Covalent Polyisobutylene-Paclitaxel Conjugates for Controlled Release from Potential Vascular Stent Coatings.

The development of covalent polyisobutylene (PIB)-paclitaxel (PTX) conjugates as a potential approach to controlling drug release from vascular stent coatings is described. PIB-PTX materials containing ∼24 and ∼48 wt % PTX, conjugated via ester linkages, were prepared. The PTX release profiles were compared with those of physical mixtures of PTX with carboxylic acid-functionalized PIB and with the triblock copolymer polystyrene-b-PIB-b-polystyrene (SIBS).

Functional polymer laminates from hyperthermal hydrogen induced cross-linking.

The use of a hyperthermal hydrogen induced cross-linking process to prepare laminates comprising polypropylene, poly(isobutylene-co-isoprene), and poly(vinyl acetate) is described. In this new, milder alternative to conventional plasma techniques, neutral molecular hydrogen projectiles were used to create carbon radicals on impacted surfaces by collision-induced dissociation of C-H bonds, and this process was used to cross-link polymers on a polypropylene surface. It was demonstrated that multiple layers of cross-linked materials could be added, creating polymer laminates with each layer introducing new functionalities and properties.

Ultrathin gold nanoframes through surfactant-free templating of faceted pentagonal silver nanoparticles.

Ultrathin gold nanoframes (up to 1.6 nm) were prepared via templating upon well-defined faceted silver morphologies. Starting with silver decahedra, small quantities of gold (1-10 mol% relative to the amount of silver) were selectively deposited on the nanoparticle edges under optimized reducing conditions.

Synthesis of size-controlled faceted pentagonal silver nanorods with tunable plasmonic properties and self-assembly of these nanorods.

Monodisperse size-controlled faceted pentagonal silver nanorods were synthesized by thermal regrowth of decahedral silver nanoparticle (AgNPs) in aqueous solution at 95 degrees C, using citrate as a reducing agent. The width of the silver nanorods was determined by the size of the starting decahedral particle, while the length was varied from 50 nm to 2 mum by the amount of new silver added to the growth solution. Controlled regrowth allowed us to produce monodisperse AgNPs with a shape of elongated pentagonal dipyramid (regular Johnson solid, J(16)).

Direct structural transformation of silver platelets into right bipyramids and twinned cube nanoparticles: morphology governed by defects.

Silver platelets can undergo quantitative conversion to right bipyramids and twinned cubes by regrowth with silver in conditions that preserve original 2-D structural defects in resulting 3-D morphologies.