This article presents a review on recent advances in the fatigue behavior of Ti alloys, especially the main commercial compositions for orthopedic applications. In the case of well-known Ti–6Al–4V alloy, the major concern is related to the effect of the surface modification necessary to improve the osseointegration. The introduction of surface discontinuities due to the growth of a porous oxide layer, or the roughness development, may severely affect the fatigue performance depending on the level of alteration. In the case of additive manufactured Ti–6Al–4V, the fatigue response is also influenced by inherent defects of as-built parts. Regarding the recently developed metastable β alloys, information about the fatigue properties is still scarce and mainly related to the effect of second phase precipitates, which are introduced to optimize the mechanical properties. The fatigue behavior of the Ti alloys is complex, as is their microstructure, and should not be neglected when the alloys are being developed or improved to be applied in medical devices.

Nature has developed myriad ways for organisms to interact with their environment using light and electronic signals. Optical and electronic properties can be observed macroscopically by measuring light emission or electrical current, but are conferred at the molecular level by the arrangement of small biological molecules, specifically proteins. Here, we present a brief overview of the current uses of proteins for applications in optical and electronic materials. We provide the natural context for a range of light-emitting, light-receiving, and electronically conductive proteins, as well as demonstrate uses in biomaterials. Examples of how genetic engineering has been used to expand the range of functional properties of naturally occurring proteins are provided. We touch on how approaches to patterning and scaffolding optical and electronic proteins can be achieved using proteins with this inherent capability. While much research is still required to bring their use into the mainstream, optical and electronic proteins have the potential to create biomaterials with properties unmatched using conventional chemical synthesis.

More regions of the world are looking to decarbonize electricity production using wind and solar power generation. This major transition from traditional power sources comes with a number of technological difficulties for grid operators and a myriad of political, economic, and technological options to correct these issues. Often, the root problem associated with renewable power generation is posed as one of generation intermittency. The current grid model is based on one where generation is continually altered to match the current demand of the end users, so naturally the focus trends toward what can be done to make the intermittent generation match the daily demand. This has led to a strong focus on developing new energy-storage systems to create systems which are capable of shifting energy at the scale that will be necessary to support grids with a high penetration of renewable resources.

The linear and nonlinear mechanical properties of recombinant protein polymer networks are reviewed, with particular emphasis on how to tune elastic and dissipative behavior through selection of cross-linking strategy. The design strategies used to produce modular recombinant protein polymer networks through chemical or physical cross-linking will be discussed. In particular, we will highlight how key parameters such as polymer concentration, molecular weight, architecture, cross-link density, and association strength influence mechanics of protein polymer networks. Tuning these parameters enables control of viscoelastic properties and formation of materials with applications in tissue engineering, drug delivery, and sustainable self-healing materials.

Biological materials represent a major source of inspiration to engineer protein-based polymers that can replicate the properties of living systems. Combined with our ability to control the molecular structure of proteins at the single amino acid level, this results in a vast array of attractive possibilities for materials science, an interest that is undeniably related to simplified procedures in gene synthesis, cloning, and biotechnological production. In parallel, it has been increasingly appreciated that living organisms exploit liquid–liquid phase separation (LLPS) to fabricate extracellular structures. In this article, we discuss the central role of protein LLPS in the fabrication of selected biological structures, including biological adhesives and hard biomolecular composites, and how physicochemical lessons from these systems are being replicated in synthetic analogs. Recent translational applications of protein LLPS are highlighted, notably aqueous-resistant adhesives, stimuli-responsive therapeutics carriers, and matrix materials for green structural composites.