The development of a butyrylcholinesterase porous pellet for innovative detection of cholinesterase inhibitors

The effect of different types of lactose monohydrate on the stability of acetylcholinesterase immobilized on carriers designed to detect nerve agents

“…Eur. 10, the sieve analysis was used to obtain pellets of 0.8–1.25 mm, which is the ideal carrier size for loading into detection tubes 19 . Such pellets were then impregnated with acetylcholinesterase, which was obtained from the brain tissue of the nucleus caudatus ( Sus scrofa f. domestica ).…”

“…The Ellman's test solution (ETS) was prepared by mixing 0.2 mL ATChI solution and 15 mL of the Ellman's work solution. The ATChI and ETS were stable for 24 h. For the test of inhibition, physostigmine test solutions (PTS) with concentration of 0.25, 0.5, 1.0, 2.0 or 4.0 mg L −1 were prepared according to the standard methodology 19,25 …”

“…Otherwise, a yellow color develops on the pellets within a few seconds, which is visible to the naked eye or detectable spectrophotometrically. The disadvantage of this reaction is often an indistinct transition from white to yellow, which was investigated in other studies 19,25,26 . However, during longer storage and especially at higher temperatures, the carriers continued to turn brown, which could be problematic when stored, particularly in subtropical and tropical countries.…”

“…The first‐mentioned – colorimetric detectors – use enzymes for detection and are therefore often referred to as biosensors. These also include detection tubes, newly containing cholinesterase immobilized on a carrier in the form of pellets, 18,19 which have many advantages over other types of detectors, such as low cost, simplicity of use, portability, providing fast detection with a high sensitivity 6,20 and ability to detect even unknown substances which act by the same mechanism (i.e. cholinesterase inhibitor) 15,21 .…”

“…On the other hand, it is extremely expensive, available only in small quantities and therefore disadvantageous for larger production. For these reasons, lactose was used instead, as it concurrently improves the stability of an enzyme while it also acts as a filler in the preparation of pellets 19 . However, there are several types of lactose monohydrate that differ in particle size and shape or method of preparation, due to which they may differ distinctly in affecting the stability of the enzyme.…”