24 research outputs found
AFM study of morphology and mechanical properties of a chimeric 2 spider silk and bone sialoprotein protein for bone regeneration
Atomic force microscopy (AFM) was used to assess a
new chimeric protein consisting of a fusion protein of the consensus
repeat for Nephila clavipes spider dragline protein and bone sialoprotein
(6merþBSP). The elastic modulus of this protein in film
form was assessed through force curves, and film surface roughness
was also determined. The results showed a significant difference
among the elastic modulus of the chimeric silk protein, 6merþBSP,
and control films consisting of only the silk component (6mer). The
behavior of the 6merþBSP and 6mer proteins in aqueous solution in
the presence of calcium (Ca) ions was also assessed to determine
interactions between the inorganic and organic components related
to bone interactions, anchoring, and biomaterial network formation.
The results demonstrated the formation of protein networks in the
presence of Ca2þ ions, characteristics that may be important in the
context of controlling materials assembly and properties related to
bone formation with this new chimeric silk-BSP protein.Silvia Games thanks the Foundation for Science and Technology (FCT) for supporting her Ph.D. grant, SFRH/BD/28603/2006. This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283), the Chimera project (PTDC/EBB-EBI/109093/2008) funded by the FCT agency, the NIH (P41 EB002520) Tissue Engineering Resource Center, and the NIH (EB003210 and DE017207)
Recent advances and perspectives on starch nanocomposites for packaging applications
Starch nanocomposites are popular and abundant materials in packaging sectors. The aim of this work is to review some of the most popular starch nanocomposite systems that have been used nowadays. Due to a wide range of applicable reinforcements, nanocomposite systems are investigated based on nanofiller type such as nanoclays, polysaccharides and carbonaceous nanofillers. Furthermore, the structures of starch and material preparation methods for their nanocomposites are also mentioned in this review. It is clearly presented that mechanical, thermal and barrier properties of plasticised starch can be improved with well-dispersed nanofillers in starch nanocomposites
Ordering of fullerene and carbon nanotube thin films under energetic ion impact
We report the ordering of carbon nanostructures under energetic ion irradiation at low fluence (<5 x 10(11) ions/cm(2)). Fullerene thin films and multiwalled carbon nanotube (MWCNT) films were irradiated with 200 MeV Au and 60 MeV Ni ions at different ion fluences, respectively. The changes in the irradiated films have been investigated by means of Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction, and Raman spectroscopy. FTIR and Raman spectroscopy show the improvement of vibration strength in low fluence irradiated fullerene and MWCNT films. X-ray diffraction analysis on low fluence irradiated fullerene films revealed the structural order along the (220) atomic planes. (C) 2008 American Institute of Physics
Field emission from oriented tin oxide rods
Tin oxide (SnO2) films were grown on silicon substrates by a wet chemical route. It was found from scanning electron microscopy investigations that oriented SnO2 rods normal to the substrates were obtained. Field emission studies were carried out in diode configuration in an all metal ultra high vacuum chamber at a base pressure ~ 1.33 × 10-8 mbar. The 'onset' field required to draw 0.1 μA/cm2 current density from the emitter cathode was found to be ~ 3.4 V/μm for SnO2 rods. The field emission current and applied field follows the Folwer-Nordheim relationship in low field regime. The observed results indicate that the field emission characteristics of chemically grown SnO2 structures are comparable to the vapor grown nanostructures