26 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
(6merĂŸBSP). 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, 6merĂŸBSP,
and control films consisting of only the silk component (6mer). The
behavior of the 6merĂŸBSP 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 Ca2ĂŸ 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)
Recombinant human osteopontin expressed in Nicotiana benthamiana stimulates osteogenesis related genes in human periodontal ligament cells.
Tissue engineering aims to utilise biologic mediators to facilitate tissue regeneration. Several recombinant proteins have potential to mediate induction of bone production, however, the high production cost of mammalian cell expression impedes patient access to such treatments. The aim of this study is to produce recombinant human osteopontin (hOPN) in plants for inducing dental bone regeneration. The expression host was Nicotiana benthamiana using a geminiviral vector for transient expression. OPN expression was confirmed by Western blot and ELISA, and OPN was purified using Ni affinity chromatography. Structural analysis indicated that plant-produced hOPN had a structure similar to commercial HEK cell-produced hOPN. Biological function of the plant-produced hOPN was also examined. Human periodontal ligament stem cells were seeded on an OPN-coated surface. The results indicated that cells could grow normally on plant-produced hOPN as compared to commercial HEK cell-produced hOPN determined by MTT assay. Interestingly, increased expression of osteogenic differentiation-related genes, including OSX, DMP1, and Wnt3a, was observed by realtime PCR. These results show the potential of plant-produced OPN to induce osteogenic differentiation of stem cells from periodontal ligament in vitro, and suggest a therapeutic strategy for bone regeneration in the future
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PEGâpeptide conjugates
The remarkable diversity of the self-assembly behavior
of PEGâpeptides is reviewed, including self-assemblies formed by PEGâpeptides with ÎČ-sheet and α-helical (coiled-coil) peptide sequences. The modes of self-assembly in solution and in the solid state are discussed. Additionally, applications in bionanotechnology and synthetic materials science are summarized
Control of silicification by genetically engineered fusion proteins: silkâsilica binding peptides [forthcoming]
Monodisperse, âHighlyâ Positively Charged Protein Polymer Drag-Tags Generated in an Intein-Mediated Purification System Used in Free-Solution Electrophoretic Separations of DNA
Mechanical and Physical Properties of Recombinant Spider Silk Films Using Organic and Aqueous Solvents
Designing two self-assembly mechanisms into one viral capsid protein
ELP-CP, a structural fusion protein of the thermally responsive elastin-like polypeptide (ELP) and a viral capsid protein (CP), was designed, and its assembly properties were investigated. Interestingly, this protein-based block copolymer could be self-assembled via two mechanisms into two different, well-defined nanocapsules: (1) pH-induced assembly yielded 28 nm virus-like particles, and (2) ELP-induced assembly yielded 18 nm virus-like particles. The latter were a result of the emergent properties of the fusion protein. This work shows the feasibility of creating a self-assembly system with new properties by combining two structural protein elements
Effect of Surfactants on the Self-Assembly of a Model Elastin-like Block Corecombinamer: From Micelles to an Aqueous Two-Phase System
Enzyme-Degradable Self-Assembled Nanostructures from Polymer-Peptide Hybrids
The peptide PVGLIG, which is known to be selectively cleaved by the tumor-associated enzyme matrix metalloproteinase-2 (MMP-2), was conjugated to a-alkene poly(trimethylene carbonate) (PTMC) blocks of varying sizes via UV-initiated thiol-ene "click" chemistry. The PTMC precursor was synthesized by metal-free ring-opening polymerization using ally! alcohol as an initiator and an N-heterocyclic carbene as an organic catalyst. The unprecedented PVGLIG-b-PTMC hybrids were self-assembled in aqueous solution and various submicrometer-sized morphologies obtained by a nanoprecipitation process. Characterization of particle morphology was carried out by multiangle dynamic light scattering (DLS) and static light scattering (SLS) evidencing spherical nanoparticles with different morphologies and narrow size distributions. Microstructure details were also observed on transmission electron micrographs and were in good agreement with light scattering measurements showing the assembly of core shell, large compound micelles, and vesicle morphologies, the particle morphology varying with the hydrophilic weight fractions (f) of the hybrids. These nanostructures displayed selective degradation in the presence of the cancer-associated enzyme MMP-2, as probed by the morphological change both by TEM and DLS. All these results demonstrated that PVGLIG-b-PTMC hybrids were suitable to target the tumor microenvironment