Production of porous Calcium Phosphate (CaP) ceramics with aligned pores using ceramic/camphene-based co-extrusion

Micro- and Nanoparticulate Hydroxyapatite Powders as Fillers in Polyacrylate Bone Cement-A Comparative Study

Acrylate polymer-based bone cements constitute the most popular bonding agents used in regenerative surgery. Due to their inferior biocompatibility, however, these materials are often enriched with ceramic additives including hydroxyapatite (HAp). The aim of this paper was to perform a comparative study of the acrylate cements filled with different content (3–21%) of nano- and microscale hydroxyapatite. The work concerns a comparison of times and temperatures of the cross-linking reaction, as well as morphology, glass transition temperature, and principal mechanical properties of the resulting composites. Before being used as a filler, both HAp forms were subjected to an in-depth characterization of their morphology, specific surface area, pore size distribution, and wettability as well as chemical composition and structure. For that purpose, such analytical techniques as scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, tensiometry, Brunauer–Emmett–Teller surface area analysis, differential scanning calorimetry, Shore D hardness test, and Charpy impact test were used. The results indicated a drop of cross-linking temperature and an extension of setting time with the addition of µHAp. The µHAp-filled acrylate composites were characterized by a globular surface morphology, higher glass transition temperature, and lower hardness and impact strength compared to nHAp-filled materials. This relationship was evident at higher nHAp concentrations.

Natural and synthetic polymers/bioceramics/bioactive compounds-mediated cell signalling in bone tissue engineering

Bone is a highly integrative and dynamic tissue of the human body. It is continually remodeled by bone cells such as osteoblasts, osteoclasts. When a fraction of a bone is damaged or deformed, stem cells and bone cells under the influence of several signaling pathways regulate bone regeneration at the particular locale. Effective therapies for bone defects can be met via bone tissue engineering which employs drug delivery systems with biomaterials to enhance cellular functions by acting on signaling pathways such as Wnt, BMP, TGF-β, and Notch. This review provides the current understanding of polymers/bioceramics/bioactive compounds as scaffolds in activation of signaling pathways for the formation of bone.