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Title: 3D Printing of Biodegradable Polymeric Microneedles for Transdermal Drug Delivery Applications
Microneedle (MN) technology is an optimal choice for the delivery of drugs via the transdermal route, with a minimally invasive procedure. MN applications are varied from drug delivery, cosmetics, tissue engineering, vaccine delivery, and disease diagnostics. The MN is a biomedical device that offers many advantages including but not limited to a painless experience, being time-effective, and real-time sensing. This research implements additive manufacturing (AM) technology to fabricate MN arrays for advanced therapeutic applications. Stereolithography (SLA) was used to fabricate six MN designs with three aspect ratios. The MN array included conical-shaped 100 needles (10 × 10 needle) in each array. The microneedles were characterized using optical and scanning electron microscopy to evaluate the dimensional accuracy. Further, mechanical and insertion tests were performed to analyze the mechanical strength and skin penetration capabilities of the polymeric MN. MNs with higher aspect ratios had higher deformation characteristics suitable for penetration to deeper levels beyond the stratum corneum. MNs with both 0.3 mm and 0.4 mm base diameters displayed consistent force–displacement behavior during a skin-equivalent penetration test. This research establishes guidelines for fabricating polymeric MN for high-accuracy and low-cost 3D printing.  more » « less
Award ID(s):
2100850 2100739
PAR ID:
10514874
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
MDPI
Date Published:
Journal Name:
Pharmaceutics
Volume:
16
Issue:
2
ISSN:
1999-4923
Page Range / eLocation ID:
237
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  1. ; ; ; ; ; ; ; ; ; ; et al (, Advanced Materials Interfaces)
    Abstract Microneedle (MN) technology offers a powerful approach for transdermal delivery enabling painless injection and facilitating self‐administration without the need for professional assistance. However, the weak mechanical strength of MNs can lead to inefficient drug delivery and serious skin irritation if the MNs fracture during administration and leave fragments under the skin. Thus, the MNs need to be mechanically robust to avoid fracture during penetration through the skin while maintaining efficient drug delivery. Herein, the polymer‐based MNs with layer‐by‐layer (LbL) films of silica (SiO2) nanoparticles (NPs) and a polycation (poly(diallyldimethylammonium chloride) (PDADMAC)) followed by hydrothermal calcination are reinforced. The mechanical strength of the MNs is significantly improved after LbL assembly and shows lower threshold pressure to penetrate skins. Moreover, their drug loading and releasing properties are significantly enhanced due to an increase in the surface area and interfacial interaction. These SiO2nanoparticle‐containing LbL thin films have great potential for the surface modification of 3D microstructured devices such as MNs, as evidenced by their enhanced mechanical strength and drug coating efficiency that result in a promising MN drug delivery model. 
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  2. ; ; ; ; ; ; (, Frontiers in Bioengineering and Biotechnology)
    Microneedles (MNs) are micrometer-sized arrays that can penetrate the skin in a minimally invasive manner; these devices offer tremendous potential for the transdermal delivery of therapeutic molecules. Although there are many conventional techniques for manufacturing MNs, most of them are complicated and can only fabricate MNs with specific geometries, which restricts the ability to adjust the performance of the MNs. Herein, we present the fabrication of gelatin methacryloyl (GelMA) MN arrays using the vat photopolymerization 3D printing technique. This technique allows for the fabrication of high-resolution and smooth surface MNs with desired geometries. The existence of methacryloyl groups bonded to the GelMA was verified by 1 H NMR and FTIR analysis. To examine the effects of varying needle heights (1000, 750, and 500 µm) and exposure times (30, 50, and 70 s) on GelMA MNs, the height, tip radius, and angle of the needles were measured; their morphological and mechanical properties were also characterized. It was observed that as the exposure time increased, the height of the MNs increased; moreover, sharper tips were obtained and tip angles decreased. In addition, GelMA MNs exhibited good mechanical performance with no breakage up to 0.3 mm displacement. These results indicate that 3D printed GelMA MNs have great potential for transdermal delivery of various therapeutics. 
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  4. ; ; ; ; (, Lab on a Chip)
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