Further development of silk sericin as a biomaterial: comparative investigation of the procedures for its isolation from Bombyx mori silk cocoons

Photothermal and Antibacterial PDA@Ag/SerMA Microneedles for Promoting Diabetic Wound Repair

Diabetic foot ulcer (DFU) is a common and severe complication of diabetes characterized by wound neuropathy, ischemia, and susceptibility to infection, making its treatment difficult. Dressings are commonly used in treating diabetic wounds; however, they have disadvantages, including lack of flexibility and mechanical strength, lack of coagulation activity, resistance to biodegradation, and low drug delivery efficiency. Developing more effective strategies for diabetic wound treatment has become a new focus. Microneedles (MN) can be used as a drug delivery platform for DFU wounds, allowing safe, effective, painless and minimally invasive medication administration through the skin. Herein, PDA@Ag/SerMA microneedles were prepared by combining the photothermal properties of polydopamine (PDA), the antimicrobial properties of argentum (Ag), and the ability of sericin methacryloyl (SerMA) to promote cell mitosis to accelerate wound healing and treat diabetic ulcer wounds. The results revealed that PDA@Ag/SerMA microneedles exhibited approximately 100% antimicrobial efficacy against Staphylococcus aureus and Escherichia coli under 808 nm near-infrared (NIR) irradiation. Furthermore, the wound healing rate of mice reached 95% within 12 days, which demonstrated the excellent antibacterial properties and wound healing efficacy of PDA@Ag/SerMA microneedles at cellular and animal levels, providing a potential solution for treating DFU.

Silk Sericin and Its Effect on Skin Wound Healing: A State of the Art

Despite the significant progress in wound healing, chronic skin wounds remain a challenge for today's medicine. Due to the growing popularity of natural materials, silk protein-based dressings are gaining more attention in this field. Most studies refer to silk fibroin because sericin has been considered a waste product for years. However, sericin is also worth noting. Sericin-based dressings are mainly studied in cell cultures or animals. Sericin is the dressings' main component or can be included in more complex, advanced biomaterials. Recent studies highlight sericin's important role, noting its biocompatibility, biodegradability, and beneficial effects in skin wound healing, such as antibacterial activity, antioxidant and anti-inflammatory effects, or angiogenic properties. Developing sericin-based biomaterials is often simple, free of toxic by-products, and inexpensive, requiring no highly sophisticated apparatus. As a result, sericin-based dressings can be widely used in wound healing and have low environmental impact. However, the literature in this area is further limited. The following review collects and describes recent studies showing silk sericin's influence on skin wound healing.

Melatonin/Sericin Wound Healing Patches: Implications for Melanoma Therapy

Melatonin and sericin exhibit antioxidant properties and may be useful in topical wound healing patches by maintaining redox balance, cell integrity, and regulating the inflammatory response. In human skin, melatonin suppresses damage caused by ultraviolet radiation (UVR) which involves numerous mechanisms associated with reactive oxygen species/reactive nitrogen species (ROS/RNS) generation and enhancing apoptosis. Sericin is a protein mainly composed of glycine, serine, aspartic acid, and threonine amino acids removed from the silkworm cocoon (particularly Bombyx mori and other species). It is of interest because of its biodegradability, anti-oxidative, and anti-bacterial properties. Sericin inhibits tyrosinase activity and promotes cell proliferation that can be supportive and useful in melanoma treatment. In recent years, wound healing patches containing sericin and melatonin individually have attracted significant attention by the scientific community. In this review, we summarize the state of innovation of such patches during 2021-2023. To date, melatonin/sericin-polymer patches for application in post-operational wound healing treatment has been only sparingly investigated and it is an imperative to consider these materials as a promising approach targeting for skin tissue engineering or regenerative dermatology.

Silk Industry Waste Protein-Derived Sericin Hybrid Nanoflowers for Antibiotics Remediation via Circular Economy

