Microfluidic Piston Pump for Accurate Insulin Bolus Dosing
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Solution Overview
Problem
Current bolus dosing systems in insulin pumps face issues such as valve sticking or leaking, incorrect dosing, and failure to reset, leading to incomplete or inaccurate medication delivery.
Innovation Solution
The development of a microfluidic circuit-based device with a basal and bolus flow path, featuring a piston pump with a button, resilient arm, and protrusion mechanism to prevent partial dosing and ensure accurate bolus delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piston pump with check valves is used in a microfluidic circuit, then dosing accuracy is improved, but device complexity increases
Solution Approach 1:
The device divides the fluid delivery system into separate basal and bolus flow paths, each with dedicated components. The piston pump is segmented into distinct functional zones (filling chamber, dispensing chamber) with separate check valves (inlet check valve, outlet check valves), allowing independent control and reducing interference between functions while maintaining precision.
Solution Approach 2:
Check valves are introduced as intermediary components between the reservoir and piston pump, and between the piston pump and delivery site. These valves mediate the fluid flow by allowing movement in one direction while preventing backflow, enabling the piston pump to achieve precise dosing without direct exposure to flow control complexities.
2Reliability
If check valves are added to control flow direction, then dosing reliability is improved, but manufacturing difficulty increases
Solution Approach 1:
The check valves are designed with localized flow control features positioned at specific critical points in the microfluidic circuit (inlet to piston pump, outlet from piston pump). This localized approach provides reliable flow direction control exactly where needed while keeping other portions of the device simpler to manufacture.
Solution Approach 2:
The check valve design uses replicated structures that can be manufactured using standard microfluidic fabrication techniques. The valve mechanisms are designed as copyable components that can be produced through lithography and etching processes, making them manufacturable without requiring complex assembly operations.
3Measurement precision
If a piston pump mechanism is implemented, then bolus dose accuracy is improved, but the number of moving parts increases
Solution Approach 1:
The piston pump mechanism merges the piston, check valves, and flow control features into an integrated microfluidic structure. The piston itself incorporates flow control surfaces, and the check valves are integrated into the same structural platform, reducing the number of separate moving parts while maintaining dosing accuracy.
Solution Approach 2:
The piston structure serves multiple functions simultaneously: it acts as a flow control element, a sealing element, and a mechanical actuator for dosing. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing the overall number of moving parts.
4Reliability
If the piston pump is designed to prevent partial dosing, then dosing reliability is improved, but device complexity increases
Solution Approach 1:
The check valves are positioned and designed to preemptively prevent partial dosing by blocking unintended flow paths before they can occur. The inlet check valve prevents premature filling, while the outlet check valves prevent premature dispensing, creating a preliminary protective mechanism that ensures complete dosing cycles without requiring complex control systems.
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 reliable and accurate bolus dosing, with a volume variation within ±10% of the targeted dose, and is designed for fail-safe operation to prevent medication from flowing directly into the patient.
Implementation Method 1
a resilient arm attached to a protrusion... the resilient arm flexes towards the second channel... the resilient arm moves the protrusion towards the first channel
Implementation Method 2
a spring disposed about the button, wherein the spring is configured to bias the button in an extended position, which corresponds to the first position of the piston
Implementation Method 3
releasing the button to move the piston... to increase a pressure within the bolus chamber to deliver the bolus dose
Data Source
AI summary
Devices and methods for administering a medication in fluid form, the systems and methods including a basal flow path and a bolus flow path in parallel to the basal flow path. The bolus flow path comprises a first check valve, a second check valve downstream of the first check valve, a piston pump disposed between the first valve and the second valve, and a pilot operated valve in parallel to the piston pump.