Conducting polymer and multi-walled carbon nanotubes nanocomposites based amperometric biosensor for detection of organophosphate

• Nanocomposites of Poly(3,4-ethylenedioxythiophene) and MWCNTs has been used for the immobilization of acetylcholinesterase.
• AChE inhibition based electrochemical biosensor is a useful technique for the organophosphate (OP) detection.
• Detection limit of malathion is 1 fM. Recoveries of malathion from the spiked lettuce sample ranged between 96-98%.
• High reactivation efficiency (99%) of AChE by aldoxime reagent and shelf life (30 days).

A nanocomposite consisting of conducting polymer (CP)- Poly(3,4-ethylenedioxythiophene) (PEDOT) and multi-walled carbon nanotubes (MWCNTs) has been deposited electrochemically onto the surface of fluorine doped tin oxide (FTO) sheets for the analysis of malathion organophosphate (OP). The –COOH functionalization of MWCNTs has been done for the covalent immobilization of an enzyme acetylcholinesterase (AChE). The prepared PEDOT-MWCNTs/FTO and AChE/PEDOT-MWCNTs/FTO bioelectrodes were characterized by Fourier transform infrared spectrometry (FTIR), Field emission-scanning electron microscopy (FE-SEM) and electrochemical studies. Various optimization studies were done for different parameters including pH of 0.1 M phosphate buffer solution (PBS) (7.5), AChE concentration (50 mU), substrate concentration (0.3 mM) and inhibition time (10 min). The detection limit for malathion was calculated to be 1 fM within the linear range 1 fM to 1 μM. The inhibited AChE could be regenerated to 99% by 2-PAM. The storage stability and reusability of the prepared bioelectrode is observed to be 30 days and seven times, respectively. Recoveries of malathion from the spiked lettuce sample ranged between 96–98% using the developed bioelectrode.

Bioelectrode/biosensor based on nanocomposites consisting of conducting polymer (CP) and multi-walled carbon nanotubes (MWCNTs) as a suitable platform have been used for the immobilization of acetylcholinesterase (AChE) enzyme for the electrochemical sensing of organophosphate (OP) upto 1 fM.Figure optionsDownload as PowerPoint slide