Low-cost and cleanroom-free fabrication of microneedles

Abstract

We present a facile, low-cost and cleanroom-free technique for the fabrication of microneedles using molds created by laser ablation. Microneedle mold with high aspect ratios is achieved on acrylic sheet by engraving a specific pattern of crossover lines (COL) using CO 2 laser cutter. Ablating COL pattern on the acrylic sheet creates a sharp conical shape in the center of the design. We have shown that a variety of microneedle shapes with different heights and tip angles can be easily achieved by changing the number and the length of the COL. Polydimethylsiloxane (PDMS) microneedles were fabricated by casting the PDMS on the mold. The resulted PDMS microneedles are oxygen plasma treated and then silanized. Another PDMS layer is casted on PDMS microneedles and detached after curing. The silanization prevents those two layers of PDMS from bonding to each other and makes them easily detachable. After detachment of the PDMS mold of microneedles, the mold is used to fabricate degradable polyvinyl alcohol microneedle patch suitable for transdermal drug delivery. The release kinetics of the needles are also shown and discussed in order to prove the applicability of the needles.

Progress in Microneedle-Mediated Protein Delivery

“…Then, after mold fabrication, microneedles can be replicated on it. MN masters are usually produced by techniques such as photolithography using deep X-ray lithography of Lithographie Galvanoformung Abformung [13,16] and ultraviolet (UV) lithography [17], laser ablation [18], micromilling and microgrinding [19,20], additive manufacturing [21,22], laser percussion drilling [13,16], and deep reactive ion etching (DRIE) [23]. The produced master can be re-used to make multiple molds, and each mold can be used several times for MN fabrication after appropriate cleaning.…”

“…The involvement of high temperatures makes this process unsuitable for the direct encapsulation of protein, limiting the application to post-encapsulation. In solvent casting, a polymer solution is added into the mold, and after that, the vacuum and/or centrifugation steps are performed to fill the mold microcavities [18,19,21,[29][30][31][32]. Long evaporation times may compromise the activity of the protein, in addition to being economically expensive [33].…”

Ultrasonically and Iontophoretically Enhanced Drug-Delivery System Based on Dissolving Microneedle Patches

“…In vitro drug release. Gelatin hydrogel (10 wt%; Sigma Aldrich, gel strength ~300 g Bloom, Type A) derived from porcine skin was used as the model tissue for the drug release studies 11,43 . The polymer membrane (Parafilm M, American National Can, Chicago, IL) was pierced with microneedles and placed on the hydrogel surface.…”

Polymeric Microneedle Arrays: Versatile Tools for an Innovative Approach to Drug Administration

“…[16] The fabrication procedure is reported as illustrated in Figure 1. The answer is not trivial since the prototypes made for an experimental project are fabricated with care and attention that can be only dedicated to handmade items.…”