Developing water-stable and adaptive supramolecular materials is of great importance in various research fields. Here, we demonstrate a new kind of water-stable, adaptive, and electroactive supramolecular ionic materials (SIM) that is formed from the aqueous solutions of imidazolium-based dication and dianionic dye (i.e., 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS) through ionic self-assembly. The formed SIM not only shows good thermostability and unique optical and electrochemical properties that are raised from precursors of the SIM, but also exhibits good water-stability, salt-stability, and adaptive encapsulation properties toward some heterocyclic cationic dye molecules. UV–vis and FT-IR results demonstrate that this encapsulation property is essentially based on the electrostatic interactions between the guest dye molecules and ABTS in the SIM. The application of the SIM prepared here is illustrated by the development of a new electrochemical sensor for NADH sensing at a low potential. This study not only opens a new avenue to the preparation of the supramolecular materials, but also provides a versatile platform for electrochemical (bio)sensing.Keywords: adaptive encapsulation; biosensor; electrochemistry; supramolecular ionic materials; water-stable;

An excellent electrochemical sensing platform has been designed by combining the huge specific surface area of carbon nanotubes (CNTs) and the remarkable conductivity of ionic liquid (IL). IL can easily untangle CNTs bundles and disperse CNTs by itself under grinding condition due to the π–π interaction between CNTs and IL. The resulting nanocomposites showed an augmentation on the voltammetric and amperometric behaviors of electrocatalytic activity toward O2 and NADH. Therefore, such an efficient platform was developed to fabricate mediator-free oxygen sensor and glucose biosensor based on glucose dehydrogenase (GDH). O2 could be determined in the range of zero to one hundred percent of O2 content with the detection limit of 126 μg L−1 (S/N = 3). The glucose biosensor which was constructed by entrapping GDH into chitosan on the nanocomposites modified glassy carbon electrode surface, exhibited good electrocatalytic oxidation toward glucose with a detection limit of 9 μM in the linear range of 0.02–1 mM. We also applied the as-prepared sensors to detect oxygen and glucose in real blood samples and acquired satisfied results.Highlights► An excellent sensing platform based on CNTs and IL has been designed. ► The CNTs-IL nanocomposites enhanced electrocatalytic activity of O2 and NADH. ► Mediator-free O2 sensor and glucose biosensor was developed. ► The as-prepared sensors were applied in real blood samples.