Biosensor Based On Decorated Graphene Nanocomposite For Detection Of Cholinesterase Inhibitors

Cholinesterase inhibitors show their activities through attacking the hydroxyl moiety of serine in the ’active site’ of acetylcholinesterase (AChE), thus inhibiting the function of this enzyme. Finally they lead to the disorders of the neurotransmitters’ delivery, causing serious health problem. There are three kinds of cholinesterase inhibitors including organophosphates, carbamates and quaternary ammonium. The high toxicity of organophosphates and some carbamates are used to be pesticides in agriculture. While other carbamates and quaternary ammonium mainly be used in clinical medicine, enhancing the nerve impluse to cure some diseases.Different structures of the inhibitors have different pathways for the inhibition and poisoning therapy of the cholinesterases. Based on this idea, we constructed new biosensors to investigate the reactions between the inhibitors and cholinesterases of different structures in this paper. The main researches were summarized as follows:(1) We construct a novel AChE biosensor based on prussian blue nanocubes/reduced graphene oxide (PBNCs/rGO) nanocomposite for detection of organophosphorus pesticides (OPs). The obtained PBNCs/rGO based AChE biosensor exhibits high electrocatalytic activity towards the oxidation of thiocholine, hydroxyl product of acetylthiocholine chloride by AChE. It shows rapid response and high sensitivity for detection of monocrotophos with a linear range from1.0to600ng/ml and a detection limit of0.1ng/ml.(2) Pesticides including organophosphates (OPs) and carbamates are widely used in agriculture due to their high insecticidal activity. They show high toxicity to AChE in different pathways. Different structures of the pesticides lead to differences in the process of the inhibition, reactivation and aging in the exposure. So we propose an electrochemical method to investigate the relationship with the structure and the different pathway in toxicity and therapy, using a stable AChE biosensor based on simple and efficient self-assembling AChE to graphene nanosheet (GN)-AuNPs nanocomposite modified electrode.(3) AChE and butyrylcholinesterase (BuChE) are two important enzymes in organisms. AChE has an important role in the conduction of nerve excitability, as it can catalyze hydroltsis of acetylcholine. These two enzymes are similar but also have some distinguish in the structure, so there will be many different situations when they react with different inhibitors. We constructed an AChE biosensor based on GNs-PtNPs nanocomposite modified electrode which can rapidly and sensitively detect the activity of anti-cholinesterase inhibitors, to investigate the relationship of the structures and inhibitors activities to different cholinesterase.