Electroosmotic Pump for Drug Injection with Alternating Pressure
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Solution Overview
Problem
Miniaturized and automated insulin injectors face challenges in maintaining stability due to back pressure caused by reactions between the drug and biological fluid at the cannula or needle tip, leading to blockage issues, especially during small or slow injections.
Innovation Solution
A drug injection device utilizing an electroosmotic pump that operates in an immediate bolus injection mode, controlled by an amount-based injection sequence. This sequence includes pulse blocks defining voltage or current pulses to alternately generate negative and positive pressure, ensuring stable drug injection without blockage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If insulin injectors are miniaturized and automated, then user convenience is improved, but operation stability deteriorates due to back pressure blockage
Solution Approach 1:
The patent employs periodic alternating polarity pulses applied to the electroosmotic pump to create cyclic pressure changes. The controller alternates between positive and negative voltage pulses, causing the pump to periodically generate positive pressure (for drug discharge) and negative pressure (for backflow prevention and blockage clearance). This periodic action maintains stable operation by preventing continuous back pressure accumulation while enabling automated convenient injection.
2Measurement precision
If drug injection amount is small or injection speed is slow, then dosage precision is improved, but blockage phenomenon worsens due to back pressure
Solution Approach 1:
The controller applies alternating polarity pulses with optimized duty cycles to achieve precise small-volume injection while preventing blockage. During the positive pulse phase, a controlled amount of drug is injected with high precision; during the negative pulse phase, back pressure is relieved and any potential blockages are cleared. This periodic alternation enables accurate dosing even at slow injection rates without suffering from back pressure-induced blockage.
Solution Approach 2:
The patent dynamically adjusts pulse width, amplitude, and frequency parameters of the electroosmotic pump based on injection requirements. For small dosage precision needs, the controller uses lower amplitude pulses with optimized width; for blockage prevention, it introduces negative polarity phases. This parameter modulation allows the system to maintain both dosage precision and blockage resistance across varying injection conditions.
3Reliability
If electroosmotic pump alternately generates negative and positive pressure, then drug injection stability is improved, but device complexity increases
Solution Approach 1:
The electroosmotic pump structure inherently provides the pressure alternation function through its design. The pump chamber and membrane configuration automatically convert alternating polarity electrical signals into alternating pressure outputs without requiring additional mechanical components or complex control mechanisms. This self-service capability achieves stable injection with relatively simple device architecture.
Solution Approach 2:
The patent replaces complex mechanical pressure control systems with an electroosmotic pump driven by electrical pulses. Instead of using mechanical pumps, valves, or pressure regulators to achieve alternating pressure, the system uses electrical field control of fluid movement through the electroosmotic effect. This substitution simplifies the overall device while maintaining injection stability.
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 effectively injects a fixed amount of drug by setting the amount-based injection sequence, preventing blockages and ensuring accurate and stable drug delivery, even during small or slow injections.
Implementation Method 1
a drug injector configured to suck a drug from a drug storage by electrochemically operating an electroosmotic pump and discharge an sucked drug to an injection target
Implementation Method 2
the at least one pulse block defines a pair of pulse signals including a forward pulse and a reverse pulse that are applied to the electroosmotic pump to alternately generate negative pressure and positive pressure
Data Source
AI summary
A drug injection device includes a drug injector configured to suck a drug from a drug storage by electrochemically operating an electroosmotic pump and discharge an sucked drug to an injection target; and a controller configured to output, to the drug injector, a control signal corresponding to an amount-based injection sequence for causing the electroosmotic pump to operate in an immediate bolus injection mode, wherein the amount-based injection sequence includes at least one pulse block defining a voltage pulse or a current pulse to be applied to the electroosmotic pump, the at least one pulse block defines a pair of pulse signals including a forward pulse and a reverse pulse that are applied to the electroosmotic pump to alternately generate negative pressure and positive pressure, and the electroosmotic pump alternately generates negative pressure and positive pressure for each pulse block to suck and discharge the drug.