Hybrid Spider Silk with Inorganic Nanomaterials

High-performance functional biomaterials are becoming increasingly requested. Numerous natural and artificial polymers have already demonstrated their ability to serve as a basis for bio-composites. Spider silk offers a unique combination of desirable aspects such as biocompatibility, extraordinary mechanical properties, and tunable biodegradability, which are superior to those of most natural and engineered materials. Modifying spider silk with various inorganic nanomaterials with specific properties has led to the development of the hybrid materials with improved functionality. The purpose of using these inorganic nanomaterials is primarily due to their chemical nature, enhanced by large surface areas and quantum size phenomena. Functional properties of nanoparticles can be implemented to macro-scale components to produce silk-based hybrid materials, while spider silk fibers can serve as a matrix to combine the benefits of the functional components. Therefore, it is not surprising that hybrid materials based on spider silk and inorganic nanomaterials are considered extremely promising for potentially attractive applications in various fields, from optics and photonics to tissue regeneration. This review summarizes and discusses evidence of the use of various kinds of inorganic compounds in spider silk modification intended for a multitude of applications. It also provides an insight into approaches for obtaining hybrid silk-based materials via 3D printing

Modulating Surface Properties of the Linothele fallax Spider Web by Solvent Treatment

[Image: see text] Linothele fallax (Mello-Leitão) (L. fallax) spider web, a potentially attractive tissue engineering material, was investigated using quantitative peak force measurement atomic force microscopy and scanning electron microscopy with energy dispersive spectroscopy both in its natural state and after treatment with solvents of different protein affinities, namely, water, ethanol, and dimethyl sulfoxide (DMSO). Native L. fallax silk threads are densely covered by globular objects, which constitute their inseparable parts. Depending on the solvent, treating L. fallax modifies its appearance. In the case of water and ethanol, the changes are minor. In contrast, DMSO practically removes the globules and fuses the threads into dense bands. Moreover, the solvent treatment influences the chemistry of the threads’ surface, changing their adhesive and, therefore, biocompatibility and cell adhesion properties. On the other hand, the solvent-treated web materials’ contact effect on different types of biological matter differs considerably. Protein-rich matter controls humidity better when wrapped in spider silk treated with more hydrophobic solvents. However, carbohydrate plant materials retain more moisture when wrapped in native spider silk. The extracts produced with the solvents were analyzed using nuclear magnetic resonance (NMR) and liquid chromatography–mass spectrometry techniques, revealing unsaturated fatty acids as representative adsorbed species, which may explain the mild antibacterial effect of the spider silk. The extracted metabolites were similar for the different solvents, meaning that the globules were not “dissolved” but “fused into” the threads themselves, being supposedly rolled-in knots of the protein chain

Synthesis of Al2O3–SiO2–MgO ceramics with hierarchical porous structure

Abstract A series of asymmetric cordierite ceramics with hierarchical porous structure were prepared and characterized. The macroporous support was obtained from natural raw materials (bauxite, silica sand, kaolinite, talc, and alumina) via ceramic technology. The prepared ceramic discs were characterized by a narrow pore size distribution. The average pore size was about 9.5 μm, and the open porosity was estimated to be 30%. Coating the discs with micro/mesoporous cordierite layer was performed using the sol–gel approach. Three-component sols were obtained from organic or inorganic precursors. Corresponding gels were calcined at 1200 °C to form the cordierite structure. The nature of precursor was found to affect the pore volume distribution. Narrow pore volume distribution was observed when organic precursors were used. Another key factor to control the parameters of final material was the drying condition. Supercritical drying of the gels has allowed us to increase the surface area in two orders of magnitude comparing with conventional drying procedure

Native Spider Silk-Based Antimicrobial Hydrogels for Biomedical Applications

Novel antimicrobial natural polymeric hybrid hydrogels based on hyaluronic acid (HA) and spider silk (Ss) were prepared using the chemical crosslinking method. The effects of the component ratios on the hydrogel characteristics were observed parallel to the primary physicochemical characterization of the hydrogels with scanning electron microscopic imaging, Fourier-transform infrared spectroscopy, and contact angle measurements, which confirmed the successful crosslinking, regular porous structure, exact composition, and hydrophilic properties of hyaluronic acid/spider silk-based hydrogels. Further characterizations of the hydrogels were performed with the swelling degree, enzymatic degradability, viscosity, conductivity, and shrinking ability tests. The hyaluronic acid/spider silk-based hydrogels do not show drastic cytotoxicity over human postnatal fibroblasts (HPF). Hydrogels show extraordinary antimicrobial ability on both gram-negative and gram-positive bacteria. These hydrogels could be an excellent alternative that aids in overcoming antimicrobial drug resistance, which is considered to be one of the major global problems in the biomedical industry. Hyaluronic acid/spider silk-based hydrogels are a promising material for collaborated antimicrobial and anti-inflammatory drug delivery systems for external use. The rheological properties of the hydrogels show shear-thinning properties, which suggest that the hydrogels could be applied in 3D printing, such as in the 3D printing of antimicrobial surgical meshes

The application of geometric-morphometric shape analysis to Middle Paleolithic bone retouchers from the Altai Mountains, Russia

