A new ethanol biosensor based on polyfluorene-g-poly(ethylene glycol) and multiwalled carbon nanotubes

Functionalization of the conjugated polymers has gained considerable interest in the biomedical engineering and biosensing applications as distinct properties can be imparted to the corresponding pristine analogues. In the present work, we report a novel sensing platform for the quantification of ethanol through a macromolecular design involving polyfluorene-g-poly(ethylene glycol) (PF-g-PEG) and multiwalled carbon nanotubes (MWCNTs). First, poly(ethylene glycol) with fluorene functionality (PEG-FL) was synthesized with a one-step procedure and characterized. The nanotube modified electrodes were then used as working electrodes for the electropolymerization of PEG-FL macromonomer to form PF-g-PEG films on the electrode surface. Finally, alcohol oxidase enzyme was immobilized on the modified surfaces. Similar devices without MWCNTs or PF-g-PEG were prepared and compared. Sensor properties for selective ethanol detection were investigated and it was found that PF-g-PEG modified MWCNTs exhibited the highest sensing ability. The potential practical application of the fabricated biosensor is demonstrated in alcoholic drinks for the analysis of ethanol contents.