(2019) Surface modification of pH-responsive poly(2-(tert-butylamino)ethyl methacrylate) brushes grafted on mesoporous silica nanoparticles,

This paper introduces the synthesis of well-defined 2-(tert-butylamino)ethyl methacrylate-b-poly(ethylene glycol) methyl ether methacrylate diblock copolymer, which has been grafted onto mesoporous silica nanoparticles (PTBAEMA-b-PEGMEMA-MSNs) via atom transfer radical polymerization (ATRP). The ATRP initiators were first attached to the MSN surfaces, followed by the ATRP of 2-(tert-butylamino)ethyl methacrylate (PTBAEMA). CuBr2/bipy and ascorbic acid were employed as the catalyst and reducing agent, respectively, to grow a second polymer, poly(ethylene glycol) methyl ether methacrylate (PEGMEMA). The surface structures of these fabricated nanomaterials were then analyzed using Fourier Transform Infrared (FTIR) spectroscopy. The results of Thermogravimetric Analysis (TGA) show that ATRP could provide a high surface grafting density for polymers. Dynamic Light Scattering (DLS) was conducted to investigate the pH-responsive behavior of the diblock copolymer chains on the nanoparticle surface. In addition, multifunctional pH-sensitive PTBAEMA-b-PEGMEMA-MSNs were loaded with doxycycline (Doxy) to study their capacities and long-circulation time.