Adsorption of Proteins on Mesoporous Molecular Sieves

Mesoporous molecular sieves such as MCM-41 and SBA-15 have many desirable properties for applications as separations media. Their high surface area (~ 1000 m2. g-1) and tuneable uniform pore size of 1.8 – 40 nm make them ideal for size exclusion separations of proteins and other biological molecules of importance in the food and pharmaceutical industries. However, the stability of MCM-41 in aqueous solution is limited. Therefore, in this work a hydrophobic coating has been applied to siliceous MCM-41 using hexamethyldisilazane to reduce degradation of the structure by hydrolysis and so increase its stability in water. This coating was covalently bound to the pore and particle surfaces and was stable in the presence of water for at least 12 days. The protein adsorption properties of the coated material compare favourably to the uncoated material, with up to 100 % more lysozyme adsorbed on the coated material than untreated MCM-41. The increased capacity and stability of this material make it promising for protein separation based on both size exclusion and chemical selectivity