Cobalt doped NiFe2O4 on 3D nickel foam substrate for electrochemical detection of uric acid

The development of a facile and cost-effective uric acid (UA) sensor is of significant importance in the diagnosis of hyperuricemia so that further complications in our body can be avoided due to the early detection. Herein, pristine NiFe2O4 and cobalt-doped NiFe2O4 CoxNi1-xFe2O4 (x = 0.01, 0.03, 0.05) were synthesised and coated on nickel foam (NF) to fabricate a new electrode and was investigated for non-enzymatic UA detection in Phosphate Buffer Saline (PBS, pH = 7.4). The Co0.01Ni0.99Fe2O4 showed better electrochemical activity compared to the pristine NiFe2O4 due to its higher electrochemically-active surface area. The linear response for the UA sensing using amperometric studies was observed in the range of 4 μM to 5.28 mM with a short response time with a detection limit of (LoD) 6.38 μM and a sensitivity of 2.898 mA mM−1 cm−2. The selectivity of the developed biosensor was studied by adding interferents and it showed no prominent interferents as validated using Differential Pulse Voltammetry (DPV). The stability, repeatability and reproducibility of the electrode was also studied. The fabricated Co0.01Ni0.99Fe2O4@NF biosensor was further used to detect UA in spot-urine samples showing recovery between 78 to 92 % and therefore it has promising applications in clinics where highly sensitive and selective biosensors are required.