Time-Gated Raman spectroscopy to improve chemical sensitivity for in-situ bioreactor monitoring

This project proposes to demonstrate the capabilities of timegated Raman spectroscopy (TG-RS) to improve the SNR ratio of Raman data using a traditional chemometrics approach (PLS) and a calibration free approach (iterative optimization technology, IOT).
Categories
Process control
Data

Industry Need

  • Raman spectroscopy has seen widespread application as a process analytical technology for bioreaction monitoring. 
  • Traditional Raman spectroscopy (TRS) struggles with fluorescence emission (common to many components in bioreactions). 
  • Fluorescence interference decreases the signal-to-noise ratio (SNR) of the acquired spectra, reducing interpretability. 
  • Time-gated Raman spectroscopy (TG-RS) overcomes fluorescence interference by taking advantage of the delay between Raman signal and fluorescence emission. 

Approach

  • Interpretation of Raman spectra is accomplished by employing chemometric models, namely partial least squares (PLS).  
  • Developing and calibrating these models can be demanding, particularly in complex bioreaction systems. Calibration-free models based on linearly additive pure component spectra offer a favorable alternative, but non-linear interferences (e.g., fluorescence) reduces model performance.  
  • Mitigating interference via TG-RS enables pure component model approaches. 

NIPTE and Pfizer have teamed up to demonstrate the ability of TG-RS to reduce fluorescence and improve SNR of key metabolites in bioreactions. The superior SNR will enable the development and comparison of PLS and pure component models for the quantification of these metabolites during bioreactions of industrially relevant organisms.  

Impacts

TG-RS is expected to significantly improve the ability to monitor chemical conditions in bioreactors.

Demonstrate that combining TG-RS and pure component modeling improves bioreaction monitoring capability while reducing calibration resource burden in a system ready for industrial deployment

The real-time data collected during reactor monitoring can be used as an input in a control strategy to maximize product yield and quality while minimizing inefficiencies that lead to product failure and loss of profit.

Use the real-time data collected during reactor monitoring as an input in a control strategy to maximize product yield and quality while minimizing inefficiencies that lead to product failure and loss of profit

Broad acceptance and implementation of TG-RS as an industry standard technology for bioreaction monitoring

Demonstrate the suitability of TG-RS for regulators as an appropriate process analytical technology (PAT) system

Work will demonstrate the suitability of TG-RS for regulators as an appropriate process analytical technology (PAT) system

Create broad acceptance and implementation of TG-RS as an industry standard technology for bioreaction monitoring

Value Statement/Outcomes

Time-gated Raman spectroscopy (TG-RS) delivers a superior Signal-to-Noise Ratio (SNR) by isolating Raman signals from fluorescence, allowing for more precise tracking of key metabolites compared to traditional methods. By enabling "calibration-free" models, this technology can reduce the time required for model development and calibration by an estimated 50% to 70% compared to labor-intensive partial least squares (PLS) approaches. This enhanced spectral clarity directly mitigates the risk of batch failures in complex bioreactions, leading to higher yield consistency and a significant reduction in the thousands of dollars lost during a single failed industrial run.

Publications

Anderson, Carl., Presenter, NIIMBL National Meeting conference, Washington D.C., June 26, 2025.

Posters

Anderson, C., Conference Participant, PC 5.2-134: Enhancing Analytical Sensitivity in Upstream Bioreactions Using Time-gated Raman Spectroscopy, NIIMBL National Meeting, Washington, D.C., June 26, 2025.

Presentations

Anderson, Carl., Presenter, NIIMBL National Meeting conference, Washington D.C., June 25, 2025.

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Project Lead

National Institute for Pharmaceutical Technology and Education, Inc (NIPTE)

National Institute for Pharmaceutical Technology and Education, Inc (NIPTE)

Participating Organizations

Pfizer, Inc.

Pfizer, Inc.