Asymmetric Bi-Stable Dome Actuator for Low-Force MAP Delivery

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Solution Overview

Problem

Existing microprojection array applicators face challenges in delivering high-density microprojection arrays at high speeds with minimal user trigger force and pressure, causing discomfort to patients, especially in self-administration scenarios, particularly for geriatric and pediatric populations.

Innovation Solution

The use of compact, self-contained mechanical energy storage devices with asymmetric bi-stable metal domes, encased to reduce trigger force and enhance velocity, allowing for high-speed delivery of microprojection arrays with minimal discomfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional microprojection array applicators are used, then the device can deliver microprojection arrays, but the trigger force required is high causing discomfort to patients

Engineering Contradiction:

Improvetrigger forceVSAvoidease of self-administration

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The dome is pre-loaded with mechanical energy before use, storing potential energy that is released during triggering. This preliminary energy storage allows the system to deliver high projection forces without requiring high trigger forces from the user, thereby reducing discomfort and enabling self-administration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The applicator transitions from a static energy storage system to a dynamic one by using a bi-stable dome that can rapidly transition between stable states. This dynamic behavior allows the stored mechanical energy to be released quickly, providing high delivery speed with low trigger force

Inventive Principle:

Principle #15Dynamics

2Speed

If high trigger force is applied to accelerate the microprojection array, then the delivery speed increases, but the patient experiences discomfort and pain

Engineering Contradiction:

Improvedelivery speedVSAvoidpatient discomfort

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

Mechanical energy is pre-stored in the dome through pre-loading, creating a reservoir of energy ready for release. This allows the system to achieve high delivery speeds without requiring high instantaneous forces from the trigger, thereby avoiding patient discomfort while maintaining effective penetration speed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The bi-stable dome utilizes periodic or pulsed energy release through its snap-through mechanism, converting stored potential energy into kinetic energy in a rapid, controlled manner. This periodic action enables high-speed delivery with minimal sustained force application, reducing patient discomfort

Inventive Principle:

Principle #19Periodic action

3Volume of moving object

If a compact energy storage device is used, then the applicator size is reduced, but the energy storage capacity may be limited

Engineering Contradiction:

Improveapplicator sizeVSAvoidenergy storage capacity

Core Design Contradiction:

Volume of moving objectVSUse of energy by moving object

Solution Approach 1:

The dome's mechanical properties are optimized by changing parameters such as thickness, radius, and material composition to achieve maximum energy storage density. This allows the compact dome to store sufficient mechanical energy for effective microprojection delivery while maintaining a small form factor suitable for portable applicators

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The dome is constructed from high-strength, high-elasticity materials that provide superior energy storage capacity per unit volume. These composite or specialized materials enable the compact energy storage device to maintain both small size and adequate energy capacity for effective microprojection array delivery

Inventive Principle:

Principle #40Composite materials

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 devices achieve high velocities (18-24 m/s) with low trigger forces (10-25 N), effectively delivering microprojection arrays without causing discomfort, suitable for self-administration and targeting challenging populations.

Implementation Method 1

asymmetric bi-stable metal domes, encased to reduce trigger force and enhance velocity

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

compact, self-contained mechanical energy storage devices

Methodology Applied

Scientific EffectMechanical energy storage: Mechanical Accumulator

Data Source

PatentEP4218893B1Compact high mechanical energy storage and low trigger force actuator for the delivery of microprojection array patches (MAP)

Publication Date: 2025.10.01 VAXXAS PTY LTD

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AI summary

The present invention relates to devices and methods for providing a triggering mechanism which lowers the trigger force to activate the trigger mechanism to a comfortable range of while still preserving or increasing the speed at which the triggering mechanism accelerates or imparts velocity to a device attached to the triggering mechanism. The present invention further relates to improved applicators for administering microprojection arrays to skin and methods of administering microprojection arrays. In particular, the present invention relates to compact stable self-contained mechanical energy storage for delivery of a medical device such as a microprojection array.