Upcycling Compact Discs Into Ultra‐Stable, Flexible, and Stretchable Nanoporous Gold Electrodes for Enhanced Biosensing Performance

Soft wearable biosensors have demonstrated not only reliable functionality and comfortable long‐term monitoring but also significant economic and environmental advantages. Along with the advancements in soft bioelectronics, the use of sustainable materials and technologies in fabrication has gained significant attention, with a focus on upcycling obsolete electronics. Despite recent advancements in upcycled bioelectronics, they have yet to demonstrate high performance or optimal electrical conductivity under continuous mechanical deformations, which are necessary for prolonged wearable devices. In this work, we develop high‐performance and mechanically robust flexible and stretchable upcycled bioelectronics by utilizing nanoporous gold (NPG) on a gold film (GF) substrate harvested from a compact disc (CD). The fabrication process leverages desktop office fabrication tools, incorporating a DIY mechanical cutter for consistent patterning and a thermal laminator for effective insulation. The CD‐based NPG electrodes demonstrate biomechanical compliance and robustness, maintaining long‐term functionality and stable electrical conductivity under dynamic mechanical deformation. The engineered CD‐based NPG platform also exhibits superior electrochemical nitrite sensing and on‐skin biopotential measurements, including electrocardiogram, electromyography, and frontal electrooculography, with reliable reproducibility and reusability. The NPG upcycled CD biosensing system offers a transformative solution of obsolete electronics into advanced sensing platforms while addressing key challenges in bioelectronic applications.