Green fluorescent protein-multi walled carbon nanotube based polymeric membrane electrode for bismuth ion detection

Abstract

Developing a sensor that is selective only to the target metal type remains a major challenge. Polymeric membrane electrodes are versatile devices with exceptional analytical simplicity and are frequently used in environmental analysis. A novel polymeric membrane electrode (PME) was proposed for the determination of bismuth ions with high sensitivity. In an unconventional approach, Green Fluorescent Protein (GFP) was used as an ionophore in the fabrication of PME electrodes. GFP, a member of the fluorescent protein family, has emerged as biocompatible tools, especially for biomedical applications, bioimaging, intracellular monitoring, sensors, and optical devices, and has attracted great attention thanks to its unique advantages. In this study, a high performance compatible PME has been developed by solvent casting method integrating GFP doped elastomeric multi-walled carbon nanotubes (MCNTs) into conductive plasticized polyvinyl chloride (PVC). The high metal-binding affinity of GFP made these proteins potential ionophores in the PME structure. The morphological structures of the produced GFP-doped MWCNT were characterized by HRTEM. Potentiometric behaviors and performance of the produced bismuth selective PME are summarized for both analytical and real examples. The prepared electrode exhibited Nernstian behavior with a slope of 19 ± 1 mV and a low detection limit of 4.3 × 10−6 M, and the electrode response time was observed as <40–45 s.