Carboxylated single-walled carbon nanotube thin-film (SWCNT-TF) is demonstrated as a pH electrode and a platform for enzymatic potentiometric acetylcholine biosensors. SWCNT is layer-by-layer assembled with a positively charged polyelectrolyte on the metal electrode. The open circuit potential on SWCNT-TF electrode is measured with reference to an Ag/AgCl electrode in various pH buffers. With the aid of acetylcholinesterase (AchE), acetylcholine (Ach) is successfully detected using the SWCNT-TF pH electrode that demonstrates Nernst potential of -43 mV/pH. AchE-modified electrode has a sensing resolution of 10 μM of Ach and sensitivity of 19 mV/decade. The SWCNT-TF pH electrode fabricated by layer-by-layer self-assembly may play an important role in micro/nanoscale electrochemical sensors.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the support of NSF Grant No. CMMI 0735268 . Parts of this work were carried out in the Characterization Facility and the Nanofabrication Center, University of Minnesota, which are partially supported by NSF.
Copyright 2012 Elsevier B.V., All rights reserved.
- Acetylcholine sensor
- Carbon nanotube
- Electrochemical biosensor
- Thin film
- pH sensor