Exploring the Potential of Timegated® Raman and SERS for Bioprocess Monitoring

Research highlight | Biotechnology Progress

Fluorescence from biological culture media can make Raman spectroscopy challenging in bioprocess monitoring. Could combining Timegated® Raman spectroscopy with surface-enhanced Raman spectroscopy (SERS) help overcome this limitation?

A study published in Biotechnology Progress investigated the potential of combining these techniques to analyze metabolites during Escherichia coli cultivation. 

Combining Raman Techniques for Better Spectral Insight

The researchers compared three Raman approaches;Timegated® Raman, NIR Raman and micro-Raman with and without SERS enhancement.

The study focused on cell-free supernatant samples collected during E. coli bioreactor cultivations. Researchers investigated changes in the concentrations of glucose, acetate, AMP and cAMP under varying substrate availability.

The objective was to evaluate how the different Raman techniques performed in identifying and quantifying metabolites in complex biological samples.

What Did the Researchers Find?

The study highlighted three important findings:

• SERS improved spectral detail. In most cases, SERS increased the number of identifiable Raman signals and produced better-resolved spectra.
• Timegated® Raman enabled clear spectral identification. The technique produced well-defined Raman peaks comparable to micro-Raman, supporting the identification of compounds in the samples.
• NIR Raman performed better for quantitative analysis. When combined with multivariate data analysis, NIR Raman provided superior results for quantifying analytes, both with and without SERS nanoparticles.

What Does This Mean for Bioprocess Research?

The findings demonstrate the potential of combining Raman spectroscopy with SERS to gain more detailed chemical information from complex biological samples.

They also highlight the importance of selecting the appropriate Raman technique based on the analytical objective, whether the priority is identifying compounds or quantifying specific metabolites.

For researchers exploring Raman-based bioprocess monitoring, the study provides valuable insights into the opportunities and trade-offs associated with different measurement approaches.

Read the Original Research

Comparison of Time-Gated Surface-Enhanced Raman Spectroscopy (TG-SERS) and Classical SERS Based Monitoring of Escherichia coli Cultivation Samples

Kögler, M. et al. (2018), Biotechnology Progress, 34(6), 1533–1542.

Read the original publication