A 3D electrochemical biosensor based on Super-Aligned Carbon NanoTube array for point-of-care uric acid monitoring

Uric acid analysis is extremely important for gout prognosis, diagnosis and treatment. Previous technologies either lack specificity or exhibit poor performance, and thus could not meet the need of Point-of-Care (POC) uric acid monitoring. Here we present for the first time, a novel electrochemical biosensor based on 3D Super-Aligned Carbon NanoTube (SACNT) array to facilitate POC uric acid monitoring. The working electrode of the biosensor is composed of an orderly 3D SACNT array immobilized with uricase through a precipitation and crosslinking procedure. Such biosensor possesses a higher enzyme density, significantly larger contact area with reactants and could maintain the intact SACNT structure and its excellent conductivity after modification. The developed 3D SACNT array electrochemical biosensor benefits from high specific surface area, high electro-catalytic activity and large contact area with analytes, and demonstrates high sensitivity of 518.8 μA/(mM⋅cm²), wide linear range of 100-1000 μM and low limit of detection of 1 μM for uric acid. Dynamic uric acid monitoring has been achieved using the presented biosensor. And the obtained results in serum samples had no significant difference compared with those obtained using the FDA-approved electrochemical analyzer (Paired T-test, p > 0.05). These demonstrated that the technology can potentially be applied in POC monitoring of other biomolecules to improve prognosis, diagnosis and treatment outcomes of metabolic diseases.