Bioinspired chitosan-xanthan gum self-assembled nanosponge incorporating natural deep eutectic solvent: batch adsorption, mechanism, sustainability, and selective non-nutritive sweetener elimination.

A bio-inspired self-assembled nanosponge, constructed from a binary chitosan-xanthan gum (CX) gelling network incorporating a [betaine]:[tannic acid] natural deep eutectic solvent (NADES), is introduced as an innovative platform for the selective tracing of emerging non-nutritive sweeteners (NNSs) in waters and non-alcoholic beverages, due to their growing environmental relevance. The molar ratio of NADES precursors, CS-to-XG weight proportion, and NADES fraction within the CX network were optimized. Physicochemical characterization corroborated that the nanosponge possesses a porous, channel-like configuration, with outstanding aqueous stability and controlled swelling while preserving structural resilience. An adsorption capacity of 103.492-117.281 mg g-1 was achieved via synergistic electrostatic, hydrogen-bonding, and π-π interactions, ascribable to multiple crosslinking and high density of accessible active sites. The nanosponge was implemented in a one-step micro-solid-phase extraction (μ-SPE) method, affording selectivity (α, 102.50-554.00), LOQ (0.05-0.07 μg L-1), precision (RSD, 2.09-3.84%), and recoveries (RR, 93.82-107.16%), with minimal matrix effect (ME, 2.29-4.02%) and desirable re-usability ( five cycles). The BAGI (75/100), AGREE (0.74/1.0), and AES (81/100) tools validated the practicality and sustainability of the procedure.