Synthesis of ordered mesoporous silica spheres with controllable diameter in micrometer

A new procedure for the synthesis of mesoporous silica spheres with controlled particle size (9.0-17.6 μm) and pore size (2.3-4.8 nm) was developed. It was based on the hydrothermal syntheses by mixing nonionic surfactant EO₂₀PO₃₀EO₂₀ (P65) and TEOS under static acidic conditions. The size of spheres was controlled by adjusting the synthesis temperature, the synthesis time, and the amount of added KCl. The pore size of the spheres was controlled by adding the 1,3,5-trimethylbenzene (TMB) or changing the hydrothermal temperature and characterized by nitrogen adsorption-desorption analysis, whereas the size of the spheres was analyzed by scanning electron microscopy (SEM) and further confirmed by the laser scattering particle size distribution analyzer. The bio-immobilization ability of such mesoporous silica spheres was characterized by protein adsorption analysis. Mesoporous silica spheres with the largest pore size (4.8 nm) among all materials under investigation showed the highest specific immobilization amount of lysozyme (192 mg/g), while the spheres with smaller pore size (≤4.3 nm) have markedly low immobilization amount (≤42 mg/g). These mesoporous silica spheres with diameter ∼10 μm in size may be readily used as a good substrate in high performance liquid chromatography (HPLC).