Double-Interlinked Colloidal Gels for Programable Fabrication of Supraparticle Architectures

Engineering colloidal gel inks with suitable features for fabricating robust supraparticle architectures through 3D printing may overcome the challenges of precisely controlling nanoparticles spatial distribution across multiple scales. Herein, oppositely charged proteinaceous-polymeric nanoparticles are combined to generate multi-component colloidal gel (COGEL) inks for fabricating supraparticle volumetric architectures. Leveraging on different nano-functional units, double-interlinked supraparticle assemblies are established via electrostatic interactions and on-demand covalent photocrosslinking. The COGEL inks are readily processable through in-air extrusion 3D printing, forming stable colloidal filaments. 3D printing yielded architecturally defined and robust supraparticle constructs that supported human stem cells attachment and cytoskeletal spreading. Owing to double interparticle interlinks the fabricated supraparticle constructs remained stable under physiological conditions and high/low shear stress, improving over the lower mechanical stability of single-interlinked platforms. Double-interlinked COGELs are processable via suspension 3D printing, unlocking the freeform volumetric writing of nanoparticle inks in protein-based hydrogels volume. The dual-interlinked COGEL technology opens new possibilities for generating user-defined supraparticle architectures with precise volumetric distribution of nanoparticles, both in-air and in-hydrogel platforms. The freedom to select modular multi-particle combinations, as well as the rapid 3D programming of COGEL inks, broadens the range of modular colloidal materials that can be fabricated for a variety of biomedical applications.