Microneedle Array Fabrication Using Wire Bonding and Microfluidics
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Solution Overview
Problem
Current microneedle arrays face challenges with scaling, manufacturing, and drug efficacy, particularly in delivering vaccinations, and are hindered by the need for complex drug coating processes and the limitations of traditional hypodermic needles, which contribute to needle phobia and increased healthcare costs.
Innovation Solution
A method for fabricating microneedle arrays using a conductive wire to create friction welds and applying a wire weakening process to form solid microneedles of varying heights and diameters, integrated with microfluidic channels for drug delivery, enabling efficient and scalable production and painless drug administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hypodermic needles are used for drug delivery, then drug administration can be achieved, but needle phobia and needle stick injuries increase leading to higher healthcare costs
Solution Approach 1:
The invention divides the traditional single large needle into an array of multiple microneedles (e.g., 9-100 microneedles per array), where each microneedle has a diameter of 10-500 micrometers. This segmentation reduces the trauma and fear associated with needle insertion while maintaining effective drug delivery through the combined effect of multiple insertion points
Solution Approach 2:
The invention transitions from conventional hypodermic needle injection (single point penetration) to microneedle arrays that create multiple micro-channels across the skin surface. This dimensional change from 1D single-point injection to 2D array distribution enables painless drug delivery by engaging fewer nerve endings while delivering adequate dosage through cumulative effect
2Ease of operation
If microneedle arrays are used to reduce trauma and pain, then patient comfort improves, but manufacturing complexity and scaling challenges increase
Solution Approach 1:
The wire bonding process, originally developed for semiconductor interconnects, is adapted to fabricate microneedle arrays. This universal application of an existing mature manufacturing process enables microneedle production using standard industrial equipment, avoiding the need for specialized microneedle fabrication facilities and reducing overall system complexity
Solution Approach 2:
The invention replaces traditional mechanical microneedle fabrication methods (such as laser drilling, electroforming, or micromolding) with a wire bonding process that uses controlled wire deposition and fracturing. This substitution leverages an established, highly automated process from the semiconductor industry, simplifying manufacturing while enabling precise control of microneedle geometry and position
3Productivity
If wire bonding process is used to fabricate microneedles, then manufacturing scalability improves, but control over microneedle height uniformity becomes challenging
Solution Approach 1:
The wire bonding process parameters (wire feed rate, bonding force, ultrasonic power) are pre-optimized and programmed into the wire bonder before fabrication begins. This preliminary setup ensures consistent microneedle height across large arrays by maintaining precise control over wire extrusion and bonding conditions throughout the manufacturing process
Solution Approach 2:
The wire bonding system incorporates real-time feedback control through sensors that monitor bonding force, wire position, and ultrasonic vibration. This feedback mechanism allows the system to automatically adjust parameters during fabrication to maintain uniform microneedle heights, compensating for variations in wire properties or substrate conditions
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 allows for the rapid, cost-effective, and reliable fabrication of microneedle arrays that can be used without medical supervision, reducing healthcare expenditures and overcoming issues related to needle phobia and needle stick injuries by enabling effective drug delivery through microfluidic channels and electroporation or iontophoresis.
Implementation Method 1
applying a force to a conductive wire to create a friction weld between the wire and a substrate
Implementation Method 2
applying a wire weakening process at a desired microneedle length to cause the wire to break at the desired microneedle length
Implementation Method 3
rapidly moving a bonder head of the wire bonder to a return position
Data Source
AI summary
A method of fabricating a microneedle is disclosed, including: applying a force to a conductive wire to create a friction weld between the wire and a substrate; extruding the wire and interrupting the wire bonding process; and applying a wire weakening process at a desired microneedle length to cause the wire to break at the desired microneedle length. A microneedle array includes a substrate and a plurality of solid microneedles provided on the substrate. Adjacent microneedles may have different heights and different diameters. The substrate defines a plurality of microfluidic channels each having a channel outlet. the channel outlets provided adjacent the bases of the plurality of solid microneedles to enable drug delivery. The method and array overcome issues with needle stick injuries and needle phobia, and can be used without direct medical supervision, thus reducing healthcare expenditure.