ABSTRACT
Introduction: Bone diseases, aging and traumas can cause bone loss and lead to bone defects. Treatment of bone defects is challenging, requiring chirurgical procedures. Bone grafts are widely used for bone replacement, but they are limited and expensive. Due to bone graft limitations, natural, semi-synthetic, synthetic and composite materials have been studied as potential bone-graft substitutes. Desirable characteristics of bone-graft substitutes are high osteoinductive and angiogenic potentials, biological safety, biodegradability, bone-like mechanical properties, and reasonable cost. Herein, we prepared and characterized potential bone-graft substitutes composed of calcium phosphate (CP) - a component of natural bone, and chitosan (CS) - a biocompatible biopolymer. Methods CP-CS composites were synthetized, molded, dried and characterized. The effect of drying temperatures (38 and 60 °C) on the morphology, porosity and chemical composition of the composites was evaluated. As well, the effects of drying temperature and period of drying (3, 24, 48 and 72 hours) on the mechanical properties - compressive strength, modulus of elasticity and relative deformation-of the demolded samples were investigated. Results Scanning electron microscopy and gas adsorption-desorption analyses of the CS-CP composites showed interconnected pores, indicating that the drying temperature played an important role on pores size and distribution. In addition, drying temperature have altered the color (brownish at 60 °C due to Maillard reaction) and the chemical composition of the samples, confirmed by FTIR. Conclusion Particularly, prolonged period of drying have improved mechanical properties of the CS-CP composites dried at 38 °C, which can be designed according to the mechanical needs of the replaceable bone.
ABSTRACT
O objetivo deste estudo foi avaliar os efeitos da membrana (filme) de quitosana no processo de reparação de feridas cutâneas distais em equinos. Foram induzidas feridas cutâneas nas regiões metacarpianas e metatarsianas de quatro equinos adultos. No grupo tratado, oito feridas foram recobertas com membrana de quitosana e, no grupo controle, apenas higienização com solução de cloreto de sódio 0,9%. No período experimental, foram avaliados o diâmetro da ferida, formação de tecido de granulação exuberante, tipo de exsudato que a recobria, análise histológica, bem como as características da membrana de quitosana (plasticidade durante manipulação e presença ou ausência da membrana a cada troca). A membrana de quitosana não interferiu no tempo de cicatrização, podendo servir como material de recobrimento de feridas cutâneas, potencialmente com vantagens, se for empregada como meio condutor de substâncias que interfiram positivamente no processo cicatricial, abrindo campo para novos estudos.
The aim of this study was to evaluate the effects of chitosan film on wound repair in horse distal limb. Skin wounds were induced on metacarpus and metatarsus region of four adults horses. On treat group, eight wounds were covered with chitosan film and on control group sodium chlorid 0.9% was used. During the experimental period, it was evaluated the wound diameter, exuberant granulation tissue formation, kind of exudat, histological analyzes, and some characteristics of the chitosan film (plasticity during handling and presence or absence of film on each change). The chitosan film had not interfered on healing time, might serving to cover skin wounds, with potential advantages, if it is used as a conductive of substances that interfere positively in the healing process, opening a field to news studies.