Stretchable biofuel cells as wearable textile-based self-powered sensors

Abstract

Highly stretchable textile-based biofuel cells (BFCs), acting as effective self-powered sensors, have been fabricated using screen-printing of customized stress-enduring inks. Due to synergistic effects of nanomaterial-based engineered inks and the serpentine designs, these printable bioelectronic devices endure severe mechanical deformations, e.g., stretching, indentation, or torsional twisting. Glucose and lactate BFCs with the single enzyme and membrane-free configurations generated the maximum power density of 160 and 250 µW cm−2 with the open circuit voltages of 0.44 and 0.46 V, respectively. The textile-BFCs were able to withstand repeated severe mechanical deformations with minimal impact on its structural integrity, as was indicated from their stable power output after 100 cycles of 100% stretching. By providing power signals proportional to the sweat fuel concentration, these stretchable devices act as highly selective and stable self-powered textile sensors. Applicability to sock-based BFC and self-powered biosensor and mechanically compliant operations was demonstrated on human subjects. These stretchable skin-worn “scavenge-sense-display” devices are expected to contribute to the development of skin-worn energy harvesting systems, advanced non-invasive self-powered sensors and wearable electronics on a stretchable garment.

Nanomaterial‐Enabled Wearable Sensors for Healthcare

“…Simultaneous and continuous monitoring of sweat profile during exercise can be conducted using wearable electrochemical sensors. [66,199] As illustrated in Figure 10d, by wearing the device consisting of a multiplexed sensor array and a flexible printed circuitry board in the form of a wristband or headband, variations of skin temperature, electrolytes, and sweat metabolites in perspiration can be monitored wirelessly using a customized app on a smart phone. [199] The sweat analysis enabled real-time assessment of the physiological and metabolic state and provided important information for disease diagnosis and athletic performance evaluation.…”

“…Another CNT-silver nanoink based BFCs with textile substrate were exploited as self-powered sensors that can harvest energy from perspiration for probing sweat metabolites (glucose and lactate). [66] Dehydration can be a risk factor and symptoms for various diseases. To facilitate tracking of this health indicator in a wearable form factor, our group has recently demonstrated the moni toring of skin humidity using a compliant AgNW/PDMS based interdigitated electrode.…”

“…[5] The power can be harvested from various sources including temperature difference and mechanical sources such www.advancedsciencenews.com www.advhealthmat.de as body movements and vibrations. [66,67,75,131,133,162,200,201] In an effort toward self-powered sensors, a sensor structure shown in Figure 5d was used as a triboelectric nanogenerator (TENG). [131] Power can be generated from various mechanical stimuli such as pressing, stretching, twisting, and sound driven vibrations due to the change in the air gap.…”

“…Direct spinning of CNTs onto a substrate or into yarns [53][54][55] and electrospinning of nanofibers or NWs were reported to produce fiber-like nanomaterials. [56][57][58][59] In addition, novel direct printing or writing techniques [60,61] such as inkjet printing, [62] gravure printing, [63,64] screen printing, [65][66][67] nozzle jet printing, [26] and direct writing [68,69] enabled the fabrication of wearable sensors that possess complex patterns with high resolution.…”

“…CNT and Ag ink [66] Glucose and lactate Sweat 3.14 ± 0.2 µW cm −2 mm −1 (glucose), CNT [199] Glucose, lactate, Na + , and K + graphene/AuNP hybrid structure was fabricated by prestraining the substrate and then releasing the strain. [177] Figure 6h shows the fabricated stretchable photodetector attached on a contact lens.…”