Generic Molding Platform for Simple, Low‐Cost Fabrication of Polymeric Microneedles

Abstract

Micromolding technology is widely used for the fabrication of polymer microneedles for transdermal and intradermal drug delivery applications. Geometric features of microneedles in molding are solely determined by geometry of the master mold template. Fabrication of master mold template usually involves costly and cumbersome technologies due to small feature sizes typical of microneedles. In this research, a novel molding platform is designed that is fabricated using low‐cost and simple techniques with flexibility of producing large number of microneedle geometries. The proposed molding platform eliminates need for developing multiple mold templates for fabrication of various geometries of polymer microneedles. Utility of this molding platform is demonstrated in polylactic acid‐based solid thermoplastic microneedles and polyacrylic acid‐based dissolvable microneedles with various aspect ratio settings. Various microneedles fabricated at heights differing with resolution of as low as 100 µm are successfully achieved using specified settings in the molding platform. The suitability of fabricated microneedles for drug delivery applications is evaluated by in vitro and in vivo testing.

Macroscale Conjugated Microporous Polymers: Controlling Versatile Functionalities Over Several Dimensions

“…As an interdisciplinary topic the generation of macroscale CMPs combine diverse synthetic methodologies. For example, the combination of CMPs with polymer processing technologies and porous polymer chemistries, e.g., 3D printing, [209] microfluidics, [210] wet/electro-spinning, [211] composite blending, [212] and molding, [213] to name just a few, brings exciting opportunities. With more efforts along this line, we can foresee that macroscale CMPs can generate novel products for industrial applications.…”

Translation of Polymeric Microneedles for Treatment of Human Diseases: Recent Trends, Progress, and Challenges

“…Flash modulus and polymer MN fractures are important for mechanical resistance, as the insertion capability of the polymerbased MN is reflected here [27]. Researches can also combine the mechanical power of two or more polymers and additional materials [45]. Furthermore, during polymer selection, the target tissue for the MN must be called transdermal or non-transdermal [46,47].…”

“…Several systemic approaches to these issues, especially with sterile MN production and stability, have been published in the literature. Sterilization is based on gamma-ray irradiation, as required by the European Pharmacopoeia [45]. Depending upon the form of the polymeric matrix, this process may affect polymeric MNs differently [357].…”

“…For their therapeutic transition, the limited drug loading potential of MNs is a limiting factor since their scale and volume are small [355]. Researchers have employed centrifugation, refilling, and evaporation of micro cardiogram enrichment with medicinal substances and drug-laden nanoparticles [45]. Another path toward improv-ing the capacity of drug loading may be to develop larger MN patches or produce novel polymers with higher solubility or loading capacities for drug molecules [357].…”

Microneedle-based bioassays

“…[40][41][42] The designed master template can initially be produced via etching, lithography, micromachining, or 3D printing. 43,44 Complementary negative molds can be produced with curable materials such as polydimethylsiloxane (PDMS). Some negative molds are commercially available with customizable designs, which can enhance the productivity, reduce the batch-to-batch variability, and facilitate access to MN fabrication techniques.…”