title: pH-Responsive dendritic core-shell architectures as amphiphilic nanocarriers for polar drugs.
abstract: In this paper a simple general synthetic concept was used to generate dendritic core-shell architectures based on hyperbranched poly(ethylene imine) cores and different shells which contain aliphatic chains and poly(ethylene glycol) chains, respectively. Using these dendritic core-shell architectures as nanocarriers we studied the encapsulation and transport of polar drugs, such as congo red. The results showed that the acid labile nanocarriers exhibited much higher transport capacities for congo red than the bare poly(ethylene imine). This gives an opportunity for the controlled release of encapsulated dyes and drugs by a pH-triggered cleavage of the imine bond. In two cases the pH-sensitivity was studied and a relatively high stability of the imine bond was observed at pH 8, while fast cleavage occurred at pH 5-7. This pH difference correspond to the pH-shift in malignant tissues (tumor, infection) compared to normal tissue, which could trigger the release of the encapsulated drugs.
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
authors.forename: Shangjie
authors.initials: S
authors.lastname: Xu
authors.forename: Michael
authors.initials: M
authors.lastname: Krämer
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D002021:Buffers; D002725:Chloroform; D004396:Coloring Agents / Q000737:chemistry; D050091:Dendrimers / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007097:Imines / Q000138:chemical synthesis / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry; D011095:Polyethylenes / Q000138:chemical synthesis / Q000737:chemistry; D012995:Solubility; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013678:Technology, Pharmaceutical / Q000379:methods; D014050:Toluene
chemical_list: D000447:Aldehydes; D002021:Buffers; D004396:Coloring Agents; D050091:Dendrimers; D004337:Drug Carriers; D007097:Imines; D011095:Polyethylenes; C505405:poly(ethylene imine); D014050:Toluene; D011092:Polyethylene Glycols; D002725:Chloroform