A blood collection device inspired by leeches

Painless and minimally invasive blood sampling may soon be possible thanks to this prototype suction cup device.

Taking cues from leeches, scientists have developed a blood collection device that avoids the dreaded needle.

“Inspired by the structure and anatomy of leeches, we wondered how these creatures attach to their hosts, bite through the skin and effectively draw in a large volume of blood in a relatively short time by creating a vacuum,” explains Nicole Zoratto, a researcher at ETH Zürich in Switzerland and the main author of this work in an email.

According to Zoratto research, approximately 70% of medical decisions are based on the results obtained from blood samples. However, for some, the experience of having their blood drawn can be harrowing – nearly a third of patients report needle phobia, which can lead many to avoid necessary medical procedures.

Although the team is still in the testing phase, they hope that one day their new device could be used on children and adults with needle phobia and be widely available in low- and middle-tier countries. “The device is characterized by simplicity and cost-effectiveness (…), providing access to reliable and cheap diagnostics,” Zoratto added.

Traditional blood collection, in which blood is drawn directly from a vein, also requires both trained personnel and the safe disposal of used needles. In the United States alone, more than 10% of needle stick injuries involve blood collection and pose a serious risk of infection to healthcare workers.

Such problems are even more serious in resource-constrained environments. With the new leech blood sampler, Zoratto and her team hope to eliminate these current shortcomings.

Say goodbye to painful needles

Leeches use suction cups to attach to the host and, unlike needles, they painlessly penetrate the skin with their tiny teeth, releasing anticoagulant saliva that prevents blood from clotting. They then swallow to create a negative pressure that helps draw in the blood.

Mimicking these features, the team designed a suction cup with 20-30 tiny microneedles inside, imitating the teeth of a leech, and a compartment containing an anticoagulant to prevent blood clotting.

A suction cup designed to be placed on the arm creates pressure to draw capillary blood located in small vessels near the surface of the skin. Zoratto explains that unlike other technologies, their device does not contain complex components such as microfluidic channels by design, making its future production simpler and cheaper.

“The simple design of our device does not require expensive microfluidic components, which allows its production without the need for technologically advanced production plants,” she said. “Simple manufacturing combined with low-cost materials can reduce production costs.

“We hope this will, in turn, make it easier to set up manufacturing plants even in resource-constrained environments, ensuring a consistent global supply chain even in less developed countries.”

The idea is that once the sample is collected, the device can be safely packaged and sent to a laboratory for analysis. Alternatively, the team designed the device to be easily integrated into standard bedside kits for rapid testing and detection of diseases such as malaria and HIV.

“The device described in the article is a preliminary prototype, (…) several stages of device optimization are required, and above all, their safety of use should be assessed. Moreover, these studies are complex and expensive,” noted Zoratto. In a press release provided by ETH Zurich, the group indicates that it is looking for a partner that could raise more funding to support such research.

The device was found to be safe in animal models, but further clinical trials are needed. While Zoratto wasn’t able to provide more details, she says the next version of the device will be biodegradable.

“We are currently working on a fully biodegradable version of our device that will cope with (…) waste disposal,” she added.

Reference: Nicole Zoratto et al., Bioinspired and economical device for minimally invasive blood collectionAdvanced Learning (2024) DOI: 10.1002/advs.202308809