Amphiphilic Hyperbranched Poly Research Articles

Competitive Supramolecular Encapsulation of Amphiphilic Hyperbranched Polymers Made from A2 and BB`2 Type Monomers. 1. Polyaddition of 1-(2-aminoethyl)piperazine to Divinyl Sulfone

The competitive host-guest encapsulations of palmityl chloride-modified amphiphilic hyperbranched poly(amido-amine) (HPAMAM-PC) and poly(sulfone-amine) (HPSA-PC) to selected pairs of dyes are reported. Water- soluble and chloroform-insoluble dyes, such as methyl orange (MO), methyl blue (MB), rose bengal (RB), fluorescein so- dium (FSS), eosin Y (EY) and phloxine B (PB), can be transferred from aqueous phase into chloroform phase by the HPAMAM-PC and HPSA-PC. UV/Vis spectra were used to determine the loading capabilities (Cloads) of different dyes in the case of single-dye encapsulations (Exp I). Four pairs of dyes: (1) MO and RB, (2) MO and PB, (3) MO and EY, (4) MO and FSS, were chosen to perform comparative experiments to investigate the influence of competitive interactions on the Cloads of dye pairs. As a result, in the cases of one-step double-dye encapsulations (Exp II) and gradual double-dye en- capsulations (Exp III), we found three kinds of competitive relationships: (1) The Cload of MO decreased significantly in the presence of either RB or PB, compared with the Cload in the single-dye encapsulation, while the existence of MO did not affect the encapsulations to RB and PB greatly, (2) the Cloads of both dyes decreased if they were encapsulated simul- taneously by HPAMAM-PC or HPSA-PC (MO & EY), (3) FSS can hardly be encapsulated by the hyperbranched poly- mers with the existence of MO in the aqueous solution. 1 H NMR, FTIR and thermogravimetric analysis (TGA) were used to confirm the resulting competitive encapsulations. Relatively selective constant to MO (Rdye/MO) was defined to measure the competitive ability of each dye to MO quantitatively. The competitive abilities of RB, PB were larger than that of MO, while EY almost equal to MO and FSS lower than MO. The size of the dye molecules, electrostatic acid-base interactions between the dye molecules and the polymers, the interaction between different dyes were considered to be the main causes of the results.

Micelles formed by self‐assembly of hyperbranched poly[(amine‐ester)‐co‐(D,L‐lactide)] (HPAE‐co‐PLA) copolymers for protein drug delivery

AbstractBACKGROUND: The aim of the work presented was to synthesize a series of amphiphilic hyperbranched poly[(amine‐ester)‐co‐(D,L‐lactide)] (HPAE‐co‐PLA) copolymers and study the formation of copolymeric micelles. These copolymeric micelle systems are expected to be potential candidates for applications in protein drug delivery.RESULTS: The chemical structures of the copolymers were confirmed by Fourier transform infrared spectroscopy, 13C NMR and thermogravimetric analysis. Fluorescence spectroscopy and dynamic light scattering confirmed the formation of copolymeric micelles of the HPAE‐co‐PLA copolymers. The maintenance of stability of bovine serum albumin (BSA) during release from micelles in vitro was also measured using circular dichroism and fluorescence spectrometry.CONCLUSION: Novel hyperbranched HPAE‐co‐PLA copolymers have been synthesized. Conjugation of PLA to HPAE was proved to be an available method for the preparation of micelles for protein delivery. The BSA‐loaded micelles showed enhanced encapsulation efficiency and the structural stability of BSA was retained during the release process. The hyperbranched polymeric micelles could be useful as drug carriers for protein drug delivery systems. Copyright © 2008 Society of Chemical Industry

Dye-Encapsulation Selectivity of Amphiphilic Dendritic Boxes

Amphiphilic hyperbranched polyamidoamine (PAMAM) and poly(sulfone-amine) (HPSA) were prepared and their dye-encapsulation properties were investigated. Both of them can carry water-soluble dyes from aqueous solution into chloroform. The selectivity of host to guests and the influence of interaction between different dyes on loading capacity were also investigated by performing comparable experiments. Encapsulation capacities are considered to have relationship with the water-solubility of the hyperbranched polymer core, the polarity difference between the hydrophilic core and the hydrophobic shell, the molecular structure of dyes, and the interactions between dyes.

Influence of alkyl chains of amphiphilic hyperbranched poly(ester amine)s on the phase‐transfer performances for acid dye and the aggregation behaviors at the interface

AbstractHyperbranched poly(ester amine) (HPEA) with terminal secondary amine groups was synthesized by the Michael addition reaction between piperazine and trimethylolpropanetriacrylate with a molar ratio of 13:6. It was further reacted with a series of aliphatic acid chlorides, including stearoyl chloride, dodecanoyl chloride, and octanoyl chloride, to yield three modified amphiphilic hyperbranched polymers, which were termed HPEA‐C18, HPEA‐C12, and HPEA‐C8, respectively. These polymers were characterized with Fourier transform infrared, 1H NMR, gel permeation chromatography, and differential scanning calorimetry measurements. Because of the existence of interior tertiary amine groups, the modified amphiphilic polymers were used as host molecules to extract the guest acid dye, methyl orange (MO), from the aqueous layer to the organic layer on the basis of the acid–base interaction. The influences of the pH of the aqueous layer and the length of the alkyl chains in the modified polymers on the phase‐transfer performances were investigated. The results indicated that more MO molecules could be extracted at a lower pH because of the formation of more quaternary ammonium ions within the host molecules. As the length of the alkyl chains in the modified polymers increased, both the transfer capability and the intermolecular aggregation at the interface were enhanced. The extracted MO could be reversibly released from the organic layer to the aqueous layer under basic conditions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2921–2930, 2005

Synthesis and Properties of Amphiphilic Hyperbranched Poly(dimethylsiloxane) Possessing Hydrophilic Terminal Group

The amphiphilic hyperbranched poly(dimethylsiloxane) (HPDMS) bearing dimethylamine groups on the terminal position was synthesized and characterized. The obtained polymer exhibited low viscosity, and good solubility in ether, THF, and acidic aqueous solution. In the acidic aqueous polymer solution, UV-vis absorption and photo luminescence of water-insoluble chromic compounds such as diphenylhexatriene were measured in order to investigate solvating power of hyperbranched poly(dimethylsiloxane)s. It has turned out from the UV absorbance data that a HPDMS solubilized about five molecules of 1,6-diphenylhexatriene.

Fluorescence Studies on the Hydrophobic Association of Pyrene-Labeled Amphiphilic Hyperbranched Poly(sulfone−amine)s

Pyrene-labeled amphiphilic hyperbranched poly(sulfone−amine)s (Py-Am-HPSA) with a hydrophilic hyperbranched core and different amounts of hydrophobic tails were synthesized by end-capping of pyrene-labeled hyperbranched poly(sulfone−amine) (Py-HPSA) with palmitoyl chloride. The characterization of fluorescence showed that the excimer-to-monomer intensity ratio (IE/IM) increased with increasing content of hydrophobic units in polymers. In the range pH below 7, Py-Am-HPSA displayed the ordinary concentration-quenching effect of fluorescence for monomer emission and excimer emission, while the ratio of IE/IM monotonically increases with the increase of polymer concentration. With the rise of concentration of Py-Am-HPSA, IE/IM increases slightly and then significantly as it reaches the critical point where the concentration is 2−5 g/L. The acidity (or pH) of the aqueous solution has a great influence on the association behavior of Py-Am-HPSA. In the range pH 6.5−8, the ratio of IE/IM for Py-Am-HPSA increases ...