Recent Advances in Development of Functional Spider Silk-Based Hybrid Materials

Superflexible Carbon Nanofibers for Multidimensional Complex Deformation Sensing in Soft Robots

Soft robots can make complex motions or deformations due to their infinite freedom, which poses great challenges for monitoring their motion and position. While previous investigations of flexible sensing either focused on stretchable or compression deformations in one or two directions, the complex multidimensional deformations that occur on the surfaces of soft robots have been frequently overlooked. In this work, inspired by spider silk, superflexible carbon nanofibers with a bundled structure were biomimetically designed and fabricated using electrospinning technology and carbonization treatment. The fabricated fibers can be microscopically folded at 180° and can sustain multidimensional shrinkage deformation without microstructural damage during 200,000 times of repeated folding. In addition, the fibers process ultrasmall bending resistance that is two orders of magnitude lower than that of A4 paper and commercial conductive fibers, demonstrating excellent flexibility that is ideal for fabricating sensors in soft robots. Combining the study of origami techniques and mechanical simulations, the bending resistance of the fibers was found to have a step change in response to different deformation angles and radii. As a demonstration, a sensor based on this flexible carbon nanofiber successfully monitors the irregular shrinkage deformation of soft parts, showing great potential in applications of grasping, recognition, and perception. This work sheds light on the design of ultraflexible conductive carbon materials and provides an avenue for the extreme shape-morphing monitoring of soft robots.

Spider minor ampullate silk protein nanoparticles: an effective protein delivery system capable of enhancing systemic immune responses

Spider silk proteins (spidroins) are particularly attractive due to their excellent biocompatibility. Spider can produce up to seven different types of spidroins, each with unique properties and functions. Spider minor ampullate silk protein (MiSp) might be particularly interesting for biomedical applications, as the constituent silk is mechanically strong and does not super-contract in water, attributed to its amino acid composition. In this study, we evaluate the potential of recombinant nanoparticles derived from Araneus ventricosus MiSp as a protein delivery carrier. The MiSp-based nanoparticles were able to serve as an effective delivery system, achieving nearly 100% efficiency in loading the model protein lysozyme, and displayed a sustained release profile at physiological pH. These nanoparticles could significantly improve the delivery efficacy of the model proteins through different administration routes. Furthermore, nanoparticles loaded with model protein antigen lysozyme after subcutaneous or intramuscular administration could enhance antigen-specific immune responses in mouse models, through a mechanism involving antigen-depot effects at the injection site, long-term antigen persistence, and efficient uptake by dendritic cells as well as internalization by lymph nodes. These findings highlight the transnational potential of MiSp-based nanoparticle system for protein drug and vaccine delivery.

Super-Toughness Carbon Nanotube Yarns by Bio-Inspired Nano-Coiling Engineering

Lightweight structural materials are commonly used as effective fillers for advanced composites with high toughness. This study focused on enhancing the toughness of direct-spun carbon nanotube yarns (CNTYs) by controlling the micro-textural structure using a water-gap-based direct spinning. Drawing inspiration from the structural features of natural spider silk fibroin, characterized by an α-helix in the amorphous region and β-sheet in the crystalline region, multiscale bundles within CNTYs are reorganized into a unique nano-coil-like structure. This nano-coiled structure facilitated the efficient dissipation of external mechanical loads through densification with the rearrangement of multiscale bundles, improving specific strength and strain. The resulting CNTYs exhibited exceptional mechanical properties with toughness reaching 250 J g-1, making them promising alternatives to commercially available fibers in lightweight, high-toughness applications. These findings highlight the significance of nano-coiling engineering for emulating bio-inspired micro-textural structures, achieving remarkable enhancement in the toughness of CNTYs.

Structural conversion of the spidroin C-terminal domain during assembly of spider silk fibers

The major ampullate Spidroin 1 (MaSp1) is the main protein of the dragline spider silk. The C-terminal (CT) domain of MaSp1 is crucial for the self-assembly into fibers but the details of how it contributes to the fiber formation remain unsolved. Here we exploit the fact that the CT domain can form silk-like fibers by itself to gain knowledge about this transition. Structural investigations of fibers from recombinantly produced CT domain from E. australis MaSp1 reveal an α-helix to β-sheet transition upon fiber formation and highlight the helix No4 segment as most likely to initiate the structural conversion. This prediction is corroborated by the finding that a peptide corresponding to helix No4 has the ability of pH-induced conversion into β-sheets and self-assembly into nanofibrils. Our results provide structural information about the CT domain in fiber form and clues about its role in triggering the structural conversion of spidroins during fiber assembly.

Porous protein crystals: synthesis and applications

Large-pore protein crystals (LPCs) are an emerging class of biomaterials. The inherent diversity of proteins translates to a diversity of crystal lattice structures, many of which display large pores and solvent channels. These pores can, in turn, be functionalized via directed evolution and rational redesign based on the known crystal structures. LPCs possess extremely high solvent content, as well as extremely high surface area to volume ratios. Because of these characteristics, LPCs continue to be explored in diverse applications including catalysis, targeted therapeutic delivery, templating of nanostructures, structural biology. This Feature review article will describe several of the existing platforms in detail, with particular focus on LPC synthesis approaches and reported applications.

Applications of selected polysaccharides and proteins in dentistry: A review

In the last ten years, remarkable characteristics and a variety of functionalities have been created in biopolymeric materials for clinical dental applications. This review gives an overview of current knowledge of natural biopolymers (biological macromolecules) in terms of structural, functional, and property interactions. Natural biopolymers such as polysaccharides (chitosan, bacterial cellulose, hyaluronic acid, and alginate) and polypeptides (collagen and silk fibroin) have been discussed for dental uses. These biopolymers exhibit excellent properties alone and when employed with other composite molecules making them ideal for treatment of periodontitis, endodontics, dental pulp regeneration and oral wound healing. These biopolymers together with the composite materials exhibit better biocompatibility, inertness, elasticity and flexibility which makes them a leading candidate to be used for other dental applications like caries management, oral appliances, dentures, dental implants and oral surgeries.

