A rapid SERS method for label-free bacteria detection using polyethylenimine-modified Au-coated magnetic microspheres and Au@Ag nanoparticles

Chongwen Wang, Junfeng Wang, Min Li, Xinyan Qu, Kehan Zhang, Zhen Rong*, Rui Xiao, Shengqi Wang

*此作品的通讯作者

科研成果: 期刊稿件文章同行评审

142 引用 (Scopus)

摘要

A rapid, sensitive, and label-free SERS detection method for bacteria pathogens is reported for the first time. The method, which is based on the combination of polyethylenimine (PEI)-modified Au-coated magnetic microspheres (Fe3O4@Au@PEI) and concentrated Au@Ag nanoparticles (NPs), was named the capture-enrichment-enhancement (CEE) three-step method. A novel Fe3O4@Au microsphere with monodispersity and strong magnetic responsiveness was synthesized as a magnetic SERS substrate and amino functionalized by PEI self-assembly. The negatively charged bacteria were quickly captured and enriched by the positively charged Fe3O4@Au@PEI microspheres, and the bacteria SERS signal was synergistically enhanced by using Fe3O4@Au@PEI microspheres and Au@Ag NPs in conjunction. The CEE three-step method proved useful in tap water and milk samples, and the total assay time required was only 10 min. Results further demonstrated that the CEE three-step method could be a common approach for detecting a wide range of bacteria, as verified by its detection of the Gram-positive bacterium E. coli and Gram-positive bacterium S. aureus at a detection limit of as low as 103 cells per mL. Therefore, our CEE three-step method offered the significant advantages of short assay time, simple operating procedure, and higher sensitivity than previously reported methods of SERS-based bacteria detection.

源语言英语
页(从-至)6226-6238
页数13
期刊The Analyst
141
22
DOI
出版状态已出版 - 21 11月 2016
已对外发布

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