Raman scattering from single WS2 nanotubes in stretched PVDF electrospun fibers.

Inorganic WS2 nanotubes (INT-WS2) were embedded into sub-µm polyvinylidene fluoride-co-hexafluropropylene (PVDF-HFP) electrospun fibers. In this report we explore the Raman scattering spectroscopy from a single nanotube during stretching of individual nanocomposite fibers. Red shifts of up to ∼4.7 cm-1 for A1g and E WS2 bands were found before reaching the "tearing point" of the fibers. These shifts may correlate with up to ∼2.8% of the WS2 nanotube elongation. Moreover, the absence of the A1g and E bands' broadening, as well as the nonappearance of the E shear mode in the nanotube Raman spectra, suggest the stretching of the nanotubes as a whole (including inner layers). These results point to the excellent adhesion of the nanotubes' surface to the polymer and to the effective load transfer from the polymer to the WS2 nanotube. In order to elucidate the nature of interaction between the polymer and the nanofiller, we modeled the deformation of composite fibers using an elastic lattice spring model (LSM). The results of the model are fully consistent with our interpretation.

Characterization and activity of sonochemically-prepared BSA microspheres containing Taxol--an anticancer drug.

Proteinaceous microspheres of BSA (Bovine Serum Albumin) containing an anticancer drug, Taxol (paclitaxel) were fabricated using a sonochemical procedure and then assayed for chemical and biological activity. The sonochemical reaction did not compromise the drug, which became encapsulated in the BSA microspheres. The amount of the anticancer drug in the microspheres was determined by HPLC. Anticancer activity of the proteinaceous microspheres encapsulating the Taxol was tested on Mouse Multiple Myeloma cell line MPC-11. The influence of the Taxol microspheres on the cancer cells was different from pristine Taxol. It was found that Taxol in combination with the organic solvent causes the death of cancer cells.

Antibiotic nanoparticles embedded into the Parylene C layer as a new method to prevent medical device-associated infections.

Tetracycline nanoparticles (NPs) were synthesized and simultaneously deposited on Parylene-C coated glass slides using ultrasound irradiation. The optimization of the process conditions, the specific reagent ratio and the precursor concentration resulted in the formation of uniform NPs with an average size of ∼50 nm. These novel tetracycline NP coated-surfaces were tested against two common bacterial pathogens, Escherichia coli and Staphylococcus aureus, and were found to be extremely potent against both bacteria, suggesting that these antibiotic NPs provide the Parylene surface with self-sterilizing properties. Finally, the mechanism describing the formation of tetracycline NPs and their subsequent deposition on the Parylene C surface is presented.

Encapsulating bioactive materials in sonochemically produced micro- and nano-spheres.

By the early 90s, K. S. Suslick had developed a method using high-intensity ultrasound to make aqueous suspensions of proteinaceous microcapsules filled with water-insoluble liquids. This method was extended on the one hand to include (instead of proteins) starch, chitosan, DNA, RNA, PEG, and more. The second direction was the encapsulation of drugs, dyes, magnetic and other materials in various micro- and nanocapsules. The current paper will review the materials that were encapsulated in various spheres using high-intensity ultrasound. The amount encapsulated, its release from the sphere, bioactivity, and application aspects will be discussed.

Forming nanoparticles of water-soluble ionic molecules and embedding them into polymer and glass substrates.

This work describes a general method for the preparation of salt nanoparticles (NPs) made from an aqueous solution of ionic compounds (NaCl, CuSO(4) and KI). These nanoparticles were created by the application of ultrasonic waves to the aqueous solutions of these salts. When the sonication was carried out in the presence of a glass microscope slide, a parylene-coated glass slide, or a silicon wafer the ionic NPs were embedded in these substrates by a one-step, ultrasound-assisted procedure. Optimization of the coating process resulted in homogeneous distributions of nanocrystals, 30 nm in size, on the surfaces of the substrates. The morphology and structure of each of the coatings were characterized by physical and chemical methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). After 24 h of leaching into water the nanoparticles of the inorganic salts were still present on the slides, and complete leaching of nanoparticles occurred only after 96 h. A mechanism of the ultrasound-assisted coating is proposed.

Sonochemically prepared BSA microspheres containing Gemcitabine, and their potential application in renal cancer therapeutics.

This report demonstrates the formation and characterization of sonochemically prepared bovine serum albumin (BSA)-Gemzar (Gemcitabine) microspheres and shows their increased anticancer activity compared to pristine Gemzar. The amount of loaded Gemzar was determined by light absorption measurements. The BSA-Gemzar composite was analyzed and characterized by optical microscopy and scanning electron microscopy. The release kinetics of Gemzar from the proteinaceous microspheres was tested. The BSA-Gemzar composite was examined for its anticancer activity (in vitro) in renal cancer cells (RCC, 786-O cells) using [(3)H]thymidine incorporation assays. It was found that the influence of the Gemzar-loaded microspheres on the cancer cells was significantly greater than that of an equimolar concentration of pristine Gemzar.