Stretchable Enzymatic Biofuel Cells Based on Microfluidic Structured Elastomeric Polydimethylsiloxane with Wrinkled Gold Electrodes

Various sensors and electronic devices are recently developed to monitor human health in mechanically flexible or even stretchable forms for intimate contact with non-flat curvilinear surfaces of the human body. For successful operation of these devices, finding a proper way to electrically power them is very important. In this work, glucose/oxygen fueled enzymatic biofuel cells (EBFCs) based on microfluidic structured elastomeric polydimethylsiloxane substrate with wrinkled gold (Au) electrodes are suggested for power supply. For doing that, firstly, bottom surface of microfluidic channel is covered with buckled Au electrodes for stretchability. By microfluidic design showing capillary imbibition through fluidic channels, loading of catalyts is promoted. Interestingly, buckled Au electrodes induce much better anodic and cathodic reaction rates than those of non-buckled Au electrodes by 25% and 33%, respectively. This is because surface area and the amount of catalyst loading in electrodes increase by Au wrinkling. In evaluations of EBFCs using the buckled Au electrodes, maximum power density reaches 7.1 ± 0.64 µW cm⁻², while they show decent performance of 5.4 ± 0.49 µW cm⁻² even under external stretching. Taken together, it is corroborated that such proposed stretchable EBFCs are alternative for providing electrical power in wearable or implantable devices.