3D Printed Multi-Functional Hydrogel Microneedles Based on High-Precision Digital Light Processing

Abstract

Traditional injection and extraction devices often appear painful and cumbersome for patients. In recent years, polymer microneedles (MNs) have become a novel tool in the field of clinical medicine and health. However, the cost of building MNs into any shapes still remains a challenge. In this paper, we proposed hydrogel microneedles fabricated by high-precision digital light processing (H-P DLP) 3D printing system. Benefits from the sharp protuberance and micro-porous of the hydrogel microneedle, the microneedle performed multifunctional tasks such as drug delivery and detection with minimally invasion. Critical parameters for the fabrication process were analyzed, and the mechanical properties of MNs were measured to find a balance between precision and stiffness. Results shows that the stiffness and precision were significantly influenced by exposure time of each layer, and optimized printing parameters provided a balance between precision and stiffness. Bio-compatible MNs based on our H-P DLP system was able to execute drug injection and drug detection in our experiments. This work provided a low-cost and fast method to build MNs with 3D building, qualified the mechanical performance, drug injection, drug detection ability of MNs, and may be helpful for the potential clinical application.

Tailoring Atomoxetine Release Rate from DLP 3D-Printed Tablets Using Artificial Neural Networks: Influence of Tablet Thickness and Drug Loading

“…So far, DLP printers have demonstrated their capacity to create dental models with high accuracy [ 22 ], as well as patient-specific drug delivery devices, including microneedle arrays on finger splints [ 23 ], hydrogel microneedles [ 24 ], non-dissolving suppository molds [ 25 ] and various implants [ 26 ]. Despite numerous advantages, the potential application of the DLP technique in the production and optimization of oral dosage forms has not been fully explored.…”

3D-printed microneedles in biomedical applications

“…Despite changing design features, the tip radii of MNs were at the range of 20–40 μm. Furthermore, higher printing layer heights result in faster printing, while yielding lower surface quality ( Krieger et al., 2019 ; Yao et al., 2020 ). Two-photon polymerization with a 780 nm light wavelength was used to produce soft elastomeric MN replica molds.…”

“…Based on the DLP 3D printing technology, a new setup was built with high precision to print in micro-scale, being utilized for fabrication of MNs with a photosensitive hydrogel, which was cured with different blue light ( Yao et al., 2020 ). Alginate hydrogel (5 wt%), which is similar to human skin in terms of mechanical properties, was used as an artificial skin to study drug injection, extraction, and detection by the fabricated MNs.…”

“…Moreover, regardless of the substantial attention received by 3D printing, achieving higher resolution is an existing challenge. SLA, TPP, and DLW can produce MNs with acceptable resolutions (5 μm); nevertheless, limited biocompatible materials are supported with these methods, whereas mechanical properties are not of a satisfactory degree ( Chia and Wu, 2015 ; Ligon et al., 2017 ; Ngo et al., 2018 ; Yao et al., 2020 ). Therefore, future studies can be focused on developing faster 3D printing methods without compromising the resolution.…”

Microneedle-based bioassays

“…The design and fabrication of MNs determine their specic bioassay features. Many strategies (e.g., etching, 22,23 lithography, [24][25][26] micromachining, [27][28][29] and threedimensional (3D) printing [30][31][32] ) have been used for these purposes. Etching is one of the traditional methods to directly fabricate MNs through chemical reagents or physical ions, and is especially used to produce metal-based MNs.…”