Hybrid protein-copper nanoflowers have emerged as promising materials with diverse applications in biocatalysis, biosensing, and bioremediation. Sericin, a waste biopolymer from the textile industry, has shown potential for fabricating such nanoflowers. However, the influence of the molecular weight of sericin on nanoflower morphology and peroxidase-like activity remains unexplored. This work focused on the self-assembly of nanoflowers using high- and low-molecular-weight (HMW and LMW) silk sericin combined with copper(II) as an inorganic moiety. The peroxidase-like activity of the resulting nanoflowers was evaluated using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and hydrogen peroxide (H2O2). The findings revealed that high-molecular-weight sericin hybrid nanoflowers (HMW-ShNFs) exhibited significantly higher peroxidase-like activity than low-molecular-weight sericin hybrid nanoflowers (LMW-ShNFs). Furthermore, HMW-ShNFs demonstrated superior reusability and storage stability, thereby enhancing their potential for practical use. This study also explored the application of HMW-ShNF for ciprofloxacin degradation to address the environmental and health hazards posed by this antibiotic in water. The results indicated that HMW-ShNFs facilitated the degradation of ciprofloxacin, achieving a maximum degradation of 33.2 ± 1% at pH 8 and 35 °C after 72 h. Overall, the enhanced peroxidase-like activity and successful application in ciprofloxacin degradation underscore the potential of HMW-ShNFs for a sustainable and ecofriendly remediation process. These findings open avenues for the further exploration and utilization of hybrid nanoflowers in various environmental applications.

A Sterile, Injectable, and Robust Sericin Hydrogel Prepared by Degraded Sericin

The application of sericin hydrogels is limited mainly due to their poor mechanical strength, tendency to be brittle and inconvenient sterilization. To address these challenges, a sericin hydrogel exhibiting outstanding physical and chemical properties along with cytocompatibility was prepared through crosslinking genipin with degraded sericin extracted from fibroin deficient silkworm cocoons by the high temperature and pressure method. Our reported sericin hydrogels possess good elasticity, injectability, and robust behaviors. The 8% sericin hydrogel can smoothly pass through a 16 G needle. While the 12% sericin hydrogel remains intact until its compression ratio reaches 70%, accompanied by a compression strength of 674 kPa. 12% sericin hydrogel produce a maximum stretch of 740%, with breaking strength and tensile modulus of 375 kPa and 477 kPa respectively. Besides that, the hydrogel system demonstrated remarkable cell-adhesive capabilities, effectively promoting cell attachment and, proliferation. Moreover, the swelling and degradation behaviors of the hydrogels are pH responsiveness. Sericin hydrogel releases drugs in a sustained manner. Furthermore, this study addresses the challenge of sterilizing sericin hydrogels (sterilization will inevitably lead to the destruction of their structures). In addition, it challenges the prior notion that sericin extracted under high temperature and pressure is difficult to directly cross-linked into a stable hydrogel. This developed hydrogel system in this study holds promise to be a new multifunctional platform expanding the application area scope of sericin.

A comprehensive review of recent advances in silk sericin: Extraction approaches, structure, biochemical characterization, and biomedical applications

Silks are natural polymers that have been widely used for centuries. Silk consists of a filament core protein, termed fibroin, and a glue-like coating substance formed of sericin (SER) proteins. This protein is extracted from the silkworm cocoons (particularly Bombyx mori) and is mainly composed of amino acids like glycine, serine, aspartic acid, and threonine. Silk SER can be obtained using numerous methods, including enzymatic extraction, high-temperature, autoclaving, ethanol precipitation, cross-linking, and utilizing acidic, alkali, or neutral aqueous solutions. Given the versatility and outstanding properties of SER, it is widely fabricated to produce sponges, films, and hydrogels for further use in diverse biomedical applications. Hence, many authors reported that SER benefits cell proliferation, tissue engineering, and skin tissue restoration thanks to its moisturizing features, antioxidant and anti-inflammatory properties, and mitogenic effect on mammalian cells. Remarkably, SER is used in drug delivery depending on its chemical reactivity and pH-responsiveness. These unique features of SER enhance the bioactivity of drugs, facilitating the fabrication of biomedical materials at nano- and microscales, hydrogels, and conjugated molecules. This review thoroughly outlines the extraction techniques, biological properties, and respective biomedical applications of SER.

