Reproducible E. coli detection based on label-free SERS and mapping

• Published in: Talanta (Oxford) 2016-01, Vol.146, p.457-463
• Main Authors: Yang, Danting, Zhou, Haibo, Haisch, Christoph, Niessner, Reinhard, Ying, Yibin
• Format: Article
• Language: English
• Subjects: Discriminant analysis; E. coli; Escherichia coli - chemistry; Escherichia coli - isolation & purification; Label-free; Limit of Detection; Reproducibility of Results; SERS; Single bacterium cell; Spectrum Analysis, Raman - instrumentation; Spectrum Analysis, Raman - methods; Temperature
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2015.09.006

The biosensing for rapid detection of bacteria based on surface-enhanced Raman scattering (SERS) has been widely explored for recent years. It is still a challenge to achieve a high sensitive, reproducible label free detection method for bacteria. In this work, a label-free SERS detection method of Escherichia coli based on incubation with silver colloid was reported. Optimized incubation conditions including shaking speed, time and temperature were used to help construct a rapid SERS method for E. coli analysis. It was found that the enhancement of the Raman signal of E. coli could be achieved to 1.8×104cps (counts per second) with high reproducibility. Three strains of E. coli DSM 1116/498/5695 could be successfully discriminated using such SERS method combining discriminant analysis. Finally, the lowest concentration of E. coli at 1×105cell/mL can be detected by SERS mapping. Thus, our detection method offers higher sensitivity and reproducibility compared to previously reported label free simple-mixing methods, opening an avenue for developing various SERS-based biosensor. [Display omitted] •Label-free SERS detection for E. coli was established.•Optimized incubation conditions of E. coli in Ag colloids were obtained.•Three strains of E. coli were successfully discriminated.•Different concentrations of E. coli could be detected by SERS mapping.