Biocompatible Polymer Microneedle Manufacturing via Mold Solidification
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Solution Overview
Problem
Current methods for manufacturing microneedles face challenges such as pain during skin penetration, medicine degradation, complex manufacturing processes, and difficulty in achieving consistent shape and size, which hinder effective transdermal delivery and cosmetic applications.
Innovation Solution
A method involving a mold with spaced conical holes filled with a biocompatible polymer solution using stoppers and/or a vacuum pump, followed by solidification, to create microneedles with appropriate diameter, hardness, and length for painless skin penetration and efficient medicine delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a subcutaneous injection needle is used, then medicine can be delivered effectively, but it causes patient pain, local skin damage, and bleeding
Solution Approach 1:
The injection system is segmented into multiple microneedles (each with diameter 10-100 μm) arranged in an array, replacing a single large-bore needle. Each microneedle creates its own channel, collectively delivering medicine effectively while individual microneedles are too thin to cause significant pain or damage
Solution Approach 2:
The needle diameter parameter is changed from 100 μm or more (subcutaneous needle) to 10-100 μm (microneedle). This parameter change enables the needle to penetrate the horny layer and deliver medicine transdermally while being too thin to cause pain or significant skin damage
2Object-affected harmful factors
If the microneedle diameter is reduced to 10-100 μm for painless penetration, then skin penetration is achieved, but manufacturing precision and shape consistency become difficult
Solution Approach 1:
Mold cavities with precise conical geometries are prepared in advance before microneedle manufacturing. These pre-formed molds ensure that when biocompatible polymer solution is injected and solidified, the microneedles automatically acquire consistent shapes and sizes (diameter 10-100 μm, length 0.5-2 mm) without requiring post-manufacturing adjustment
Solution Approach 2:
The mold cavity geometry is copied into the microneedle structure through solidification of polymer solution in the mold. This copying process ensures high shape and size consistency across all microneedles in the array, with each microneedle being an exact replica of the mold cavity shape
3Shape
If a solid microneedle is manufactured by etching or photolithography, then structure is achieved, but medicine delivery capability is insufficient
Solution Approach 1:
The microneedle material state is changed from solid (etched or photolithographed structures) to a solidified polymer solution containing dissolved or suspended medicine. This parameter change enables the microneedle to deliver medicine effectively, as the medicine is already incorporated in the material itself
Solution Approach 2:
The microneedle is made as a composite material system where biocompatible polymer (such as hyaluronic acid, gelatin, or collagen) serves as the matrix and medicine is distributed within it. This composite structure enables simultaneous achievement of mechanical integrity for skin penetration and medicine delivery capability
4Reliability
If medicine is mounted in capsule form by photolithography, then medicine delivery is enabled, but microneedle hardness deteriorates
Solution Approach 1:
The medicine incorporation method is changed from discrete capsule mounting to homogeneous mixing at the molecular or micro-level within the polymer solution. This parameter change maintains uniform distribution of medicine without creating stress concentration points that would reduce hardness, while still enabling effective medicine delivery
Solution Approach 2:
The medicine is homogeneously distributed within the biocompatible polymer solution before solidification. This homogeneous distribution ensures uniform medicine delivery across all microneedles and maintains consistent mechanical properties (hardness and strength) throughout the microneedle structure
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 the production of microneedles that can penetrate deep into the skin without pain, ensure accurate delivery of medicine, and are manufactured aseptically with a consistent shape and size, allowing for efficient transdermal delivery and cosmetic applications.
Implementation Method 1
a vacuum pump
Implementation Method 2
solidifying the biocompatible polymer solution
Data Source
AI summary
A method of manufacturing a biocompatible polymer-based microneedle, the method comprising: (a) a primary filling step of covering, by stoppers, upper sides of multiple holes, which are formed to be spaced apart from one another, penetrate a mold, and each have a conical shape, and injecting a biocompatible polymer solution containing an appropriate amount of active ingredient by using filling needles; (b) a secondary filling step of injecting a biocompatible polymer solution containing an excipient by using the filling needles; (c) a step of solidifying the biocompatible polymer solution; and (d) a step of attaching a pad to an upper portion of the mold and then detaching the pad from the mold. The microneedle manufactured by the present invention may solve problems of degeneration of medicine, insufficient hardness, and a loss of medicine caused by a complicated process and a long manufacturing time.