Nanocellulose-lysozyme colloidal gels via electrostatic complexation

Biohybrid colloids were fabricated based on electrostatic complexation between anionic TEMPO-oxidized cellulose nanofibrils (TO-CNF) and cationic hen egg white lysozyme (HEWL). By altering the loading of HEWL, physical colloidal complexes can be obtained at a relatively low concentration TO-CNF (0.1 wt%). At neutral pH, increasing HEWL induces an increase in charge screening, as probed by zeta-potential, resulting enhanced aggregation gel formation. Systematic rheological testing shows that mechanical reinforcement prepared biohybrid gels is easily achieved HEWL. However, due to weak nature complexation, formed exhibit partial destruction when subjected cyclic shear stresses. Still, they resist thermo-cycling up 90 °C. Finally, pH responsiveness complex was demonstrated adjusting above below isoelectric point representing facile mechanism tune gelation TO-CNF/HEWL complexes. This work highlights potential using form hybrid colloids, demonstrates tunability morphology rheology ratio two components pH.