Optical Sensor Holding Device for Bioreactor Bags
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Solution Overview
Problem
Disposable bioreactors with flexible plastic bags pose challenges in maintaining optical sensors, such as pH and dissolved oxygen sensors, inside the culture due to support structure limitations and chemical incompatibility, leading to inconsistent measurements and potential leakage.
Innovation Solution
An optical sensor holding device is integrated inside the bioreactor bag via welding, using a sensor holding part made from compatible materials like polyethylene, with an adaptor part outside the bag to securely position an optical fibre, employing a locking mechanism and mirror to direct light to the sensor, ensuring stable and chemical-compatible attachment without requiring support structure adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sensors are provided from the upper side of the bag, then installation is convenient, but the sensor may not remain inside the culture all the time
Solution Approach 1:
The sensor holding device is divided into separate components: a sensor holder that attaches to the bag and a support structure that positions the sensor. This segmentation allows the sensor to be securely positioned at the bottom while maintaining installation convenience through modular assembly.
Solution Approach 2:
The sensor holding device extends vertically from the bottom of the bag, using the vertical dimension to position the sensor above the bag bottom while keeping it submerged in the culture. This dimensional approach resolves the conflict between bottom positioning for stability and upper positioning for convenience.
2Ease of manufacture
If optical sensors are attached directly on the bag material, then attachment is simple, but chemical incompatibility prevents direct attachment
Solution Approach 1:
The sensor holding device acts as an intermediary component between the bag material and the optical sensor. It provides a chemically compatible interface that can be attached to the bag while supporting the sensor, eliminating direct contact between incompatible materials.
Solution Approach 2:
The sensor holding device utilizes composite construction with materials selected for chemical compatibility with both the bag material and the optical sensor. This composite approach ensures compatibility across all interfaces while maintaining attachment simplicity.
3Reliability
If the sensor assembly is made bulky, then sensor positioning is stable, but it disrupts culture mixing and may not remain under the liquid surface
Solution Approach 1:
The sensor holding device employs a flat, thin-profile design that resembles a film or shell structure. This minimizes the device's volume and ensures it remains submerged under the liquid surface without disrupting culture mixing, while still providing stable sensor positioning through its distributed support structure.
4Reliability
If the bioreactor requires support structure adaptation for sensor attachment, then sensor attachment is secure, but adaptability to existing systems is reduced
Solution Approach 1:
The sensor holding device is designed as a universal attachment system that can be installed on existing bioreactor bags without requiring modifications to the support structure. Its multi-functional design allows it to secure the sensor while maintaining compatibility with various existing 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
The solution ensures consistent sensor placement and operation within the bioreactor, minimizing leakage risks and allowing the bioreactor to be freely moved, while maintaining a flat profile that does not disrupt culture mixing, thus enhancing measurement reliability and adaptability to existing systems.
Implementation Method 1
Such an optical sensor, sometimes called a sensor spot, is a spot of a dye material typically comprising two different fluorescent materials. When the sensor spot is illuminated, fluorescent substances of the spot will emit light.
Implementation Method 2
A sensor holding part is provided inside the bag and is integrated with the bag by means of for example welding.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a
AI summary
An optical sensor holding device adapted to be integrated with a flexible bag, said device comprising - a bag attachment part made from a material that can be welded to the flexible bag; - a sensor attachment part made from a material to which an optical sensor spot can be attached, wherein the sensor attachment part is forced into an opening in the bag attachment part that is slightly smaller than the sensor attachment part such that the sensor attachment part is kept firmly in place and leakage is minimized.