Natural Coatings and Surface Modifications on Magnesium Alloys for Biomedical Applications.

Magnesium (Mg) alloys have great potential in biomedical applications due to their incomparable properties regarding other metals, such as stainless steels, Co-Cr alloys, and titanium (Ti) alloys. However, when Mg engages with body fluids, its degradation rate increases, inhibiting the complete healing of bone tissue. For this reason, it has been necessary to implement protective coatings to control the rate of degradation. This review focuses on natural biopolymer coatings used on Mg alloys for resorbable biomedical applications, as well as some modification techniques implemented before applying natural polymer coatings to improve their performance. Issues such as improving the corrosion resistance, cell adhesion, proliferation, and biodegradability of natural biopolymers are discussed through their basic comparison with inorganic-type coatings. Emphasis is placed on the expected biological behavior of each natural polymer described, to provide basic information as a reference on this topic.

Evaluation of Colombian Crops Fibrous Byproducts for Potential Applications in Sustainable Building Acoustics.

Local production of construction materials is a valuable tool for improving the building sector sustainability. In this sense, the use of lignocellulosic fibers from local species becomes an interesting alternative to the development of such materials. As it is thought that the properties of fiber-based materials are dependent on the fibers properties, the knowledge of such properties is fundamental to promote materials development. This study compares the physical, morphological, acoustic, and mechanical characteristics of coir (Cocos nucifera) and fique (Furcraea Agavaceae) fibers and panels. The chemical composition appears to be associated with the general behavior of the fibers and panels, regarding higher tensile strength, thermal degradation behavior, and water absorption. In most tests, fique had the upper hand, showing superior performance; however, on thermal degradation and water absorption, both materials had similar behavior. The sound absorption measurement showed that the fiber diameter affects the sound absorption at high frequencies, where fique panels showed better performance than coir panels.

Development of novel three-dimensional scaffolds based on bacterial nanocellulose for tissue engineering and regenerative medicine: Effect of processing methods, pore size, and surface area.

Despite the efforts focused on manufacturing biological engineering scaffolds for tissue engineering and regenerative medicine, a biomaterial that meets the necessary characteristics for these applications has not been developed to date. Bacterial nanocellulose (BNC) is an outstanding biomaterial for tissue engineering and regenerative medicine; however, BNC's applications have been focused on two-dimensional (2D) medical devices, such as wound dressings. Given the need for three-dimensional (3D) porous biomaterials, this work evaluates two methods to generate (3D) BNC scaffolds. The structural characteristics and physicochemical, mechanical, and cell behaviour properties were evaluated. Likewise, the effects of the pore size and surface area in the mechanical performance of BNC biomaterials and their cell response in a fibroblast cell line are discussed for the first time. In this study, a new method is proposed for the development of 3D BNC scaffolds using paraffin wax. This new method is less time-consuming, more robust in removing the paraffin and less aggressive toward the BNC microstructure. Moreover, the biomaterial had regular porosity with good mechanical behaviour; the cells can adhere and increase in number without overcrowding. Regarding the pore size and surface area, highly interconnected porosities (measuring approximately 60 µm) and high surface area are advantageous for the biomaterial's mechanical properties and cell behaviour. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 348-359, 2019.