Microneedle Array Mold Electrical Field Modulation
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Solution Overview
Problem
Microneedle arrays face challenges in preferentially disposing electrospun fibers within the microneedles rather than the backing, leading to reduced drug delivery efficiency and increased costs due to fiber waste on the surface.
Innovation Solution
A mold with a nonconductive surface layer and a conductive underlying layer is used to modulate the electrical field during electrospinning, ensuring fibers are deposited preferentially within the microneedle features, thereby increasing the proportion of fibers within the microneedles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrospinning is performed onto a wholly conductive mold, then the electrospinning process can be completed, but a large amount of fibers are deposited in the backing rather than in the microneedles, reducing drug delivery efficiency and increasing cost
Solution Approach 1:
The mold surface is designed with non-uniform conductivity: the recessed regions (where microneedles form) have different conductivity properties than the raised regions (backing). This local variation in electrical conductivity directs fiber deposition preferentially into the recessed microneedle regions while preventing excessive deposition on the backing surface, thereby improving manufacturing precision and reducing fiber waste.
2Productivity
If more fibers are deposited in the backing, then the electrospinning process is simpler, but less drug is delivered and cost increases due to wasted drug in the backing
Solution Approach 1:
By creating spatially varying conductivity across the mold surface, the invention ensures that electrospun fibers are preferentially deposited in the recessed microneedle regions where they will be delivered into tissue, rather than on the backing surface. This local differentiation maximizes drug delivery efficiency while minimizing waste of expensive therapeutic agents.
3Manufacturing precision
If fibers are preferentially disposed within microneedles, then drug release control and cost are improved, but achieving this preferential disposition is difficult
Solution Approach 1:
The mold incorporates regions of different electrical conductivity at its surface - specifically, the recessed regions have different conductivity than the raised regions. This local quality variation provides a straightforward mechanism to control fiber deposition location without requiring complex multi-component mold structures, achieving precise fiber location control with relatively simple structural modifications.
Solution Approach 2:
The invention changes the electrical conductivity parameter of the mold surface in different regions to control fiber deposition. By adjusting the conductivity parameter locally across the mold surface, the process achieves precise control over where fibers are deposited, enabling preferential placement in microneedles versus backing without complex mechanical or geometric modifications.
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 enhances drug delivery efficiency by ensuring a higher proportion of fibers are embedded within the microneedles, reducing waste and costs, while also increasing the mechanical strength of the microneedles for effective skin penetration.
Implementation Method 1
depositing, by electrospinning, a plurality of fibers onto a first surface of a mold
Implementation Method 2
A mold with a nonconductive surface layer and a conductive underlying layer is used to modulate the electrical field during electrospinning
Data Source
AI summary
Systems and methods are provided for fabricating microneedle arrays that includes electrospun fibers preferentially disposed within the microneedles of the array. Providing the electrospun fibers preferentially in the microneedles allows for more of a drug or other substance present in the fibers to be deposited into tissue or to provide other benefits. A mold for forming the microneedle arrays includes an insulating surface layer. The insulating surface layer affects the electric field during electrospinning such that electrospun fibers are deposited preferentially within the microneedle cavities of the mold relative to the surface of the mold. A bulk material can then be applied to the mold to form the bulk of the microneedles with electrospun fibers embedded within and a backing layer to which the microneedles are attached.