Here, we apply geometric-morphometric shape analysis to Middle Paleolithic bone retouchers from Chagyrskaya Cave in the Altai Mountains of southern Siberia. The cave contains evidence of the easternmost manifestation of the Micoquian industry, associated with Neanderthals at end of MIS4 and the beginning of MIS3. Taphonomic and scar pattern analyses were performed first on random samples exhibiting appropriate characteristics. Several retouchers produced on intentionally modified blanks were identified in our sample, suggesting that some of the Chagyrskaya Cave bone retouchers can be described as formal tools. All retouchers from Chagyrskaya Cave exhibit a similar general morphology. The most variable group is comprised of complete retouchers without blank modifications. Retouchers exhibiting minor damage affect the general pattern of variability and it is not possible to identify them only by means of geometric-morphometric shape analysis. Complete retouchers with blank modifications fall within the range of variability of complete retouchers without blank modification, suggesting intentional shaping of blanks to conform to a standard template. The range of variability of the bone retouchers does not differ significantly from that of the most highly modified lithic artifacts at Chagyrskaya – plano-convex bifaces – which may indicate intentional shape control for such artifacts. Geometric-morphometric analysis indicates that the anatomical origin of bone blanks does not significantly influence the retouchers’ shape, which may point to strict blank selection and, at the same time, intentional modification. Our results raise questions regarding the integration of retouchers into a complex, multidimensional “chaine-op´eratoire” as well as the nature of Neanderthal cognitive abilities. Geometric-morphometric shape analysis represents a major step forward in the study of prehistoric retoucher

Coordination-driven innovations in low-energy catalytic processes: advancing sustainability in chemical production

Catalysis stands as a cornerstone in chemical synthesis, pivotal in advancing sustainable manufacturing pathways. The evolution from energy-intensive to sustainable catalytic processes has marked a transformative shift, notably exemplified by low-energy catalytic methods. These processes, operating under milder conditions and emphasizing selectivity and recyclability, represent the forefront of sustainable chemistry. This review navigates through an array of low-energy chemical reactions, highlighting their diverse applications and culminating in exploration of recent strides within low-energy catalytic processes. For example, the review explores the uses of low-energy catalytic processes in applications such as enzyme mimicking, biodiesel production, carbon dioxide capture, and organic synthesis. Additionally, it covers enzymatic catalysis and photocatalysis for carbon dioxide transformations, energy applications, and water treatment. Notably, the review emphasizes the low-energy catalytic capabilities of single-atom catalysis (SAC) and diatomic catalysts (DACs), recognizing their exceptional performance in catalyzing reactions at minimal activation energies while maintaining high efficiency and selectivity under mild conditions. By elucidating the modulation of electronic structure and offering a microelectronic perspective, the review aims to elucidate the mechanisms underlying the catalytic activity of SAC and DACs. Emphasizing the interplay between coordination chemistry principles and catalytic efficacy, the review elucidates the indispensable role of coordination complexes in fortifying the sustainability of these processes. By spotlighting the fusion of coordination chemistry with catalysis, this review aims to underscore their collective influence in shaping the landscape of sustainable chemical production.<br/

Turn a Shrimp into a Firefly: Monitoring Tissue pH in Small Crustaceans Using an Injectable Hydrogel Sensor with Infrared Excitation and Visible Luminescence

Various implantable optical sensors are an emerging tool in animal physiology and medicine that may provide real-time information about body fluids without tissue extraction. Such sensors are often fluorescence-based and require strong visible external illumination during signal acquisition, which causes anxiety or even stress for small animals and thus may influence the physiological parameters being measured. In order to overcome this obstacle, here, we combined a fluorescent molecular pH probe with upconverting particles within a hydrogel fiber suitable for injection into small crustaceans. The green luminescence of the particles under non-visible infrared illumination excited fluorescence of the molecular probe and allowed for pH measurements after correction of the probe readout for luminescence intensity. The developed optical setup based on a common microscope ensured effective visualization of the sensor and spectral pH measurements through the translucent exoskeleton of the amphipod (Amphipoda, Crustacea) Eulimnogammarus verrucosus, endemic to ancient Lake Baikal. Testing the sensors in these cold-loving crustaceans under environmentally relevant temperature increases showed alkalization of amphipod internal media by 0.2 soon after the start of the experiment, while further increases led to acidification by 0.5. The applied approach for simple sensor preparation can be useful in building other implantable optical sensors for light-sensitive organisms

Efficient extraction of multivalent cations from aqueous solutions into sitinakite-based sorbents

A highly selective adsorbent for multivalent cationic species based on a sitinakite-type titanosilicate was prepared from a leucoxene ore enrichment waste. The synthesized material was used as for the selective removal of alkali-earth strontium (II) and barium (II) cations as well as for the cationic species based on the natural isotopes of uranium, radium, and thorium from aqueous solutions. The influence of such parameters as the pH, the initial concentration of the ions, the presence of other electrolytes on the sorption parameters was investigated. The sorption capacity of the synthesized material at ambient conditions is 80 and 110 mg/g for Sr2+ and Ba2+, respectively, and it rises with increasing temperature. Furthermore, the material shows a high selectivity towards radionuclides of radium, uranium, and thorium. By using the current titanosilicate materials, the extracting degree of over 99% could be achieved when extracting these species from their respective standard aqueous solutions. The origin of the high adsorption selectivity for cationic complexes of thorium and uranium is rationalized based on periodic density functional theory calculations. The obtained results indicate that the described materials could be promising and inexpensive sorbents for the selective extraction of radioactive isotopes and particularly those of Sr, Ba and U, Th, Ra.ChemE/Algemee