Anal Chem. 2019 Sep 3;91(17):10988-10995. doi: 10.1021/acs.analchem.9b01027. Epub 2019 Aug 19.
Antibiotic susceptibility test (AST) is essential in clinical diagnosis of serious bacterial infection, such as sepsis, while it typically takes 2-5 days for sample culture, antibiotic treatment, and reading result. Detecting metabolites secreted from bacteria with surface-enhanced Raman scattering (SERS) enables rapid determination of antibiotic susceptibility, reducing the AST time to 1-2 days. However, it still requires 1 day of culture time to obtain sufficient quantity of bacteria for sample washing, bacterial extraction, and antibiotic treatment. Additionally, the whole procedure, manually performed in open environment, often suffers from contamination and human error. To address the above problems, a microfluidic system integrating membrane filtration and the SERS-active substrate (MF-SERS) was developed to perform on-chip bacterial enrichment, metabolite collection, and in situ SERS measurements for antibiotic susceptibility test. Using as the prototype bacterium, the lowest SERS detection limit of bacterial concentration of the MF-SERS system is 10 CFU/mL, which is 4 orders of magnitude lower than that using centrifugation-purification procedure, significantly shortening the bacterial culture time. The bacteria and secreted metabolites are enclosed during bacterial trapping, metabolite filtration, and SERS detection, thus minimizing possible contamination and human errors. Finally, the successful demonstration of AST on with a concentration of 10 CFU/mL is presented. Overall, the MF-SERS system with a miniature size and well-confined microenvironment allows the integration of multiple bacteria processes for bacterial enrichment, culture, and determination of AST.
抗生素药敏试验（AST）在严重细菌感染的临床诊断中至关重要，如败血症，而样本培养、抗生素治疗和读取结果通常需要 2-5 天。通过表面增强拉曼散射（SERS）检测从细菌分泌的代谢物，可以快速确定抗生素的敏感性，将 AST 时间缩短至 1-2 天。然而，仍然需要 1 天的培养时间来获得足够数量的细菌进行样品洗涤、细菌提取和抗生素处理。此外，整个过程在开放环境中手动进行，经常受到污染和人为错误的影响。为了解决上述问题，开发了一种将膜过滤和 SERS 活性衬底集成在一起的微流控系统（MF-SERS），用于进行芯片上的细菌富集、代谢物收集和原位 SERS 测量，以进行抗生素药敏试验。以 作为原型菌，MF-SERS 系统对细菌浓度的最低 SERS 检测限为 10 CFU/mL，比离心纯化程序低 4 个数量级，大大缩短了细菌培养时间。在细菌捕获、代谢物过滤和 SERS 检测过程中，细菌和分泌的代谢物被封闭，从而最大限度地减少了可能的污染和人为错误。最后，成功地对浓度为 10 CFU/mL 的 进行了 AST 演示。总体而言，该 MF-SERS 系统具有微型尺寸和良好的封闭微环境，允许集成多个细菌过程，用于细菌富集、培养和 AST 确定。
