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.

Upconversion metal (Zr, Hf, and Ta) oxide aerogels.

A major obstacle in developing upconversion aerogels is the incompatibility of the highly-developed porosity and the crystal structure required for converting light to a shorter wavelength. We propose a novel method for creating a sol-gel procedure for synthesizing metal (Zr, Hf, and Ta) oxide upconverison aerogels uniformly doped with Er3+ and Yb3+ by precisely adjusting the calcination conditions.

Toxicity Patterns of Clinically Relevant Metal Oxide Nanoparticles.

Nanostructured drugs are being approved for clinical use, although there is a serious deficit of systematic studies of these materials. Data on toxicity of nanoparticles (NPs) can vary due to different methods of preparation, size, and shape. We investigated the toxicity against cultured human cells, the acute toxicity in mice, and the influence on conjugative transfer of antibiotic resistance genes of clinically relevant NPs such as TiO2, ZrO2, HfO2, Ta2O5, Fe3O4, and AlOOH. NPs were synthesized as aqueous sols by the same method in aqueous solution, with almost identical size 2-10 nm. None of these NPs was cytotoxic at concentrations compatible with water solubility. Furthermore, TiO2, HfO2, Ta2O5, Fe3O4, and AlOOH were not toxic to mice after oral administration. However, ZrO2 showed rather high toxicity, with LD50 2277.8 mg/kg. Experiments with plasmid transfer between bacteria demonstrated that AlOOH NPs were the most hazardous since this material promoted the emergence of resistance to antibiotics. Thus, although our metal oxide NPs are largely non-toxic, their properties may differ in specific biological situations.