Funnel Microneedle Arrays for Low-Force Drug Insertion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microneedles face challenges in tissue insertion due to their small size, requiring high application forces and complex applicators, and manufacturing limitations such as limited material loading and inaccuracies in mold filling, especially for substances with low solubility in water.
Innovation Solution
Incorporating funnel portions into microneedle designs and manufacturing methods to enhance tissue insertion efficiency, increase substance loading, and improve mold filling accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microneedles are made small in size to target superficial tissue layers, then pain-free insertion is achieved, but tissue insertion becomes difficult and requires high application force
Solution Approach 1:
The microneedle is divided into two distinct segments: a base portion that is wider and easier to insert into the skin, and a tip portion that is narrower for delivering the substance. This segmentation allows the wider base to penetrate the skin barrier with lower force while the narrow tip delivers the payload, resolving the contradiction between small size for pain-free insertion and sufficient insertion capability.
Solution Approach 2:
The microneedle employs asymmetric geometry where the base portion has a larger cross-sectional area than the tip portion. This asymmetric design creates a mechanical advantage where the wider base can be inserted into the skin more easily while the narrower tip effectively delivers the substance, addressing the force requirement issue.
2Ease of manufacture
If conventional molding methods are used to manufacture microneedle arrays, then manufacturing process is simple, but manufacturing precision and reproducibility deteriorate
Solution Approach 1:
The invention changes the manufacturing approach by transitioning from conventional molding to a combination of laser-induced polymerization for creating the base portion and microfluidic dispensing for the tip portion. This parameter change in the manufacturing process enables precise control over microneedle dimensions and positioning while maintaining ease of manufacture through automated processes.
Solution Approach 2:
The invention replaces conventional mechanical molding processes with laser-induced polymerization and microfluidic dispensing. This substitution of mechanical systems with optical and fluid-based systems enables higher manufacturing precision and reproducibility while maintaining process simplicity through automation.
3Ease of manufacture
If microneedle volume is limited to match mold cavity size, then manufacturing is feasible, but material loading capacity deteriorates
Solution Approach 1:
The microneedle is segmented into a base portion and a tip portion, allowing the base portion to be manufactured using conventional molding methods while the tip portion is filled using microfluidic dispensing. This segmentation enables the base to be produced at scale while the tip can be precisely filled with the required amount of substance, resolving the contradiction between manufacturing feasibility and material loading capacity.
Solution Approach 2:
The base portion is pre-formed using laser-induced polymerization or conventional molding, creating a structure that can be subsequently filled with the substance of interest using microfluidic dispensing. This preliminary action allows the base to be manufactured efficiently while enabling precise control over the amount of substance loaded into the tip portion.
4Ease of manufacture
If conventional fluid dispensing systems are used to fill microneedle molds, then dispensing process is simple, but filling accuracy and reproducibility deteriorate
Solution Approach 1:
The invention replaces conventional mechanical fluid dispensing systems with laser-induced polymerization for base formation and microfluidic dispensing for tip filling. This substitution enables precise control over material placement and volume while maintaining process simplicity through automated optical and fluid-based systems.
Solution Approach 2:
The invention changes the dispensing parameters by using laser-induced polymerization for the base portion and controlled microfluidic flow for the tip portion. This parameter change enables precise control over the volume and position of materials while maintaining ease of manufacture through automated processes.
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.