Exaddon Research in MRS Advances - Microneedles for Drug Delivery

Hollow Copper Microneedles Made by Local Electrodeposition‑based Additive Manufacturing

29 September, 2022 by

Edward White

SEM picture of a hollow copper microneedle 3D printed with Exaddon's CERES system. — Scanning electron micrograph of a hollow copper microneedle taken at a 45° angle tilt

In a research collaboration between Exaddon, North Carolina State University State University and the University of North Carolina at Chapel Hill, hollow microneedles were created out of copper using Exaddon's local electrodeposition-based additive manufacturing process.

Published in Materials Research Society Advances, the study demonstrates the potential use of Exaddon's pioneering metal additive micromanufacturing (µAM) technology to manufacture hollow copper needles for drug delivery.

Exaddon's CERES µAM print system was used to print the needles, in this instance 431 µm in height. According to the article, "x-ray photoelectron spectroscopy showed the presence of copper, oxygen, copper, silicon, and sulfur and the absence of toxic impurities in a solid microneedle." Accordingly, the 3D printing of copper microneedles may be an appropriate method of manufacturing biocompatible structures suitable for transdermal drug delivery.

Paper reference: Sachan, R., Schürch, P., Testa, P. et al. Hollow copper microneedle made by local electrodeposition-based additive manufacturing. MRS Advances 6, 893–896 (2021). Springer

Using 3D Printing for Transdermal Drug Delivery

Transdermal drug delivery is an increasingly important topic, especially since the attention which vaccines have received over the past 2 years.

Long-lasting, slow-release drug delivery is preferred for treatment of certain illnesses and diseases, and this can be addressed through use of transdermal microneedle arrays, as opposed to conventional single-site needles. However, use of microneedles brings its own challenges:

- Needles need to be long enough to penetrate undulations in the skin at a micron level

- Entire needle aperture needs to be below the stratum corneum (the elastic outermost layer of the skin) in order for the drug to be delivered effectively

- This requires high resolution manufacturing to create an accurate needle opening; if the opening isn't fully below the stratum corneum, the drug will disperse over the skin surface

Much research has already been conducted in this area using techniques such as two-photon polymerization (2PP), but as Roger Narayan and the joint team propose in the paper above, microscale metal 3D printing could be a viable solution.

Pictured is an Exaddon demo needle printed in pure copper with the CERES system. The aperture is around 40 µm in height. Overall needle height 140 µm.

A demo needle printed in pure copper with the CERES system. Aperture diameter 40 µm, needle height 140 µm.

The Exaddon CERES print system; a stand-alone technology for microscale additive manufacturing of metals.

The CERES µAM print system in brief:

- 3D print microscale metal objects directly in situ (eg on a chip surface) via electrodeposition

- Object size range <1 µm to 1000 µm

- Resolution is less than 1 µm

- Room temperature process

- No post processing necessary

- Print in pure metal; copper, gold, nickel, and more

Edward White 29 September, 2022

Using 3D Printing for Transdermal Drug Delivery

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