Microstructure of the silk fibroin-based hydrogel scaffolds derived from the orb-web spider Trichonephila clavata

Due to the unique properties of the silk fibroin (SF) made from silkworm, SF-based hydrogels have recently received significant attention for various biomedical applications. However, research on the SF-based hydrogels isolated from spider silks has been rtricted due to the limited collection and preparation of naïve silk materials. Therefore, this study focused on the microstructural characteristics of hydrogel scaffolds derived from two types of woven silk glands: the major ampullate gland (MAG) and the tubuliform gland (TG), in the orb-web spider Trichonephila clavate. We compared these spider glands with those of the silk fibroin (SF) hydrogel scaffold extracted from the cocoon of the insect silkworm Bombyx mori. Our FESEM analysis revealed that the SF hydrogel has high porosity, translucency, and a loose upper structure, with attached SF fibers providing stability. The MAG hydrogel displayed even higher porosity, as well as elongated fibrous structures, and improved mechanical properties: while the TG hydrogel showed increased porosity, ridge-like or wall-like structures, and stable biocapacity formed by physical crosslinking. Due to their powerful and versatile microstructural characteristics, the MAG and TG hydrogels can become tailored substrates, very effective for tissue engineering and regenerative medicine applications.

Spider Silk Protein Forms Amyloid-Like Nanofibrils through a Non-Nucleation-Dependent Polymerization Mechanism

Amyloid fibrils-nanoscale fibrillar aggregates with high levels of order-are pathogenic in some today incurable human diseases; however, there are also many physiologically functioning amyloids in nature. The process of amyloid formation is typically nucleation-elongation-dependent, as exemplified by the pathogenic amyloid-β peptide (Aβ) that is associated with Alzheimer's disease. Spider silk, one of the toughest biomaterials, shares characteristics with amyloid. In this study, it is shown that forming amyloid-like nanofibrils is an inherent property preserved by various spider silk proteins (spidroins). Both spidroins and Aβ capped by spidroin N- and C-terminal domains, can assemble into macroscopic spider silk-like fibers that consist of straight nanofibrils parallel to the fiber axis as observed in native spider silk. While Aβ forms amyloid nanofibrils through a nucleation-dependent pathway and exhibits strong cytotoxicity and seeding effects, spidroins spontaneously and rapidly form amyloid-like nanofibrils via a non-nucleation-dependent polymerization pathway that involves lateral packing of fibrils. Spidroin nanofibrils share amyloid-like properties but lack strong cytotoxicity and the ability to self-seed or cross-seed human amyloidogenic peptides. These results suggest that spidroins´ unique primary structures have evolved to allow functional properties of amyloid, and at the same time direct their fibrillization pathways to avoid formation of cytotoxic intermediates.

Secretion-Catalyzed Assembly of Protein Biomaterials on a Bacterial Membrane Surface

Protein-based biomaterials have played a key role in tissue engineering, and additional exciting applications as self-healing materials and sustainable polymers are emerging. Over the past few decades, recombinant expression and production of various fibrous proteins from microbes have been demonstrated; however, the resulting proteins typically must then be purified and processed by humans to form usable fibers and materials. Here, we show that the Gram-positive bacterium Bacillus subtilis can be programmed to secrete silk through its translocon via an orthogonal signal peptide/peptidase pair. Surprisingly, we discover that this translocation mechanism drives the silk proteins to assemble into fibers spontaneously on the cell surface, in a process we call secretion-catalyzed assembly (SCA). Secreted silk fibers form self-healing hydrogels with minimal processing. Alternatively, the fibers retained on the membrane provide a facile route to create engineered living materials from Bacillus cells. This work provides a blueprint to achieve autonomous assembly of protein biomaterials in useful morphologies directly from microbial factories.

Factors Influencing Properties of Spider Silk Coatings and Their Interactions within a Biological Environment

Biomaterials are an indispensable part of biomedical research. However, although many materials display suitable application-specific properties, they provide only poor biocompatibility when implanted into a human/animal body leading to inflammation and rejection reactions. Coatings made of spider silk proteins are promising alternatives for various applications since they are biocompatible, non-toxic and anti-inflammatory. Nevertheless, the biological response toward a spider silk coating cannot be generalized. The properties of spider silk coatings are influenced by many factors, including silk source, solvent, the substrate to be coated, pre- and post-treatments and the processing technique. All these factors consequently affect the biological response of the environment and the putative application of the appropriate silk coating. Here, we summarize recently identified factors to be considered before spider silk processing as well as physicochemical characterization methods. Furthermore, we highlight important results of biological evaluations to emphasize the importance of adjustability and adaption to a specific application. Finally, we provide an experimental matrix of parameters to be considered for a specific application and a guided biological response as exemplarily tested with two different fibroblast cell lines.

A Density Functional Theory (DFT) Perspective on Optical Absorption of Modified Graphene Interacting with the Main Amino Acids of Spider Silk

We investigated the possible adsorption of each of the main building blocks of spider silk: alanine, glycine, leucine, and proline. This knowledge could help develop new biocompatible materials and favors the creation of new biosensors. We used ab initio density functional theory methods to study the variations in the optical absorption, reflectivity, and band structure of a modified graphene surface interacting with these four molecules. Four modification cases were considered: graphene with vacancies at 5.55% and fluorine, nitrogen, or oxygen doping, also at 5.55%. We found that, among the cases considered, graphene with vacancies is the best candidate to develop optical biosensors to detect C=O amide and differentiate glycine and leucine from alanine and proline in the visible spectrum region. Finally, from the projected density of states, the main changes occur at deep energies. Thus, all modified graphene's electronic energy band structure undergoes only tiny changes when interacting with amino acids.

Advances in Functionalization of Bioresorbable Nanomembranes and Nanoparticles for Their Use in Biomedicine

Bioresorbable nanomembranes (NMs) and nanoparticles (NPs) are powerful polymeric materials playing an important role in biomedicine, as they can effectively reduce infections and inflammatory clinical patient conditions due to their high biocompatibility, ability to physically interact with biomolecules, large surface area, and low toxicity. In this review, the most common bioabsorbable materials such as those belonging to natural polymers and proteins for the manufacture of NMs and NPs are reviewed. In addition to biocompatibility and bioresorption, current methodology on surface functionalization is also revisited and the most recent applications are highlighted. Considering the most recent use in the field of biosensors, tethered lipid bilayers, drug delivery, wound dressing, skin regeneration, targeted chemotherapy and imaging/diagnostics, functionalized NMs and NPs have become one of the main pillars of modern biomedical applications.

