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.

Tumors, trauma, and congenital defects require volume restoration of soft tissues. Tissue engineering provides an alternative source for substituting these defects. Cell encapsulation into hydrogels provides a three-dimensional microenvironment. Spheroids of cells provide close packing and increase cell-to-cell contacts resulting in differentiation. Gelatin is a natural polymer with low immunogenicity and preserved amino acid motifs for cell adhesion and proliferation. In the present study, a soft photo-crosslinked gelatin methacrylate (GelMA) hydrogel with long in vitro lifetime was synthesized. Stem cells (dental pulp derived, DPSC) and endothelial cells (umbilical cord derived, HUVEC) were formed into spheroids to induce prevascular network formation and encapsulated into GelMA (10% weight/volume). Results showed high cell viability, better gel mechanical properties, and longer HUVEC sprouting with spheroids compared to the same combination of cells. Altogether, the photo-crosslinked GelMA hydrogels with DPSC and HUVEC spheroids provided a promising tissue engineering and vascularization strategy in vitro.

The multidrug resistance (MDR) is a widely observed phenotype that contributed to the major obstacle of impairing the outcome of cancer chemotherapy. With the aim to reverse MDR in the breast cancer cell line, the autophagy-related 7 (ATG7) small interfering RNA (siRNA) capable of downregulating the cellular autophagy level was loaded into a cationic nanostructured lipid carrier (NLC) with doxorubicin (Dox) to build a platform (NLC/D-R) for effective chemotherapy of breast cancer. Our results revealed that NLC/D-R was well-dispersed nanoparticles with satisfy protection to siRNA. In addition, NLC/D-R also exerted a sufficient drug release of both cargos under an acidic environment with high stability and biocompatibility at the physiological environment. Furthermore, NLC/D-R showed a preferable transfection profile to PEI 25k. The downregulated autophagy level in NLCF-7/Adr cells resulted in reverse of MDR and accumulated Dox retention in cells. The in vitro cytotoxicity using both cells on flat surfaces and multicellular tumor spheroid (NLCTS) model confirmed that NLC/D-R showed much elevated anticancer performance than NLC/Dox or NLC/siRNA, which suggested the synergistic effect between anti-autophagy and chemotherapy.

Conventional computed tomography (CT) remains the workhorse of cross-sectional medical imaging. But dual- and multi-energy CT allows for more specific material decomposition, enabling distinct advantages in the clinical setting. In this review, we describe the basic principles behind material decomposition in dual- and multi-energy CT, outline the techniques used to acquire images, and explore how enhanced material decomposition leads to improved patient care. We also explore areas of active research and future directions, including photon-counting CT, that have the potential to revolutionize CT in clinical use.

The thermal expansion coefficient (CTE) is a vital design parameter for reducing the thermal-stress-induced structural failure of electronic chips/devices. At the micro- and nano-scale, the typical size range of the components in chips/devices, the CTEs are probably different from that of the bulk materials, but an easy and accurate measurement method is still lacking. In this paper, we present a simple but effective method for determining linear CTEs of micro-scale materials only using the prevalent nanoindentation system equipped with a heating stage for precise temperature control. By holding a constant force on the sample surface, while heating the sample at a constant rate, we measure two height–temperature curves at two positions, respectively, which are close to each other but at different heights. The linear CTE is obtained by analyzing the difference of height change during heating. This method can be applied to study the size effect or surface effect of CTE of embedded micro-scale structures, aiding the failure analysis and structural design in the semiconductor industry.

Grain refinement has been applied to enhance the materials strength for miniaturization and lightweight design of nuclear equipment. It is critically important to investigate the low-cycle fatigue (LCF) properties of grain refined 316LN austenitic stainless steels for structural design and safety assessment. In the present work, a series of fine-grained (FG) 316LN steels were produced by thermo-mechanical processes. The LCF properties were studied under a fully reversed strain-controlled mode at room temperature. Results show that FG 316LN steels demonstrate good balance of high strength and high ductility. However, a slight loss of ductility in FG 316LN steel induces a significant deterioration of LCF life. The rapid energy dissipation in FG 316LN steels leads to the reduction of their LCF life. Dislocations develop rapidly in the first stage of cycles, which induces the initial cyclic hardening. The dislocations rearrange to form dislocations cell structure resulting in cyclic softening in the subsequent cyclic deformation. Strain-induced martensite transformation appears in FG 316LN stainless steels at high strain amplitude (Δε/2 = 0.8%), which leads to the secondary cyclic hardening. Moreover, a modified LCF life prediction model for grain refined metals predicts the LCF life of FG 316LN steels well.

Austenitic stainless steel is used in several industrial branches due to its mechanical and thermal properties, and to its good corrosion resistance. With low cost and biocompatibility, it is used to manufacture prostheses and devices for bone fixation. However, direct contact with body fluids may cause corrosion. Thin films of FeAlCr intermetallic alloy can be used to increase service life of prostheses and avoid replacement surgeries. The aim of this work was to cover the austenitic stainless steel to study the effect of target–substrate distance on the film characteristics. Coatings were performed using the magnetron sputtering technique with the substrate positioned at different distances from the target. The influence on film thickness, morphology, roughness, and adhesion to the substrate was investigated. The thin films of FeAlCr (160 nm thick deposited at 100 mm far from the substrate) were formed by smaller particles (11.2 nm long), densely packed (551,000 particles/mm2), with flat and regular appearance, and greater adherence to the substrate.