|
|
|
Bioreactor Analyte Monitoring with NIR Spectroscopy
Introduction
- Bioreactors are an important emergent tool for development of pharmaceuticals, cells and tissue
- Bioreactors are transitioning from research to mainstream production environments
- Currently, there is significant undercapacity in the pharmaceutical bioreactor market
- Opportunity costs are in the hundreds of millions because demand for bioreactor produced drugs cannot be met
- InLight Solutions has demonstrated technical feasibility for a Bioreactor monitor that enables optimal cell growth, higher reliability, shorter runs, and superior yields
Most bioreactions are batch processes
- Bioreactor run can last as long as 120 days, so losing a batch is potentially very costly
- Significant effort is put into monitoring to ensure a batch run is successful
- Based on checks, new growth media is infused and waste removed to facilitate cell growth
- In general, the process is labor intensive and open loop between adjustments
- Fluid dynamics limit the capacity of a bioreactor
- Labor requirements to monitor and adjust a bioreactor limit production scale-up
Measurement of glucose and lactate during monitoring, control
- The commonly measured analytes (oxygen, carbon dioxide, pH and temperature) don’t give a complete picture of the cell reaction
- Measurement of glucose, lactate during a bioreactor run usually requires removal of liquid from system
- Potential for contamination
- Labor intensive
- Undersampling of reaction
- 30+ minute time lag between acquiring sample, bench-top/lab analysis and adjustment of bioreactor
- Monitoring gaps and lack of sensor integration make closed-loop control a challenge
- Growth not optimized, batch runs take longer, cells stressed
NIR spectroscopy expands bioreactor monitoring capabilities
- Additional important analytes for monitoring cell metabolism include:
- Glucose, glutamine (food for cells)
- Lactate (waste product)
- Other analytes of interest include:
- Urea, bicarbonate, ammonia
- Potential for monitoring additional amino acids, sugars, proteins, and lipids
Advantages of NIR spectroscopy for bioreactor monitoring
- Continuous monitoring of bioreactor
- Reduced chance of contamination because system not compromised by periodic removal of bioreactor media for measurement/monitoring
- More info to characterize, control and optimize the process resulting in shorter runs, higher reliability and superior yields
- Multiple analytes measured with a single spectral measurement
- Flash analysis of bioreactor media
- No need for discrete sensor per analyte
- Multivariate spectroscopy has built-in diagnostic capabilities that provide confidence in the results
InLight is a leader in the development of NIR spectroscopy applications
- InLight has spent 10 years developing a noninvasive glucose monitor based on NIR spectroscopy
- InLight has extensive experience and expertise in measuring numerous analytes in vitro and in vivo
- In vitro work includes whole blood, serum and aqueous media
- In vivo work includes glucose, alcohol, urea and arterial blood gases in tissue
- Bioreactor application plays to InLight’s strengths:
- Spectroscopy, chemometrics, statistics
- Clinical chemistry, tissue optics, clinical research
- Optical, mechanical and electrical engineering
NASA Bioreactor Monitoring Feasibility Project
Project overview
- InLight collaborated with NASA to demonstrate proof of concept
- InLight developed a prototype based on our proprietary Fourier transform spectrometer equipped with a NIR compatible flow cell
- InLight demonstrated simultaneous measurement by near infrared spectroscopy of the following analytes in GTSF-2 cell culture media:
- Glucose, glutamine
- Lactate, urea
- pH, HCO3-, pCO2
Bioreactor monitor concept breadboard
Picture of Breadboard w/o Cover
Bioreactor monitoring demonstration overview
- Built custom breadboard system for demonstration
- Developed calibrations for glucose, glutamine, lactate, urea, pH and HCO3-
- Spectral measurement of doped GTSF-2 samples in which analytes of interest were intentionally varied in an orthogonal manner
- Partial least squares regression technique applied to collected spectra and analyte reference values
- pCO2 calculated from pH and HCO3-
- Applied analyte calibrations prospectively to a set of validation samples
- Results of validation summarized on following pages
Examples of NIR measurement performance
Bioreactor monitor concept breadboard
- As demonstrated in these plots, spectroscopic measurement error is independent of concentration. Competing sensor technologies generally have proportional errors.
NIR accurately measures analytes in GTSF-2
| Analyte |
Concentration Range |
Standard Deviation |
Standard Error of Prediction |
R² |
| Glucose |
19 – 350 mg/dL |
98.2 |
4.7 mg/dL |
0.998 |
| Lactate |
0 – 47 mg/dL |
16.0 |
1.3 mg/dL |
0.994 |
| Urea |
0 – 14 mg/dL |
5.1 |
0.6 mg/dL |
0.995 |
| Glutamine |
0 – 67 mg/dL |
23.8 |
3.7 mg/dL |
0.976 |
| pH |
7.0 – 7.9 |
0.24 |
0.026 |
0.989 |
| Bicarbonate |
8.7 – 21.2 mmol |
3.2 |
0.7 mmol |
0.932 |
| pCO2 (calc) |
5.7 – 69.5 mmHg |
20.5 |
2.3 mmHg |
0.996 |
NIR can measure additional analytes in GTSF-2
- Based on InLight’s in vitro work in blood, plasma and serum, the bioreactor monitoring analyte menu can be expanded to include:
- Ammonia
- Albumin
- Total Protein
- Triglycerides
- HDL, LDL and total cholesterol
- Bilirubin
- Fructose
- Galactose
Summary
- Demonstrated feasibility of bioreactor monitoring with NIR spectroscopy
- Great accuracy and precision
- Negligible protein coating of optical flow cell during 40 day bioreactor cell run
- Good potential to measure other analytes in GTSF-2
- Information already contained in spectral measurement
- Integration of NIR continuous bioreactor monitoring with closed loop control will facilitate production
- Optimal cell growth, higher reliability, shorter runs, superior yields
- InLight is excited by this opportunity and is seeking an industry partner to move forward
For information on Bioreactor Analyte Monitoring Applications,
please contact Info@InLightSolutions.com
|