Biomimetic Scaffolds for Tendon Tissue Regeneration

Tendon tissue connects muscle to bone and plays crucial roles in stress transfer. Tendon injury remains a significant clinical challenge due to its complicated biological structure and poor self-healing capacity. The treatments for tendon injury have advanced significantly with the development of technology, including the use of sophisticated biomaterials, bioactive growth factors, and numerous stem cells. Among these, biomaterials that the mimic extracellular matrix (ECM) of tendon tissue would provide a resembling microenvironment to improve efficacy in tendon repair and regeneration. In this review, we will begin with a description of the constituents and structural features of tendon tissue, followed by a focus on the available biomimetic scaffolds of natural or synthetic origin for tendon tissue engineering. Finally, we will discuss novel strategies and present challenges in tendon regeneration and repair.

Resistance to Degradation of Silk Fibroin Hydrogels Exposed to Neuroinflammatory Environments

Central nervous system (CNS) diseases represent an extreme burden with significant social and economic costs. A common link in most brain pathologies is the appearance of inflammatory components that can jeopardize the stability of the implanted biomaterials and the effectiveness of therapies. Different silk fibroin scaffolds have been used in applications related to CNS disorders. Although some studies have analyzed the degradability of silk fibroin in non-cerebral tissues (almost exclusively upon non-inflammatory conditions), the stability of silk hydrogel scaffolds in the inflammatory nervous system has not been studied in depth. In this study, the stability of silk fibroin hydrogels exposed to different neuroinflammatory contexts has been explored using an in vitro microglial cell culture and two in vivo pathological models of cerebral stroke and Alzheimer's disease. This biomaterial was relatively stable and did not show signs of extensive degradation across time after implantation and during two weeks of in vivo analysis. This finding contrasted with the rapid degradation observed under the same in vivo conditions for other natural materials such as collagen. Our results support the suitability of silk fibroin hydrogels for intracerebral applications and highlight the potentiality of this vehicle for the release of molecules and cells for acute and chronic treatments in cerebral pathologies.

Laser-Induced Fabrication of Micro-Optics on Bioresorbable Calcium Phosphate Glass for Implantable Devices

In this study, a single-step nanosecond laser-induced generation of micro-optical features is demonstrated on an antibacterial bioresorbable Cu-doped calcium phosphate glass. The inverse Marangoni flow of the laser-generated melt is exploited for the fabrication of microlens arrays and diffraction gratings. The process is realized in a matter of few seconds and, by optimizing the laser parameters, micro-optical features with a smooth surface are obtained showing a good optical quality. The tunability of the microlens' dimensions is achieved by varying the laser power, allowing the obtaining of multi-focal microlenses that are of great interest for three-dimensional (3D) imaging. Furthermore, the microlens' shape can be tuned between hyperboloid and spherical. The fabricated microlenses exhibited good focusing and imaging performance and the variable focal lengths were measured experimentally, showing good agreement with the calculated values. The diffraction gratings obtained by this method showed the typical periodic pattern with a first-order efficiency of about 5.1%. Finally, the dissolution characteristics of the fabricated micropatterns were studied in a phosphate-buffered saline solution (PBS, pH = 7.4) demonstrating the bioresorbability of the micro-optical components. This study offers a new approach for the fabrication of micro-optics on bioresorbable glass, which could enable the manufacturing of new implantable optical sensing components for biomedical applications.

Bi-terminal fusion of intrinsically-disordered mussel foot protein fragments boosts mechanical strength for protein fibers

Microbially-synthesized protein-based materials are attractive replacements for petroleum-derived synthetic polymers. However, the high molecular weight, high repetitiveness, and highly-biased amino acid composition of high-performance protein-based materials have restricted their production and widespread use. Here we present a general strategy for enhancing both strength and toughness of low-molecular-weight protein-based materials by fusing intrinsically-disordered mussel foot protein fragments to their termini, thereby promoting end-to-end protein-protein interactions. We demonstrate that fibers of a ~60 kDa bi-terminally fused amyloid-silk protein exhibit ultimate tensile strength up to 481 ± 31 MPa and toughness of 179 ± 39 MJ*m^-3, while achieving a high titer of 8.0 ± 0.70 g/L by bioreactor production. We show that bi-terminal fusion of Mfp5 fragments significantly enhances the alignment of β-nanocrystals, and intermolecular interactions are promoted by cation-π and π-π interactions between terminal fragments. Our approach highlights the advantage of self-interacting intrinsically-disordered proteins in enhancing material mechanical properties and can be applied to a wide range of protein-based materials.

Methods for Silk Property Analyses across Structural Hierarchies and Scales

Silk from silkworms and spiders is an exceptionally important natural material, inspiring a range of new products and applications due to its high strength, elasticity, and toughness at low density, as well as its unique conductive and optical properties. Transgenic and recombinant technologies offer great promise for the scaled-up production of new silkworm- and spider-silk-inspired fibres. However, despite considerable effort, producing an artificial silk that recaptures the physico-chemical properties of naturally spun silk has thus far proven elusive. The mechanical, biochemical, and other properties of pre-and post-development fibres accordingly should be determined across scales and structural hierarchies whenever feasible. We have herein reviewed and made recommendations on some of those practices for measuring the bulk fibre properties; skin-core structures; and the primary, secondary, and tertiary structures of silk proteins and the properties of dopes and their proteins. We thereupon examine emerging methodologies and make assessments on how they might be utilized to realize the goal of developing high quality bio-inspired fibres.

