, gold nanoparticles are gently concentrated without forming aggregates, which are then captured by hydrogel matrix. The resulting microgels have a concentration of gold nanoparticles ≈30 times higher and show Raman intensity two orders of magnitude higher than those with no enrichment. In addition, even distribution of gold nanoparticles results in uniform Raman intensity, providing high signal reproducibility. Moreover, as the matrix of the microgel serves as a molecular filter, large adhesive proteins are rejected, which enables the direct detection of small molecules dissolved in the protein solution. It is believed that this advanced SERS platform is useful for in situ detection of toxic molecules in complex mixtures such as biological fluids, foods, and cosmetics.
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