Construction and amperometric biosensing performance of a novel platform containing carbon nanotubes-zinc phthalocyanine and a conducting polymer

A novel glucose oxidase (GOx) based amperometric biosensor utilizing a conducting polymer (CP), multi walled carbon nanotubes (MWCNTs) and a novel water soluble zinc phthalocyanine (ZnPc) was constructed. For this purpose, a novel ZnPc was synthesized to examine the role of being a part of support material for enzyme deposition. High water solubility was achieved with the introduction of tetra quaternized imidazolyl moieties at the peripheral positions of phthalocyanine. In order to fabricate the proposed biosensor, a graphite electrode was firstly modified with poly[9,9-di-(2-ethylhexyl)- fluorenyl-2,7-diyl] end capped with N,N-Bis(4- methylphenyl)-4-aniline (PFLA) and MWCNTs. Then, GOx was co-immobilized with ZnPc onto the modified surface. To the best our knowledge, a sensor design which combines conjugated polymer/MWCNTs/ZnPc was attempted for the first time and this approach resulted in improved biosensor characteristics. The constructed biosensor showed a linear response for glucose between 0.025-1.0 mM with a detection limit of 0.018 mM. KMapp and sensitivity values were calculated as 0.53 mM and 82.18 μAmm−1 cm−2, respectively. Moreover, scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques were used to investigate the surface modifications. Finally, fabricated biosensor was tested on beverages for glucose detection successfully.