In this study, bioactive hydroxyapatite nanoparticles were prepared by two different methods: wet chemical precipitation and biomimetic precipitation. The aim was to evaluate the morphology, particle-size, crystallinity and phases of the powders obtained by traditional wet chemical precipitation and the novel biomimetic precipitation using a supersaturated calcium solution. The nanoparticles were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results revealed that the nanoparticles were formed by hydroxyapatite with a high crystallinity and controlled morphology. Additionally, it was found that the shape and size of the nanoparticles can be modified with each preparation method

A family of polymer substrates which consists of a vinyl backbone chain with the side groups –COO(CH₂)_xCH₃, with x = 0, 1, 3, 5 was prepared. Substrates with decreasing stiffness, characterised by the elastic modulus at 37 °C, and similar chemical groups were obtained. Firstly, we have investigated whether these minute variations in polymer chemistry lead to differences in fibronectin (FN) adsorption: the same FN density was obtained on every substrate (450 ng cm⁻²) but the supramolecular organisation of the protein at the material interface, as obtained with AFM, was different for x = 0 and the other surfaces (x = 1, 3, 5). Consequently, this allows one to use a set of substrates (x = 1, 3, 5) to investigate the effect of substrate stiffness on cell behavior as the unique physical parameter, i.e. after ruling out any influence of the length of the side group on protein conformation. Moreover, the importance of investigating the intermediate layer of proteins at the cell-material interface is stressed: the effect of x = 0 and x = 1 on cell behavior cannot be ascribed to the different stiffness of the substrate anymore, since the biological activity of the protein on the material surface was also different. Afterwards, initial cellular interaction was investigated using MC3T3-E1 osteoblasts-like cells and focusing on actin cytoskeleton development, focal adhesion formation and the ability of cells to reorganize the adsorbed FN layer on the different substrates. Image analysis was used to quantify the frequency distribution of the focal plaques, which revealed broader distributions on the stiffer substrates, with formation of larger focal plaques revealing that cells exert higher forces on stiffer substrates.

Diseases caused by infections are becoming harder to treat as the antibiotics used become less effective. A combination of strategies to develop active biomaterials that enhance antibacterial effects are desirable, especially ones that cause fewer side effects and promote healing properties. The combination of nanotechnology with substances that have intrinsic antibacterial activity can result in the advance of innovative biomedical materials. In this sense, the goal of this work is to provide a summary of natural rubber latex materials obtained from the Hevea brasiliensis tree loaded with metallic and metal oxide nanoparticles. These nanoparticles have unique size-dependent chemical and physical characteristic that make them appropriate for use in pharmaceutical and medical devices, while natural rubber latex is a natural and biocompatible polymer with an intrinsic antibacterial effect. Moreover, we outline here the origin, extraction methods, and composition of natural rubber latex and different techniques for the synthesis of nanoparticles, including physical, chemical, and biological approaches. Finally, we summarize, for the first time, the state of the art in obtaining natural rubber-based materials with metallic and metallic oxide nanoparticles for biomedical applications.