A leech-like device may provide a pain-free alternative to capillary blood sampling.

Researchers in Switzerland have designed a prototype of a suction cup device that contains microneedles, capable of collecting enough capillary blood for point-of-care tests or laboratory analyses.

Zoratto N, Klein-Cerrejon D, Gao D, et al. (2024). A bioinspired and cost-effective device for minimally invasive blood sampling. Advanced Sci. 2024;202308809. Online

Professor David Klein Cerrejon, co-author of the research and a professor of drug formulation and delivery at ETH Zurich, told MDLinx about the invention.

“This combination of microneedles and the suction cup, inspired by the leech, could basically move into this niche where you need a bit more blood than what you can get with a finger prick, as for a more reliable analysis, and where you get a bit less than what you get from a vein puncture. But you have the benefit that it's basically more or less painless. And you can hide the needles inside, which then solves these needlestick problems and everything else that is related to it,” he said.Leeches adhere to a human with a suction cup–like mouth. Then, they use their teeth to create a puncture in the skin, and suck to draw out blood.

Inspired by the leech, the researchers created a device that mimics its anatomy.  

A suction cup hides the microneedles that mimic the micro teeth of the leech. The device also has a storage reservoir that contains anticoagulant for the collection of blood. This is similar to the salivary secretions of the leech.

Phillips AJ, Govedich FR, Moser WE, et al. Leeches in the extreme: morphological, physiological, and behavioral adaptations to inhospitable habitats. Int J Parasitol Parasites Wildl. 2020;12:318–325.

The researchers say the hidden microneedles could make capillary blood sampling easier for patients with a needle phobia.

“The main idea, of course, is to get rid of the bigger needle just because a lot of people are really afraid of needles, and not only the children, but also older people—they usually have suffered from needle phobia, needle fear. So this was one of our main aims,” said Nicole Zoratto, PhD, to MDLinx. Dr. Zoratto is lead author of the study and a professor of drug formulation and delivery at ETH Zurich.

The researchers are also hopeful the device could be beneficial for use in low- and middle-income countries where resources could be limited.

“The standard for healthcare systems is that we have the vein puncture to draw these larger amounts of blood, that you can use then for laboratory analysis. So this is the standard way that it's done in healthcare facilities, but you need trained specialists for that,” Dr. Klein Cerrejon told MDLinx.

“When we think of low-income countries with limited resources, we have two big problems. First, we are lacking healthcare specialists. Second is the risk of needlestick injuries, because people are not properly trained,  which means we then have  problems with diseases that are transmitted by blood. So when there's a needlestick injury, that's a huge problem for healthcare workers. Disposal is another issue. Usually in these lower-income settings, the waste disposal systems are not really there.”

The device is just a prototype at this stage, and the researchers say more work is needed before it could be deployed in clinical settings.

More research may also be needed to determine if individuals with needle phobia respond well to the device.

“To fully answer that, we would need to run tests on this with volunteers. But there’s studies

Aldawood FK, Andar A, Desai S, et al. A comprehensive review of microneedles: types, materials, processes, characterizations and applications. Polymers (Basel). 2021;13(16): 2815.

that show that patients accept microneedles more than big needles, and as they are not seeing them during the entire application, it should be better, but we have no proof for that at the moment,” Dr. Klein Cerrejon said.