Linear Optical Loss Probe for Bioreactor Cell Density Monitoring
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Solution Overview
Problem
Current turbidity meters used in bioreactors for monitoring cell density in bioreactors provide non-linear and ambiguous results due to their reliance on incoherent light sources and large optical beams, leading to inaccurate measurements beyond 1 AU of optical loss, and are unable to maintain a linear response over the dynamic range of cell growth processes.
Innovation Solution
A cell density probe utilizing a monochromatic light source at 830 nm, phase-sensitive detection, and apertured detection system to limit the solid angle of light collection, ensuring adherence to Beer's law and providing a linear response over a broader range of cell densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If incoherent light sources and large optical beams are used in turbidity meters, then the device complexity is reduced, but measurement precision deteriorates due to non-linear and ambiguous results beyond 1 AU of optical loss
Solution Approach 1:
The patent changes the parameters of the light source from incoherent to coherent (laser), and from broad bandwidth to monochromatic (specific wavelength), which fundamentally alters the optical interaction with the sample and enables linear measurements over extended dynamic ranges
Solution Approach 2:
The patent replaces the mechanical/optical system of incoherent light sources with a coherent laser system, utilizing the superior coherence properties of laser light to achieve precise measurements through reduced scattering and improved signal-to-noise ratio
2Ease of manufacture
If incoherent light sources and large optical beams are used, then the ease of manufacture is improved, but measurement precision deteriorates due to inability to maintain linear response over dynamic range
Solution Approach 1:
The patent changes the light source parameters to coherent and monochromatic, which enables the system to maintain linear response over the entire dynamic range of cell densities, resolving the contradiction between ease of manufacture and measurement precision
3Measurement precision
If monochromatic light source and apertured detection system are used, then measurement precision is improved through adherence to Beer's law, but device complexity increases
Solution Approach 1:
The patent changes the light source to monochromatic and introduces aperture optics to control the beam profile and scattering geometry, which together enable strict adherence to Beer's law and linear response across the dynamic range
Solution Approach 2:
The patent replaces incoherent light with coherent laser light and introduces phase-sensitive detection, utilizing the superior optical properties of coherent light to achieve precise measurements while managing system complexity through optimized optical design
4Ease of operation
If conventional turbidity probes are used, then the ease of operation is maintained, but reliability deteriorates due to non-linear and ambiguous results
Solution Approach 1:
The patent changes the optical parameters of the light source and detection system to ensure linear and reliable measurements, while maintaining ease of operation through automated real-time monitoring capabilities
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The probe achieves a linear and accurate measurement of cell density in real-time, extending the dynamic range and maintaining measurement integrity over a wider range of cell concentrations compared to existing systems, allowing for precise monitoring of bioprocesses.
Implementation Method 1
A cell density probe utilizing a monochromatic light source at 830 nm, phase-sensitive detection, and apertured detection system to limit the solid angle of light collection, ensuring adherence to Beer's law
Implementation Method 2
A cell density probe utilizing a monochromatic light source at 830 nm, phase-sensitive detection, and apertured detection system
Implementation Method 3
apertured detection system to limit the solid angle of light collection, ensuring adherence to Beer's law and providing a linear response over a broader range of cell densities
Data Source
AI summary
An optical loss probe utilized as a bioreactor process monitor manifesting a substantially linear response in optical loss vs. concentration of scatterers present in an aqueous medium in the range of between about 0 AU and about 4.0 AU, said probe comprising:i) a light source,ii) an optical detector, andiii) an optical gap between said light source and said optical detector, said optical detector having a receiving aperture configured such that the solid angle of acceptance of the light passing through said optical gap and impinging on said optical detector is less than π/50 radians.