Synthesis of Poly(2-Hydroxyethyl Methacrylate) (PHEMA)-Based Superparamagnetic Nanoparticles for Biomedical and Pharmaceutical Applications.

The performance of polymeric nanomaterials relies greatly upon their properties which are intimately related to the methods of fabrication of their materials. Among various synthetic polymers the polymers of 2-hydroxyethyl methacrylate (PHEMA) maintains a prime position in the biomedical field due to their useful physicochemical properties and suitability for controlled drug delivery applications. Furthermore, the addition of iron oxide to PHEMA nanoparticles imparts superparamagnetism to the nanoparticles and expands the range of their uses to include magnetic drug targeting applications.

Proton Transfer Pathways of 2,2'-Bipyridine-3,3'-diol in pH Responsive Fatty Acid Self-Assemblies: Multiwavelength Fluorescence Lifetime Imaging in a Single Vesicle.

Fatty acids are known to form different supramolecular aggregates in aqueous solutions depending on the pH of the medium. The dynamics of the transformation of oleate micelles into oleic acid/oleate vesicles has been investigated using a pH-sensitive intramolecular proton transfer fluorophore, 2,2'-bipyridine-3,3'-diol [BP(OH)]. Different prototropic forms of BP(OH) exist in different pH values of the system, and thus, the ground state and the excited state dynamics of BP(OH) have been modulated in these confined media.

Macroscopic, neat, single-walled carbon nanotube fibers.

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers.

Functionalization of carbon nanotubes by free radicals.

Free radicals generated by decomposition of benzoyl peroxide in the presence of alkyl iodides have been used to derivatize small-diameter single-wall carbon nanotubes (HiPco tubes). The degree of functionalization, estimated by thermal gravimetric analysis, is as high as 1 in approximately 5 carbons in the nanotube framework. The derivatized nanotubes exhibits remarkably improved solubility in organic solvents.

Covalent sidewall functionalization of single wall carbon nanotubes.

Alkyllithium reagents may be used to attach alkyl groups to the sidewalls of fluoro nanotubes. Thermal gravimetric analysis combined with UV-vis-Nir spectroscopy has been used to provide a quantitative measure of the degree of functionalization. SWNTs prepared using the HiPco process exhibit a higher degree of alkylation than SWNTs from the laser-oven method, indicating that the smaller diameter fluoro tubes are alkylated more readily.

Thermal rearrangements of spiro[2.4]hepta-1,4,6-trienes.

Thermolysis of spiro[2.4]hepta-1,4,6-triene (1a) at 50 degrees C yielded bicyclo[3.2.