Hierarchical mesoporous silicas templated by PE-b-PEO-b-PLA triblock copolymer for fluorescent drug delivery

A series of triblock copolymers, poly(ethylene-b-ethylene oxide-b-lactide), are synthesized through ring-opening polymerization by using commercially available poly(ethylene-b-ethylene oxide) as a macro-initiator. Hierarchical mesoporous silica with tetragonal cylindrical and face-centered cubic pores with uniform pore size is successfully synthesized through an evaporator-induced self-assembly method using these templates. The mesoporous silica materials are characterized by small angle X-ray scattering, transmission electron microscopy and nitrogen adsorption/desorption isotherm analyses. In addition, the fluorescein isothiocyanate isomer is used as a model drug and loaded into the hierarchical mesoporous silica materials. The drug loading capacity of the materials has been measured by photoluminescence (PL) spectrophotometer at an excitation wavelength of 495 nm and emission wavelength of 518 nm, and the loading capacity is measured to be 90.4 μg mg-1. It has been found that the release kinetics is influenced by the nanostructure of these hierarchical mesoporous silica materials.