Novel nanocomposites from spider silk–silica fusion (chimeric) proteins

Abstract

Silica skeletal architectures in diatoms are characterized by remarkable morphological and nanostructural details. Silk proteins from spiders and silkworms form strong and intricate self-assembling fibrous biomaterials in nature. We combined the features of silk with biosilica through the design, synthesis, and characterization of a novel family of chimeric proteins for subsequent use in model materials forming reactions. The domains from the major ampullate spidroin 1 (MaSp1) protein of Nephila clavipes spider dragline silk provide control over structural and morphological details because it can be self-assembled through diverse processing methods including film casting and fiber electrospinning. Biosilica nanostructures in diatoms are formed in aqueous ambient conditions at neutral pH and low temperatures. The R5 peptide derived from the silaffin protein of Cylindrotheca fusiformis induces and regulates silica precipitation in the chimeric protein designs under similar ambient conditions. Whereas mineralization reactions performed in the presence of R5 peptide alone form silica particles with a size distribution of 0.5-10 m in diameter, reactions performed in the presence of the new fusion proteins generate nanocomposite materials containing silica particles with a narrower size distribution of 0.5-2 m in diameter. Furthermore, we demonstrate that composite morphology and structure could be regulated by controlling processing conditions to produce films and fibers. These results suggest that the chimeric protein provides new options for processing and control over silica particle sizes, important benefits for biomedical and specialty materials, particularly in light of the all aqueous processing and the nanocomposite features of these new materials.biomaterials ͉ nanostructures ͉ silaffin ͉ biomineralization ͉ ceramics C omplex mineralized composite systems in nature provide rich ground for insight into mechanisms of biomineralization and novel materials designs (1-4). Some of the more common sources of inspiration include seashells, insect exoskeletons, extracellular matrices involved in bone and other hard tissues, and biosilica skeletons. The formation of natural inorganic-organic composites is a multistep process, including the assembly of the extracellular matrix, the selective transportation of inorganic ions to discrete organized compartments with subsequent mineral nucleation, and growth delineated by preorganized cellular compartments. Silica skeletons found in nature are based on nanoscale composites wherein the organic components, usually proteins, are functional parts of the skeletal structures while also serving as silica-forming components (5, 6). As a result, materials' toughness is improved, strength is retained, and fine morphological control is achieved, all hallmark attributes of biological composites.Silica is widespread in biological systems and serves different functions, including support and protection in single-celled organisms, such as diatoms through to higher plants and animals (7,8...

Preparation and Photocatalytic Activity of TiO2-Wrapped Cotton Nanofiber Composite Catalysts

“…With regard to these biopolymers, nanocrystalline cellulose (NCC), which is nanosized cellulose fiber, has a number of fascinating characteristics, such as containing a large number of active hydroxyl groups on its surface, environmentally friendly nature, low cost, nanoscale dimension, and unique optical properties and utilities (de Souza Lima et al 2004;Beck-Candanedo et al 2005;Klemm et al 2005;Foo et al 2006;Klemm et al 2006;Thakur and Thakur 2014;Thakur and Voicu 2016). Recently, to explore multifunctional nanocellulose hybrid composites, many different nanocellulose-inorganic hybrid composite materials have been prepared for applications in various fields.…”

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Synthesis of Bioinorganic Antimicrobial Peptide Nanoparticles with Potential Therapeutic Properties

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“…c (Gomes et al, 2011), silver ion-binding peptides (Currie et al, 2011), and silica-binding peptides (Wong Po Foo et al, 2006). These hybrids may be applied as a film and coating material to improve the surface properties of biomaterials.…”