Multilayered Microneedle Patch Fabrication for Rapid Tip Detachment
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Solution Overview
Problem
Existing microneedle technologies face challenges with incomplete drug delivery due to mechanical strength and stability issues, requiring prolonged skin contact, which can cause allergic reactions and are difficult to produce in multilayered structures.
Innovation Solution
A method for manufacturing multilayer microneedles using precision layer-by-layer deposition of biopolymers in a dimethylpolysiloxane mold, with adaptive injection heads for precise dosing and rapid detachment, allowing for quick dissolution of the middle layer and controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional microneedles are fabricated on sticky flat patches, then they can be attached to the skin surface, but they do not completely penetrate into the skin and require prolonged contact time
Solution Approach 1:
The microneedle structure is divided into multiple layers with different dissolution rates. The tip layer contains the drug payload and is designed to dissolve slowly over time, while the base layer dissolves rapidly within 15-25 minutes to enable detachment. This segmentation allows complete drug delivery from the tip layer even after brief skin contact, resolving the contradiction between reliable drug delivery and reduced skin contact time.
Solution Approach 2:
The microneedles are pre-formed with a multilayer structure where the tip layer is already prepared with the complete drug payload before application. This preliminary preparation ensures that all drug is delivered through the needle tip during insertion and subsequent dissolution, eliminating the need for prolonged skin contact to achieve complete drug delivery.
2Ease of manufacture
If water-soluble polymers are used for microneedles, then they dissolve and release drugs after contact with interstitial fluid, but they have drawbacks in mechanical strength and stability
Solution Approach 1:
The microneedle employs a composite multilayer structure where each layer uses water-soluble polymers with optimized properties. The tip layer uses polymers providing mechanical strength for penetration, while the base layer uses polymers optimized for rapid dissolution. This composite approach maintains the ease of manufacture and drug release mechanisms of water-soluble polymers while achieving the required mechanical strength through structural design.
Solution Approach 2:
Different regions of the microneedle have different material properties tailored to their specific functions. The tip layer uses polymers with higher mechanical strength and controlled dissolution rate for stable penetration and sustained drug release, while the base layer uses polymers with rapid dissolution characteristics for easy detachment. This local optimization resolves the contradiction between mechanical strength requirements and ease of manufacture.
3Ease of operation
If multilayered structures are produced, then rapid detachment and controlled drug release are achieved, but the manufacturing complexity increases
Solution Approach 1:
The manufacturing process creates a segmented multilayer structure where each layer has distinct dissolution characteristics. The tip layer is formed first with drug incorporation, followed by the base layer with rapid-dissolve properties. This segmentation enables rapid detachment of the base layer while maintaining controlled drug release from the tip layer, achieving ease of operation through a systematic manufacturing approach.
Solution Approach 2:
The multilayer structure acts as an intermediary mechanism between the applied microneedle and the skin. The base layer serves as a temporary carrier that rapidly dissolves to enable detachment, while the tip layer remains as the active drug delivery component. This intermediary design achieves rapid detachment and controlled release without requiring complex manufacturing, as the layers are formed through sequential deposition processes.
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 method enables rapid detachment of microneedle tips from the skin within 15-25 minutes, with the remaining tips dissolving within 24 hours, ensuring complete drug delivery and reducing skin contact time, minimizing allergic reactions and infection risk.
Implementation Method 1
sequential precision layer-by-layer biopolymer aqueous solution deposition
Implementation Method 2
quick-dissolving middle layer... rapid detachment of the MN tips from DDMN base after attachment of the MN patch to the skin
Implementation Method 3
Biodegradable MNs have been actively studied recently. The advantage of this type of MNs is extended drug release. The MNs are composed of biodegradable materials that have higher drug payloads with no potential biohazardous waste after application to the skin
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3b
AI summary
An apparatus for manufacturing a multilayer microneedle patch and a method to manufacture a multilayer microneedle patch is disclosed along with multilayer microneedle patches.