A low molecular weight gel formed by cationic surfactant 1-dodecylpyridinium bromide in acetone/water: its characterisation and implication for enzyme immobilisation

A novel cationic surfactant-based gelling system is presented in this report. The cationic surfactant 1-dodecylpyridinium bromide (DPB) in the mixture of acetone and water can form gels without additive. The gel structure and the gelation mechanism were studied using techniques of rheology, microscopy, FT-IR and ¹H NMR spectroscopy. The present results indicate that the DPBs in acetone/water driven by hydrogen bonding, van der Waals force and other non-covalent interactions can self-assemble into rod-like fibers, and the fibers intertwined into a three-dimensional network. Laccase and horseradish peroxidase entrapped in the gel are biologically and/or electrochemically active. In addition, the present gel does not swell in the hydrophobic ionic liquid [Bmim]PF₆, showing its great promise in green biocatalysis and biotransformation.