Highly sensitive neurotoxin detection using disposable acetylcholinesterase biosensors at elevated temperatures

The sensitivity of acetylcholineste rase (AChE) biosensors toward neurotoxic insecticides is crucial for their practical application. Especially when low concentrations of neurotoxic organophosphates and carbamates are targeted, the sensitivity of AChE biosensors is often not sufficient for all analytes. The immobilization of a commercial AChE isolated from Electrophorus electricus by cross-linking with glutaraldehyde in the presence of bovine serum albumine on a screen-printed electrode resulted in a biosensor with an increased operational stability toward elevated temperature. Incubation for 30 min at 30 degrees C in solution did not reduce the sensor's enzyme activity and 60 min at 100 degrees C in a dry state caused only a 14% activity loss. These findings could be exploited to either enhance the sensitivity of the AChE biosensor by increasing the temperature during sample incubation by 10 degrees C or to accelerate the test by 100% while keeping the initial sensitivity.