Growth of Ultrastable Protein–Silica Composite Crystals

Protein crystals were obtained in a wide range of silica gel concentrations, 2.0–22.0% (v/v), using the counter-diffusion technique. The protein crystal lattice incorporates silica fibers during their growth, making the crystal appear optically translucent while maintaining the diffraction quality. The effect of the silica fibers on the nucleation and growth morphology is discussed, and the amount of incorporated silica matrix is quantified. The practical implications of the presence of a high hygroscope phase on the crystal properties are discusse, and the improvement of the mechanical properties and stability of the crystals is shown. These reinforced protein crystals, able to include large amounts of silica, open a new range of possibilities for the characterization of protein crystals and the application in the biotechnological industry.