Microneedle Arrays of Polyhydroxyalkanoate by Laser-Based Micromolding Technique

Although many delivery systems have been proposed to improve drug permeation through the skin, all of them suffer from several limitations. This drives a continuous search for innovative systems that can provide safe and effective transdermal drug delivery solutions. In line with this, microneedle (MN) arrays, a hybrid combination of hypodermic injections and transdermal patches, have been proposed. MNs consist of microscale needles that can pierce the skin by a simple, minimally invasive, and painless route, enabling the transport of drugs and macromolecules into the human body. This study reports, for the first time, the use of a biobased, biodegradable, and biocompatible polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), for the fabrication of a biopolymer-based MN patch. Molds of poly(dimethylsiloxane) were prepared by direct laser writing technology, a low-cost and mask-less technology, and used to produce biodegradable P(3HB-co-3HV) MNs by a thermosetting process. The best results were obtained with a laser power of 30 W at 0.15 m/s with a spiral model as the pattern. The obtained MNs had a length of 0.69 mm and a diameter of 0.33 mm, ideal for painless penetration of the skin. Additionally, the produced MNs had good mechanical properties and the ability to be successfully impregnated with the fluorescent dye Rhodamine 6G. These features render P(3HB-co-3HV) a promising material for the development of MNs with improved functionality.