Silk-Based Biomaterials for Designing Bioinspired Microarchitecture for Various Biomedical Applications

Biomaterial research has led to revolutionary healthcare advances. Natural biological macromolecules can impact high-performance, multipurpose materials. This has prompted the quest for affordable healthcare solutions, with a focus on renewable biomaterials with a wide variety of applications and ecologically friendly techniques. Imitating their chemical compositions and hierarchical structures, bioinspired based materials have elevated rapidly over the past few decades. Bio-inspired strategies entail extracting fundamental components and reassembling them into programmable biomaterials. This method may improve its processability and modifiability, allowing it to meet the biological application criteria. Silk is a desirable biosourced raw material due to its high mechanical properties, flexibility, bioactive component sequestration, controlled biodegradability, remarkable biocompatibility, and inexpensiveness. Silk regulates temporo-spatial, biochemical and biophysical reactions. Extracellular biophysical factors regulate cellular destiny dynamically. This review examines the bioinspired structural and functional properties of silk material based scaffolds. We explored silk types, chemical composition, architecture, mechanical properties, topography, and 3D geometry to unlock the body's innate regenerative potential, keeping in mind the novel biophysical properties of silk in film, fiber, and other potential forms, coupled with facile chemical changes, and its ability to match functional requirements for specific tissues.

Recent Developments of Silk-Based Scaffolds for Tissue Engineering and Regenerative Medicine Applications: A Special Focus on the Advancement of 3D Printing

Regenerative medicine has received potential attention around the globe, with improving cell performances, one of the necessary ideas for the advancements of regenerative medicine. It is crucial to enhance cell performances in the physiological system for drug release studies because the variation in cell environments between in vitro and in vivo develops a loop in drug estimation. On the other hand, tissue engineering is a potential path to integrate cells with scaffold biomaterials and produce growth factors to regenerate organs. Scaffold biomaterials are a prototype for tissue production and perform vital functions in tissue engineering. Silk fibroin is a natural fibrous polymer with significant usage in regenerative medicine because of the growing interest in leftovers for silk biomaterials in tissue engineering. Among various natural biopolymer-based biomaterials, silk fibroin-based biomaterials have attracted significant attention due to their outstanding mechanical properties, biocompatibility, hemocompatibility, and biodegradability for regenerative medicine and scaffold applications. This review article focused on highlighting the recent advancements of 3D printing in silk fibroin scaffold technologies for regenerative medicine and tissue engineering.

Progress in silk and silk fiber-inspired polymeric nanomaterials for drug delivery

The fields of drug and gene delivery have been revolutionized by the discovery and characterization of polymer-based materials. Polymeric nanomaterials have emerged as a strategy for targeted delivery because of features such as their impressive biocompatibility and improved availability. Use of naturally derived polymers in these nanomaterials is advantageous due to their biodegradability and bioresorption. Natural biopolymer-based particles composed of silk fibroins and other silk fiber-inspired proteins have been the focus of research in drug delivery systems due to their simple synthesis, tunable characteristics, and ability to respond to stimuli. Several silk and silk-inspired polymers contain a high proportion of reactive side groups, allowing for functionalization and addition of targeting moieties. In this review, we discuss the main classes of silk and silk-inspired polymers that are being used in the creation of nanomaterials. We also focus on the fabrication techniques used in generating a tunable design space of silk-based polymeric nanomaterials and detail how that translates into use for drug delivery to several distinct microenvironments.

Biomedical applications of silk and its role for intervertebral disc repair

Intervertebral disc (IVD) degeneration (IDD) is the main contributor to chronic low back pain. To date, the present therapies mainly focus on treating the symptoms caused by IDD rather than addressing the problem itself. For this reason, researchers have searched for a suitable biomaterial to repair and/or regenerate the IVD. A promising candidate to fill this gap is silk, which has already been used as a biomaterial for many years. Therefore, this review aims first to elaborate on the different origins from which silk is harvested, the individual composition, and the characteristics of each silk type. Another goal is to enlighten why silk is so suitable as a biomaterial, discuss its functionalization, and how it could be used for tissue engineering purposes. The second part of this review aims to provide an overview of preclinical studies using silk-based biomaterials to repair the inner region of the IVD, the nucleus pulposus (NP), and the IVD's outer area, the annulus fibrosus (AF). Since the NP and the AF differ fundamentally in their structure, different therapeutic approaches are required. Consequently, silk-containing hydrogels have been used mainly to repair the NP, and silk-based scaffolds have been used for the AF. Although most preclinical studies have shown promising results in IVD-related repair and regeneration, their clinical transition is yet to come.

Spider-Silk-Inspired Nanocomposite Polymers for Durable Daytime Radiative Cooling

Passive daytime radiative cooling (PDRC) materials, that strongly reflect sunlight and emit thermal radiation to outer space, demonstrate great potential in energy-saving for sustainable development. Particularly, polymer-based PDRC materials, with advantages of easy-processing, low cost, and outstanding cooling performance, have attracted intense attention. However, just like other polymer devices (for example polymer solar cells) working under sunlight, the issue of durability related to mechanical and UV properties needs to be addressed for large-scale practical applications. Here, a spider-silk-inspired design of nanocomposite polymers with potassium titanate (K₂ Ti₆ O₁₃ ) nanofiber dopants is proposed for enhancing the durability without compromising their cooling performance. The formed tough interface of nanofiber/polymer effectively disperses stress, enhancing the mechanical properties of the polymer matrix; while the K₂ Ti₆ O₁₃ can absorb high-energy UV photons and transform them into less harmful heat, thereby improving the UV stabilities. Taking poly(ethylene oxide) radiative cooler as an example for demonstration, its Young's modulus and UV resistance increase by 7 and 12 times, respectively. Consequently, the solar reflectance of nanocomposite poly(ethylene oxide) is maintained as constant in a continuous aging test for 720 h under outdoor sunlight. The work provides a general strategy to simultaneously enhance both the mechanical stability and the UV durability of polymer-based PDRC materials toward large-scale applications.

