Simple biosensing method to detect DMMP based on QCM transducer and acetylcholine esterase sensitive film.

A simple and stable method to detect dimethyl methylphosphonate (DMMP) was studied. Through direct monitoring of acetylcholinesterase (AChE) inhibition without histological substrate, the concentration of DMMP was sensitively detected. In the experimental setup, a liquid-gas interface was developed to improve the oscillation stability of quartz crystal microbalances (QCMs) and to prevent protein denaturation of AChE. AChE was immobilised on the surface of gold electrodes on QCM by creating a cross-linked gel with glutaraldehyde. Experimental results showed that the prepared biosensor had a frequency fall of ~4 Hz when a concentration of 1 ng/ml increment occurred for liquid DMMP. Furthermore, the detection was repeatable and selective to only DMMP. Frequency response to DMMP in gas phase was also studied. The considerable frequency response and its complete recovery showed that the sensor had wide application potential in attack defence and public safety construction. [ABSTRACT FROM AUTHOR]