Fiber-crafted biofuel cell bracelet for wearable electronics

• Published in: Biosensors & bioelectronics 2021-05, Vol.179, p.113107-113107, Article 113107
• Main Authors: Yin, Sijie, Liu, Xiaohan, Kaji, Tatsuya, Nishina, Yuta, Miyake, Takeo
• Format: Article
• Language: English
• Subjects: Bioelectric Energy Sources; Biofuel cell; Biofuels; Biosensing Techniques; Electronics; Enzyme electrode; Humans; Ionic gel; Sweat; Wearable devices; Wearable Electronic Devices
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2021.113107

Wearable devices that generate power using sweat have garnered much attention in the field of skin electronics. These devices require high performance with a small volume and low production rate of sweat by living organisms. Here we demonstrate a high-power biofuel cell bracelet based on the lactate in human sweat. The biofuel cell was developed by using a lactate oxidase/osmium-based mediator/carbon nanotube fiber for lactate oxidation and a bilirubin oxidase/carbon nanotube fiber for oxygen reduction; the fibers were woven into a hydrophilic supportive textile for sweat storage. The storage textile was sandwiched between a hydrophobic textile for sweat absorption from the skin and a hydrophilic textile for water evaporation to improve sweat collection. The performance of the layered cell was 74 μW at 0.39 V in 20 mM artificial sweat lactate, and its performance was maintained at over 80% for 12 h. Furthermore, we demonstrated a series-connection between anode/cathode fibers by tying them up to wrap the bracelet-type biofuel cell on the wrist. The booster six-cell bracelet generated power at 2.0 V that is sufficient for operating digital wrist watches. •A high-power biofuel cell bracelet based on the lactate in human sweat was developed with flexible enzyme/mediator/CNT fibers.•The BFC was developed by using a LODLOD/osmium-based mediator/CNT fiber for lactate oxidation and a BOD/CNT fiber for oxygen reduction.•The performance of the layered cell was 74 μW at 0.39 V in 20 mM artificial sweat lactate, and its performance was maintained at over 80% for 12 h.•The booster six-cell bracelet generated power at 2.0 V that is sufficient for operating digital wrist watches.