Short dextran-solanesol block copolymer as a bio-based platform for multifunctional wormlike micelles

Biohybrid block copolymer micelles from natural components hold great promise for biomedical applications; however, intrinsically shear-responsive systems featuring high-aspect-ratio structures remain underexplored. In this study, multifunctional biohybrid wormlike micelles were designed using block copolymers of dextran [α-(1 → 6)-glucan] and plant-derived solanesol, generating dextran_n-block-solanesol (Dex_n-b-Sol; n = average degree of dextran polymerization) via click chemistry. These systems self-assembled in water into core-shell nanostructures with hydrophilic dextran shells and hydrophobic solanesyl cores. Varying the dextran chain length enabled tuning of the micelle morphology: Dex₉-, Dex₁₈, and Dex₂₅-b-Sol formed spherical or less turbid aggregates, whereas Dex₆-b-Sol yielded flexible wormlike micelles with an aspect ratio of ∼100. These micelles exhibited dual critical micelle concentrations and concentration-dependent morphological transitions, as confirmed by transmission electron microscopy, small-angle X-ray scattering, and rheological studies. At high concentrations, these entangled worms displayed tunable viscoelasticity, pronounced shear thinning (tan δ ≈ 1), and injectability. The micelles efficiently encapsulated flavonoid drugs, namely quercetin and quercetin 3-O-β-D-glucoside (Q3G). Additionally, when incorporated into calcium-crosslinked alginate beads, they markedly enhanced bead integrity by increasing the Young's modulus, especially for Q3G. This fully bio-based Dex_n-b-Sol platform enables robust drug encapsulation, shear-responsive rheology, and mechanical reinforcement, providing a sustainable basis for biomedical soft materials.