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Here we present the synthesis of porous platinum–palladium macrobeams templated from high aspect ratio Magnus’ salt needle derivatives. The combination of [PtCl4]2− and/or [PdCl4]2− with [Pt(NH3)4]2+ ions results in salt needles ranging from 15 to 300 µm in length. Electrochemical reduction of the salt templates results in porous macrobeams with a square cross-section. Porous side wall texture and elemental composition was controlled with initial platinum to palladium salt ratio. Macrobeam free-standing films exhibited a specific capacitance up to 11.73 F/g and a solvent accessible surface area of 26.6 m2/g. These salt-templated porous platinum–palladium macrobeams offer a promising material for fuel cell catalysis.

High resolution bioimaging is not only critical to the study of cellular structures and processes but it also has important applications in drug delivery and therapeutics. Fluorescent nanodiamonds (NDs) are excellent candidates for long-term bioimaging and tracking of biological structures at the nanoscale. Encapsulating NDs in natural biopolymers like silk fibroin (SF) widens their biomedical applications. Here we report the synthesis, structural and optical characterization of ND incorporated SF nanospheres. The photoluminescence from optical defects within the NDs is found to increase when encapsulated in the SF spheres. The encapsulated NDs are applied in vitro to investigate the intracellular mobility compared to bare NDs. The diffusion rate of encapsulated NDs is shown to improve due to SF coating. These ND-SF spheres are envisioned as highly suitable candidates for bioinjectable imaging and drug release carriers for targeted drug delivery applications.

Here gelatin biotemplated platinum aerogels were prepared from gelatin hydrogels equilibrated in K2PtCl4 solutions ranging from 1-250 mM and reduced with sodium borohydride before supercritical drying in liquid CO2. Scanning electron microscopy revealed an average ligament diameter of 40.6 ± 9.7 nm and a pore size range of ∼10 – 200 nm. Thermogravimetric analysis correlated the ratio of metal content to biotemplate mass as a function of equilibrated platinum ion solution, and X-ray diffractometry indicated platinum metal with no detectable oxide phases. Electrochemical impedance spectroscopy indicated a specific capacitance of 1.92 F/g, with a corresponding specific electrochemical accessible surface area of 6.39 m2/g. Cyclic voltammetry performed in H2SO4 demonstrated biotemplated platinum aerogel potential for catalytic and energy storage applications.

Visually tracking the subtle aspects of biological systems in real time during tissue culture remains challenging. Herein, we demonstrate the use of bioactive, cytocompatible, and biodegradable inverse opals from silk as a multifunctional substrate to transduce both the optical information and cells during tissue culture. We show that these substrates can visually track substrate degradation in various proteases during tissue digestion and protein deposition during the growth of mesenchymal stem cells. Uniquely, these substrates can be integrated in multiple steps of tissue culture for simple-to-use, visual, and quantitative detectors of bioactivity. These substrates can also be doped, demonstrated here with gold nanoparticles, to allow additional control of cell functions.

Nobel metal composite aerogel fibers made from flexible and porous biopolymers offer a wide range of applications, such as in catalysis and sensing, by functionalizing the nanostructure. However, producing these composite aerogels in a defined shape is challenging for many protein-based biopolymers, especially ones that are not fibrous proteins. Here, we present the synthesis of silk fibroin composite aerogel fibers up to 2 cm in length and a diameter of ~300 &mu, m decorated with noble metal nanoparticles. Lyophilized silk fibroin dissolved in hexafluoro-2-propanol (HFIP) was cast in silicon tubes and physically crosslinked with ethanol to produce porous silk gels. Composite silk aerogel fibers with noble metals were created by equilibrating the gels in noble metal salt solutions reduced with sodium borohydride, followed by supercritical drying. These porous aerogel fibers provide a platform for incorporating noble metals into silk fibroin materials, while also providing a new method to produce porous silk fibers. Noble metal silk aerogel fibers can be used for biological sensing and energy storage applications.

