Synthesis of ultra small nanoparticles (< 50 nm) of mesoporous MCM-48 for bio-adsorption

Mono-dispersed spherical MCM-48 mesoporous silica nanoparticles (MSN) with cubic Ia3d mesostructure were synthesized under different stirring conditions using hexadecyltrimethyl ammonium bromide as structure directing agent and EO₂₀PO₇₀EO₂₀ copolymer as particle size control. Results indicated that the EO₂₀PO₇₀EO₂₀ works well in the reduction of nanoparticle size. In addition, increasing the stirring rate transformed mesoporosity from 2-D hexagonal P6mm to 3-D cubic Ia3d. The biomolecule adsorption properties of prepared ultra small nanoparticles of MCM-48 were compared with that of MCM-48 with ten times larger particle sizes. MCM-48 with smaller particle sizes adsorbed much more vitamin B12 compared with MCM-48 with larger particles. In addition, diffusion of vitamin in the intraparticle spaces occurred only for MCM-48 with ultra-small nanoparticles.