Ancient fibrous biomaterials from silkworm protein fibroin and spider silk blends: Biomechanical patterns

Silkworm silk protein fibroin and spider silk spidroin are known biocompatible and natural biodegradable polymers in biomedical applications. The presence of β-sheets in silk fibroin and spider spidroin conformation improves their mechanical properties. The strength and toughness of pure recombinant silkworm fibroin and spidroin are relatively low due to reduced molecular weight. Hence, blending is the foremost approach of recent studies to optimize silk fibroin and spidroin's mechanical properties. As summarised in the present review, numerous research investigations evaluate the blending of natural and synthetic polymers. The effects of blending silk fibroin and spidroin with natural and synthetic polymers on the mechanical properties are discussed in this review article. Indeed, combining natural and synthetic polymers with silk fibroin and spidroin changes their conformation and structure, fine-tuning the blends' mechanical properties. STATEMENT OF SIGNIFICANCE: Silkworm and spider silk proteins (silk fibroin and spidroin) are biocompatible and biodegradable natural polymers having different types of biomedical applications. Their mechanical and biological properties may be tuned through various strategies such as blending, conjugating and cross-linking. Blending is the most common method to modify fibroin and spidroin properties on demand, this review article aims to categorize and evaluate the effects of blending fibroin and spidroin with different natural and synthetic polymers. Increased polarity and hydrophilicity end to hydrogen bonding triggered conformational change in fibroin and spidroin blends. The effect of polarity and hydrophilicity of the blending compound is discussed and categorized to a combinatorial, synergistic and indirect impacts. This outlook guides us to choose the blending compounds mindfully as this mixing affects the biochemical and biophysical characteristics of the biomaterials.

Bioselectivity of silk protein-based materials and their bio-inspired applications

Adhesion to material surfaces is crucial for almost all organisms regarding subsequent biological responses. Mammalian cell attachment to a surrounding biological matrix is essential for maintaining their survival and function concerning tissue formation. Conversely, the adhesion and presence of microbes interferes with important multicellular processes of tissue development. Therefore, tailoring bioselective, biologically active, and multifunctional materials for biomedical applications is a modern focus of biomaterial research. Engineering biomaterials that stimulate and interact with cell receptors to support binding and subsequent physiological responses of multicellular systems attracted much interest in the last years. Further to this, the increasing threat of multidrug resistance of pathogens against antibiotics to human health urgently requires new material concepts for preventing microbial infestation and biofilm formation. Thus, materials exhibiting microbial repellence or antimicrobial behaviour to reduce inflammation, while selectively enhancing regeneration in host tissues are of utmost interest. In this context, protein-based materials are interesting candidates due to their natural origin, biological activity, and structural properties. Silk materials, in particular those made of spider silk proteins and their recombinant counterparts, are characterized by extraordinary properties including excellent biocompatibility, slow biodegradation, low immunogenicity, and non-toxicity, making them ideally suited for tissue engineering and biomedical applications. Furthermore, recombinant production technologies allow for application-specific modification to develop adjustable, bioactive materials. The present review focusses on biological processes and surface interactions involved in the bioselective adhesion of mammalian cells and repellence of microbes on protein-based material surfaces. In addition, it highlights the importance of materials made of recombinant spider silk proteins, focussing on the progress regarding bioselectivity.

Bioengineering of spider silks for the production of biomedical materials

Spider silks are well known for their extraordinary mechanical properties. This characteristic is a result of the interplay of composition, structure and self-assembly of spider silk proteins (spidroins). Advances in synthetic biology have enabled the design and production of spidroins with the aim of biomimicking the structure-property-function relationships of spider silks. Although in nature only fibers are formed from spidroins, in vitro, scientists can explore non-natural morphologies including nanofibrils, particles, capsules, hydrogels, films or foams. The versatility of spidroins, along with their biocompatible and biodegradable nature, also placed them as leading-edge biological macromolecules for improved drug delivery and various biomedical applications. Accordingly, in this review, we highlight the relationship between the molecular structure of spider silk and its mechanical properties and aims to provide a critical summary of recent progress in research employing recombinantly produced bioengineered spidroins for the production of innovative bio-derived structural materials.

High-Strength Collagen-Based Composite Films Regulated by Water-Soluble Recombinant Spider Silk Proteins and Water Annealing

Spider silk has attracted extensive attention in the development of high-performance tissue engineering materials because of its excellent physical properties, biocompatibility, and biodegradability. Although high-molecular-weight recombinant spider silk proteins can be obtained through metabolic engineering of host bacteria, the solubility of the recombinant protein products is always poor. Strong denaturants and organic solvents have thus had to be exploited for their dissolution, and this seriously limits the applications of recombinant spider silk protein-based composite biomaterials. Herein, through adjusting the temperature, ionic strength, and denaturation time during the refolding process, we successfully prepared water-soluble recombinant spider major ampullate spidroin 1 (sMaSp1) with different repeat modules (24mer, 48mer, 72mer, and 96mer). Then, MaSp1 was introduced into the collagen matrix for fabricating MaSp1-collagen composite films. The introduction of spider silk proteins was demonstrated to clearly alter the internal structure of the composite films and improve the mechanical properties of the collagen-based films and turn the opaque protein films into transparency ones. More interestingly, the composite film prepared with sMaSp1 exhibited better performance in mechanical strength and cell adhesion compared to that prepared with water-insoluble MaSp1 (pMaSp1), which might be attributed to the effect of the initial dissolved state of MaSp1 on the microstructure of composite films. Additionally, the molecular weight of MaSp1 was also shown to significantly influence the mechanical strength (enhanced to 1.1- to 2.3-fold) and cell adhesion of composite films, and 72mer of sMaSp1 showed the best physical properties with good bioactivity. This study provides a method to produce recombinant spider silk protein with excellent water solubility, making it possible to utilize this protein under environmentally benign, mild conditions. This paves the way for the application of recombinant spider silk proteins in the development of diverse composite biomaterials.

