Publication details
New principle for the direct real-time monitoring of interaction of cholinesterase and its inhibitors
| Authors | |
|---|---|
| Year of publication | 2003 |
| Type | Article in Periodical |
| Magazine / Source | Biosensors & Bioelectronics |
| MU Faculty or unit | |
| Citation | |
| Field | Biochemistry |
| Keywords | cholinesterase; inhibitor; piezoelectric; biosensor; real-time |
| Description | A new method for the sensitive detection of cholinesterase inhibitors based on real-time monitoring using a piezoelectric biosensor. The cholinesterase inhibitor paraoxon was immobilized on the sensing surface via a chelate complex as the recognition element. At first, the conjugate of N?mercaptoundecanoic acid (MUA) with Ná, Ná-bis (carboxymethyl)-L-Lysine (NTA-Lys) was chemisorbed to form a self-assembled monolayer on the surface of the gold electrode of the piezosensor. In the next step, paraoxon-spacer-hexahistidine conjugate was linked to the MUA-Lys-NTA layer via the chelate complex with Ni2+. The paraoxon-modified surface thus obtained was applied for the binding of human butyrylcholinesterase. Regeneration of the sensing surface was achieved by splitting the chelate complex with EDTA and depositing a fresh layer of Ni2+ followed by addition of the paraoxon-spacer-hexahistidine. In the presence of free inhibitors like diisopropylfluorphosphate (DFP), binding of BChE to the surface-bound paraoxon was decreased. In this way, a competitive affinity assay for organophosphorus compounds was developed. The limit of detection for DFP as a model compound was 10 nmol/l (approx. 2 mg/l). This new concept seems suitable for constructing biosensors for the group-specific detection of cholinesterase-inhibiting substances like insecticides in the field. |
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