School of Chemistry and Environment, Guangdong Ocean University, Analytical and Testing Center of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Intelligent Equipment for South China Sea Marine Ranching, Zhanjiang, 524088, China.
Guangxi Engineering Research Center of Processing & Storage of Characteristic and Advantage Aquatic Products, Guangxi Academy of Fishery Sciences, Nanning, 530021, China.
Anal Chim Acta. 2024 Sep 1;1320:343034. doi: 10.1016/j.aca.2024.343034. Epub 2024 Jul 27.
Bacillus cereus (B. cereus) is a widespread conditional pathogen that affects food safety and human health. Conventional methods such as bacteria culture and polymerase chain reaction (PCR) are difficult to use for rapid identification of bacterial spores because of the relatively long analysis times. From a human health perspective, there is an urgent need to develop an ultrasensitive, rapid, and accurate method for the detection of B. cereus spores.
The study proposed a new method for rapidly and sensitively detecting the biomarkers of bacterial spores via surface-enhanced Raman spectroscopy (SERS) combined with electrochemical enrichment. The 2,6-Pyridinedicarboxylic acid (DPA) was used as the model analyte to acts as a biomarker of B. cereus spores. The SERS substrate was developed via the in-situ generation of Ag nanoparticles (AgNPs) in a cuttlebone-derived organic matrix (CDOM). Because of the depletion of chitin reduction sites on the CDOM, the pores of the porous channels expanded. The pores diameter of the AgNPs/CDOM porous channel was found to be in the range of 0.7-1.3 nm through molecular diffusion experiments. Based on the porosity of AgNPs/CDOM substrates and the high sensitivity of SERS substrates, the sensor can rapidly and accurately electronically enrich DPA in 40 s with the limit of detection (LOD) of 0.3 nM.
The results demonstrate that electrochemically assisted SERS substrates can be served as a high sensitivity electrochemical-enrichment device for the rapid and sensitive detection of bacterial spores with minimal interference from potentially coexisting species in biological samples. In this study, it opens up a platform to explore the application of porous channels in natural bio-derived materials in the field of food safety.
蜡状芽孢杆菌（B. cereus）是一种广泛存在的条件致病菌，影响食品安全和人类健康。由于分析时间相对较长，传统的方法，如细菌培养和聚合酶链反应（PCR），难以用于快速鉴定细菌孢子。从人类健康的角度来看，迫切需要开发一种用于快速、准确检测 B. cereus 孢子的超灵敏方法。
本研究提出了一种利用表面增强拉曼光谱（SERS）结合电化学富集快速灵敏检测细菌孢子生物标志物的新方法。2,6-吡啶二甲酸（DPA）被用作 B. cereus 孢子的生物标志物。SERS 基底通过在乌贼骨衍生的有机基质（CDOM）中就地生成 Ag 纳米颗粒（AgNPs）来开发。由于 CDOM 上甲壳素还原位点的耗尽，多孔通道的孔扩张。通过分子扩散实验发现，AgNPs/CDOM 多孔通道的孔径在 0.7-1.3nm 范围内。基于 AgNPs/CDOM 基底的多孔性和 SERS 基底的高灵敏度，该传感器可以在 40s 内快速准确地对 DPA 进行电子富集，检测限（LOD）为 0.3nM。
结果表明，电化学辅助 SERS 基底可以作为一种高灵敏度的电化学富集装置，用于快速灵敏地检测细菌孢子，最小化生物样品中潜在共存物质的干扰。在本研究中，它为探索多孔通道在食品安全领域天然生物衍生材料中的应用开辟了一个平台。
