A Bendable Biofuel Cell-Based Fully Integrated Biomedical Nanodevice for Point-of-Care Diagnosis of Scurvy.

Fully integrated nanodevices that allow the complete functional implementation without an external accessory or equipment are deemed to be one of the most ideal and ultimate goals for modern nanodevice design and construction. In this work, we demonstrate the first example of a bendable biofuel cell (BFC)-based fully integrated biomedical nanodevice with simple, palm-sized, easy-to-carry, pump-free, cost-saving, and easy-to-use features for the point-of-care (POC) diagnosis of scurvy from a single drop of untreated human serum (down to 0.2 μL) by integrating a bendable and disposable vitamin C/air microfluidic BFC (micro-BFC) (named iezCard) for self-powered vitamin C biosensing with a custom mini digital LED voltmeter (named iezBox) for signal processing and transmission, along with a ″built-in″ biocomputing BUFFER gate for intelligent diagnosis. Under the simplicity- and practicability-oriented idea, a cost-effective strategy (e.g., biomass-derived hierarchical micro-mesoporous carbon aerogels, screen-printed technique, a single piece of Kimwipes paper, LED display, and universal components) was implemented for nanodevice design rather than any top-end or pricey method (e.g., photolithography/electron-beam evaporation, peristaltic pump, wireless system, and 3D printing technique), which enormously reduces the cost of feedstock down to ∼USD 2.55 per integrated kit including a disposal iezCard (∼USD 0.08 per test) and a reusable iezBox (∼USD 2.47 for large-scale tests). These distinctive and attractive features allow such a fully integrated biomedical nanodevice to fully satisfy the basic requirements for POC diagnosis of scurvy from a single drop of raw human serum and make it particularly appropriate for resource-poor settings, where there is a lack of medical facilities, funds, and qualified personnel.