Implantable Microneedle with Swellable Polymer Tip
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Solution Overview
Problem
Conventional microneedle manufacturing methods face challenges such as inefficient drug delivery, rapid microneedle dissolution, skin damage, and bacterial infections due to the deformation of microneedles during manufacturing and the inability to uniformly apply polymer solutions, leading to quantitative drug delivery issues and economic inefficiencies.
Innovation Solution
A method involving a microneedle with a swellable polymer coating layer applied only to the tip, which swells upon moisture exposure to engage with skin tissue, allowing for selective drug delivery and easy separation from the microneedle, preventing tissue damage and bacterial infections, while using a sacrificial layer to facilitate coating and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mold is filled with polymer solution to manufacture microneedle, then the microneedle can be formed, but the needle shape is deformed during the process and water-soluble polymer is not easily filled into hydrophobic mold
Solution Approach 1:
The patent uses a sacrificial layer made of hydrophobic material as an intermediary between the hydrophobic mold and water-soluble polymer. The sacrificial layer is first formed in the mold, then the water-soluble polymer solution is coated on top. This mediator allows the hydrophobic mold to work with water-soluble polymers without direct contact, preventing deformation and filling difficulties.
Solution Approach 2:
The microneedle structure is segmented into multiple functional layers: a sacrificial layer at the base and a polymer coating layer on top. This segmentation allows each layer to perform its specific function - the sacrificial layer provides structural support during manufacturing and enables easy release, while the polymer layer contains the drug and provides the desired functionality.
2Quantity of substance
If drug is contained in the entire patch during manufacturing, then the microneedle can be formed, but quantitative drug delivery is difficult and large amount of drug is lost
Solution Approach 1:
The patent applies local quality by placing the drug-containing polymer coating only on the tip portion of the microneedle rather than the entire microneedle. This localized application ensures that the drug is delivered precisely where needed (at the insertion point) and prevents drug loss from areas that do not contact the tissue.
Solution Approach 2:
The patent extracts the drug from the bulk patch material and concentrates it only in the coating layer on the microneedle tip. This extraction approach allows precise control of the drug quantity delivered while eliminating unnecessary drug in non-contact areas, thereby reducing drug waste.
3Duration of action of stationary object
If conventional microneedle dissolves rapidly in body, then the microneedle can be easily eliminated, but long-term release of drug is not achieved
Solution Approach 1:
The patent uses composite materials consisting of a sacrificial layer (providing structural stability) and a polymer coating layer containing the drug. The sacrificial layer maintains the microneedle's structural integrity during insertion and initial contact, while the polymer coating layer controls drug release over the desired time period, achieving both stability and sustained release.
4Ease of operation
If microneedle attaches to skin, then the microneedle can be firmly positioned, but skin damage or bacterial infection may occur
Solution Approach 1:
The patent employs a disposable microneedle design where the sacrificial layer is intended to remain in the body temporarily to provide positioning and sealing, while the polymer coating layer with drug is delivered. The sacrificial layer acts as a temporary, biocompatible placeholder that fulfills its function and then is naturally eliminated, preventing long-term foreign body presence that could cause infection.
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 quantitative drug delivery, prevents skin damage and bacterial infections, and allows for the microneedle to be used as an implantable drug delivery system or tissue adhesive, with the swellable polymer coating layer remaining in the body to fill holes and adhere tissues effectively.
Implementation Method 1
the coating layer is made of the swellable polymer. Thus, when the microneedle according to the present disclosure is inserted into the body, the swellable polymer based coating layer swells and is mechanically engaged with the skin tissue in the body
Implementation Method 2
coating a swellable polymer solution on a surface of the tip of the microneedle while the stage is tilted at a predefined inclination, thereby forming a coating layer thereon
Implementation Method 3
coating an incompletely crosslinked swellable polymer solution on a surface of a tip of a microneedle so that at least a portion of an interface or a surface of the incompletely crosslinked swellable polymer is selectively dissolved in a short time in moisture, thereby to form a coating layer
Data Source
AI summary
An implantable microneedle and a manufacturing method therefor is disclosed. The implantable microneedle includes a coating layer for covering at least one part of the surface of a tip part of the microneedle. When exposed to moisture, the coating layer can be separated from the tip part of the microneedle and thus be implanted.