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This work presents a novel composite hydrogel consisting of silk fibroin (SF) and nanohydroxyapatite (nanoHA) prepared by a new and innovative method using ethanol as gelling agent capable of forming hydrogels in few minutes. The properties of the composite material, such as the microstructure as well as the chemical and physical properties were studied. Moreover in␣vitro studies of osteoblastic citocompatibility were performed. The microporosity and macroporosity obtained combined with interconnected porous structure and a uniform dispersion of nanoHA particles throughout the fibroin matrix makes composite hydrogel suitable for bone regeneration. The compression modulus of composite hydrogels was increased as the nanoHA concentration increased from 10 to 15 wt.% and the water uptake ability of these materials decreased with the incorporation of nanoHA. The metabolic and alkaline phosphatase activities of osteoblastic cells were improved with the incorporation of nanoHA in the SF matrix providing a more promising material for bone tissue engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] • nHAp/PLDLLA composites with wt.% ratio: 10/90 and 20/80 were prepared by an-extrusion process. • Structural properties of the filler and polymeric blends were characterized in detail. • Mechanical results and density values were reported as close to human bone. • Contact angle analysis showed a favored growth of tissue on the biocomposite containing 10 wt% nHAp. • The PLDLLA-based composite can be an excellent candidate for bone reconstruction implants. A novel, bone-reconstruction dedicated polymeric-nanohydroxyapatite material has been prepared for 3D-printed implant. The composites of poly(L-lactide- co -D,L-lactide) (PLDLLA) and nanosized hydroxyapatite were prepared by a co-rotating twin-screw extrusion. Structural properties of the filler and polymeric blends were characterized by XRD (X-ray Powder Diffraction), SEM (Scanning Electron Microscopy), and EDS mapping (energy dispersive spectroscopy), FT-IR (Fourier-transformed infrared spectroscopy), and NMR (Nuclear Magnetic Resonance) technics. Molar masses of the composites at various preparation steps were also investigated. The structural studies and thermogravimetric analysis proved a successful preparation of the nanohydroxyapatite and its nanocomposites. Mechanical results in conjunction with density values, reported as close to human bone, evidenced usability of this novel material for internal bone fixation implant. Contact angle analysis showed favored growth of tissue on the biocomposite containing 10 wt% of the filler. The PLDLLA-based composite can be an excellent candidate for bone reconstruction implants due to their superior mechanical properties, bioactivity, and complete resorbability. [ABSTRACT FROM AUTHOR]

A new kind of tissue engineering scaffold materials of needle-like nano-hydroxyapatite (n-HA) and polyamide (PA) biocomposite is prepared by co-solution, co-precipitation method and water treatment under normal atmospheric pressure. The n-HA crystals uniformly distribute in the composite with a crystal size of 10–20 nm in diameter by 70–90 nm in length. The n-HA/PA composite has good homogeneity, high n-HA content (65 wt%), and high bioactivity. Strong molecule interactions and chemical bondings are present between the n-HA and PA in the composite, which are verified by IR, XPS and XRD. The composite has excellent mechanical properties close to the natural bone. The porous 3-D scaffold is made by injection foaming method, which has not only macropores, but also micropores on the walls of macropores. The porosity is 80% and the average macropore diameter is about 300 μm of the composite.The n-HA/PA composite can be used for tissue engineering and bone repair or substitute. [Copyright &y& Elsevier]

• Functionalized nHAp was obtained using arginine or polyethylenimine. • Resulted nanoparticles were comparatively characterized relative to used modifiers. • Linear polyethylenimine coated hydroxyapatite had the best DNA binding ability. • Use of LPEI functionalized nHAp in biocomposites recipe had a strengthening effect. • The 3D constructs demonstrated rapid self–recovery and fatigue resistant behavior. Functionalized nano-hydroxyapatite (nHAp) was obtained by wet chemical technique, using arginine (Arg) or polyethylenimine (branched-bPEI, or linear-LPEI) as cationic modifiers and dispersing agents. TEM, FT-IR, SEM, DLS and WAXD characterization results showed that the prepared nanoparticles possessed needle- or plate-like morphologies and Arg and PEI were successfully grafted onto nHAp. LPEI functionalized nHAp exhibited a good similitude with biological apatite and the best DNA binding ability. In addition, the incorporation of nHAp/LPEI nanoparticles within collagen/dimethylsilanediol hyaluronate-based porous matrices pointed out a significant improvement of the compressive modulus of biocomposites: up to a six-fold increase, compared with the polymer matrix without fillers. Moreover, the composite sponges revealed high toughness during five consecutive compression tests without any permanent deformation and cracks. Therefore, nHAp/LPEI nanoparticles could be considered promising materials for biomedical applications, like gene carrier or reinforcement filler with strong interfacial adhesion in biocomposites for bone engineering. [ABSTRACT FROM AUTHOR]