Nature-inspired mineralization of a wood membrane as a sensitive electrochemical sensing device for in situ recognition of chiral molecules

Abstract

The artificial solid-state nanopore/nanochannel based electrochemical sensing technique has demonstrated great advantages such as high sensitivity and minimalized equipment. However, its application is largely hindered by complex routes and high expense for fabrication. Here, we develop low-cost and easily accessible channels based on natural wood and present a pathway to utilize the wood membrane for local electrochemistry applications. Inspired by the natural mineralization of wood, Prussian blue (PB), an artificial peroxidase (POD)-like mimetic, is mineralized in wood channels via a contra-diffusion technique. Using glucose enantiomers (L/D-Glu) as model analysts, a target-activated strategy is used for chiral molecule recognition by combining glucose oxidase (GOx) with PB-modified wood channels. In the as-proposed hybrid channels, GOx catalyzes the oxidation of only D-Glu to gluconic acid and H₂O₂. These products dramatically activate the POD-like activity of PB and further trigger the oxidation of the uncharged substrate 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) to cationic species (ABTS˙⁺) in the channels. More importantly, benefitting from the confinement effect of the channel and the asymmetrical mineralization of PB, a significantly selective and sensitive identification of D-Glu is achieved. This study provides a promising way to use natural wood as a novel channel membrane to replace artificial channels for constructing electrochemical sensing platforms.