Nonenzymatic amperometric glucose sensing of platinum, copper sulfide, and tin oxide nanoparticle-carbon nanotube hybrid nanostructures

We fabricated highly sensitive nonenzymatic amperometric glucose biosensors using platinum (Pt), copper sulfide (Cu₂S), and tin oxide (SnO ₂) nanocrystal- (NC) carbon nanotube (CNT) hybrid nanostructures, where the NCs were grown in situ on the CNTs by the solvothermal method. The double-walled CNT series respond more sensitively than the multiwalled CNT series. The relative sensitivity of the NCs follows the order Pt > Cu ₂S > SnO₂. The highest sensing ability of the Pt NC-CNT nanostructures guarantees a sensitivity of 280 μAcm^-2 mM ^-1 over a wide concentration range from 0.2 μM to 12 mM at pH ) 7.2 in phosphate buffer saline solution. The synergetic combination of the electrocatalytic activity of the NCs and the electrical network formed through their direct binding with the CNTs enhances the sensing ability of the NC-CNT hybrid nanostructures. The sensitivity, selectivity, and stability of these NC-CNT hybrid nanostructures demonstrated their potential for use as novel nonenzymatic glucose sensors.