Rapidly Fabricated Microneedle Arrays Using Magnetorheological Drawing Lithography for Transdermal Drug Delivery

Abstract

Microneedle arrays (MAs) are among the most promising transdermal drug delivery systems in the last decades due to its minimally invasive nature, convenient operation, and first-pass-metabolism avoidance. However, most MA fabrication methods are difficult to operate, need multiple steps, or require expensive equipment. A novel magnetorheological drawing lithography approach was proposed to rapidly fabricate a flexible microneedle array (FMA) for transdermal drug delivery. A 3D structural liquid MA was drawn in one step from the droplets of curable magnetorheological fluid and maintained its shape under an external magnetic field. The liquid MA was subsequently solidified and sputter-coated with the Ti/Au film to fabricate FMA. FMA morphology, mechanical properties, and transdermal drug delivery performance in vitro were experimentally investigated. FMA consisted of a 5 × 5 cone-shaped microneedle array on a PET flexible substrate. FMA exhibited good strength and excellent penetration performance. It could easily penetrate into skin without breakage, creating microchannels for the promotion of skin permeability. Drugs could be well permeated and diffused in the skin along the microchannels created by FMA. Finally, a dissolvable microneedle array (DMA) was also fabricated by a micromolding technique using FMA as a master template. The DMA exhibited good dissolvable and permeable performance in the agarose block.

A Review on Structural Configurations of Magnetorheological Fluid Based Devices Reported in 2018–2020

“…Further, the device can refine the design of damping forces in different directions to realize the control of damping variation in multi-directions. Furthermore, using a drawing lithography approach, some MRF microneedles were fabricated for minimally invasive surgery, transdermal drug delivery, and smart wearable equipment (Chen Z. P. et al, 2018;Chen et al 2019a;Chen et al, 2019b). In a gradient magnetic field, the MRF is magnetized and generates fusiform patterns, which results in different forms of microneedle arrays after heating and solidifying, as shown in Figure 10C.…”

Preparation of Microneedle Array Mold Based on MEMS Lithography Technology

“…In recent years, special processing technology has developed rapidly. In addition to the above three methods, it also includes some novel preparation methods such as 3D printing technology [ 23 ], laser processing [ 24 ], drawing lithography [ 25 ], etc. The MEMS process can manufacture microneedles with different shapes, angles, and surface contours, and effectively enhance the strength and toughness of the microneedles, enabling them to perform different functions in various fields.…”

3D-printed microneedles in biomedical applications

“…Using polyacrylic acid, trimethylolpropane triacrylate, and photopolymerizable derivatives of polyethylene glycol as well as polycaprolactone, MNs with 1,000 μm height, 333 μm base width, and 2.3 μm tip radius were produced by CLIP ( Johnson et al., 2016 ). Furthermore, magnetorheological drawing lithography (MRDL) AM method, which needs no masks and molds, has been introduced ( Chen et al., 2018 , 2019c ) for fabricating flexible MNAs ( Ren et al., 2017 ). To achieve cost-effective rapid mass production, droplets of the polymerized mix of epoxy novolac resin with iron microparticles on a polyimide substrate were drawn, assisted by a magnetic field, to form liquid MNAs, which were solidified by applying hot air and vacuuming.…”