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The exceptional elastic resilience of some protein materials underlies essential biomechanical functions with broad interest in biomedical fields. However, molecular design of elastic resilience is restricted to amino acid sequences of a handful of naturally occurring resilient proteins such as resilin and elastin. Here, we exploit non-resilin/elastin sequences that adopt kinetically stabilized, random coil–dominated conformations to achieve near-perfect resilience comparable with that of resilin and elastin. We also show a direct correlation between resilience and Raman-characterized protein conformations. Furthermore, we demonstrate that metastable conformation of proteins enables the construction of mechanically graded protein materials that exhibit spatially controlled conformations and resilience. These results offer insights into molecular mechanisms of protein elastomers and outline a general conformation-driven strategy for developing resilient and functional protein materials. 

Biological wastewater treatment is the process in which contaminants can be removed or degraded by various microorganisms to eliminate the negative impact on environment and human health. Given the fact that traditional physical and chemical purification methods are high-cost, unsustainable and unspecific, biotreatment is playing an increasingly important role in the wastewater treatment field. The effective implementation of biotreatment strategy relies strongly on the intrinsic degradation capability of the microorganisms as well as their interaction with pollutants. In this review, we will focus on recent technological advances in engineering and improving biotreatment at both biocatalyst and bioreactor levels. Specifically, we will discuss the progress in synthetic biology for enhancing biosorption and biotransformation, and the challenges in applying engineered microorganisms on contaminated sites. We will further review the latest developments in bioreactor design, particularly the prospects of additive manufacturing/bioprinting to further optimize the mass transport inside bioreactors through complex 3-D structures and flexible material selections. These research efforts are redefining the frontier of biotreatment, and opening up new opportunities for cost-effective, efficient, and sustainable wastewater treatment. 

Living electronics that converges the unique functioning modality of biological and electrical circuits has the potential to transform both fundamental biophysical/biochemical inquiries and translational biomedical/engineering applications. This article will review recent progress in overcoming the intrinsic physiochemical and signaling mismatches at biological/electronic interfaces, with specific focus on strategic approaches in forging the functional synergy through: (1) biohybrid electronics, where genetically encoded bio-machineries are hybridized with electronic transducers to facilitate the translation/interpretation of biologically derived signals; and (2) biosynthetic electronics, where biogenic electron pathways are designed and programmed to bridge the gap between internal biological and external electrical circuits. These efforts are reconstructing the way that artificial electronics communicate with living systems, and opening up new possibilities for many cross-disciplinary applications in biosynthesis, sensing, energy transduction, and hybrid information processing. 

Extracellular electron transfer (EET) is a process performed by electrochemically active bacteria (EAB) to transport metabolically-generated electrons to external solid-phase acceptors through specific molecular pathways. Naturally bridging biotic and abiotic charge transport systems, EET offers ample opportunities in a wide range of bio-interfacing applications, from renewable energy conversion, resource recovery, to bioelectronics. Full exploration of EET fundamentals and applications demands technologies that could seamlessly interface and interrogate with key components and processes at relevant length scales. In this review, we will discuss the recent development of nanoscale platforms that enabled EET investigation from single-cell to network levels. We will further overview research strategies for utilizing rationally designed and integrated nanomaterials for EET facilitation and efficiency enhancement. In the future, EET components such as c -cytochrome based outer membranes and bacterial nanowires along with their assembled structures will present themselves as a whole new category of biosynthetic electroactive materials with genetically encoded functionality and intrinsic biocompatibility, opening up possibilities to revolutionize the way electronic devices communicate with biological systems.