School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China; Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou 325000, China.
School of Biomedical Engineering, School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325001, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Nov 15;301:122941. doi: 10.1016/j.saa.2023.122941. Epub 2023 May 30.
Salmonella should be absent in pharmaceutical preparations and foods according to the regulations. However, up to now, rapid and convenient identification of Salmonella is still full of challenge. Herein, we reported a label-free surface-enhanced Raman scattering (SERS) method for direct identification of Salmonella spiked in drug samples based on a characteristic bacterial SERS marker assisted by a high-performance SERS chip and a selective culture medium. The SERS chip being fabricated through in situ growth of bimetallic Au-Ag nanocomposites on silicon wafer within 2 h, featured a high SERS activity (EF > 10), good uniformity and batch-to-batch consistency (RSD < 10 %), and satisfactory chemical stability. The directly-visualized SERS marker at 1222 cm originated from bacterial metabolite hypoxanthine was robust and exclusive for discrimination of Salmonella with other bacterial species. Moreover, the method was successfully used for direct discrimination of Salmonella in mixed pathogens by using a selective culture medium, and could identify Salmonella contaminant at ∼1 CFU spiked level in a real sample (Wenxin granule, a botanical drug) after 12 h of enrichment. The combined results showed that developed SERS method is practical and reliable, and could be a promising alternative for rapid identification of Salmonella contamination in pharmaceutical and foods industries.
根据规定，沙门氏菌不应存在于药物制剂和食品中。然而，迄今为止，快速、便捷地鉴定沙门氏菌仍然充满挑战。在此，我们报道了一种基于特征细菌 SERS 标记物的无标记表面增强拉曼散射（SERS）方法，该方法结合高性能 SERS 芯片和选择性培养基，可直接鉴定药物样品中污染的沙门氏菌。通过在 2 小时内将双金属 Au-Ag 纳米复合材料原位生长在硅片上，制备出 SERS 芯片，其具有高 SERS 活性（EF>10）、良好的均匀性和批间一致性（RSD<10%），以及令人满意的化学稳定性。源自细菌代谢产物次黄嘌呤的直接可视化 SERS 标记物稳健且专一地用于区分沙门氏菌与其他细菌种类。此外，该方法还成功地用于使用选择性培养基直接区分混合病原体中的沙门氏菌，并且可以在富集 12 小时后识别真实样品（温心颗粒，一种植物药物）中约 1 CFU 污染水平的沙门氏菌。综合结果表明，所开发的 SERS 方法实用可靠，可作为药物和食品工业中快速鉴定沙门氏菌污染的一种有前途的替代方法。
