Due to its great amount of microstructure and property possibilities as well as its high thermodynamic stability and superior mechanical performance, the new class of material known as high-entropy alloys (HEAs) has aroused great interest in the research community over the last two decades. Recent works have investigated the potential for applying this material in several strategical conditions such as high temperature structural devices, hydrogen storage, and biological environments. Concerning the biomedical field, several papers have been recently published with the aim of overcoming the limitations of conventional alloys, such as corrosion, fracture, incompatibility with bone tissue, and bacterial infection. Due to the low number of available literature reviews, the aim of the present work is to consolidate the information related to high-entropy alloys developed for biomedical applications (bioHEAs), mainly focused on their microstructure, mechanical performance, and biocompatibility. Topics such as phases, microstructure, constituent elements, and their effect on microstructure and biocompatibility, hardness, elastic modulus, polarization resistance, and corrosion potential are presented and discussed. The works indicate that HEAs have high potential to act as candidates for complementing the materials available for biomedical applications.

Traditional biomaterials like CoCrMo, Ti, and stainless-steel face challenges due to their instability in biological settings. As an alternative, exploring multicomponent alloys is viewed as a viable path for bettering both mechanical performance and biocompatibility. Our research explores the potentiality of the MoNbNiTiZr based alloy for biomedical applications. The microstructural characterization was realized using X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM/EDS). We also conducted Vickers microhardness tests and assessed it’s in vitro biocompatibility and antibacterial action against S. aureus and S. aureus HU25 strains relative to cp-Ti. Our observations denote that this alloy showcases a triphasic structure, consisting of dendritic and interdendritic zones with BCC, HCP, and Laves formations. A microhardness of is approximately 576.5 HV align with values for comparable multicomponent alloys in the biomedical field. Pertaining to its antibacterial efficiency and in vitro compatibility, this alloy manifests commendable antibacterial performance and relevant compatibility in comparison with cp-Ti.

Material selection is one of the most relevant and challenging steps in engineering projects. In this study, we focused on selecting polymers with low density and stiffness for upper limb orthoses that help in the recovery of patients who have undergone cerebrovascular accident (CVA). CES EduPack 2011 software was used to compare the density and Young's modulus of different polymers. The merit index aided in the classification of these materials, which were applied to 3D orthosis models for computer simulations in FreeCAD 0.19.4 software. Using the simulation data, a decision matrix was developed using the Pahl & Beitz method to classify polymers according to the weighted property index. The decision matrix using the simulated and merit index data indicated polyethylene terephthalate (PET) and polylactic acid (PLA) as the best polymers for upper limb orthoses. The weighted property index values were 127.34 and 123.19, respectively. It is noteworthy that polyethylene terephthalate glycol (PETG - adaptation of PET) is an alternative to 3D printing filaments, and PLA is one of the main filaments.

RESUMO As restaurações dentárias que são realizadas com resinas compostas apresentam aspecto estético muito satisfatório, com coloração próxima à do dente e propriedades mecânicas aceitáveis. O grande desafio destas resinas é que tenham o mesmo, ou semelhante, desempenho mecânico que o dente original. O presente trabalho foi desenvolvido com o objetivo de avaliar as partículas inorgânicas do composto Al2O3-0,5B2O3-SiO2, produzidas pela técnica de spray pirólise (USP) para aplicação em resinas compostas dentárias. A síntese das partículas foi realizada empregando o método sol-gel, com os precursores nitrato de alumínio, ácido bórico e tetraetilortosilicato TEOS com pH da solução de 1,5. A fim de verificar as propriedades das partículas realizou-se caraterização físico-química pelo método de adsorção e dessorção de nitrogênio via BET, análise por MEV, FTIR, DRX, DTA-TGA, RMN e ensaio mecânico de tração. As imagens obtidas por MEV indicaram que as partículas eram esféricas de granulometria média de 1,26 ± 0,04 µm, sendo classificadas como microhíbridas. Pelos difratogramas observou-se característica amorfa, confirmando que o método de síntese aplicado é eficiente para a produção de materiais vítreos. Os testes com resina composta experimental apresentaram taxa de polimerização aceitável (16 e 9%), mas baixa resistência à compressão mecânica: entre 9,55 e 13,27 MPa.