title: Magnetic and pH-sensitive nanoparticles for antitumor drug delivery.
abstract: A dually responsive nanocarrier with multilayer core-shell architecture was prepared based on Fe(3)O(4)@SiO(2) nanoparticles coated with mPEG-poly(l-Asparagine). Imidazole groups (pK(a)∼6.0) were tethered to the side chains of poly(l-Asparagine) segments by aminolysis. These nanoparticles were expected to be sensitive to both magnetic field and pH environment. The obtained materials were characterized with FTIR, dynamic light scattering, ζ-potential, TEM, TGA and hysteresis loop analysis. It was found that this Fe(3)O(4)@SiO(2)-polymer complex can form nano-scale core-shell-corona trilayer particles (∼250 nm) in aqueous solution. The Fe(3)O(4)@SiO(2), poly(L-Asparagine) and mPEG segments serve as a super-paramagnetic core, a pH-sensitive shell, and a hydrophilic corona, respectively. An antitumor agent, doxorubicin (DOX), was successfully loaded into the nanocarrier via combined actions of hydrophobic interaction and hydrogen bonding. The drug release profiles displayed a pH-dependent behavior. DOX release rate increased significantly as the ambient pH dropped from the physiological pH (7.4) to acidic (5.5). This is most likely due to protonation and a change in hydrophilicity of the imidazole groups in the poly(l-Asparagine) segments. This new approach may serve as a promising platform to formulate magnetic targeted drug delivery systems.
authors.affiliation: Key Laboratory of Functional Polymer Materials, Institute of Polymer Chemistry, Nankai University, Tianjin 300071, PR China.
authors.forename: Shufang
authors.initials: S
authors.lastname: Yu
authors.forename: Guolin
authors.initials: G
authors.lastname: Wu
authors.forename: Xin
authors.initials: X
authors.lastname: Gu
authors.forename: Jingjing
authors.initials: J
authors.lastname: Wang
authors.forename: Yinong
authors.initials: Y
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Gao
authors.forename: Jianbiao
authors.initials: J
authors.lastname: Ma
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology*; D016503:Drug Delivery Systems; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D060328:Magnetic Phenomena; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013818:Thermogravimetry
chemical_list: D000970:Antineoplastic Agents; D011108:Polymers; D012996:Solutions; D012822:Silicon Dioxide; D004317:Doxorubicin