Functionalization and Reinforcement of Recombinant Spider Dragline Silk Fibers by Confined Nanoparticle Formation

Spider dragline silk is a remarkable protein fiber that is mechanically superior to almost any other natural or synthetic material. As a sustainable supply of natural dragline silk is not feasible, recombinant production of silk fibers with native-like mechanical properties and non-native physiochemical functions is highly desirable for various applications. Here, we report a new strategy for simultaneous functionalization and reinforcement of recombinant spider silk fibers by confined nanoparticle formation. First, a mimic silk protein (N16C) of spider Trichonephila clavipes was recombinantly produced and wet-spun into fibers. Drawing the as-spun fibers in water led to post-drawn fibers more suitable for the templated synthesis of nanoparticles (NPs) with uniform distribution throughout the synthetic fibers. This was exemplified using a chemical precipitation reaction to generate copper sulfide nanoparticle-incorporated fibers. These fibers and the derived fabric displayed a significant photothermal effect as their temperatures could increase to over 40 °C from room temperature within 3 min under near-infrared laser irradiation or simulated sunlight. In addition, the tensile strength and toughness of the nanofunctionalized fibers were greatly enhanced, and the toughness of these synthetic fibers could reach 160.1 ± 21.4 MJ m^-3, which even exceeds that of natural spider dragline silk (111.19 ± 30.54 MJ m^-3). Furthermore, the confined synthesis of gold NPs via a redox reaction was shown to improve the ultraviolet-protective effect and tensile mechanical properties of synthetic silk fibers. These results suggest that our strategy may have great potential for creating functional and high-performance spider silk fibers and fabrics for wide applications.

Fluorescent Hybrid Material Based on Natural Spider Silk and Carbon Dots for Bioapplication

Since the outcome of an operation largely depends on the quality of wound healing, it is one of the most challenging stages in surgery. Today, wound closure is mostly undertaken by means of a surgical suture. Good surgical sutures are biocompatible and biodegradable and possess excellent mechanical properties. Preferably, these sutures demonstrate optical activity for bacteria detection as there is a risk of surgical site infections. In this study, a solution, which fulfills all the requirements for manufacturing a multifunctional hybrid material, is proposed. In this work, a method for the in situ modification of spider silk with fluorescent carbon dots has been developed. The basic concept is the use of silk fibers as both the main framework for tissue regeneration and a carbon source during carbon dot synthesis. The resulting hybrid material exhibits strong photoluminescence in the red region of the spectrum (590 nm) when irradiated with blue light (480 nm). The proposed approach potentially allows for simultaneous wound closure and pathogen detection.

An overview on electrospinning and its advancement toward hard and soft tissue engineering applications

One of the emerging technologies of the recent times harboring nanotechnology to fabricate nanofibers for various biomedical and environmental applications are electrospinning (nanofiber technology). Their relative ease in use, simplicity, functionality and diversity has surpassed the pitfalls encountered with the conventional method of generating fibers. This review aims to provide an overview of electrospinning, principle, methods, feed materials, and applications toward tissue engineering. To begin with, evolution of electrospinning and its typical apparatus have been briefed. Simultaneously, discussion on the production of nanofibers with diversified feed materials such as polymers, small molecules, colloids, and nanoparticles and its transformation into a powerful technology has been dealt with. Further, highlights on the application of nanofibers in tissue engineering and the commercialized products developed using nanofiber technology have been summed up. With this rapidly emerging technology, there would be a great demand pertaining to scalability and environmental challenge toward tissue engineering applications.

An economical approach for peptide synthesis via regioselective C-N bond cleavage of lactams

An economical, solvent-free, and metal-free method for peptide synthesis via C-N bond cleavage using lactams has been developed. The method not only eliminates the need for condensation agents and their auxiliaries, which are essential for conventional peptide synthesis, but also exhibits high atom economy. The reaction is versatile because it can tolerate side chains bearing a range of functional groups, affording up to >99% yields of the corresponding peptides without racemisation or polymerisation. Moreover, the developed strategy enables peptide segment coupling, providing access to a hexapeptide that occurs as a repeat sequence in spider silk proteins.

Engineering Three-Dimensional Vascularized Cardiac Tissues

Heart disease is one of the largest burdens to human health worldwide and has very limited therapeutic options. Engineered three-dimensional (3D) vascularized cardiac tissues have shown promise in rescuing cardiac function in diseased hearts and may serve as a whole organ replacement in the future. One of the major obstacles in reconstructing these thick myocardial tissues to a clinically applicable scale is the integration of functional vascular networks capable of providing oxygen and nutrients throughout whole engineered constructs. Without perfusion of oxygen and nutrient flow throughout the entire engineered tissue not only is tissue viability compromised, but also overall tissue functionality is lost. There are many supporting technologies and approaches that have been developed to create vascular networks such as 3D bioprinting, co-culturing hydrogels, and incorporation of soluble angiogenic factors. In this state-of-the-art review, we discuss some of the most current engineered vascular cardiac tissues reported in the literature and future directions in the field. Impact statement The field of cardiac tissue engineering is rapidly evolving and is now closer than ever to having engineered tissue models capable of predicting preclinical responses to therapeutics, modeling diseases, and being used as a means of rescuing cardiac function following injuries to the native myocardium. However, a major obstacle of engineering thick cardiac tissue remains to be the integration of functional vasculature. In this review, we highlight seminal and recently published works that have influenced and pushed the field of cardiac tissue engineering toward achieving vascularized functional tissues.

Silk Hydrogel for Tissue Engineering: A Review

AIM

This review aims to explore the importance of silk hydrogel and its potential in tissue engineering (TE).

BACKGROUND

Tissue engineering is a procedure that incorporates cells into the scaffold materials with suitable growth factors to regenerate injured tissue. For tissue formation in TE, the scaffold material plays a key role. Different forms of silk fibroin (SF), such as films, mats, hydrogels, and sponges, can be easily manufactured when SF is disintegrated into an aqueous solution. High precision procedures such as micropatterning and bioprinting of SF-based scaffolds have been used for enhanced fabrication.

REVIEW RESULTS

In this narrative review, SF physicochemical and mechanical properties have been presented. We have also discussed SF fabrication techniques like electrospinning, spin coating, freeze-drying, and physiochemical cross-linking. The application of SF-based scaffolds for skeletal, tissue, joint, muscle, epidermal, tissue repair, and tympanic membrane regeneration has also been addressed.

CONCLUSION

SF has excellent mechanical properties, tunability, biodegradability, biocompatibility, and bioresorbability.

CLINICAL SIGNIFICANCE

Silk hydrogels are an ideal scaffold matrix material that will significantly impact tissue engineering applications, given the rapid scientific advancements in this field.

