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Jelen C.,University of Pisa | Mattei G.,University of Pisa | Montemurro F.,University of Pisa | Montemurro F.,Let People Move Research Institute | And 6 more authors.
Materials Science and Engineering C | Year: 2013

Bone TE uses a scaffold either to induce bone formation from surrounding tissue or to act as a carrier or template for implanted bone cells or other agents. We prepared different bone tissue constructs based on collagen, gelatin and hydroxyapatite using genipin as cross-linking agent. The fabricated construct did not present a release neither of collagen neither of genipin over its toxic level in the surrounding aqueous environment. Each scaffold has been mechanically characterized with compression, swelling and creep tests, and their respective viscoelastic mechanical models were derived. Mechanical characterization showed a practically elastic behavior of all samples and that compressive elastic modulus basically increases as content of HA increases, and it is strongly dependent on porosity and water content. Moreover, by considering that gradients in cellular and extracellular architecture as well as in mechanical properties are readily apparent in native tissues, we developed discrete functionally graded scaffolds (discrete FGSs) in order to mimic the graded structure of bone tissue. These new structures were mechanically characterized showing a marked anisotropy as the native bone tissue. Results obtained have shown FGSs could represent valid bone substitutes. © 2012 Elsevier B.V.


De Maria C.,University of Pisa | De Maria C.,Let People Move Research Institute | Rincon J.,University of Texas at El Paso | Duarte A.A.,University of Texas at El Paso | And 2 more authors.
Polymers for Advanced Technologies | Year: 2013

Agarose hydrogels find wide applications in different fields such as biological sciences, tissue engineering and food industry, and its use has been investigated in many fields ranging from electronics to crystallography. Usually, agarose structures are made by casting, and more recently some attempts have been made to build agarose structures by additive manufacturing. All of the fabrication methods are based on thermo-reversible gelling properties of agarose gel. A new method to fabricate agarose microstructures in a binary solvent composed of water and dimethyl sulfoxide is presented and modelled in this paper. This new method allows building agarose structures by an additive layer-by-layer approach using a modified inkjet printer. The fabrication method and printing device are described in detail. Furthermore, finite-element model simulations, which predict with high confidence the final line width of the printed structures, are discussed and analysed. Mechanical properties of printed gel structures are comparable with those obtained by gel casting, as demonstrated by tensile testing. The presented results demonstrate the feasibility of this approach to fabricate agarose structures with more complex shapes that can be done by casting. © 2013 John Wiley & Sons, Ltd.


Mantovani G.,University of Ottawa | Lamontagne M.,University of Ottawa | Varin D.,University of Ottawa | Cerulli G.G.,Let People Move Research Institute | Beaule P.E.,University of Ottawa
Journal of Biomechanics | Year: 2012

Gait adaptations are persistent after total hip arthroplasty and can depend on the type of surgery. This study focused on two surgical approaches: anterior and lateral. To analyze gait adaptations, biomechanical analyses usually employ an a priori selection of the parameters that leads to incomplete or redundant information. In contrast, Principal Component Analysis (PCA) provides an efficient transformation of the dataset by automatically identifying the major sources of variability. The purpose of this study was to investigate differences in level-walking among three groups of participants using PCA: patients undergoing an anterior surgical approach, patients undergoing a lateral surgical approach, and healthy controls. Biomechanical descriptions of the extracted principal components aided in the interpretation of the statistically significant results obtained from multivariate analysis of covariance (MANCOVA) tests. A point system was introduced to summarize the results and guide the interpretation. PCA captured reduced magnitude in sagittal and frontal moments in the anterior approach group, and reduced sagittal peaks angle in the lateral group, as previously found with traditional analyses. PCA also identified significant pattern delays in the anterior group, unnoticed in previous studies. In conclusion, neither surgical approach restored normal gait functionality because lower extremity kinetics and kinematics alterations persisted at 300-day follow-up after the surgery, regardless of the technique. © 2012 Elsevier Ltd.


Cerulli G.,Nicolas Foundation Onlus | Cerulli G.,Let People Move Research Institute | Cerulli G.,International Orthopedics and Traumatology Institute | Cerulli G.,University of Perugia | And 5 more authors.
Joints | Year: 2013

Rupture of the anterior cruciate ligament is one of the most common ligament injuries in sports traumatology. The need for surgical anterior cruciate ligament reconstruction is justified by its anatomical characteristics. Key considerations when choosing a graft include the potential for bone integration and the risk of failure. Bone sclerosis around the tunnel affects the integration of the graft. For this reason, one aspect upon which orthopedic surgeons should focus is the biology of the bone-graft interface. Although the BPTB graft is still used, hamstrings and synthetic grafts have become increasingly widespread and popular over the years. An allograft certainly requires more long-term follow-up to validate its use in response to functional, clinical and biological requirements. © 2013, CIC Edizioni Internazionali s.r.l. All rights reserved.

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