Shape Memory Polymer Catheter for Variable Flow Area
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Solution Overview
Problem
Current catheters face challenges in having a large enough lumen for therapeutic treatment while maintaining a small outer diameter for easy insertion and removal, as they either have large inner diameters with corresponding large outer diameters or small inner diameters with small outer diameters, limiting their versatility and ease of use.
Innovation Solution
A catheter made from shape memory polymers that can change configuration in response to temperature, allowing for a small outer diameter for insertion and a larger inner diameter for treatment, and returning to a small diameter for easy removal, utilizing polymeric materials with distinct phase transition temperatures to facilitate these changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the catheter has a large inner diameter lumen for therapeutic treatment, then the flow area is improved, but the outer diameter becomes large which complicates insertion and removal
Solution Approach 1:
The catheter employs a dynamically configurable lumen structure that can change its diameter based on operational requirements. The lumen transitions from a compressed state during insertion to an expanded state during therapeutic treatment, allowing the catheter to adapt its flow area while maintaining a small outer diameter for easy insertion and removal.
Solution Approach 2:
The catheter utilizes shape memory polymers that undergo phase transitions at specific temperatures to change the lumen's diameter. By controlling the temperature parameter, the lumen can expand to provide adequate flow area for therapy or contract to minimize the outer diameter for insertion and removal, resolving the contradiction between flow area and ease of operation.
2Ease of operation
If the catheter has a small outer diameter for easy insertion, then the ease of operation is improved, but the inner diameter lumen becomes small which reduces flow area for treatment
Solution Approach 1:
The catheter's lumen is designed to dynamically expand after insertion to provide adequate flow area. The shape memory polymer structure allows the lumen to transition from a compressed state during insertion to an expanded state during therapy, ensuring both easy insertion and sufficient flow area are achieved.
Solution Approach 2:
By utilizing temperature-induced phase transitions in shape memory polymers, the catheter lumen can change its diameter parameter. The lumen remains compressed at lower temperatures during insertion for ease of operation, then expands when temperature increases to provide adequate flow area for therapeutic treatment.
3Productivity
If the catheter lumen is expanded to increase flow area, then the volumetric flow rate is improved, but the outer diameter increases which may occlude body vessels
Solution Approach 1:
The catheter employs local quality changes where only the lumen interior expands to increase flow area, while the outer diameter remains constrained. The shape memory polymer structure allows differential expansion within the lumen while maintaining the outer diameter at a size appropriate for vessel insertion, thus increasing volumetric flow rate without risking vessel occlusion.
Solution Approach 2:
The catheter utilizes controlled parameter changes in the lumen's internal diameter through temperature-induced phase transitions in shape memory polymers. This allows the lumen to expand and increase volumetric flow rate while the outer diameter parameter remains controlled to prevent vessel occlusion, resolving the contradiction between productivity and harmful effects.
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
This design significantly increases the volumetric flow rate with minimal increase in outer diameter, allowing for effective therapeutic treatment and easy catheter removal without occluding the body vessel, as demonstrated by the substantial increase in flow rate with moderate diameter expansion.
Implementation Method 1
The elongated member is formed of a polymeric material including shape memory polymers having a first phase transition temperature and a second phase transition temperature that is less than the first phase transition temperature but is greater than about room temperature. At about room temperature, the elongated member is in a first configuration. The elongated member is heated to a first temperature of at least the second phase transition temperature where the elongated member self-configures to a second configuration.
Implementation Method 2
The elongated member is formed of a polymeric material including shape memory polymers having a first phase transition temperature and a second phase transition temperature that is less than the first phase transition temperature but is greater than about room temperature.
Data Source
Figure 1A~1B
Figure 1C~1E
Figure 2A
AI summary
In at least one embodiment of the present invention, a catheter for insertion into a patient's body is provided. The catheter comprises an elongated member having a proximal portion extending to a distal portion. A lumen is formed through the proximal and distal portions. The elongated member is formed of a polymeric material including shape memory polymers having a first phase transition temperature and a second phase transition temperature that is less than the first phase transition temperature but is greater than about room temperature. The elongated member has a first configuration at about room temperature for insertion into the patient's body and self-configures to a second configuration at a first temperature of at least the second phase transition temperature for fluid communication with the patient's body. At least a portion of the lumen has a larger flow area in the second configuration than in the first configuration.