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.
- Acetylcholine sensor
- Carbon nanotube
- Electrochemical biosensor
- Thin film
- pH sensor