In brief

When designed for balanced sampling efficiency and minimal pain, a transepidermal microprojection array outperformed traditional skin scraping methods in sampling clinically relevant deep skin fungi.

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Unearthing skin-deep fungi

26 Jun 2023

A new 3D-printed microneedle array could prove a more effective, less invasive diagnostic tool to extract disease-causing fungi from deep skin layers.

For some fungal species, living on human skin is like being on a tropical island vacation. The skin provides warm and moist conditions, and its natural oils contain abundant nutrients for fungi to feed on. While harmless fungi make up a small percentage of our skin’s natural microbiome, others can trigger problematic skin conditions such as athlete’s foot.

Diagnosing skin infections often involves doctors swabbing the affected site’s surface, stripping it with tape, or scraping it with a scalpel to sample its microbiome for lab tests. However, these methods don’t work well for some infections caused by fungi, which tend to thrive in the skin’s deeper layers.

“Currently, the only way to sample microbes from deep skin is a punch biopsy,” said Kun Liang, a Project Leader at the A*STAR Skin Research Labs (A*SRL). As such biopsies are both invasive and painful—performed by using circular incisions to remove skin tissue—dermatologists tend to default to skin scrapings for suspected fungal infections, which may not detect the real culprits at large.

Seeking a less uncomfortable option to sample the deep skin microbiome, Liang’s team joined forces with A*SRL Senior Principal Investigator Thomas Dawson and team, as well as clinical collaborator Hong Liang Tey from Singapore’s National Skin Centre. Together, they developed a transepidermal microprojection array (MPA), a 3D-printed device with tiny, needle-shaped structures to penetrate the skin and extract a fraction of the microbes beneath.

One major challenge was finding a balanced design that would reach deep enough to find suspicious fungi while minimising patient discomfort. “By making use of 3D printing’s rapid customisability, we fabricated a variety of MPAs with different geometries, heights, sizes and densities,” said Liang.

After extensive testing on skin models, the team landed on an optimal design. The prototype MPA was then tested on the scalps of healthy study participants and compared with tape and swab tests. They found the MPA was not only as sensitive as the two conventional methods, but it was also able to detect a greater variety of clinically-relevant fungal species that could cause disease.

With their sights set on commercialising the technology, Liang and colleagues are planning follow-up clinical studies at the NSC. They aim to compare the MPA’s efficacy with current clinical standards for skin sampling from patients with fungal infections, with hopes that it may add to the dermatologist’s diagnostic toolkit in future.

“Further studies are also needed to streamline and optimise the identification and analysis pipeline after MPA sampling to ensure a smooth transition to clinical use,” said Liang.

The team also intends to explore the MPA’s unique capabilities as a research tool, using it to study the connections between its microbiotic samples and overall skin health.

The A*STAR-affiliated researchers contributing to this research are from the A*STAR Skin Research Labs (A*SRL).

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Liang, K., Leong, C., Loh, J.M., Chan, N., Lim, L., et al. A 3D-printed transepidermal microprojection array for human skin microbiome sampling. Proceedings of the National Academy of Sciences 119 (30), e2203556119 (2022). | article

About the Researcher

Kun Liang is a Project Leader in the Model Development Team at the A*STAR Skin Research Labs (A*SRL). He completed his bachelor’s degree in Biomedical Engineering at Duke University, after which he received his PhD in Integrative Science and Engineering from NUS and completed a postdoctorate fellowship at ETH Zürich. He joined A*SRL and the Skin Research Institute of Singapore (SRIS) in 2019. His current research focuses on designing biomaterials for various skin-related healthcare applications such as transcutaneous delivery, skin diagnostic tools and skin tissue engineering.

This article was made for A*STAR Research by Wildtype Media Group