An inkjet-printed smartphone-supported electrochemical biosensor system for reagentless point-of-care analyte detection

In this work, we developed an inkjet-printed electrochemical enzyme-based biosensor system which can work with the smartphone for the point-of-care analyte detection. Inkjet printing technique was applied to functionalize electrodes. Multi-walled carbon nanotubes were used as the enzyme carrier to enhance the enzyme loading. Enzyme immobilization was realized through layer-by-layer printing strategy by crosslinking ink components (BSA and glutaraldehyde) between printing layers. Reagents for the enzyme catalyzed reaction were preloaded onto the working electrode to eliminate the use of traditional electrochemical cell. In addition, a versatile smartphone Android application was developed for real-time data processing on multiple occasions. Phosphate in the artificial saliva was measured to demonstrate the feasibility of the proposed biosensor system. The miniaturized biosensor system presents a wide linear range with rapid response time (less than 10 s). High selectivity and stability of the sensor demonstrate its practical use for saliva test. The proposed biosensor system can be applicable for various analyte detection by exchanging the sensing elements and reagents. And the biosensor system can be easily operated by users without specific training. In all, this study demonstrated a novel fabrication strategy of integrated biosensor system which has great potentiality for point-of-care applications. Our proposed sensor system demonstrates a reliable and reproducible biosensor fabrication route that has meaningful reference for similar point-of-care biosensor systems.