作者：Tuanwei Liu, Wei Zhang, Tao Song, Xinlin Yang*, Chenxi Li
关键字：Doule-shell hollow microspheres; NO reservior; Controlled release; pH and thermo dual-responisve
论文来源：期刊
具体来源：Polym. Chem., 6 (17), 3305-3314 (2015). DOI: 10.1039/C5PY00001G
发表时间：2015年

Nitric oxide-releasing hollow double-layered polymer microspheres (HDPMs) with both pH- and thermo-responsive properties in aqueous media are designed and prepared by a multi-step process. Silica/polymer (SiO₂/P(bocAmEMA-co-EGDMA)) core-shell microspheres with boc-protected secondary amino groups are synthesized by distillation precipitation copolymerization of 2-(ethyl(boc)amino)ethyl methacrylate (bocAmEMA) functional monomer and ethyleneglycol dimethacrylate (EGDMA) in presence of 3-(methacryloxy) propyltrimethoxysilane (MPS) modified silica nanospheres as seeds. Hollow double-shelled polymer microspheres with secondary amino groups are prepared by distillation precipitation copolymerization of N-isopropylacrylamide (NIPAAm) with 2-(dimethylamino) ethyl methacrylate (DMAEMA) and EGDMA in presence of SiO₂/P(bocAmEMA-co-EGDMA) core-shell microspheres as seeds to obtain SiO₂/P(bocAmEMA-co-EGDMA)/P(EGDMA-co-DMAEMA-co-NIPAAm) tri-layer microspheres with subsequent removal of silica core by hydrogen fluoride aqueous solution and deprotection of secondary amino groups with CF₃CO₂H. Hollow polymer microspheres with N-diazenuimdiolated NO donors are prepared by the reaction between secondary amino groups of hollow P(AmEMA-co-EGDMA)/P(EGDMA-co-DMAEMA-co-NIPAAm) microspheres and high pressure of NO (5.0 atm) under basic condition (CH₃ONa). The resultant microspheres are systematically characterized by TEM, FT-IR, TGA, elemental analysis and dynamic laser scattering (DLS). The final N-diazeniumdiolated hollow double-shelled microspheres show a controlled NO release behavior dependent on the pH and temperature in the environment.