Biomimetic silica formation: Effect of block copolypeptide chemistry and solution conditions on silica nanostructure

The formation of biomimetic silica in the presence of a series of Lys-b-Gly block copolypeptides and the influence of polypeptide chemistry and solution conditions on the morphology and porosity of biomimetic silica was reported. The hydrodynamic radii of the biomimetic silica is found to be between 135 and 360 nm, which shows that the objects formed are vesicles or aggregates of micelles. Thermogravimetric analysis (TGA) shows that the as-synthesized materials made using Lys-b-Gly polypeptides contain 30 an 33 wt block copolypeptides. The morphology of biomimetic silica particles depends on the concentration of silicic acid and phosphate ions and an increase in phosphate ion content leads to the evolution of morphology from plates and spheres. The poly-lysine acts as an interface where biomimetic silica polymerization is enhanced by electrostatic forces with the protonated lysine side-chain amine groups.