Hydrogel Barrier for Backflow Mitigation in Subcutaneous Infusion
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Solution Overview
Problem
Subcutaneous infusion devices face challenges with fluid backflow, which can interfere with sensor operations and lead to inaccurate readings, particularly when combined with a sensor in a single device, and result in inefficient delivery and increased patient discomfort.
Innovation Solution
The integration of an expandable member, such as a biocompatible hydrogel or swellable polymer, coupled to the infusion cannula to mitigate backflow by expanding radially upon contact with bodily fluids, creating a barrier between the infusion outlet and the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the infusion cannula and sensor are integrated in a single device with close proximity, then the overall footprint and number of needle insertions are reduced, but fluid backflow from the infusion cannula interferes with sensor operation causing inaccurate readings
Solution Approach 1:
A hydrogel barrier is introduced as an intermediary substance between the infusion cannula and the sensor. This hydrogel absorbs excess fluid and prevents backflow from reaching the sensor, thereby maintaining measurement precision while allowing the integrated device structure to remain in place
Solution Approach 2:
The device is segmented into distinct functional zones: an infusion zone with the cannula, a barrier zone with the hydrogel, and a sensing zone with the sensor. This spatial segmentation allows each component to function independently without interference, resolving the contradiction between integration and measurement accuracy
2Area of stationary object
If the infusion media is delivered at or near the subcutaneous site of the sensor element, then the device footprint is reduced, but stabilizers in the infusion media interfere with the sensor signal
Solution Approach 1:
The hydrogel acts as a mediator that absorbs and contains the infusion media, preventing it from directly contacting the sensor. This allows the infusion media to be delivered close to the sensor without the stabilizers interfering with the sensor signal
Solution Approach 2:
The hydrogel creates a localized containment zone around the infusion cannula outlet, concentrating the absorption function in a specific area. This local quality enhancement allows the sensor to operate accurately while the infusion occurs in close proximity
3Productivity
If the volume of infusion media is increased during a bolus, then the infusion effectiveness is improved, but the local tissue analyte is diluted causing sensor signal decay
Solution Approach 1:
The hydrogel serves as a buffer that absorbs the bolus volume locally, preventing the infusion media from directly diluting the tissue analyte around the sensor. This allows effective bolus delivery while maintaining sensor signal strength
Solution Approach 2:
The hydrogel changes the physical parameters of the infusion process by absorbing excess fluid volume and controlling its distribution. This parameter change prevents analyte dilution while maintaining infusion effectiveness
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 configuration maintains accurate sensor readings by reducing fluid interference with the sensor while ensuring efficient infusion and minimizing patient discomfort through improved fluid absorption and reduced needle insertions.
Implementation Method 1
The expandable member comprises a biocompatible hydrogel and/or a swellable polymer
Implementation Method 2
The expandable member is configured to expand in a radially outward direction when in the presence of bodily fluid
Implementation Method 3
The expandable member is configured to expand in a radially outward direction when in the presence of bodily fluid
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3D
AI summary
Systems and methods for mitigating backflow in subcutaneous infusion devices are disclosed. A medical device can include base having a surface configured to be placed against a patient's skin and a subcutaneous assembly coupled to the base and configured to be inserted through the patient's skin when the surface of the base is placed against the patient's skin. The subcutaneous assembly includes an infusion cannula defining a lumen extending therethrough and configured to infuse fluid therethrough, and a sensor configured to sense a biological analyte. An expandable member (e.g., a swellable material) is coupled to a radially outer surface of the subcutaneous assembly. The expandable member is configured to expand in a radially outward direction when in the presence of bodily fluid, thereby at least partially blocking a flow path from the distal end portion of the infusion cannula to the sensor.