Chloroplasts extracted from spinach leaves were entrapped in B. mori silk fibroin films to investigate the maintenance of their photosynthetic activity in a dry environment. Chloroplast stability was studied under various storage conditions (different temperature and light cycles) using electron microscopy, spectroscopic analysis and measuring of their photosynthetic activity (i.e. oxygen production). When compared to other environments previously investigated, silk fibroin films enhanced the preservation of the chloroplasts' photosynthetic activity.

Bioengineering techniques for producing fibers from biomaterials is a growing requirement in medical device technology research and development environments. Scale-up and control of diameter, shape, and length of fibrous proteins and elastomeric polymers are essential to produce defined and consistent materials for experimentation and clinical use. Here, we developed a novel wet spinning fiber extruder and spooler system engineered to draw precipitated fibers several meters in length across five spools. By controlling both the extrusion and spooling rate, the diameter of the fiber can be controlled on the order of 10–1000 µm. Using this system, we extruded and spooled precipitated Type-1 Collagen fibers up to 7.5 m in length on a single spool with a controllable diameter range of 30–50 µm. Furthermore, this device facilitated bundling of fibers directly on the spool in order to create 1–12 cm long fiber bundles for experimentation. This system may be used in the laboratory to scale up biomaterial fiber production to produce degradable scaffolds made from synthetic or natural materials for a range of biomedical applications.

Artificial chemosensory devices have a wide range of applications in industry, security, and medicine. The development of these devices has been inspired by the speed, sensitivity, and selectivity by which the olfactory system in animals can probe the chemical nature of the environment. In this review, we examine how molecular and cellular components of natural olfactory systems have been incorporated into artificial chemosensors, or bioelectronic sensors. We focus on the biological material that has been combined with signal transduction systems to develop artificial chemosensory devices. The strengths and limitations of different biological chemosensory material at the heart of these devices, as well as the reported overall effectiveness of the different bioelectronic sensor designs, is examined. This review also discusses future directions and challenges for continuing to advance development of bioelectronic sensors.

In natural systems, directed self-assembly of structural proteins produces complex, hierarchical materials that exhibit a unique combination of mechanical, chemical and transport properties. This controlled process covers dimensions ranging from the nano- to the macroscale. Such materials are desirable to synthesize integrated and adaptive materials and systems. We describe a bio-inspired process to generate hierarchically defined structures with multiscale morphology by using regenerated silk fibroin. The combination of protein self-assembly and microscale mechanical constraints is used to form oriented, porous nanofibrillar networks within predesigned macroscopic structures. This approach allows us to predefine the mechanical and physical properties of these materials, achieved by the definition of gradients in nano- to macroscale order. We fabricate centimetre-scale material geometries including anchors, cables, lattices and webs, as well as functional materials with structure-dependent strength and anisotropic thermal transport. Finally, multiple three-dimensional geometries and doped nanofibrillar constructs are presented to illustrate the facile integration of synthetic and natural additives to form functional, interactive, hierarchical networks.

Nanoparticle (NP) based technologies have proved to be considerably beneficial for advances in biomedicine especially in the areas of disease detection, drug delivery and bioimaging. Over the last few decades, NPs have garnered interest for their exemplary impacts on the detection, treatment, and prevention of cancer. The full potential of these technologies are yet to be employed for clinical use. The ongoing research and development in this field demands single multifunctional composite materials that can be employed simultaneously for drug delivery and biomedical imaging. In this manuscript, a unique combination of silk fibroin (SF) and nanodiamonds (NDs) in the form of nanospheres are fabricated and investigated. The spheres were loaded with the anthracyline Doxorubicin (DoX) and the drug release kinetics for these ND-SF-DoX (NDSX) spheres were studied. NDs provided the fluorescence modality for imaging while the degradable SF spheres stabilized and released the drug in a controlled manner. The emission and structural properties of the spheres were characterized during drug release. The degradability of SF and the subsequent release of DoX from the spheres were monitored through fluorescence of NDs inside the spheres. This research demonstrates the enormous potential of the ND-SF nanocomposite platforms for diagnostic and therapeutic purposes, which are both important for pharmaceutical research and clinical settings.