Characterization and Evaluation of Silk Sericin-Based Hydrogel: A Promising Biomaterial for Efficient Healing of Acute Wounds

The present study was aimed to prepare the potent silk sericin-based hydrogels in combination with plant extracts (curcumin and banana peel powder) and silver nanoparticles (AgNPs) to accelerate the acute wound healing process. Experimental excision wounds were created in mice by biopsy puncture, and the wound healing potential of silk sericin (2%)-based hydrogel and its combinations with curcumin (2%), banana peel powder (2%), and AgNPs (2%) was estimated by calculating the percent wound contraction, healing time, histology of skin tissues, and different biochemical tests. The results showed that the mice treated with sericin-based hydrogels showed significantly (P < 0.001) high percent wound contraction as compared to negative control, and wounds were healed in 11 days. The histological evaluation also showed that wounds covered with hydrogels were healed more than the uncovered wounds. Furthermore, the results of biochemical tests revealed that the treatment groups showed a significant (P < 0.001) decrease in the serum level of pro-inflammatory cytokines (IL-6). A significant (P < 0.001) increase in anti-inflammatory cytokines (IL-10) and anti-oxidant enzymes was observed in treatment groups. The highest wound healing potential was observed by sericin-based hydrogel containing banana peel powder, leaving behind the commercially available ointment polyfax (positive control). It can be concluded that the silk sericin-based hydrogels in combination with plant extract and AgNPs can be used as natural biomaterials in wound dressing for the rapid healing of acute wounds.

Silk sericin conjugated magnesium oxide nanoparticles for its antioxidant, anti-aging, and anti-biofilm activities

The Silk sericin protein was conjugated with magnesium oxide (MgO) nanoparticles to form SS-MgO-NPs . UV, XRD, FTIR, SEM, DLS, and EDX were used to confirm the formation of SS-MgO-NPs. The absorption band of SS-MgO-NPs using UV-visible spectra was observed at 310 nm, with an average size of the nanoparticles was 65-88 nm analyzed from DLS. The presence of alcohol, CN, and CC, alkanes, alkenes, and cis alkenes, in silk sericin, is confirmed by FT-IR and may act as a stabilizing agent. Later SS-MgO-NPs were evaluated for antioxidant, antibacterial, anti-biofilm, ,anti-aging, and anticancer properties. The SS-MgO-NPs inhibited the formation of biofilm of Pseudomonas aeruginosa and Bacillus cereus. The blood compatibility of SS-MgO-NPs, delaying coagulation was observed using human, blood, and goat blood samples. The SS-MgO-NPs exhibited significant anticancer activity on MCF-7 (IC₅₀ 207.6 μg/mL) cancer cell lines. Correspondingly, SS-MgO-NPs demonstrated dose-dependent inhibition of the enzymes in the following order collagenase > elastase > tyrosinase > hyaluronidase, with IC₅₀ values of 75.3, 85.3, 133.6, and 156.3 μgmL^-1, respectively. This exhibits the compoundposses anti-aging properties. So, in in vitro settings, SS-MgO-NPs can be used as an antibacterial, anti-aging, and anticancer agent. Additionally, in vivo research is necessary to validate its therapeutic applications.

Silk Sericin: A Promising Sustainable Biomaterial for Biomedical and Pharmaceutical Applications

Silk is a natural composite fiber composed mainly of hydrophobic fibroin and hydrophilic sericin, produced by the silkworm Bombyx mori. In the textile industry, the cocoons of B. mori are processed into silk fabric, where the sericin is substantially removed and usually discarded in wastewater. This wastewater pollutes the environment and water sources. However, sericin has been recognized as a potential biomaterial due to its biocompatibility, immunocompatibility, biodegradability, anti-inflammatory, antibacterial, antioxidant and photoprotective properties. Moreover, sericin can produce hydrogels, films, sponges, foams, dressings, particles, fibers, etc., for various biomedical and pharmaceutical applications (e.g., tissue engineering, wound healing, drug delivery, cosmetics). Given the severe environmental pollution caused by the disposal of sericin and its beneficial properties, there has been growing interest in upcycling this biomaterial, which could have a strong and positive economic, social and environmental impact.

Study of the Antioxidative Effects of Bombyx mori Silk Sericin in Cultures of Murine Retinal Photoreceptor Cells

The availability of natural substances able to fulfill the role of antioxidants in a physiologic environment is important for the development of therapies against diseases associated with excessive production of reactive oxygen species and ensuing oxidative stress. Antioxidant properties have been reported episodically for sericin, a proteinaceous constituent of the silk thread in the cocoons generated by the larvae of the Lepidoptera order. We investigated the sericin fractions isolated from the cocoons spun by the domesticated (Bombyx mori) silkworm. Three fractions were isolated and evaluated, including two peptidoid fractions, the crude sericin and the purified (dialyzed) sericin, and the non-peptidoid methanolic extract of the crude fraction. When subjected to Trolox equivalent antioxidant capacity (TEAC) assay, the extract showed much higher antioxidant capacity as compared to the crude or purified sericin fractions. The three fractions were also evaluated in cultures of murine retinal photoreceptor cells (661 W), a cell line that is highly susceptible to oxidants and is crucially involved in the retinopathies primarily caused by oxidative stress. The extract displayed a significant dose-dependent protective effect on the cultured cells exposed to hydrogen peroxide. In identical conditions, the crude sericin showed a certain level of antioxidative activity at a higher concentration, while the purified sericin did not show any activity. We concluded that the non-peptidoid components accompanying sericin were chiefly responsible for the previously reported antioxidant capacity associated with sericin fractions, a conclusion supported by the qualitative detection of flavonoids in the extract but not in the purified sericin fraction.

