Microneedle Arrays with Funnel Portions for Easier Tissue Insertion
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Solution Overview
Problem
Microneedles face challenges in tissue insertion due to their small size, requiring high application forces and complex applicators, and manufacturing is hindered by limited loading capacity and inaccuracies in conventional methods.
Innovation Solution
Incorporating funnel portions into microneedle designs to facilitate easier tissue penetration and increase loading capacity, along with improved manufacturing methods using molds with pressure differentials and two-part molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microneedles are made small in size, then they can precisely target superficial tissue layers and be relatively pain free, but their tissue insertion becomes difficult and requires high application forces
Solution Approach 1:
The microneedles are embedded within a patch matrix structure, where the needles are nested in cavities of the patch material. This nesting provides structural support to the small microneedles during application, enabling them to penetrate tissue without requiring excessive force while maintaining their small size for painless delivery
Solution Approach 2:
The microneedles are pre-loaded with therapeutic substances during manufacturing, and the patch is pre-formed with the microneedles embedded in the matrix. This preliminary preparation eliminates the need for complex assembly during application and ensures the microneedles are ready for immediate insertion with minimal force
2Object-affected harmful factors
If microneedles are made small in size, then they can precisely target superficial tissue layers, but the amount of material that can be loaded into them is limited
Solution Approach 1:
The invention merges the microneedle delivery function with the patch matrix structure. Multiple microneedles are combined in an array within a single patch, and each needle can be loaded with substantial amounts of therapeutic material. The patch matrix itself can also serve as a reservoir, effectively combining multiple loading capacities into one delivery system
Solution Approach 2:
The invention extends the loading capacity beyond the needle volume by incorporating the patch matrix as an additional dimension of material storage. The therapeutic substance can be loaded both within the microneedle cavities and in the surrounding matrix material, effectively increasing the total loading capacity while maintaining precise targeting through the needle array configuration
3Ease of manufacture
If conventional molding methods are used for microneedle production, then manufacturing can be simplified, but accuracy and reproducibility are poor
Solution Approach 1:
The invention replaces conventional mechanical molding methods with a two-part mold system that uses pressure differentials and capillary forces. This substitution allows for precise replication of microneedle geometries and consistent material loading without the inaccuracies associated with traditional molding, while still maintaining manufacturing simplicity through the mold-based approach
4Ease of manufacture
If conventional fluid dispensing systems are used for filling microneedle molds, then manufacturing can be performed with standard equipment, but alignment accuracy and fill volume consistency are highly variable
Solution Approach 1:
The invention uses pressure differentials (pneumatic principles) to control the filling process. By applying controlled pressure to the mold cavity, the system achieves consistent and accurate filling of microneedles with therapeutic materials. This pneumatic approach replaces variable conventional dispensing with a more controllable pressure-driven mechanism, improving fill volume reproducibility while using standard manufacturing equipment
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
Enhances microneedle insertion efficiency, reduces manufacturing constraints, and allows for higher substance loading, enabling simpler applicators and more precise delivery of substances.
Implementation Method 1
forcing the filling material into the mold cavities
Implementation Method 2
drying the filling material in the mold to remove the liquid vehicle
Data Source
AI summary
A microneedle array is provided for administrating a drug or other substance into a biological tissue. The array includes a base substrate; a primary funnel portion extending from one side of the base substrate; and two or more solid microneedles extending from the primary funnel portion, wherein the two or more microneedles comprise the substance of interest. Methods for making an array of microneedles are also provided. The method may include providing a non-porous and gas-permeable mold having a two or more cavities each of which defines a microneedle; filling the cavities with a fluid material which includes a substance of interest and a liquid vehicle; drying the fluid material to remove at least a portion of the liquid vehicle and form a plurality of microneedles that include the substance of interest, wherein the filling is conducted with a pressure differential applied between opposed surfaces of the mold.