Microneedle Manufacturing via Pressurized Curing
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Solution Overview
Problem
Conventional methods for manufacturing microneedle elements often result in air pockets between formulations, leading to insufficient bonding and instability during demolding and use, causing microneedles to break.
Innovation Solution
A method involving a mold element filled with a first formulation under pressure during curing to expel or compress gas pockets, ensuring a stable bond between formulations, and potentially using multiple formulations with simultaneous curing and pressurization to minimize cavity size and enhance bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods fill mold openings with liquid formulation and cure it, then microneedle tips are formed, but air pockets occur between formulations causing insufficient bonding and instability
Solution Approach 1:
The mold opening is pre-filled with a first formulation (backing formulation) before adding the second formulation (tip formulation). This preliminary action ensures that the bonding interface is established first, and subsequent curing and pressurization eliminate air pockets at this interface, preventing bonding defects before they can cause instability.
Solution Approach 2:
The curing process is combined with dynamic pressurization applied during curing. This dynamic approach allows the formulation to be compressed while curing, actively expelling air pockets from the bonding interface between formulations, thereby eliminating the harmful air pockets that would otherwise cause bonding failures.
2Ease of manufacture
If air pockets occur between formulations during curing, then manufacturing is simpler, but microneedles break during demolding and use due to instability
Solution Approach 1:
The mold is pre-filled with backing formulation and cured before adding tip formulation. This preliminary curing creates a stable base structure first, ensuring that when the second formulation is added and cured, the bonding interface is already established and can withstand subsequent handling and demolding without causing microneedle breakage.
Solution Approach 2:
Pressurization is applied dynamically during the curing process of both formulations. This dynamic pressurization compresses the formulations together at the bonding interface, expelling air pockets and creating strong interfacial bonding, thereby ensuring structural integrity that prevents microneedle breakage during demolding and use.
3Manufacturing precision
If volume reduction occurs due to drying of solvent, then formulation cures properly, but uneven concave surface forms on tip formulation
Solution Approach 1:
The mold opening is pre-filled with backing formulation and cured before adding tip formulation. This preliminary action creates a stable base that supports the tip formulation during its own curing process. The backing formulation acts as a cushion that compensates for the volume reduction of the tip formulation as it dries, preventing the formation of uneven concave surfaces.
Solution Approach 2:
Pressurization is applied during the curing of both formulations. This dynamic pressurization compensates for the volume reduction that occurs as solvents evaporate during curing. The continuous pressure ensures that the formulation remains in contact with the mold walls and maintains a uniform convex surface, preventing concave deformations.
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
This approach results in more stable microneedle elements with improved bonding and reduced likelihood of breakage, as the pressurization during curing eliminates air pockets and increases the bonding surface, enhancing the microneedle's structural integrity.
Implementation Method 1
Due to drying, there is a reduction in volume, in particular due to a reduction of a solvent, such as water and/or ethanol, of the formulation
Implementation Method 2
the first formulation is pressurized during curing... the applied pressure causes compression of the air pocket
Data Source
AI summary
A method for manufacturing a microneedle element, including the following steps: providing a mold element for the microneedle elements to be manufactured, filling the mold element with a first formulation, curing the first formulation, and pressurizing the first formulation during curing. Furthermore, a microneedle element and a device for manufacturing a microneedle element.