title: Highly magneto-responsive multilayer microcapsules for controlled release of insulin.
abstract: In this study, magneto-responsive polyelectrolyte multilayer microcapsules were successfully prepared by the formation of shell with biocompatible iron oxide nanoparticles (Fe₃O₄ NPs) and polyallylamine hydrochloride (PAH) by layer-by-layer (LbL) self-assembly technique. The self-assembled microcapsules were characterized by SEM, TEM and zeta-potential analyzer. According to the pH sensitivity of the microcapsule membrane permeability, insulin was encapsulated, with the encapsulation efficiency of 92.08±5.57%. The in vitro release behavior in an external alternating magnetic field indicated that once the magnetic field was applied, the drug release was greatly accelerated. In addition, according to the observed pulse release upon cyclic on-off operations of magnetic field, it could be assumed that the magneto-responsive microcapsules had an excellent "switching on" effect, which might be attributed to the rearrangement of shell structure caused by magnetic nanoparticles twisting and polyelectrolyte chains shaking, hence the increase of microcapsule membrane permeability and the enhancement of insulin release.
authors.affiliation: Pharmaceutical Research Institute, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China. Electronic address: clz3330@hotmail.com.
authors.forename: Chunli
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Pharmaceutical Research Institute, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Shanghai Engineering Research Centre of Molecular Therapeutics and New Drug Development, East China Normal University, Shanghai 200062, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Anhui Medical University, Meishan Road 81, Hefei 230032, China.
authors.forename: Yunkai
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Pharmaceutical Research Institute, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Ge
mesh_terms: D002214:Capsules; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry; D004337:Drug Carriers / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*; D004339:Drug Compounding; D006863:Hydrogen-Ion Concentration; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*; D007328:Insulin / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D060328:Magnetic Phenomena; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010539:Permeability; D011073:Polyamines / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012995:Solubility; D013451:Sulfonic Acids / Q000737:chemistry; D013499:Surface Properties; D015854:Up-Regulation
chemical_list: D002214:Capsules; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007004:Hypoglycemic Agents; D007328:Insulin; D058185:Magnetite Nanoparticles; D011073:Polyamines; D011108:Polymers; D013451:Sulfonic Acids; C063994:polyallylamine; C077114:styrenesulfonic acid polymer
keywords: Controlled release; Insulin; Layer-by-layer self-assembly; Magnetic field; Multilayer microcapsules