Nonenzymatic cholesterol sensor based on spontaneous deposition of platinum nanoparticles on layer-by-layer assembled CNT thin film

Platinum nanoparticles (Pt NPs) were deposited on a layer-by-layer (LBL) assembled carbon nanotube (CNT) thin film via the spontaneous reduction of H ₂PtCl ₆ at the functional defect sites of the CNT surface. This nanostructure was characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The modified electrode can be used for the nonenzymatic detection of cholesterol by chronoamperometry (CA) in neutral PBS. We also studied the optimal number of CNT layer for obtaining high sensitivity. The sensor with 24 bilayer of CNT shows very low detection limit and a wide linear range from 0.005 mM to 10 mM with a sensitivity of 8.7 μA mM ^-1 cm ^-2. The result is attributed to the LBL assembled structure and more continuous intercalated pathways for electron transport in LBL assembled CNT film and the fact that the CNT film can provide a larger surface area for Pt NP loading. The sensor has good anti-interferent properties in the presence of glucose, ascorbic acid, and dopamine.