Microneedle Applicator Guide Plate Stabilizes Insertion Depth
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Solution Overview
Problem
The reproducibility of microneedle puncture is compromised due to unstable force direction when users manually roll a microstructure apparatus, leading to variations in insertion depth and procedure.
Innovation Solution
An applicator with a resistive portion and a bending portion, comprising cylindrical members, is designed to stabilize the microneedle sheet's movement, ensuring microneedles are inserted with consistent horizontal force, using a guide plate and slider mechanism to reverse and bend the sheet, thereby increasing puncture reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If microneedles are inserted by manually rolling a roller mounted on the arm, then the device can be operated easily by hand, but the force direction becomes unstable leading to large variations in insertion depth
Solution Approach 1:
A guide plate is introduced as an intermediary component between the roller and the microneedle array. The guide plate includes a guide groove that constrains the microneedles to move along a predetermined path, ensuring that the force applied during rolling is directed consistently. This mediator translates the manual rolling motion into stable, controlled insertion without requiring precise manual force control.
Solution Approach 2:
The design changes the operational parameters by fixing the geometric constraints through the guide groove's shape and orientation. By predetermined the insertion path and angle through the guide groove geometry, the system converts variable manual force into consistent insertion parameters, achieving depth consistency despite variations in user application force.
2Device complexity
If the microneedle sheet is fed through a simple roller assembly, then the device structure remains simple, but the reproducibility of puncture is not guaranteed due to unstable force direction
Solution Approach 1:
The guide plate serves as a structural intermediary that integrates into the roller assembly without significantly increasing complexity. It provides the necessary geometric constraints through its guide groove, ensuring reliable and reproducible puncture by directing the microneedles along a fixed path during the rolling operation.
Solution Approach 2:
The roller assembly utilizes a curved surface to apply distributed force across the microneedle array during rotation. This curvature allows the rolling motion to naturally guide the microneedles into the skin at consistent angles, improving puncture reproducibility while maintaining a relatively simple cylindrical structure.
3Ease of operation
If force is applied in varying directions during manual rolling, then user comfort may be improved through flexible operation, but the insertion depth varies significantly
Solution Approach 1:
The guide groove's predetermined geometry establishes fixed insertion parameters (angle and depth) that remain constant regardless of variations in manual force direction. The system allows flexible operation while maintaining precise insertion control by decoupling the user's force application from the actual insertion parameters through the guiding mechanism.
Solution Approach 2:
The guide plate acts as a force-direction intermediary, accepting forces from various directions during manual operation and converting them into consistent, unidirectional insertion forces through its constrained groove geometry. This allows users to operate flexibly while ensuring precise, controlled insertion depth.
Data Source
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AI summary
An applicator of one aspect for applying microneedles to skin includes a resistive portion configured to apply resistance against movement of a microneedle sheet having the plurality of microneedles formed along a main surface of the sheet, and a bending portion configured to bend the microneedle sheet passed through the resistive portion to raise the microneedle from the main surface.