Synthesis of novel CoCx@C nanoparticles.

CoC(x) nanoparticles encapsulated in carbon shells were synthesized using a pulsed plasma in liquid ethanol. This is the first time that monolithic cubic phase cobalt carbide nanoparticles have been obtained. X-ray diffraction refinement of the nanoparticles showed that the lattice parameter of prepared cubic phase cobalt carbide is larger than that of CoC(x) (44-0962) and cubic phase Co (15-0806 and 01-1259). The x-ray absorption fine structure spectra near the Co K-edge of the synthesized sample indicated differences from commercial metallic cobalt and cobalt oxide samples. High resolution transmission electron microscopy revealed that a thin carbon coating covered the surface of the nanoparticles. These carbon layers might isolate core CoC(x) material from the outside environment, and allow functionalization by carboxyl groups for the further purpose of targeted drug delivery. The obtained CoC(x)@C particles, with a crystallite size of about 10 nm confirmed by the electron microscope, aggregate into 20-40 nm secondary particles in distilled water as shown by dynamic light scattering, and possess high saturation magnetization of about 120 emu g(-1). The sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay and defragmentation of deoxyribonucleic acid on MCF-7 cells after incubation with particles indicate relatively low cytotoxicity of CoC(x)@C nanoparticles, compared with micro-sized and nano-sized metallic cobalt particles and commonly used iron oxides. For the small sized CoC(x)@C particles, the release of cobalt ions was checked by a chelation method with ethylenediaminetetraacetic acid solution to be at a very low level compared with other reference materials.

Tamoxifen-resistant, ER-positive MAC 51 cell line with a high metastatic potential developed from a spontaneous breast cancer mouse model.

We developed and characterized an estrogen-responsive and ER-positive murine breast cancer cell line (MAC51) from a spontaneous breast cancer animal model. These cells are overexpressed with K8, K18 and K19 proteins in an immunofluoresence assay. Upregulation of ER alpha was observed in the immunofluoresence assay, real-time PCR analysis and western blot assay. A colocalization experiment in MAC 51 showed cytoplasmic colocalization of K18 and K19 proteins with ER α. Real-time analysis of tumor samples from engrafted animals, MAC 51, metastatic liver and metastatic ovary revealed overexpression of K8 and K18 compared to the respective controls. A hormone responsive experiment in immunodeficient mice showed highly significant decreases in estrogen and tumor volume after 14 days ovariectomization. The tumorogenicity assay showed higher (3 × 10 (5)) and lower (3 × 10(4)) concentrations of MAC 51 cells that developed tumors within 2 weeks post-transplantation. Tumor morphology and histology resembled a sarcoma pattern but our spontaneous model appeared in an adenocarcinoma pattern. Metastasis to different organs occurred through hematogenous and lymphatic routes. We assessed the potency of the anticancer effect in MAC 51 cells by treating various anticancer drugs with E2, followed by studying apoptotic gene expression profiles. E2 and E2+ tamoxifen-treated cells showed upregulation of apoptotic genes caspase 1, 3, 9, P53 and Bcl-xl but the tamoxifen- and paclitaxel-treated cells did not upregulate the apoptotic genes. Tamoxifen-resistant, ER-positive and high metastatic potential cell lines from murine origin are very rare. Also, estrogen greatly induced apoptosis in this cell line, hence MAC 51 has a greater application potential to evaluate low doses of estrogen with other targeted therapeutic drugs to treat breast cancer.

A facile UV-curing method for the preparation of transparent and conductive carbon nanotube hybrid films.

A new method for preparing flexible, transparent, and conductive multiwalled carbon nanotube (MWCNT) hybrid films with scratch resistance through a facile UV-curing method is described herein. UV-curable urethane oligomers were used as the binder between the MWCNTs and the plastic substrates. The transparency and sheet resistance of MWCNT thin films can be easily tailored by controlling the number of bar coaters. Composite films with different binder ratios were prepared to evaluate and optimize the surface abrasion resistance and adhesion parameter. Two types of MWCNT films, those with a 56% (with a 586 komega/sq sheet resistance) and a 78% transmittance (with a 22 Momega/sq sheet resistance) were obtained using the UV-curable resin, and the conductive films showed distinguished abrasion resistance and good adhesion.

Preparation of semi-conducting polymeric nanoparticles by supercritical carbon dioxide RESOLV process.

The rapid expansion of supercritical carbon dioxide solutions into a liquid solvent (RESOLV) technique with environmentally benign supercritical carbon dioxide was used to produce semi-conducting polymeric nanoparticles of fluoroalkyl ester substituted thiophenes. When the supercritical solutions of the conjugated polymer, poly[2-(3-thienyl) acetyl-3,3,4,4,5,5,6,6,7,7,8,8,8,tridecafluoro-1-octanate] (PSFTE) were expanded into aqueous solutions through a small capillary nozzle (150 microm), spherical nanoparticles in the range of 50-100 nm were obtained. However, after 15 min of expansion, the particles tended to aggregate to form larger objects due to the high surface energy of the polymeric nanoparticles. In order to prevent the agglomeration of particles, a relatively low concentration of sodium dodecyl sulphate (SDS) or NaCI was used as a stabilizing agent in aqueous solution. While NaCI did not give enough stabilization to the system, uniform spherical nanoparticles of PSFTE having an average size of 45 nm were successfully obtained by SDS stabilization.

Characterization of micellar film morphologies of semifluorinated block copolymers by AFM.

The micellar morphologies of well-defined amphiphilic block copolymers composed of 1H,1H-dihydroperfluorooctyl methacrylate (FOMA) and ethylene oxide (EO) blocks with different chain lengths were effectively investigated by using tapping mode-atomic force microscopy (TM-AFM). By spin-casting chloroform solutions, well-ordered spherical micellar films could be obtained for poly(FOMA(10k)-b-EO(10k)) and poly(FOMA(20k)-b-EO(20k)) copolymers. The atomic force microscopy (AFM) height and phase image analysis indicated that dark regions of the micelles corresponded to PEO blocks and the light regions were for PFOMA blocks. The spherical micelles with PEO corona and PFOMA core were also identified by transmission electron microscopy (TEM) and X-ray photoelectron spectrometer (XPS) analysis. The core diameters of the block-copolymer aggregates were 20 nm for poly(FOMA(10k)-b-EO(10k)) and 30 nm for poly(FOMA(20k)-b-EO(20k)) by TM-AFM, whereas slightly lower values of 17 and 26 nm were obtained from TEM. A detailed study on the inverted morphological change observed in the micelles films after annealing above glass transition temperature (T(g)) was also presented.