Abstract

Acetylcholine (ACh) biosensor is developed based on mediator-free acetylcholine oxidase (AChOx) by selfassembled monolayer (SAM) onto lab-made micro-chip. The simple cyclic voltammetry (CV) method is utilized in mediator- free system in phosphate buffer solution (PBS, 0.1M) at room conditions. The analytical parameters of AChOx fabricated electrode employed a lower detection limit (DL, 0.136 nM), a wide linear dynamic range (LDR, 1.0 nM to 1.0 mM), good linearity (R= 0.9991), and higher sensitivity (2.7329 μAmM-1cm-2) where a tiny sample volume (70.0 μL) is required. The micro-chip system executes a simple and efficient approach to immobilize the enzymes onto SAM modified surface, which can improve the biosensor performances for a large group of biomolecules in broad scale of biomedical applications in health-care fields.

Keywords: Acetylcholine oxidase, acetylcholine, cyclic voltammetry, detection limit, immobilization, linear dynamic range, mediator-free system, micro-chips, phosphate buffer solution, selectivity, self-assembled monolayer, sensitivity, stability, thioglycolic acid