Blue-emitting PEGylated hyperbranched PAMAM: transformation of cross-linked micelles to hollow spheres controlled by the PEG grafting density

Abstract

Here we reported the synthesis of polyethylene glycol 2000 monomethyl ether (PEG)ylated hyperbranched poly (amido amine) (h-PAMAM-g-PEG) and the study of an elaborate control over the structure transition by solvents. The double hydrophilic hyperbranched copolymers could form micelles with h-PAMAM core and solvophilic PEG shell in tetrahydrofuran (THF). It was found that the micellization stage was prolonged if more PEG chains were anchored onto h-PAMAM cores. After cross-linking the h-PAMAM cores, well-dispersed hollow spheres were obtained when the micelles were transferred into water from THF. More grafted PEG chains on h-PAMAM may prohibit the creation of a hollow cage upon the swelling of the hydrophilic h-PAMAM cores. Such engineered hollow spheres also retained the pH-sensitive fluorescence characteristic, identical with the luminescent behavior of the free h-PAMAM molecules. H-PAMAM-g-PEG hollow spheres with pH-sensitive fluorescence have a potential application as a drug delivery vehicle for chemotherapy.

Heparin-Mimicking Multilayer Coating on Polymeric Membrane via LbL Assembly of Cyclodextrin-Based Supramolecules

“…Though it was hard to detect the detailed assembly mechanism between these two star-shaped supramolecules, the different surface-assembled morphologies should be greatly influenced by the AA and EGMA segments. During assembly the EGMA fragments might twine around each other . In addition, introduction of EGMA fragments decreased the negative charge of the Star-PSS-EGMA; thus, the repulsion between the Star-PSS-EGMA molecules was lower than that for Star-PSS-AANa, which might also lead to the lower roughness of M-SE.…”

“…During the assembly, the EGMA fragments might twine around each other. 40 What's more, the introduction of EGMA fragments decreased the negative charge of the Star-PSS-EGMA, thus, the repulsion between the Star-PSS-EGMA molecules was lower than that for the Star-PSS-AANa, which might also lead to the lower roughness of M-SE.…”

Synthesis and characterization of hyperbranched poly(ester-amine) by Michael addition polymerization

“…Aliphatic tertiary amine-based polymers display interesting properties and have widely used as absorbents, catalysts, gene and drug carriers [ 1 ]. Among this type of polymers, the hyperbranched polymers and dendrimers with tertiary amines attract particularly interests due to their globular architecture and unique properties, such as low toxicity, pH-sensitivity, fluorescence and abundant surface functional groups [ 2 ]. Poly(ester amine)s, which are prepared by Michael addition polymerization of diacrylate and trifunctional amines, are biodegradable, and have been widely used in gene delivery with high transfection efficiency, importantly, the results reveal no or low cytotoxicity [ 3 ].…”

Implicit solvent coarse‐grained model of polyamidoamine dendrimers: Role of generation and pH

“…Polyamidoamine (PAMAM) and its derivatives have been some of the most investigated dendrimers, experimentally and computationally . Its biocompatibility opens it up to a significant number of biomedical applications which include drug delivery, imaging micelles, and protein mimicry . The importance of higher‐generation dendrimers lies in the exponential increase of terminal groups capable of being functionalized and coordinated.…”