Retroreflective Optical Monitoring for Bioreactor Culture Medium
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Solution Overview
Problem
Current methods for monitoring culture medium in bioreactors, such as measuring optical transmittance, are limited in their ability to accurately determine the state of the medium without interfering with stirrers and are not adaptable to various bioreactor shapes and sizes, leading to inefficient culture medium replacement timing and potential cell contamination.
Innovation Solution
A culture-medium-monitoring apparatus with an optical measurement unit that uses a retroreflective member to detect changes in illumination light intensity over time, allowing for precise determination of medium state and automated notification for replacement, while being compatible with different bioreactor configurations through a stirrer control system and image acquisition for phase contrast imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an illumination light beam is radiated from a direction intersecting the center axis of the bioreactor to avoid the stirrer, then the measurement can be performed without interference from the stirrer, but the measurement precision is reduced due to the limited measurement path through the culture medium
Solution Approach 1:
The patent introduces a retroreflective member to create a folded optical path that extends the measurement distance in the radial direction without requiring the light source and detector to be positioned axially. This allows the light beam to traverse a longer path through the culture medium while avoiding the central stirrer, thereby improving measurement precision without compromising reliability
Solution Approach 2:
The retroreflective member acts as an intermediary element that redirects the illumination light beam back through the culture medium to the detector. This mediator enables the light to pass through the culture medium multiple times, enhancing the measurement signal and precision while maintaining compatibility with the bioreactor's stirring operation
2Measurement precision
If the optical measurement system is designed for a specific bioreactor configuration, then the measurement precision is optimized for that configuration, but the adaptability to various bioreactor shapes and sizes is reduced
Solution Approach 1:
The optical measurement system is designed with the retroreflective member positioned on the outer surface of the bioreactor, allowing the illumination light beam to pass through the culture medium and reflect back regardless of the bioreactor's specific dimensions or shape. This universal design enables the same measurement principle to be applied across different bioreactor configurations while maintaining measurement precision
Solution Approach 2:
The system allows for flexible positioning of the illumination light beam and detector along the radial direction, enabling adaptation to different bioreactor sizes and shapes. The measurement path can be dynamically adjusted by changing the angular position or radial distance of the light source and detector, making the system versatile across various bioreactor configurations
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
Enables accurate and timely culture medium replacement, reducing cell contamination risks and improving culturing efficiency by adapting to various bioreactor shapes and sizes, and providing automated monitoring and notification systems.
Implementation Method 1
a retroreflective member that has an array in which a plurality of micro-reflective elements are arrayed, that is disposed so as to sandwich the vessel between the illuminating portion and the retroreflective member, and that reflects the illumination light beam that has passed through the culture medium in the vessel
Implementation Method 2
a light-detecting portion that detects an intensity of the illumination light beam that has passed through the culture medium in the vessel after being reflected by the retroreflective member
Implementation Method 3
The control portion determines a state of the culture medium on the basis of a change over time in the intensity of the illumination light beam
Data Source
AI summary
Provided is a culture-medium-monitoring apparatus including: an optical measurement unit that includes an illumination light source and a collecting lens that radiate an illumination light onto a culturing liquid, a retroreflective member that has an array in which micro-reflective elements are arrayed, that is disposed so as to sandwich the vessel between the retroreflective member, and the illuminating light source and the collecting lens, and that reflects the illumination light passed through the culturing liquid in the vessel, and a light detector that detects an intensity of the illumination light passed through the culturing liquid in the vessel after being reflected by the retroreflective member; and a control portion that causes the intensity of the illumination light to be repeatedly detected at a prescribed timing, and that determines a state of the culturing liquid on the basis of a change over time in the intensity of the illumination light.