RESUMO
Abstract The electrospinning device is used in the biomaterials research field nowadays for fabricating nanofibers that can be used for manufacturing artificial skin and muscular tissue, blood vessels (vascular grafts), orthopedic components (bones, cartilages, and ligaments/tendon), and peripheral or central nervous system components. Electrospun nanofibers act as ideal scaffolds for tissue engineering and drug delivery systems because they can mimic the functions of native extracellular matrices. A low cost electrospinning device was designed and built for undergraduate practical learning in the Biomaterials course in the area of Bioengineering at Universidad Autónoma de Baja California, México. The methodology includes 3D CAD designing, manufacturing of the acrylic cabinet, different collectors and the fabrication of poly (vinyl alcohol) nanofibrous scaffolds, in order to validate the functionality of the electrospinning system. The prototype is an affordable device; its cost is 95% less than the laboratory commercial devices.
Resumen El dispositivo de electrohilado es actualmente empleado en la investigación de biomateriales, utilizado para sintetizar nanofibras que ofrecen un potencial para la manufactura de piel artificial y tejido muscular, vasos sanguíneos (implantes vasculares), componentes ortopédicos (hueso, cartílago y tendones/ligamentos) y componentes del sistema nervioso central y periférico. Las nanofibras producidas por electrohilado pueden ser usadas como andamios ideales para ingeniería de tejidos y liberación controlada de fármacos debido a que mimetizan las funciones de la matriz extracelular. El dispositivo de electrohilado de bajo costo fue diseñado y construido para al aprendizaje practico de estudiantes de licenciatura en la asignatura de Biomateriales de la carrera de Bioingeniería. La metodología incluye diseños CAD 3D, manufactura del gabinete de acrílico, diferentes colectores y fabricación de los andamios de nanofibras de Poli (vinil alcohol) para validar la correcta funcionalidad del sistema de electrohilado. El prototipo es un dispositivo accesible económicamente, su costo es un 95% más barato que los dispositivos de tipo comercial.
RESUMO
Bone cements prepared with methyl methacrylate and either methacrylic acid or diethyl amino ethyl methacrylate as comonomers were characterized by infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, dynamic mechanical thermal analysis, and mechanical testing. Selected formulations containing these functionalized methacrylates were filled with hydroxyapatite and studied in terms of their properties in tension, compression and bending, and X-ray diffraction. It was found that residual monomer was not greatly affected by the presence of either acid or basic comonomers in the unfilled bone cements. In contrast, molecular weight, curing times, and glass transition temperature were composition dependent. For samples with acidic comonomer, a faster curing time, higher molecular weight, and higher glass transition temperatures were observed with respect to those with the basic comonomer. X-ray diffraction revealed that the crystalline structure was not affected by the nature of comonomer in the bone cement while scanning electron microscopy showed that hydroxyapatite remained as clusters in the bone cement. The mechanical properties of filled bone cements depended mainly on composition and type of testing. Hydroxyapatite-filled bone cements fullfilled the minimum compressive strength (70 MPa) required for bone cement use. However, the minimum tensile strength (30 MPa) was only fullfilled by cements prepared without comonomer and those containing methacrylic acid. The minimum bending strength requirement (50 MPa) was not satisfied by any of the formulations studied.