Biodegradable polymer microneedle (MN) arrays are devices used for transdermal drug delivery. Dissolvable MNs can be broken off in the skin to deliver drugs over time and diffuse into the blood stream; however, prototyping new devices is expensive and requires modification to the master template. Here, we propose a new microfabrication technique with a fused deposition modeling (FDM) 3D printer using thermoset materials such as polylactic acid. With 3D modeling software, various MN shapes can be designed and 15 MN arrays can be printed in approximately 40 minutes; furthermore, the density, length, and shape of the MNs can be adjusted easily without the need of designing a new master template. The challenge of FDM 3D printing is fabricating needles in the micrometer size region needed, owing to the low resolution of these printers. We were able to improve significantly the resolution by developing a chemical etching protocol post fabrication. Using scanning electron microscopy, we found our method reduced needle tip sizes to 57.71 ± 8.82 microns and they successfully broke off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and can release drugs over time into skin. This process allows us to rapidly prototype new designs that can be used for transdermal drug delivery.

Low cost 3D printed microneedles for transdermal drug delivery

255th National Meeting (2018)

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