Towards a fast, high specific and reliable discrimination of bacteria on strain level by means of SERS in a microfluidic device.

The interest in a fast, high specific and reliable detection method for bacteria identification is increasing. We will show that the application of vibrational spectroscopy is feasible for the validation of bacteria in microfluidic devices. For this purpose, reproducible and specific spectral pattern as well as the establishment of large databases are essential for statistical analysis. Therefore, short recording times are beneficial concerning the time aspect of fast identification. We will demonstrate that the requirements can be fulfilled by measuring ultrasonic busted bacteria by means of microfluidic lab-on-a-chip based SERS. With the applied sample preparation, high specificity and reproducibility of the spectra are achieved. Taking advantage of the SERS enhancement, the spectral recording time is reduced to 1 s and a database of 11,200 spectra is established for a model system E. coli including nine different strains. The validation of the bacteria on strain level is achieved accomplishing SVM accuracies of 92%. Within this contribution the potential of our approach of bacterial identification for future application is discussed, focusing on the time-benefit and the combination with other microfluidic applications. This journal is © The Royal Society of Chemistry 2011