Polypeptide grafted hyaluronan: A self-assembling comb-branched polymer constructed from biological components

Rheological evidence is provided demonstrating that covalent grafting of monodisperse isotactic poly(l-leucine) branches onto linear hyaluronan (HA) polysaccharide chains yields comb-branched HA chains that self-assemble into long-lived physical networks in aqueous solutions driven by hydrophobic interactions between poly(l-leucine) chains. This is in stark contrast to native (unmodified) HA solutions which exhibit no tendency to form long-lived physical networks.

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► Poly (l-Leucine) grafted HA chains self assemble into physical networks.
► This network has an elastic shear modulus ≈ 100 Pa and a loss tangent ≈ 0.25.
► It has a network lifetime > 20 s.
► It exhibits almost complete elastic strain recovery after removal of shear stress.
► No physical network formation seen in unmodified HA.