Site-Specific Functionalization of Recombinant Spider Silk Janus Fibers

Biotechnological production is a powerful tool to design materials with customized properties. The aim of this work was to apply designed spider silk proteins to produce Janus fibers with two different functional sides. First, functionalization was established through a cysteine-modified silk protein, ntagCys eADF4(κ16). After fiber spinning, gold nanoparticles (AuNPs) were coupled via thiol-ene click chemistry. Significantly reduced electrical resistivity indicated sufficient loading density of AuNPs on such fiber surfaces. Then, Janus fibers were electrospun in a side-by-side arrangement, with "non-functional" eADF4(C16) on the one and "functional" ntagCys eADF4(κ16) on the other side. Post-treatment was established to render silk fibers insoluble in water. Subsequent AuNP binding was highly selective on the ntagCys eADF4(κ16) side demonstrating the potential of such silk-based systems to realize complex bifunctional structures with spatial resolutions in the nano scale.

Deconstruction and Reassembly of Renewable Polymers and Biocolloids into Next Generation Structured Materials

This review considers the most recent developments in supramolecular and supraparticle structures obtained from natural, renewable biopolymers as well as their disassembly and reassembly into engineered materials. We introduce the main interactions that control bottom-up synthesis and top-down design at different length scales, highlighting the promise of natural biopolymers and associated building blocks. The latter have become main actors in the recent surge of the scientific and patent literature related to the subject. Such developments make prominent use of multicomponent and hierarchical polymeric assemblies and structures that contain polysaccharides (cellulose, chitin, and others), polyphenols (lignins, tannins), and proteins (soy, whey, silk, and other proteins). We offer a comprehensive discussion about the interactions that exist in their native architectures (including multicomponent and composite forms), the chemical modification of polysaccharides and their deconstruction into high axial aspect nanofibers and nanorods. We reflect on the availability and suitability of the latter types of building blocks to enable superstructures and colloidal associations. As far as processing, we describe the most relevant transitions, from the solution to the gel state and the routes that can be used to arrive to consolidated materials with prescribed properties. We highlight the implementation of supramolecular and superstructures in different technological fields that exploit the synergies exhibited by renewable polymers and biocolloids integrated in structured materials.

Synthesis and Processing of Nanomaterials Mediated by Living Organisms

Nanomaterials offer exciting properties and functionalities. However, their production and processing frequently involve complex methods, cumbersome equipment, harsh conditions, and hazardous media. The capability of organisms to accomplish this using mild conditions offers a sustainable, biocompatible, and environmentally friendly alternative. Different nanomaterials such as metal nanoparticles, quantum dots, silica nanostructures, and nanocellulose are being synthesized increasingly through living entities. In addition, the bionanofabrication potential enables also the in situ processing of nanomaterials inside biomatrices with unprecedented outcomes. In this Minireview we present a critical state‐of‐the‐art vision of current nanofabrication approaches mediated by living entities (ranging from unicellular to higher organisms), in order to expand this knowledge and scrutinize future prospects. An efficient interfacial interaction at the nanoscale by green means is within reach through this approach.

Systemic and Local Silk-Based Drug Delivery Systems for Cancer Therapy

For years, surgery, radiotherapy, and chemotherapy have been the gold standards to treat cancer, although continuing research has sought a more effective approach. While advances can be seen in the development of anticancer drugs, the tools that can improve their delivery remain a challenge. As anticancer drugs can affect the entire body, the control of their distribution is desirable to prevent systemic toxicity. The application of a suitable drug delivery platform may resolve this problem. Among other materials, silks offer many advantageous properties, including biodegradability, biocompatibility, and the possibility of obtaining a variety of morphological structures. These characteristics allow the exploration of silk for biomedical applications and as a platform for drug delivery. We have reviewed silk structures that can be used for local and systemic drug delivery for use in cancer therapy. After a short description of the most studied silks, we discuss the advantages of using silk for drug delivery. The tables summarize the descriptions of silk structures for the local and systemic transport of anticancer drugs. The most popular techniques for silk particle preparation are presented. Further prospects for using silk as a drug carrier are considered. The application of various silk biomaterials can improve cancer treatment by the controllable delivery of chemotherapeutics, immunotherapeutics, photosensitizers, hormones, nucleotherapeutics, targeted therapeutics (e.g., kinase inhibitors), and inorganic nanoparticles, among others.

Nano-fishnet formation of silk controlled by Arginine density

Silk fiber is renowned for its superb mechanical properties, such as over 7 times the toughness of Kevlar 49 Fibre. As the spider silk is tougher than any man-made fiber, there is a lot to be learned from spider silk. Recently, it has been reported that a large portion of the properties of silk is from naturally formed nano-fishnet structures of silk, but neither its formation mechanism nor its formation condition has been explained. Here, we show how the formation and disappearance of nano-fishnet of silk is determined by humidity, and how the humidity-dependency of nano-fishnet formation can be overcome by changing density of Arginine through sequence mutation. We demonstrate that the nano-fishnet-structured silk exhibits higher strength and toughness than its counterparts. This information on controllable nano-fishnet formation of silk is expected to pave the way for development of protein and synthetic fiber design. STATEMENT OF SIGNIFICANCE: Silk fibers are a very interesting material in that it exhibits superb mechanical properties such as 7 times the toughness of Kevlar 49 Fibre, despite being only composed of proteins. Therefore, it is important that we understand the principle of its high mechanical properties so that it may be applied in designing synthetic fibers. Recently, it has been reported that a large portion of its mechanical property comes from its nano-fishnet structures, but no detailed explanation on the condition or mechanism of formation. Through molecular dynamic simulations, we simulated the nano-fishnet formation of silk and analyzed the condition and mechanism behind it, and showed how the formation of nano-fishnet structures could be controlled by changing the density of Arginine residues. Our study provides information on fiber enhancement mechanism that could be applied to synthetic and protein fiber design.

