Stimuli-responsive multistage delivery system based on porous silica particles
Y.C. Cheng, X.W. Liu, F.S. Zhang, M. Ferrari
The University of Texas Health Science Center at Houston, US
Keywords: silica nanoparticle, disulfide linker, coumarin derivatives, control release
Abstract:In this research, a complex functional particle system consists of mesoporous silicon particles, silica nanoparticle, photoresponsive linker and disulfide linker was developed. The silica particle size was controllable by the timely quenching the reaction. The resulted silica nanoparticles showed a uniform size distribution (30nm) and a 2.2nm pore diameter. The mesoporous silicon particles were fabricated using our proprietary protocols as reported in previous paper. A photosensitive coumarin derivative, 7-[(3-Triethoxysilyl) propoxy] coumarin, was synthesized via a reported method 1 and the structure was successfully identified by 1H NMR spectrum and MS. A disulfide compound, 2-carboxyethyl 2-pyridyl disulfide, was synthesized from 2, 2’-Dipyridyl disulphide and 3-mercaptopropionic acid through a literature reported reaction6. Silica nanoparticles were modified with dimerized 7-[(3-Triethoxysilyl) propoxy] coumarin using solid-phase organic synthesis method. Disulfide linker functionalized silica particle were synthesized via a disulfide bond-exchange reaction. Phenanthrene and Rhodamine B were loaded into the voids of silica particles to evaluate the loading capacity and controlled release of this system. The stimuli-responsive release of phenanthrene and Rhodamine B loaded system was examined by using disulfide bond-reducing agent DTT and UV light. The release amount of phenanthrene and Rhodamine B was tested via HPLC. As a conclusion, the photoresponsive linkers and disulfide linkers can be integrated into the multistage delivery system, and are promising to improve the on-site release and controlled drug delivery.