Highly sensitive and selective enzymatic detection for hydrogen peroxide using a non-destructively assembled single-walled carbon nanotube film

This study presents a simple approach for the assembly of a free-standing conductive electronic nanofilm of single-walled carbon nanotubes (SWNTs) suitable for enzymatic electrochemical biosensors. A large-scale SWNT electronic film was successfully produced by the dialysis of p-Terphenyl-4, 4´´-dithiol (TPDT)-treated SWNTs. Furthermore, Horseradish peroxidase (HRP) was immobilized on the TPDT-SWNT electronic film, and the enzymatic detection of hydrogen peroxide (H2O2) was demonstrated without mediators. The detection of H2O2 in the negative potential range (–0.4 V vs. Ag/AgCl) was achieved by direct electron transfer of heme-based enzymes that were immobilized on the TPDT-SWNT electronic film. The SWNT-based biosensor exhibited a wide detection range of H2O2 from 10 μM to 10mM. The HRP-doped SWNT electronic film achieved a high sensitivity of 342 μmA/mM•cm2 and excellent selectivity against a variety of redox-active interfering substances, such as ascorbic acid, uric acid, and acetaminophen.