NADH sensing using a carbon nanotube electrode reinforced with a plasma-polymerized thin film

We report on an electrochemical nicotin adenine dinucleotide (NADH) sensor that is based on carbon nanotubes (CNT) and plasma-polymerized film (PPF). The configuration of sensing electrode was CNTs sandwiched between two 6 nm thick PPFs made from acetonitrile on sputtered gold thin film. We optimized the CNT concentration for casting formation onto the under PPF layer. The sensor showed high sensitivity (a sensitivity of 240 μA mM^-1 cm^-2, a detection limit of 3.9 μM at S/N = 3, +0.4 V vs. Ag/AgCl), wide dynamic range (a linear response range of 0.009-2.3 mM, a correlation coefficient of 0.993), and rapid response (< 7s in reaching 95% of maximum response). This high performance is attributed that CNTs offer excellent electrocatalytic activity and enhance electron transfer, therefore, PPF and/or plasma process are the electrochemistry-friendly platform for CNT applications.