Addressing the post‐COVID era through engineering biology

Currently, the world is faced with two fundamental issues of great importance, namely climate change and the coronavirus pandemic. These are intimately involved with the need to control climate change and the need to switch from high carbon, unsustainable economies to low carbon economies. Inherent in this approach are the concepts of the bioeconomy and the Green Industrial Revolution. The article addresses both issues, but it, principally, focusses on the development of the bioeconomy. It considers how nations are divided in relation to the use of biotechnology and synthetic biology in terms of their bioeconomy strategies. The article addresses, as a central theme, the nature and role of engineering biology in these developments. Engineering biology is addressed in terms of BioDesign, coupled with high levels of automation (including AI and machine learning) to increase reproducibility and reliability to meet industrial standards. This lends itself to distributed manufacturing of products in a range of fields. Engineering biology is a platform technology that can be applied in a range of sectors. The bioeconomy, as an engine for economic growth is addressed—in terms of moving from oil‐based economies to bio‐based economies—using biomass, for example, using selected lignocellulosic waste as a feedstock.

Protein nanofibrils for next generation sustainable water purification

Water scarcity is rapidly spreading across the planet, threatening the population across the five continents and calling for global sustainable solutions. Water reclamation is the most ecological approach for supplying clean drinking water. However, current water purification technologies are seldom sustainable, due to high-energy consumption and negative environmental footprint. Here, we review the cutting-edge technologies based on protein nanofibrils as water purification agents and we highlight the benefits of this green, efficient and affordable solution to alleviate the global water crisis. We discuss the different protein nanofibrils agents available and analyze them in terms of performance, range of applicability and sustainability. We underline the unique opportunity of designing protein nanofibrils for efficient water purification starting from food waste, as well as cattle, agricultural or dairy industry byproducts, allowing simultaneous environmental, economic and social benefits and we present a case analysis, including a detailed life cycle assessment, to establish their sustainable footprint against other common natural-based adsorbents, anticipating a bright future for this water purification approach.

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.

Progress in the application of spider silk protein in medicine

Spider silk protein has attracted much attention on account of its excellent mechanical properties, biodegradability, and biocompatibility. As the main protein component of spider silk, spidroin plays important role in spider spinning under natural circumstances and biomaterial application in medicine as well. Compare to the native spidroin which has a large molecular weight (>300 kDa) with highly repeat glycine and polyalanine regions, the recombinant spidroin was maintained the core amino motifs and much easier to collect. Here, we reviewed the application of recombinant spider silk protein eADF4(C16), major ampullate spidroin (MaSp), minor ampullate spidroin (MiSp), and the derivatives of recombinant spider silk protein in drug delivery system. Moreover, we also reviewed the application of spider silk protein in the field of alternative materials, repairing materials, wound dressing, surgical sutures along with advances in recombinant spider silk protein.

Scavenger receptor B8 improves survivability by mediating innate immunity in silkworm, Bombyx mori

Scavenger receptor class B (SR-B) is an extracellular transmembrane glycoprotein that plays a vital role in innate immunity. Although SR-Bs have been widely studied in vertebrates, their functions remained to elucidate in insects. Here, we identified and characterized a scavenger receptor class B member from the silkworm, Bombyx mori (designated as BmSCRB8). BmSCRB8 is broadly expressed in various immune tissues/organs, including fat body, gut, and hemocyte. Its expression is dramatically enhanced after challenge with different types of bacteria or pathogen-associated molecular patterns (PAMPs). The recombinant BmSCRB8 protein can detect different types of bacteria by directly binding to PAMPs and significantly improve the bacterial clearance in vivo. After knockdown of BmSCRB8, the pathogenic bacterial clearance was strongly impaired, and several AMP genes were down-regulated following E. coli challenge. Moreover, pathogenic bacteria's treatment following the depletion of BmSCRB8 remarkably decreased silkworm larvae's survival rate. Taken together, these results demonstrate that BmSCRB8 acts as a pattern recognition protein and plays an essential role in silkworm innate immunity by enhancing bacterial clearance and contributing to the production of AMPs in vivo.

Silk Fibroin as a Functional Biomaterial for Tissue Engineering

Tissue engineering (TE) is the approach to combine cells with scaffold materials and appropriate growth factors to regenerate or replace damaged or degenerated tissue or organs. The scaffold material as a template for tissue formation plays the most important role in TE. Among scaffold materials, silk fibroin (SF), a natural protein with outstanding mechanical properties, biodegradability, biocompatibility, and bioresorbability has attracted significant attention for TE applications. SF is commonly dissolved into an aqueous solution and can be easily reconstructed into different material formats, including films, mats, hydrogels, and sponges via various fabrication techniques. These include spin coating, electrospinning, freeze drying, physical, and chemical crosslinking techniques. Furthermore, to facilitate fabrication of more complex SF-based scaffolds with high precision techniques including micro-patterning and bio-printing have recently been explored. This review introduces the physicochemical and mechanical properties of SF and looks into a range of SF-based scaffolds that have been recently developed. The typical TE applications of SF-based scaffolds including bone, cartilage, ligament, tendon, skin, wound healing, and tympanic membrane, will be highlighted and discussed, followed by future prospects and challenges needing to be addressed.

Silk Particles as Carriers of Therapeutic Molecules for Cancer Treatment

Although progress is observed in cancer treatment, this disease continues to be the second leading cause of death worldwide. The current understanding of cancer indicates that treating cancer should not be limited to killing cancer cells alone, but that the target is the complex tumor microenvironment (TME). The application of nanoparticle-based drug delivery systems (DDS) can not only target cancer cells and TME, but also simultaneously resolve the severe side effects of various cancer treatment approaches, leading to more effective, precise, and less invasive therapy. Nanoparticles based on proteins derived from silkworms' cocoons (like silk fibroin and sericins) and silk proteins from spiders (spidroins) are intensively explored not only in the oncology field. This natural-derived material offer biocompatibility, biodegradability, and simplicity of preparation methods. The protein-based material can be tailored for size, stability, drug loading/release kinetics, and functionalized with targeting ligands. This review summarizes the current status of drug delivery systems' development based on proteins derived from silk fibroin, sericins, and spidroins, which application is focused on systemic cancer treatment. The nanoparticles that deliver chemotherapeutics, nucleic acid-based therapeutics, natural-derived agents, therapeutic proteins or peptides, inorganic compounds, as well as photosensitive molecules, are introduced.

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.