Assessment of fused deposition modeling (FDM) parameters for fabrication of solid and hollow microneedles using polylactic acid (PLA)

This paper investigates the limits of a Fused Deposition Modeling (FDM) process for the fabrication of solid and hollow microneedle patches. Polylactic acid (PLA), a biodegradable and biocompatible polymer, was used as the printing material. For solid microneedles, the effect of 3D printing parameters on the final quality of printed microneedles was studied. In addition, the microneedles dimensions were varied to obtain microneedles with minimal dimensions and then, to highlight the limitations of the printer used. Solid microneedle with a needle tip diameter of 348 ± 13 μm; a needle base diameter of 744 ± 25 μm and a height of 1488 ± 18 μm as minimal dimensions were successfully printed. The FDM technique, when combined with chemical post‐fabrication etching, effectively improved the size and shape of the printed solid microneedles. However, despite efforts to print hollow microneedles, the FDM process proved insufficient for achieving the desired hollow structures, indicating the need for alternative methods or techniques. Hydrolysis treatment has reduced the dimensions of the printed PLA‐based microneedles. On the other hand, printing tests were carried out to make hollow microneedle patches. The drug reservoir is a part of the microneedle patch, located within the base of the patch. The orientation of the printed object and the addition of supports to the drug reservoir were studied to facilitate the printing of hollow parts.