A new screen-printing approach that could bring more cost-effective manufacturing of wearable electronics has been developed by researchers led by Jong-Hoon Kim’s lab at Washington State University. The new electrode screen-printing process demonstrated that the structures that power wearable electronics could be produced using similar technology to that in printing t-shirts, and how the resulting electrodes can be used for health monitoring.
Existing commercial manufacturing of wearable electronics involves costly processes that require clean rooms; although some use screen printing for parts of the process, this new approach depends completely on screen printing, which is simple to set up and easy to use, with its convenience and cheapness making it suitable for mass production.
As described in the journal ACS Applied Materials and Interfaces [Park et al. ACS Appl. Mater. Interfaces (2023) DOI: 10.1021/acsami.2c17653], the electrodes were made using screen printing alone to develop a stretchable and durable circuit pattern for transferring onto fabric and then worn directly next to human skin. A multi-step process layered polymer and metal inks to produce the serpentine structures of the electrode. Although the thin pattern produced looks delicate, the electrodes are not fragile, and can be stretched by 30% and bent to 180 degrees.
In the study, numerous electrodes were printed onto a pre-treated glass slide that allows them to be easily peeled off and transferred onto an adhesive fabric and worn directly on the skin. Real-time wireless electrocardiogram (ECG) monitoring was achieved using the printed electrodes with a flexible printed circuit to accurately record heart and respiratory rate metrics, transmitting the data to a mobile phone.
Although this research concentrated on ECG monitoring, the process could be used to produce electrodes for many different areas, such as offering similar functions to smart watches and fitness trackers. As corresponding author Jong-Hoon Kim told Materials Today, “The scalable and cost-effective manufacturing of skin-conformable electrodes will have the potential to offer continuous health monitoring in the biomedical field. In addition, it can be used for persistent human-machine interfaces via biopotential signals.”
The team, which includes researchers from the Georgia Institute of Technology, Pukyong National University in South Korea and WSU Vancouver, are now extending the technology to print different electrodes and complete circuit boards for the seamless integration of microprocessors and wireless communication chips, and also hope to explore clinical applications for the machine-learning-enabled real-time diagnosis of acute heart diseases and other biopotentials.
“The scalable and cost-effective manufacturing of skin-conformable electrodes will have the potential to offer continuous health monitoring in the biomedical field"Jong-Hoon Kim
Screen printing of skin-conformable electrodes holds promise for health monitoring