Electrogravimetric Analysis by Quartz-Crystal Microbalance on the Consumption of the Neurotransmitter Acetylcholine by Acetylcholinesterase

Abstract

Electrogravimetric analysis was performed on the consumption of the neurotransmitter Acetylcholine (ACh) by Acetylcholinesterase (AChE) in situ and in real time. Michaelis-Menten assumption was achieved by using an enzyme micro-reactor in which the total enzyme was anchored in a quartz crystal microbalance chip (QCM-chip) with a strategically engineered self-assembled monolayer (SAM) of alkanethiols, which can prevent diffusion-controlled or spatially restricted kinetics. The real-time frequency changes indicated the rate of the products formation from enzymatic reaction. The QCM-chip was tested showing that it could demonstrate AChE inhibition by physostigmine.

Keywords:

• Acetyl cholinesterase
• Acetylcholine
• Neurotransmitter
• Physostigmine
• Quartz-crystal microbalance

Acknowledgments

The authors acknowledge the São Paulo State Research Funding Agency (FAPESP), the Brazilian National Research Council (CNPq), as well as the BIOTA program (FAPESP research center) and their researchers for their useful discussions. L. M. Gonçalves (SFRH/BD/76544/2011) wishes to acknowledge Portuguese Fundação para a Ciência e a Tecnologia (FCT) for his post-doctoral scholarship.