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Abstract Microneedles have recently emerged as a powerful tool for minimally invasive drug delivery and body fluid sampling. To date, high‐resolution fabrication of microneedle arrays (MNAs) is mostly achieved by the utilization of sophisticated facilities and expertise. Particularly, hollow microneedles have usually been manufactured in cleanrooms out of silicon, resin, or metallic materials. Such strategies do not support the fabrication of microneedles from biocompatible/biodegradable materials and limit the capability of multimodal drug delivery for the controlled release of different therapeutics through a combination of injection and sustained diffusion. This study implements low‐cost 3D printers to fabricate relatively large needle arrays, followed by repeatable shrink‐molding of hydrogels to form high‐resolution molds for solid and hollow MNAs with controllable sizes. The developed strategy further enables modulating surface topography of MNAs to tailor their surface area and instantaneous wettability for controllable drug delivery and body fluid sampling. Hybrid gelatin methacryloyl (GelMA)/polyethylene glycol diacrylate (PEGDA) MNAs are fabricated using the developed strategy that can easily penetrate the skin and enable multimodal drug delivery. The proposed method holds promise for affordable, controllable, and scalable fabrication of MNAs by researchers and clinicians for controlled spatiotemporal administration of therapeutics and sample collection.
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Fabrication and Characterization of Hollow Microneedle Array Using Diffraction UV Lithography
Hollow microneedles are extremely attractive to drug delivery domains with high demands from clinics and industry. However, its complicated fabrication processes have impeded its wide adoption. This paper presents a simple one-step fabrication method for hollow microneedles based on diffraction UV lithography and solid-liquid light propagation. The fabrication process utilizes bottom-up exposure of a liquid photosensitive resin through photomask patterns comprising a plurality of apertures. Hollow microneedles with various heights were fabricated in a range of 400 µm to 600 µm from a few minutes of UV exposure. The fabricated hollow microneedles were characterized with force-displacement tests showing a good tip strength of 0.35 N per single unit. A hollow fluidic test on a pig cadaver skin showed great potential for drug delivery. Also, batch fabrication with multiple height microneedles on a single substrate has demonstrated compatibility with the manufacturing process.
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- PAR ID:
- 10324520
- Date Published:
- Journal Name:
- 2021 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers)
- Page Range / eLocation ID:
- 1150 to 1153
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Microneedles are highly sought after for medicinal and cosmetic applications. However, the current manufacturing process for microneedles remains complicated, hindering its applicability to a broader variety of applications. As diffraction lithography has been recently reported as a simple method for fabricating solid microneedles, this paper presents the experimental validation of the use of ultraviolet light diffraction to control the liquid-to-solid transition of photosensitive resin to define the microneedle shape. The shapes of the resultant microneedles were investigated utilizing the primary experimental parameters including the photopattern size, ultraviolet light intensity, and the exposure time. Our fabrication results indicated that the fabricated microneedles became taller and larger in general when the experimental parameters were increased. Additionally, our investigation revealed four unique crosslinked resin morphologies during the first growth of the microneedle: microlens, first harmonic, first bell-tip, and second harmonic shapes. Additionally, by tilting the light exposure direction, a novel inclined microneedle array was fabricated for the first time. The fabricated microneedles were characterized with skin insertion and force-displacement tests. This experimental study enables the shapes and mechanical properties of the microneedles to be predicted in advance for mass production and wide practical use for biomedical or cosmetic applications.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Conference Paper:
- https://doi.org/10.1109/Transducers50396.2021.9495599
