Polyglycerol mediated covalent construction of magnetic mesoporous silica nanohybrid with aqueous dispersibility for drug delivery.

Construction of nanohybrids with chemical and colloidal stability is of great importance for the exploration of their potential applications in biomedical field. In this work, a versatile strategy based on polyglycerol (PG) mediated covalent linkage is developed to fabricate a core-satellite nanohybrid, termed MMSN, consisting of a mesoporous silica nanoparticle (MSN) as a core and many superparamagnetic iron oxide nanoparticles (SPION) on the outer surface. In this synthetic strategy, the PG grafted SPION is derivatized to convert partial periphery hydroxyl groups to carboxyl moieties, followed by attachment to aminated MSN through amide bonds. The PG layer accounting for ~17wt% of MMSN not only serves as a tether to connect the two nanoparticles but also greatly enhances the colloidal stability of the nanohybrid, resulting in no significant change in hydrodynamic diameter and zeta potential during four months. Taking advantage of the combined porosity and magnetic property of the nanohybrid, a photosensitizer chlorin e6 (Ce6) is loaded on MMSN and efficiently delivered into target cells under magnetic guidance, leading to an enhanced efficacy of photodynamic therapy (PDT). The versatile strategy presented here opens up a new route to rational design and fabrication of multifunctional nanohybrids for various biomedical purposes.