Osteoregeneration of Critical-Size Defects Using Hydroxyapatite–Chitosan and Silver–Chitosan Nanocomposites

Bone is a natural nanocomposite composed of proteins and minerals that can regenerate itself. However, there are conditions in which this process is impaired, such as extensive bone defects and infections of the bone or surrounding tissue. This study evaluates the osteoregenerative capacity of bone grafting materials in animals with induced bone defects. Colloidal chitosan dispersion nanocomposites, nanohydroxyapatite–chitosan (NHAP-Q) and nanosilver–chitosan (AgNP-Q), were synthesized and characterized. Non-critical-size defects in Wistar rats were used to evaluate the material’s biocompatibility, and critical-size defects in the calvarias of guinea pigs were used to evaluate the regenerative capacity of the bones. Moreover, the toxicity of the nanocomposites was evaluated in the heart, liver, spleen, kidneys, and skin. Histological, radiographic, and electron microscopy tests were also performed. The results showed that neither material produced pathological changes. Radiographic examination showed a significant reduction in defects (75.1% for NHAP-Q and 79.3% for AgNP-Q), angiogenesis, and trabecular formation. A toxicological assessment of all the organs did not show changes in the ultrastructure of tissues, and the distribution of silver was different for different organs (spleen > skin > heart > kidney > liver). The results suggest that both materials are highly biocompatible, and AgNP-Q achieved similar bone regeneration to that reported with autologous bone. The main research outcome of the present study was the combination of two types of NPs to enhance antimicrobial and osteoregeneration activities. These colloidal chitosan dispersions show promise as future biomaterials in the medical field for applications in fast-healing fractures, including broken bones in the oral cavity and hip replacement infections

Vilano : programa integrador de educación ambiental

El trabajo obtuvo el Segundo Premio de la Modalidad B de los 'Premios Tomás García Verdejo' a las buenas prácticas educativas en la Comunidad Autónoma de Extremadura para el curso académico 2013/2014Se describe el proyecto llevado a cabo en el IES Tamujal (Arroyo de San Serván, Badajoz) que tenía como eje central el campo de la educación ambiental. Algunas de las actividades llevadas a cabo fueron: la creación de un gabinete de curiosidades de los objetos que se encuentran en la naturaleza, elaboración de un herbario de enseñanza, desarrollo del jardín botánico del centro, un taller de botánica y un huerto escolarExtremaduraES