PROCESS IMPROVEMENT AND BIOLOGIC BEHAVIOR OF CHITOSAN BASED ABSORBABLE IMPLANTS

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Strategy to improve the mechanical properties of bioabsorbable materials based on chitosan for orthopedic fixation applications

Publication . Figueiredo, Lígia; Fonseca, Rita; Pinto, Luís F. V.; Ferreira, Frederico Castelo; Almeida, Amélia; Rodrigues, Alexandra

Bioabsorbable polymeric fixation devices have been used as an alternative to metallic implants in orthopedics,preventing the stress shielding effect and avoiding a second surgery for implant removal. However,several problems are still associated with current bioabsorbable implants, including the limited mechanical stiffness and strength, and the adverse tissue reactions generated. To minimize or even eliminate the problems associated with these implants, strategies have been developed to synthesize new implant materials based on chitosan. To overcome the brittle behavior of most 3D chitosan-based structures, glycerol and sorbitol were blended to chitosan and the effect of these plasticizers in the produced specimens was analyzed by flexural tests, Berkovich tests, scanning electron microscopy (SEM) and micro-CT analyzes. The improvement of the mechanical properties was also tested by adding ceramics, namely hydroxyapatite powder and biphasic mixtures of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP). In the plasticizers group, the best combination of the measured properties was obtained for chitosan with 10% glycerol (flexural strength of 53.8 MPa and indentation hardness of 19.4 kgf/mm2), while in the ceramics group the best mechanical behavior was obtained for chitosan with 10% HAþβ-TCP powder (flexural strength of 67.5 MPa and indentation hardness 28.2 kgf/mm2). All the tested material compositions were dense and homogeneous, fundamental condition for a good implant performance. These are encouraging results, which support the continued development of chitosan-based materials for orthopedic fixation applications.

2020-03Artigo científico

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Processing and Characterization of 3D Dense Chitosan Pieces, for Orthopedic Applications, by Adding Plasticizers

Publication . Figueiredo, Lígia; Moura, Carla; Pinto, Luís F.V.; Ferreira, Frederico Castelo; Rodrigues, Alexandra

In this work, plasticizer agents were incorporated in a chitosan based formulation, as a strategy to improve the fragile structure of chitosan based-materials. Three different plasticizers: ethylene glycol, glycerol and sorbitol, were blended with chitosan to prepare 3D dense chitosan specimens. The properties of the obtained structures were assessed for mechanical, microstructural, physical and biocompatibility behavior. The results obtained revealed that from the different specimens prepared, the blend of chitosan with glycerol has superior mechanical properties and good biological behavior, making this chitosan based formulation a good candidate to improve robust chitosan structures for the construction of bioabsorbable orthopedic implants.

2015Artigo científico

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Entidade financiadora

Fundação para a Ciência e a Tecnologia

Programa de financiamento

OE

Número da atribuição

SFRH/BD/51949/2012