Microneedle Applicator Pressure Body Dynamics

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Solution Overview

Problem

Existing microneedle plasters face challenges in uniformly pressing microneedles into the skin, leading to inconsistent application and potential jamming due to varying normal force components during the application process.

Innovation Solution

The applicator's pressure body is designed with an adjustable thrust or swivel joint, allowing for external force adjustment to increase the internal energy of a restoring device, ensuring uniform pressing of microneedles into the skin by pivoting or moving relative to the handle, with a pressure surface curvature that prevents jamming and ensures even insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the pressure body is fixed relative to the handle, then the structure is simple, but the microneedles cannot be pressed uniformly into the skin

Engineering Contradiction:
Improveuniformity of microneedle pressingVSAvoidstructure of applicator
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pressure body is made adjustable relative to the handle through a sliding or pivoting joint, allowing it to move between a rest position and a working position. This dynamic adjustment enables uniform pressing of microneedles into the skin while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The applicator allows change in the position and orientation parameters of the pressure body relative to the handle. By adjusting these parameters through external operating forces, the system achieves uniform microneedle insertion while keeping the base structure simple.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the pressure body is adjusted by external forces, then uniform pressing is achieved, but the structure becomes more complex with additional joints and mechanisms

Engineering Contradiction:
Improveconsistency of microneedle insertionVSAvoidjoint and mechanism structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The return mechanism automatically returns the pressure body to its rest position after application, eliminating the need for manual resetting. This self-service feature reduces operational complexity while maintaining the adjustable structure needed for precise microneedle insertion.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The applicator is designed as a disposable unit where the entire device including the complex joint mechanisms is discarded after single use. This approach justifies the inclusion of more complex structures during use, as no repair or maintenance is needed afterward.

Inventive Principle:
Principle #34Discarding and recovering

3Volume of moving object

If the pressure surface has a small radius, then the applicator is more compact, but the microneedles may tilt during insertion

Engineering Contradiction:
Improvesize of applicatorVSAvoidalignment of microneedles
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The curvature radius of the pressure surface is optimized to a specific range that prevents microneedle tilting while keeping the applicator compact. This parameter optimization balances the conflicting requirements of size and precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pressure surface is designed with a specific curvature rather than being flat or highly convex. This controlled curvature distributes pressure evenly across the microneedles during insertion, preventing tilting while maintaining a compact applicator design.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If the return mechanism is always loaded, then the pressure body remains in contact with the skin, but energy is continuously consumed

Engineering Contradiction:
Improvecontact pressure maintenanceVSAvoidinternal energy of return mechanism
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The return mechanism is loaded only periodically during the application process rather than continuously. The pressure body is adjusted to the working position during application and returns to rest position afterward, creating a periodic load pattern that reduces energy consumption while maintaining contact pressure when needed.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The pressure body dynamically transitions between rest and working positions, with the return mechanism engaged only during the working phase. This dynamic operation ensures reliable contact pressure during microneedle insertion while minimizing energy consumption during non-operational phases.

Inventive Principle:
Principle #15Dynamics

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 ensures that microneedles are pressed evenly and securely into the skin, minimizing the risk of jamming and ensuring consistent application, while allowing for adjustable force to maintain contact pressure, thereby enhancing the effectiveness of microneedle delivery.

Implementation Method 1

an internal return mechanism, by which the pressure body (51) can be adjusted relative to the handle (21) at least between a rest position (11) and a working position (12)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3927412B1Applicator for microneedle patch
Publication Date: 2023.09.13 LTS LOHMANN THERAPIE SYST AG
  • EP3927412B1 patent drawingFigure 1~2
  • EP3927412B1 patent drawingFigure 3
  • EP3927412B1 patent drawingFigure 4

AI summary

The invention relates to an applicator comprising a handle piece and a pressing body for a microneedle patch, which pressing body is connected to the handle piece. The invention also relates to a unit comprising an applicator of this type and comprising a microneedle patch having a multiplicity of microneedles. The pressing body is mounted for movement relative to the handle piece in a sliding joint or in a pivot joint at least between an idle position and a usage position by means of external operating forces and an internal restoring device. The pressing body has a pressing surface which is spaced apart from the pivot joint or sliding joint. In the idle position, the pressing body is not loaded by external operating forces, and the restoring device has the lowest internal energy. Furthermore, the pressing body can be moved relative to the handle piece toward the usage position by means of external operating forces acting on the pressing surface, the internal energy of the restoring device thus being increased. The present invention enables the microneedles to be pressed in substantially uniformly.