Functionality of Silk Cocoon (Bombyx mori L.) Sericin Extracts Obtained through High-Temperature Hydrothermal Method

Sericin, a textile waste, can be used for antioxidant and skin-whitening purposes. The hydrothermal method of extracting sericin is more eco-friendly than are chemical and enzymatic methods. In this study, silk cocoons were cut into pieces and then subjected to hydrothermal extraction at three temperatures (160, 200, and 220 °C) to obtain sericin extracts (Sericin160, Sericin200, and Sericin220, respectively). Antioxidant activity and tyrosinase inhibition were measured to determine the extracts' effectiveness. Sericin220 was the strongest antioxidant, with total phenol content, total flavonoid content, and ferric reducing power of 62.19 ± 0.04 mg gallic acid equivalents/g dry weight, 0.07 ± 0.01 mg quercetin equivalent/g dry weight, and 181.49 ± 0.024 mg vitamin C equivalent/g dry weight, respectively. The half-maximal inhibitory concentrations for DPPH and ABTS free-radical scavenging ability were 6.41 ± 0.05 and 0.79 ± 0.37 mg/mL, respectively. Sericin220 also exhibited the highest tyrosinase inhibition activity (70.82 ± 4.1 mg vitamin C equivalent/g), indicating its whitening potential.

Sericin based nanoformulations: a comprehensive review on molecular mechanisms of interaction with organisms to biological applications

BACKGROUND

The advances in products based on nanotechnology have directed extensive research on low-cost, biologically compatible, and easily degradable materials.

MAIN BODY

Sericin (SER) is a protein mainly composed of glycine, serine, aspartic acid, and threonine amino acids removed from the silkworm cocoon (particularly Bombyx mori and other species). SER is a biocompatible material with economic viability, which can be easily functionalized due to its potential crosslink reactions. Also, SER has inherent biological properties, which makes possible its use as a component of pharmaceutical formulations with several biomedical applications, such as anti-tumor, antimicrobials, antioxidants and as scaffolds for tissue repair as well as participating in molecular mechanisms attributed to the regulation of transcription factors, reduction of inflammatory signaling molecules, stimulation of apoptosis, migration, and proliferation of mesenchymal cells.

CONCLUSION

In this review, the recent innovations on SER-based nano-medicines (nanoparticles, micelles, films, hydrogels, and their hybrid systems) and their contributions for non-conventional therapies are discussed considering different molecular mechanisms for promoting their therapeutic applications.

Sericin based nanoformulations: a comprehensive review on molecular mechanisms of interaction with organisms to biological applications

BACKGROUND

The advances in products based on nanotechnology have directed extensive research on low-cost, biologically compatible, and easily degradable materials.

MAIN BODY

Sericin (SER) is a protein mainly composed of glycine, serine, aspartic acid, and threonine amino acids removed from the silkworm cocoon (particularly Bombyx mori and other species). SER is a biocompatible material with economic viability, which can be easily functionalized due to its potential crosslink reactions. Also, SER has inherent biological properties, which makes possible its use as a component of pharmaceutical formulations with several biomedical applications, such as anti-tumor, antimicrobials, antioxidants and as scaffolds for tissue repair as well as participating in molecular mechanisms attributed to the regulation of transcription factors, reduction of inflammatory signaling molecules, stimulation of apoptosis, migration, and proliferation of mesenchymal cells.

CONCLUSION

In this review, the recent innovations on SER-based nano-medicines (nanoparticles, micelles, films, hydrogels, and their hybrid systems) and their contributions for non-conventional therapies are discussed considering different molecular mechanisms for promoting their therapeutic applications.

