Cold-sprayed graphene sensor detects pulse in one-person test

Researchers from Virginia Commonwealth University and Florida International University have developed a cold-spray technique that deposits graphene nanoplatelets directly onto a flexible pressure sensor, producing a device that adhered to human skin and detected a wrist pulse. The peer-reviewed study involved laboratory experiments and testing on one human subject. Its results demonstrate an early wearable-sensor fabrication advance, not validated performance for continuous health monitoring or clinical use.

The researchers created a wearable pressure sensor made from polydimethylsiloxane, or PDMS, a soft, stretchable polymer that molds to the surface on which it is applied. In the proposed process, cold spray applies graphene nanoplatelets directly to the PDMS to provide durable adhesion onto human skin. Unlike conventional adhesion methods that require heating or the addition of chemicals and binders, the cold-spray method enables dry adhesion at room temperature.

The researchers reported that this approach also avoids tampering with the sensor’s other materials during application. “The sensor can be made by spraying the sensing material [graphene] directly onto a flexible surface, without glue or several complicated steps,” said Arvind Agarwal, Ph.D., chair and professor in VCU’s Department of Mechanical and Nuclear Engineering. The team evaluated the sensor through a series of experiments.

It reacted to a press-and-release sequence in 29 milliseconds and continued working after more than 5,000 presses. In testing with the single human participant, it was also able to pick up the person’s wrist pulse. These observations showed strong adhesion, mechanical robustness under repeated pressing, rapid response and the ability to register a bodily pulse under the tested conditions.

The release did not establish how the sensor would perform across a wider population, under different movement or environmental conditions, or during prolonged real-world use. Wearable sensors offer potential benefits for health monitoring, human-machine interaction and flexible electronics, but their fabrication often relies on costly, multistep processes with limited scalability. The researchers describe their method as a potential route to simpler, scalable manufacturing.

Putting graphene directly onto a flexible surface removes glue and several complicated steps from the bonding sequence, while dry, room-temperature application distinguishes it from approaches requiring heat, chemicals or binders. Whether the technique can support continuous physiological monitoring or customized health care was not established by the reported study. The work was published in ACS Applied Electronic Materials as “Cold-Spray Enabled Scalable Manufacturing of Flexible Graphene-Based Wearable Sensors.”

Subject of Research: Cold-spray fabrication of a graphene-based wearable pressure sensor for attachment to human skin

Article Title: VCU research propels wearable technology that could enhance health monitoring

Article References: VCU research propels wearable technology that could enhance health monitoring. Original publication (Bibliographic details unavailable.)

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Keywords: wearable sensors, cold spray, graphene nanoplatelets, polydimethylsiloxane, pressure sensing, human skin, flexible electronics, scalable manufacturing, research, propels, wearable, technology