title: Layer-by-layer assembled polyaspartamide nanocapsules for pH-responsive protein delivery.
abstract: Biodegradable shell cross-linked nanocapsules were prepared via layer-by-layer assembly of PADH (tertiary amine and hydrazide grafted polyaspartamide) and PACA (carboxyl and aldehyde grafted polyaspartamide) on silica spheres. Both of the polyaspartamide derivatives are water-soluble and biodegradable polymers with a protein-like structure, and obtained by aminolysis reaction of polysuccinimide. The latter is prepared by thermal polycondensation of aspartic acid. Dynamic light scattering and zeta potential measurements were used to analyze the layer-by-layer assembly process. Bovine serum albumin (BSA), as a model protein, was entrapped in the nanocapsules via electrostatic adsorption. Nanocapsules encapsulating BSA were prepared via layer-by-layer assembly on protein-entrapping amino-functionalized silica spheres, hydrazone cross-linking and silica core removal. The BSA release profiles exhibited a pH-dependent behavior. BSA release rate increased significantly as the ambient pH dropped from the physiological pH to acidic. Cell viability study suggests that the obtained polymeric nanocapsules have good biocompatibility. These kinds of novel composite nanocapsules may offer a promising delivery system for proteins.
authors.affiliation: Key Laboratory of Functional Polymer Materials of MOE, Institute of Polymer Chemistry, Nankai University, Tianjin, 300071, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Gu
authors.forename: Jingjing
authors.initials: J
authors.lastname: Wang
authors.forename: Yanming
authors.initials: Y
authors.lastname: Wang
authors.forename: Yinong
authors.initials: Y
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Gao
authors.forename: Guolin
authors.initials: G
authors.lastname: Wu
mesh_terms: D000327:Adsorption; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects; D003432:Cross-Linking Reagents / Q000737:chemistry; D006835:Hydrazones / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008027:Light; D051379:Mice; D041681:NIH 3T3 Cells; D053769:Nanocapsules / Q000737:chemistry*; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry; D012542:Scattering, Radiation; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012995:Solubility; D055672:Static Electricity; D014867:Water
chemical_list: D003432:Cross-Linking Reagents; D006835:Hydrazones; D053769:Nanocapsules; D009842:Oligopeptides; D010455:Peptides; D014867:Water; D012710:Serum Albumin, Bovine; C025252:poly-DL-succinimide; D001224:Aspartic Acid; D012822:Silicon Dioxide