Silk Sericin-Polylactide Protein-Polymer Conjugates as Biodegradable Amphiphilic Materials and Their Application in Drug Release Systems

Silk sericin (SS) is a byproduct of silk production. In order to transform it into value-added products, sericin can be used as a biodegradable and pH-responsive building block in drug delivery materials. To this end, amphiphilic substances were synthesized via the conjugation of hydrophobic polylactide (PLA) to the hydrophilic sericin using a bis-aryl hydrazone linker. PLA was esterified with a terephthalaldehydic acid to obtain aromatic aldehyde terminated PLA (PLA-CHO). In addition, lysine groups of SS were modified with the linker succinimidyl-6-hydrazino-nicotinamide (S-HyNic). Then, both macromolecules were mixed to form the amphipilic protein-polymer conjugate in buffer-DMF solution. The formation of bis-aryl hydrazone linkages was confirmed and quantified by UV-vis spectroscopy. SS-PLA conjugates self-assembled in water into spherical multicompartment micelles with a diameter of around 100 nm. Doxorubicin (DOX) was selected as a model drug for studying the pH-dependent drug release from SS-PLA nanoparticles. The release rate of the encapsulated drug was slower than that of the free drug and dependent on pH, faster at pH 5.0, and it resulted in a larger cumulative amount of drug released than at physiological pH of 7.4. The SS-PLA conjugate of high PLA branches showed smaller particle size and lower loading capacity than the one with low PLA branches. Both SS-PLA conjugates had negligible cytotoxicity, whereas after loading with DOX, the SS-PLA micelles were highly toxic for the human liver carcinoma immortalized cell line HepG2. Therefore, the SS-based biodegradable amphiphilic material showed great potential as a drug carrier for cancer therapy.

Chromatographic profiling of silk sericin for biomedical and cosmetic use by complementary hydrophylic, reversed phase and size exclusion chromatographic methods

Silk sericin (SS) is, together with silk fibroin (SF), one of the two proteins forming the silkworm cocoon. SS is ideal ingredient for cosmetic applications in the formulation of specific products for skin care and hair due to its peculiar physical-chemical composition. SS also showed a great potential in different pharmacological and biotechnological applications, as anticancer drug, anticoagulant, cell culture additive, wound healing agent and drug delivery carrier. Reasons for SS use in biomedical applications derive from its physical-chemical composition. As a consequence, a detailed characterization of SS in terms of average molecular weight, molecular weight distribution and hydro/lipophilic character is crucial to properly address and assess its quality, cosmetic or pharmacological use. In this study, the application of different and complementary chromatographic modes allows a detailed investigation of SS protein isolated from wastewater using two diverse extraction methods. Hydrophilic interaction liquid chromatography (HILIC using an AdvanceBio Glycan Map column) and reverse phase (RP using Symmetry300 C18 column) were applied to intact protein characterization to derive data on protein hydrophilicity and on hydrophobic components of the two SS preparations (SS#1 and SS#2). A higher hydrophilic character of SS#1 was observed by HILIC trace, coherently with the preparation method used, while no significant differences in hydrophobicity were detectable in the RPLC separations. Size distribution was also defined by using a SEC-UV-MS method (using TSKgel SuperSW2000 column) properly optimized to maximize both the size selectivity and the method sensitivity. Taken together, the chromatographic data allowed to better characterize the SS samples obtained by different extraction methods, and the structural properties were correlated to their biological activities.

Artificial spinning of natural silk threads

Silk producing arthropods spin solid fibres from an aqueous protein feedstock apparently relying on the complex structure of the silk protein and its controlled aggregation by shear forces, alongside biochemical changes. This flow-induced phase-transition of the stored native silk molecules is irreversible, environmentally sound and remarkably energy efficient. The process seemingly relies on a self-assembling, fibrillation process. Here we test this hypothesis by biomimetically spinning a native-based silk feedstock, extracted by custom processes, into silk fibres that equal their natural models' mechanical properties. Importantly, these filaments, which featured cross-section morphologies ranged from large crescent-like to small ribbon-like shapes, also had the slender cross-sectional areas of native fibres and their hierarchical nanofibrillar structures. The modulation of the post-draw conditions directly affected mechanical properties, correlated with the extent of fibre crystallinity, i.e. degree of molecular order. We believe our study contributes significantly to the understanding and development of artificial silks by demonstrating successful biomimetic spinning relies on appropriately designed feedstock properties. In addition, our study provides inspiration for low-energy routes to novel synthetic polymers.

