Kong Xianming, Yu Qian, Li Erwen, Wang Rui, Liu Qing, Wang Alan X
College of Chemistry, Chemical Engineering and Environment Engineering, Liaoning Shihua University, Fushun 113001, Liaoning, China.
School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA.
Materials (Basel). 2018 Mar 31;11(4):539. doi: 10.3390/ma11040539.
Diatomaceous earth-otherwise called diatomite-is essentially composed of hydrated biosilica with periodic nanopores. Diatomite is derived from fossilized remains of diatom frustules and possesses photonic-crystal features. In this paper, diatomite simultaneously functions as the matrix of the chromatography plate and the substrate for surface-enhanced Raman scattering (SERS), by which the photonic crystal-features could enhance the optical field intensity. The on-chip separation performance of the device was confirmed by separating and detecting industrial dye (Sudan I) in an artificial aqueous mixture containing 4-mercaptobenzoic acid (MBA), where concentrated plasmonic Au colloid was casted onto the analyte spot for SERS measurement. The plasmonic-photonic hybrid mode between the Au nanoparticles (NP) and the diatomite layer could supply nearly 10 times the increment of SERS signal (MBA) intensity compared to the common silica gel chromatography plate. Furthermore, this lab-on-a-chip photonic crystal device was employed for food safety sensing in real samples and successfully monitored histamine in salmon and tuna. This on-chip food sensor can be used as a cheap, robust, and portable sensing platform for monitoring for histamine or other harmful ingredients at trace levels in food products.
硅藻土，又称硅藻岩，主要由具有周期性纳米孔的水合生物二氧化硅组成。硅藻土源自硅藻壳的化石残骸，具有光子晶体特征。在本文中，硅藻土同时作为色谱板的基质和表面增强拉曼散射（SERS）的基底，通过其光子晶体特征可增强光场强度。通过在含有4 - 巯基苯甲酸（MBA）的人工水性混合物中分离和检测工业染料（苏丹红I），证实了该装置的芯片上分离性能，其中将浓缩的等离子体金胶体浇铸到分析物斑点上进行SERS测量。与普通硅胶色谱板相比，金纳米颗粒（NP）与硅藻土层之间的等离子体 - 光子混合模式可使SERS信号（MBA）强度增加近10倍。此外，这种芯片上的光子晶体装置用于实际样品中的食品安全传感，并成功监测了三文鱼和金枪鱼中的组胺。这种芯片上的食品传感器可作为一种廉价、坚固且便携的传感平台，用于监测食品中痕量水平的组胺或其他有害成分。
