Implantable Perfusion Device Microchannel Filtration
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Solution Overview
Problem
Bio-artificial pancreas devices face challenges in maintaining a sufficient substance transport rate to and from encapsulated islet cells, including nutrient supply and insulin removal, while avoiding clogging or collapsing of the semi-permeable protective layer, which affects their durability and performance over time.
Innovation Solution
An implantable perfusion device with a tubular transmission line and a perfusion chamber containing biologically active cells, featuring microchannel platelets for filtering and fluid communication, along with a flow restriction element to establish a pressure gradient, ensuring efficient nutrient supply and insulin removal, and a modular design for cell containment and anticoagulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semi-permeable protective layer is used to encapsulate islet cells, then cell containment and protection are improved, but clogging and collapsing occur over time reducing substance transport efficiency
Solution Approach 1:
The protective layer is segmented into multiple discrete micropores rather than a continuous membrane. Each micropore acts as an independent transport channel, preventing the entire structure from collapsing or clogging uniformly. This segmentation maintains reliable cell containment while ensuring sustained substance transport over time.
Solution Approach 2:
The protective layer is designed as a porous structure with controlled micropores of specific size and distribution. This porous configuration allows efficient diffusion of nutrients and insulin while providing structural stability. The porous material prevents clogging by maintaining open channels and avoids collapsing through appropriate pore size selection that balances filtration and transport functions.
2Duration of action of stationary object
If the semi-permeable protective layer is made more durable to prevent clogging and collapsing, then device longevity is improved, but substance transport efficiency may be reduced
Solution Approach 1:
The micropore parameters (size, shape, distribution, and density) are optimized to achieve the desired balance between durability and transport efficiency. By carefully controlling these parameters, the protective layer maintains structural integrity over extended periods while ensuring adequate insulin removal rates. The micropore size is specifically selected to prevent clogging while allowing efficient molecular transport.
3Reliability
If nutrient supply rate to islet cells is increased, then cell viability is improved, but the risk of clogging in the transmission line increases
Solution Approach 1:
The transmission line incorporates segmented flow channels with distributed micropores rather than a single large channel. This segmentation divides the nutrient flow into multiple smaller streams, reducing the velocity and pressure that cause clogging while maintaining adequate nutrient supply rates. Each segment independently contributes to cell viability without compromising the other segments.
Solution Approach 2:
The microporous protective layer acts as an intermediary between the transmission line and islet cells. It filters and regulates the nutrient flow, allowing adequate nutrient supply to reach cells while trapping potential clogging particles. This intermediary structure protects the transmission line from clogging while ensuring sufficient nutrient delivery for cell viability.
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 device provides a stable and efficient substance transport system, maintaining cell viability and performance over an extended period by optimizing blood flow and cell product delivery, reducing the risk of clogging and ensuring consistent insulin production.
Implementation Method 1
the fluid entrance comprising at least one first microchannel platelet and the fluid exit comprising at least one second microchannel platelet, each one of the microchannel platelets comprising at least one array of microchannels defining a fluid passage
Implementation Method 2
the flow restriction element is configured to establish a predetermined pressure excess in the inlet section versus the outlet section
Implementation Method 3
a semi-permeable protective layer around the sheet which allows diffusion of nutrients and of hormones secreted by the islet cells
Data Source
Figure 1~2
Figure 3~4
Figure 5~8
AI summary
An implantable perfusion device (2) comprises a tubular transmission line (4) with an inlet end (6), an outlet end (8) and a flow restriction element (10) located therebetween, whereby an inlet section (12) of the transmission line is defined between the inlet end and the flow restriction element and whereby an outlet section (14) of the transmission line is defined between the flow restriction element and the outlet end. Moreover, the device comprises a perfusion chamber (16) containing a load of biologically active cells and is provided with a fluid entrance (18), a fluid exit (20) and a chamber volume (22) formed therebetween. The fluid entrance comprises at least one first microchannel platelet (24) and the fluid exit comprises at least one second microchannel platelet (26), each one of the microchannel platelets comprising at least one array of microchannels (28) defining a fluid passage between respective external and internal platelet faces, the microchannels having an opening of 0.2 to 10 μm. The fluid entrance (18) of the perfusion chamber is in fluid communication with the inlet section (12) of the transmission line; and the flow restriction element (10) is configured to establish a predetermined pressure excess in the inlet section (12) versus the outlet section (14).