Bioinspired mineralization of a functionalized injectable dense collagen hydrogel through silk sericin incorporation

The incorporation of silk sericin into injectable dense collagen hydrogels represents a powerful approach to mimic the biomineralization process, together with the osteogenic stimulation of seeded mesenchymal stem cells, in vitro.

Three-Dimensionally Printed Silk-Sericin-Based Hydrogel Scaffold: A Promising Visualized Dressing Material for Real-Time Monitoring of Wounds

A wound dressing which can be convenient for real-time monitoring of wounds is particularly attractive and user-friendly. In this study, a nature-originated silk-sericin-based (SS-based) transparent hydrogel scaffold was prepared and evaluated for the visualization of wound care. The scaffold was fabricated from a hybrid interpenetrating-network (IPN) hydrogel composed of SS and methacrylic-anhydride-modified gelatin (GelMA) by 3D printing. The scaffold transformed into a highly transparent hydrogel upon swelling in PBS, and thus, anything underneath could be easily read. The scaffold had a high degree of swelling and presented a regularly macroporous structure with pores around 400 μm × 400 μm, which can help maintain the moist and apinoid environment for wound healing. Meanwhile, the scaffolds were conducive to adhesion and proliferation of L929 cells. A coculture of HaCaT and HSF cells on the scaffold showed centralized proliferation of the two cells in distributed layers, respectively, denoting a promising comfortable environment for re-epithelialization. Moreover, in vivo studies demonstrated that the scaffold showed no excessive inflammatory reaction. In short, this work presented an SS-based transparent hydrogel scaffold with steerable physical properties and excellent biocompatibility through 3D printing, pioneering promising applications in the visualization of wound care and drug delivery.

Polyethylenimine-functionalized silk sericin beads for high-performance remediation of hexavalent chromium from aqueous solution

The enhancement of the metal adsorption and remediation performance of biomass-based adsorbents is an important challenge in heavy metal removal processes. One of the most viable and practical approaches in accomplishing a high metal removal efficiency is the surface modification of natural polymer adsorbents with functional polymeric materials. In the present study, polyethylenimine (PEI)-modified silk sericin beads were fabricated. The PEI modification process was confirmed and analyzed by Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS)-based elemental analysis. The Cr(VI) remediation capabilities of PEI-modified sericin beads were analyzed by testing Cr(VI) removal from contaminated water. The results show that the Cr(VI) removal capacity of PEI-modified sericin beads was 365.3 mg/g, which is significantly higher than that of pristine sericin beads (34.56 mg/g). During the Cr(VI) removal process, Cr(VI) adsorption and reduction to Cr(III) occurred simultaneously. The results herein reveal that the synthesized PEI-modified sericin beads are a promising material for Cr(VI) adsorption and detoxification of aqueous solution.

Silk nanofibril self-assembly versus electrospinning

Natural silk fibers represent one of the most advanced blueprints for (bio)polymer scientists, displaying highly optimized mechanical properties due to their hierarchical structures. Biotechnological production of silk proteins and implementation of advanced processing methods enabled harnessing the potential of these biopolymer not just based on the mechanical properties. In addition to fibers, diverse morphologies can be produced, such as nonwoven meshes, films, hydrogels, foams, capsules and particles. Among them, nanoscale fibrils and fibers are particularly interesting concerning medical and technical applications due to their biocompatibility, environmental and mechanical robustness as well as high surface-to-volume ratio. Therefore, we introduce here self-assembly of silk proteins into hierarchically organized structures such as supramolecular nanofibrils and fabricated materials based thereon. As an alternative to self-assembly, we also present electrospinning a technique to produce nanofibers and nanofibrous mats. Accordingly, we introduce a broad range of silk-based dopes, used in self-assembly and electrospinning: natural silk proteins originating from natural spinning glands, natural silk protein solutions reconstituted from fibers, engineered recombinant silk proteins designed from natural blueprints, genetic fusions of recombinant silk proteins with other structural or functional peptides and moieties, as well as hybrids of recombinant silk proteins chemically conjugated with nonproteinaceous biotic or abiotic molecules. We highlight the advantages but also point out drawbacks of each particular production route. The scope includes studies of the natural self-assembly mechanism during natural silk spinning, production of silk fibrils as new nanostructured non-native scaffolds allowing dynamic morphological switches, as well as studying potential applications. This article is categorized under:  Biology-Inspired Nanomaterials > Peptide-Based Structures  Nanotechnology Approaches to Biology > Nanoscale Systems in Biology  Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.