Macro/microporous silk fibroin scaffolds with potential for articular cartilage and meniscus tissue engineering applications.

This study describes the developmental physicochemical properties of silk fibroin scaffolds derived from high-concentration aqueous silk fibroin solutions. The silk fibroin scaffolds were prepared with different initial concentrations (8, 10, 12 and 16%, in wt.%) and obtained by combining the salt-leaching and freeze-drying methodologies. The results indicated that the antiparallel β-pleated sheet (silk-II) conformation was present in the silk fibroin scaffolds. All the scaffolds possessed a macro/microporous structure. Homogeneous porosity distribution was achieved in all the groups of samples. As the silk fibroin concentration increased from 8 to 16%, the mean porosity decreased from 90.8±0.9 to 79.8±0.3% and the mean interconnectivity decreased from 97.4±0.5 to 92.3±1.3%. The mechanical properties of the scaffolds exhibited concentration dependence. The dry state compressive modulus increased from 0.81±0.29 to 15.14±1.70 MPa and the wet state dynamic storage modulus increased by around 20- to 30-fold at each testing frequency when the silk fibroin concentration increased from 8 to 16%. The water uptake ratio decreased with increasing silk fibroin concentration. The scaffolds present favorable stability as their structure integrity, morphology and mechanical properties were maintained after in vitro degradation for 30 days. Based on these results, the scaffolds developed in this study are proposed to be suitable for use in meniscus and cartilage tissue-engineered scaffolding.

[1]  Keiji Numata,et al.  Reinforcing silk scaffolds with silk particles. , 2010, Macromolecular bioscience.

[2]  David L. Kaplan,et al.  Mechanism of silk processing in insects and spiders , 2003, Nature.

[3]  Ung-Jin Kim,et al.  Structure and properties of silk hydrogels. , 2004, Biomacromolecules.

[4]  R. Reis,et al.  Calcium-phosphate derived from mineralized algae for bone tissue engineering applications , 2007 .

[5]  David L Kaplan,et al.  Porous 3-D scaffolds from regenerated silk fibroin. , 2004, Biomacromolecules.

[6]  J. Vacanti,et al.  Tissue engineering. , 1993, Science.

[7]  S. Mann,et al.  Bone‐like Resorbable Silk‐based Scaffolds for Load‐bearing Osteoregenerative Applications , 2009 .

[8]  M. Hull,et al.  Compressive moduli of the human medial meniscus in the axial and radial directions at equilibrium and at a physiological strain rate , 2008, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[9]  G. Vunjak‐Novakovic,et al.  Stem cell-based tissue engineering with silk biomaterials. , 2006, Biomaterials.

[10]  M B McCarthy,et al.  Functionalized silk-based biomaterials for bone formation. , 2001, Journal of biomedical materials research.

[11]  Biman B Mandal,et al.  Cell proliferation and migration in silk fibroin 3D scaffolds. , 2009, Biomaterials.

[12]  Farshid Guilak,et al.  A biomimetic three-dimensional woven composite scaffold for functional tissue engineering of cartilage. , 2007, Nature materials.

[13]  Gordana Vunjak-Novakovic,et al.  Bone Tissue Engineering Using Human Mesenchymal Stem Cells: Effects of Scaffold Material and Medium Flow , 2004, Annals of Biomedical Engineering.

[14]  Rui L Reis,et al.  Novel hydroxyapatite/chitosan bilayered scaffold for osteochondral tissue-engineering applications: Scaffold design and its performance when seeded with goat bone marrow stromal cells. , 2006, Biomaterials.

[15]  K. Ohgo,et al.  Comparative study of silk fibroin porous scaffolds derived from salt/water and sucrose/hexafluoroisopropanol in cartilage formation. , 2009, Journal of bioscience and bioengineering.

[16]  Chenhua Zhao,et al.  Structural characterization and artificial fiber formation of Bombyx mori silk fibroin in hexafluoro‐iso‐propanol solvent system , 2003, Biopolymers.

[17]  Claudio Migliaresi,et al.  Outgrowth endothelial cells isolated and expanded from human peripheral blood progenitor cells as a potential source of autologous cells for endothelialization of silk fibroin biomaterials. , 2006, Biomaterials.

[18]  Nuno M. Neves,et al.  Hydroxyapatite Reinforced Chitosan and Polyester Blends for Biomedical Applications , 2005 .

[19]  Federica Chiellini,et al.  Polymeric Materials for Bone and Cartilage Repair , 2010 .

[20]  David L Kaplan,et al.  Gel spinning of silk tubes for tissue engineering. , 2008, Biomaterials.

[21]  Xin Chen,et al.  Conformation transition kinetics of Bombyx mori silk protein , 2007, Proteins.

[22]  David L. Kaplan,et al.  Water‐Stable Silk Films with Reduced β‐Sheet Content , 2005 .

[23]  David L. Kaplan,et al.  Direct‐Write Assembly of Microperiodic Silk Fibroin Scaffolds for Tissue Engineering Applications , 2008 .

