With today's rapidly increasing demand for lithium-ion batteries (LIBs) for emerging applications, such as electric vehicles (EVs) and large-scale grid storage, it begs the question of how sustainable batteries really are. Proponents of increasing electrification of our modern society often tout the environmental benefits of using battery energy storage over traditional fossil fuels, citing direct reductions in greenhouse gas emissions, especially when paired with renewable energy generation. Unfortunately, these often leave out considerations for the “dark side” of LIBs that few manufacturers in the battery industry have addressed: how to deal with batteries at their end of life. As the world accelerates toward displacing conventional vehicles with EVs, methods of handling large volumes of spent LIBs when these devices reach their end of life have not been fully developed. This potentially results in the accumulation of battery waste that will ultimately undo the environmental benefits batteries originally sought to achieve.

Protein materials are promising candidates as the building blocks for functional and high-performance bionanocomposites, owing to their unique and well-developed nanoscale structure, rich chemical functionality, excellent mechanical properties, biocompatibility, and biodegradability. Rational integration of protein materials with synthetic organic and inorganic nanomaterials through tailored interfacial interactions leads to synergistic enhancement in the properties compared to the individual components. In this article, we discuss the recent progress in protein-based nanocomposites, which aim to harness the unique structure and properties of proteins and synthetic nanomaterials for realizing advanced materials with greatly enhanced properties. Specifically, we highlight bionanocomposites based on two β-sheet rich proteins, silk fibroin and amyloid fibril, as representative examples as well as a few other protein materials such as keratin, elastin, and collagens. We describe the biotic–abiotic interfaces, processing methods, physical properties, and potential applications of these protein nanocomposites. Considering the additional value of renewability, abundancy, and ambient processability, such bionanocomposites are promising candidates for advanced and emerging applications, such as environmental remediation, biomedicine, biosensors, and photonics.

When I began writing this article, it was just the beginning of COVID-19, when we were not yet social distancing. Everything has changed since then, but not a conviction I have disseminated for more than 25 years. More than ever, I maintain that formally addressing the critical visual component of research should be part of every researcher's education. How you visually represent your work not only communicates to others in your discipline. Crafting your visual presentations helps clarify your own thinking and, just as important, is a means of engaging the public. In these challenging times, when society is bombarded with complex information, it is more essential than ever to develop a more accessible and honest visual “language” for the public to understand and gather that information. Formal programs in teaching visual communication will help show the world, outside the research community, how to look at science, understand it, question it, and, hopefully, make smart decisions.

The ability to synthesize and assemble functional nanomaterials using proteins and peptides is an area of active research, merging various methodologies common in biochemistry and molecular biology to create a wide range of nanoscale materials with intriguing properties. These “bioenabled” nanomaterials have distinct advantages over their nonbiological counterparts, including diverse/precise chemical functionalization, benign aqueous-based processing conditions, and the inherent high specificity for targeted substrates. In parallel, the advent of synthetic biology is providing avenues to engineer novel protein chemistry and functionality, leading to commercialization in the startup sector. In this article, we provide a prospective review for fusing established methods in protein-enabled nanomaterials with those found commonly in synthetic biology. We first summarize significant findings and outcomes from the peptide and protein-enabled nanomaterials literature. The application of synthetic biology methodologies toward research areas of tangential similarity will also be summarized, including the directed evolution of enzymes for bioinorganic reactions, noncanonical amino acid engineering in proteins, and the incorporation of electrical active elements into anisotropic proteins. To conclude, we will suggest avenues for new research directions for protein-enabled nanomaterials that fully exploit the power of synthetic biology.

Living organisms have engineered remarkable protein-based materials through billions of years of evolution. These multifunctional materials have unparalleled mechanical, optical, and electronic properties and have served as inspiration for scientists to study and mimic these natural protein materials. New tools from synthetic biology are poised to revolutionize the ability to rapidly engineer and produce proteins for material applications. Specifically, advancements in new production hosts and cell-free systems are enabling researchers to overcome the significant challenges of cloning and expressing large nonnative proteins. The articles in this issue cover the mechanical and rheological properties of structural protein materials and nanocomposites; advancements in the synthesis and assembly of optical, electronic, and nanoscale protein materials; and recent development in the processing of protein materials using liquid–liquid phase separation and three-dimensional printing.

Additive manufacturing is a revolutionary three-dimensional (3D) printing technology that has applications in a vast number of fields from aerospace to biological engineering. In the field of bioengineering, it was recently discovered that the principles used in 3D bioprinting of organs and tissues could also be used to 3D print biological materials produced by genetically engineered bacteria. This new technology requires the development of modified bio-ink and optimized printing parameters to promote bacterial physiology while allowing printability. In this article, we highlight the recent advancements in additive manufacturing of engineered living materials using bacteria and their potential applications. We will discuss recent progress and significance of additive manufacturing of proteins and polypeptides produced in situ by engineered bacteria to make multifunctional materials. Finally, we discuss the challenges and prospects of this technology and highlight some of the biomaterials that may benefit from additive manufacturing with bacteria.