Potential of a sensitive uric acid biosensor fabricated using hydroxyapatite nanowire/reduced graphene oxide/gold nanoparticle.

In this study, a ternary nanocomposite consisting of gold nanoparticles (AuNPs), hydroxyapatite (HAP) nanowires, and reduced graphene oxide (rGO) is synthesized by a simple one-step hydrothermal method, which is used to modify glassy carbon electrode (GCE) for detecting uric acid. The nanocomposite is characterized through various methods such as scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. Electrochemical measurements of the modified GCE are performed in a conventional three-electrode system. Experimental results show that the obtained HAP nanowire and rGO are mixed homogeneously, and the AuNPs are deposited into this matrix. The GCE modified by the nanocomposites have superior electrocatalytic activities for uric acid. The peak current intensities of UAO (uricase)/HAP-rGO/AuNPs sensing system linearly increase as the uric acid concentration increases substantially in a range of 1.95 × 10-5 to 6.0 × 10-3  M (R2 = .9943), with a detection limit of 3.9 × 10-6  M (S/N = 3) and analytical sensitivity of 13.86 mA/M. The biosensor performs well in determining uric acid concentration in human urine samples.