Zwitterionic poly(2-(methacryloyloxy) ethyl phosphorylcholine) coated mesoporous silica particles and doping with magnetic nanoparticles

Abstract Poly(2(methacryloyloxy) ethyl phosphorylcholine) (PMPC) a zwitterionic biopolymer has been used to prepare hybrid inorganic/organic/inorganic tri-layered magnetic composite particles. Mesoporous SiO 2 particles of average diameter 284.8 nm are first prepared by sol-gel technique in presence of cetyltrimethylammonium bromride (CTAB) as template to generate porosity. The surface of mesoporous SiO 2 particles is then functionalized to introduce vinyl functionality using silane coupling agent, 3-(trimethoxysilyl) propyl methacrylate (MPS). Finally grafting of MPC is carried out on the surface of mesoporous SiO 2 particles by carrying out seeded copolymerization in presence of monomethoxy-capped poly(ethylene glycol) methacrylate (PEGMA) as a reactive steric stabilizer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The prepared composite polymer particles named as SiO 2 /P(MPC-PEGMA-EGDMA) are finally doped with magnetic iron oxide nanoparticles (Fe 3 O 4 ) via simultaneous in situ precipitation of Fe 2+ and Fe 3+ from alkali solution. The final composite particles possessed moderate paramagnetic property having magnetic susceptibility (2.22 × 10 −5 ) which is just one order less than that of reference Fe 3 O 4 nanoparticles (1.00 × 10 -4 ). A comparative adsorption behaviour of biomolecules suggested that surface of SiO 2 /P(MPC-PEGMA-EGDMA) composite particles resist protein adhesion whereas after doping with Fe 3 O 4 nanoparticles the surface has tendency to adsorb proteins.