Nanoarchitectonics Approach for Hydrogel Surface Functionalization via Self-Assembly of Terminally Modified Cello-oligosaccharides.

Advances in hydrogel research have enabled the design of bulk networks with diverse functionalities; however, precise control of interfacial properties remains a key challenge to expanding their applications, particularly in biointerfaces. Here, we report a simple and versatile surface functionalization strategy based on the self-assembly of terminally modified cello-oligosaccharides. When azido-functionalized cello-oligosaccharides dissolved in 85% phosphoric acid are applied to hydrogel surfaces, mixing with the intrinsic water within the hydrogels induces rapid self-assembly, forming nanostructured granular coatings at the interface. This method is applicable to both chemically and physically cross-linked hydrogels. The resulting azido-functionalized surfaces enable postfunctionalization via click chemistry, allowing biomolecule immobilization. As a proof of concept, antigen-conjugated hydrogels were used for the detection of specific immunoglobulin G, exhibiting selective responses even in serum-containing environments due to the antibiofouling properties of the assemblies. These findings establish terminally modified cello-oligosaccharides as a new class of interfacial modifiers for hydrogels, providing a facile route to biofunctional and antifouling interfaces for sensing and diagnostic applications.