Hydrogen-Bonding-Induced Chain Folding and Vesicular Assembly of an Amphiphilic Polyurethane
We have reported synthesis and vesicular assembly of a novel amphiphilic polyurethane with hydrophobic backbone and hydrophilic pendant carboxylic acid groups which were periodically grafted to the backbone via a tertiary amine group. In aqueous medium the polymer chain adopted a folded conformation which was stabilized by intrachain H-bonding among the urethane groups. Such a model was supported by concentration and solvent-dependent FT-IR, powder XRD, and urea-mediated “denaturation” experiments. Folded polymer chains further formed vesicular assembly which was probed by dynamic light scattering, TEM, AFM, SEM, and fluorescence microscopic studies, and dye encapsulation experiments. pH-dependent DLS and fluorescence microscopic studies revealed stable polymersome in entire tested pH window of 3.5–11.0. Zeta potential measurements showed a negatively charged surface in basic pH while a charge-neutral surface in neutral and acidic pH. MTT assay with CHO cell line indicated good cell viability.
We recently generalized the formerly alignment-dependent multivariate image analysis applied to quantitative structure–activity relationships (MIA-QSAR) method through the application of the discrete Fourier transform (DFT), allowing for its application to noncongruent and structurally dive ... more
Poly-ADP-ribosylation (PARylation) is a protein posttranslational modification (PTM) that is critically involved in many biological processes that are linked to cell stress responses. It is catalyzed by a class of enzymes known as poly-ADP-ribose polymerases (PARPs). In particular, PARP1 is ... more
This review focuses on the type A cytochrome c oxidases (CcO), which are found in all mitochondria and also in several aerobic bacteria. CcO catalyzes the respiratory reduction of dioxygen (O2) to water by an intriguing mechanism, the details of which are fairly well understood today as a r ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more