Sensing Platform Based on Carbon Paste Electrode Modified with Bismuth Oxide Nanoparticles and SWCNT for Submicromolar Quantification of Honokiol

Abstract

Honokiol is neolignan present in the magnolia bark. It displays versatile pharmacological properties—neuroprotective and anxiolytic effect, anti-cancer activity and antimicrobial effect being the most important. This paper aims to develop a voltammetric non-enzymatic biosensor for honokiol detection, quantification and monitoring in drugs and cosmetic products. The materials used in this study were synthesized and characterized by HR-XRPD, SEM, ATR-FTIR and electrochemical methods. Bi2O3, being a p-type semiconductor, was used as an electrode material. Both its semiconductivity and electrocatalytic properties result from lattice structure defects, which differ on the surface and in the bulk of the bismuth oxide crystal, and therefore are crystal size dependent. The influence of the particle size of Bi2O3 on its electrocatalytic properties was studied, and it was confirmed that Bi2O3 nanoparticles have better overall conductive/resistive and catalytic characteristics than microribbons and that the optimal electrode modification for sensing application was obtained by Bi2O3@SWCNT composite material preparation. Here, we established a sensitive electrochemical sensing platform for honokiol detection based on CP electrode modified with bismuth oxide nanoparticles and SWCNT with the 0.17 μM limit of detection, and linear operating range from 0.1 to 50 μM. The effect of potential interferents on honokiol detection was explored. Obtained results in the interference tests and the real sample analysis suggest that the developed approach is selective, accurate and reproducible. Due to the low detection limit and a wide working range, the proposed sensing platform opens great opportunities for further construction of sensors for honokiol detection and monitoring in the pharmaceutical industry and medicinal chemistry.