Hollow Microneedle Molding via Laser Ablation Without Cleanrooms
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Solution Overview
Problem
The fabrication of microneedles is challenging due to the 3D conical geometry and high aspect ratio structures, requiring expensive and time-consuming cleanroom processes like photolithography and deep X-ray lithography, making them cost-prohibitive for general drug delivery.
Innovation Solution
A cleanroom-free method using laser ablation to create microneedle molds with a cross-over line pattern, followed by casting biocompatible materials like chitosan and polydimethylsiloxane to form microneedles, allowing for efficient and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional photolithography and deep X-ray lithography methods are used to fabricate microneedles, then manufacturing precision and uniformity of needle geometry are improved, but device complexity and production cost increase significantly
Solution Approach 1:
The patent replaces complex optical lithography systems with a simple laser ablation system. The laser directly writes the microneedle pattern and geometry onto the polymer sheet in a single step, eliminating the need for photolithography masks, aligners, and deep X-ray equipment. This mechanical/thermal substitution achieves comparable or superior precision without cleanroom requirements.
Solution Approach 2:
The patent extracts the essential microneedle fabrication function from the complex cleanroom process chain. By using laser ablation, only the critical step of pattern formation remains, while all supporting infrastructure (cleanrooms, lithography equipment, multiple processing steps) is removed. This leaves a streamlined process that maintains precision without the overhead.
2Manufacturing precision
If traditional LIGA and UV lithography methods are used, then microneedle geometry precision is improved, but production time and process complexity increase
Solution Approach 1:
The laser ablation process performs preliminary action by directly creating the final microneedle geometry in a single pass. Unlike traditional methods that require sequential steps (photolithography, electroplating, molding), the laser writes the complete 3D structure directly into the material, eliminating subsequent processing time while maintaining precision.
Solution Approach 2:
The laser ablation process maintains continuity of useful action throughout fabrication. The laser beam continuously traces the microneedle pattern and depth profile in one uninterrupted operation, rather than stopping between discrete processing steps. This continuous action reduces total fabrication time while ensuring geometric consistency throughout the structure.
3Manufacturing precision
If cleanroom facilities and advanced lithography equipment are used, then microneedle manufacturing precision is improved, but production cost increases to prohibitive levels
Solution Approach 1:
The patent employs disposable polymer sheets as the substrate material. These inexpensive polymer sheets are ablated directly by the laser to create microneedles, eliminating the need for expensive reusable molds and fixtures required in traditional molding methods. The low cost of consumable polymer sheets makes the overall process economically viable while maintaining precision.
Solution Approach 2:
The patent substitutes expensive optical lithography equipment with an affordable laser ablation system. The laser, which can be obtained at a fraction of the cost of lithography tools, directly writes the microneedle pattern without requiring costly infrastructure. This equipment substitution dramatically reduces capital expenditure while achieving the required manufacturing precision.
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 with uniform geometry and reproducibility, facilitating drug delivery through the skin with improved therapeutic efficacy and reduced costs.
Implementation Method 1
creating at least one microneedle mold using laser ablation
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
Systems and methods for creating microneedle arrays capable of delivering a suitable drug dosages to subjects are provided. In one aspect, a method comprises creating at least one forming mold using laser ablation in a cross-over line pattern. The method further comprises casting a first material onto the at least one forming mold to create at least one microneedle mold. The method further comprises casting a second material onto the at least one microneedle mold to create at least one hollow microneedle.