Pore-expanded mesoporous silica nanoparticles with alkanes/ethanol as pore expanding agent

Pore-expanded mesoporous silica nanoparticles (MSNs) were synthesized using alkanes/ethanol as pore expanding agents. It is found that decane was the most efficient expanding agent to enlarge the pore size of MSNs with the well-ordered mesostructure. In the synthetic method, ethanol was an indispensable co-solvent for mixing oil expanders with aqueous solution to expand the size of cetyltrimethylammonium bromide (CTAB) micelles. The concentration of ammonia solution (NH₄OH) can be used to control the particle size, pore size, and pore structure of the MSNs. With optimized amount of ethanol and concentration of NH₄OH, a series of pore-expanded MSNs with tunable pore size and well-ordered mesostructure could be synthesized. The well-suspended particle size of the MSNs could be controlled between 50 and 100 nm. These MSNs were used to immobilize lysozyme up to 420 mg g⁻¹ silica to demonstrate the potential in intra-pore confinement of enzyme.