[24]  Claudio Migliaresi,et al.  The synergistic effects of 3-D porous silk fibroin matrix scaffold properties and hydrodynamic environment in cartilage tissue regeneration. , 2010, Biomaterials.

[25]  David L Kaplan,et al.  Biomedical applications of chemically-modified silk fibroin. , 2009, Journal of materials chemistry.

[26]  Tetsuo Asakura,et al.  Conformational characterization of Bombyx mori silk fibroin in the solid state by high-frequency carbon-13 cross polarization-magic angle spinning NMR, x-ray diffraction, and infrared spectroscopy , 1985 .

[27]  D. Hutmacher,et al.  Scaffolds in tissue engineering bone and cartilage. , 2000, Biomaterials.

[28]  David L Kaplan,et al.  Silk nanospheres and microspheres from silk/pva blend films for drug delivery. , 2010, Biomaterials.

[29]  A. Salgado,et al.  Dendrimers and derivatives as a potential therapeutic tool in regenerative medicine strategies—A review , 2010 .

[30]  Yasushi Tamada,et al.  New process to form a silk fibroin porous 3-D structure. , 2005, Biomacromolecules.

[31]  A. L. Oliveira,et al.  Sodium silicate gel as a precursor for the in vitro nucleation and growth of a bone-like apatite coating in compact and porous polymeric structures. , 2003, Biomaterials.

[32]  D. Kaplan,et al.  Porosity of 3D biomaterial scaffolds and osteogenesis. , 2005, Biomaterials.

[33]  Li Ren,et al.  Genipin-cross-linked collagen/chitosan biomimetic scaffolds for articular cartilage tissue engineering applications. , 2010, Journal of biomedical materials research. Part A.

[34]  M. Levenston,et al.  Meniscus and cartilage exhibit distinct intra-tissue strain distributions under unconfined compression. , 2010, Osteoarthritis and cartilage.

[35]  Makoto Demura,et al.  Immobilization of biocatalysts with bombyx mori silk fibroin by several kinds of physical treatment and its application to glucose sensors , 1989 .

[36]  Peter X. Ma,et al.  Scaffolds for tissue fabrication , 2004 .

[37]  Gordana Vunjak-Novakovic,et al.  Silk implants for the healing of critical size bone defects. , 2005, Bone.

[38]  Ung-Jin Kim,et al.  Three-dimensional aqueous-derived biomaterial scaffolds from silk fibroin. , 2005, Biomaterials.

[39]  R L Reis,et al.  Degradable particulate composite reinforced with nanofibres for biomedical applications. , 2009, Acta biomaterialia.

[40]  R. Naik,et al.  Thermally Induced α-Helix to β-Sheet Transition in Regenerated Silk Fibers and Films , 2005 .

[41]  David L Kaplan,et al.  Silk as a Biomaterial. , 2007, Progress in polymer science.

[42]  David L Kaplan,et al.  Water-insoluble silk films with silk I structure. , 2010, Acta biomaterialia.

[43]  Irene Georgakoudi,et al.  Bone regeneration on macroporous aqueous-derived silk 3-D scaffolds. , 2007, Macromolecular bioscience.

[44]  R. Naik,et al.  Thermally induced alpha-helix to beta-sheet transition in regenerated silk fibers and films. , 2005, Biomacromolecules.

[45]  David L Kaplan,et al.  Silk-based biomaterials. , 2003, Biomaterials.

[46]  D. Kaplan,et al.  Designing silk-based 3D architectures with controlled lamellar morphology , 2008 .

[47]  J. Vacanti,et al.  Tissue engineering : Frontiers in biotechnology , 1993 .

[48]  O. Kratky,et al.  An Unstable Lattice in Silk Fibroin , 1950, Nature.

[49]  R L Reis,et al.  Micro-computed tomography (μ -CT) as a potential tool to assess the effect of dynamic coating routes on the formation of biomimetic apatite layers on 3D-plotted biodegradable polymeric scaffolds , 2007, Journal of materials science. Materials in medicine.

[50]  T. Asakura,et al.  Solvent- and mechanical-treatment-induced conformational transition of silk fibroins studies by high-resolution solid-state carbon-13 NMR spectroscopy , 1990 .

[51]  S. Kundu,et al.  Osteogenesis of human stem cells in silk biomaterial for regenerative therapy , 2010 .

[52]  Dietmar W Hutmacher,et al.  A comparison of micro CT with other techniques used in the characterization of scaffolds. , 2006, Biomaterials.

[53]  D. Kaplan,et al.  Conformational transitions in model silk peptides. , 2000, Biophysical journal.

[54]  Alexander Augst,et al.  Bone and cartilage tissue constructs grown using human bone marrow stromal cells, silk scaffolds and rotating bioreactors. , 2006, Biomaterials.

[55]  M. Barbeck,et al.  Fine‐tuning scaffolds for tissue regeneration: effects of formic acid processing on tissue reaction to silk fibroin , 2010, Journal of tissue engineering and regenerative medicine.