Silk Research Articles

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.

Continuous Fluid Catalytic Reactor Constructed Based on In Situ Growth of MOF Immobilized Enzyme on Ordered Silk Fabric

Continuous Fluid Catalytic Reactor Constructed Based on In Situ Growth of MOF Immobilized Enzyme on Ordered Silk Fabric

Naturally Bred Korean Silkworm Cocoon Showing Strong Green Fluorescence and Its Textile-Based Environmental Sensing Applications

ABSTRACT Mulberry silkworms have provided many valuable byproducts to humans for 5,000 years. However, numerous possibilities for their utilization still exist owing to the countless varieties of silkworms. Here, we report the application of Yeonnokjam silk (pistachio silk, PS), one of the characteristic silk varieties in Korea, as a smart fabric environmental sensor. Unlike the previously reported extrinsically modified silk varieties, this new silk textile emits fluorescence under external stimuli. PS cocoons were exposed to different concentrations of HCl vapors. Due to the large surface-to-volume ratio of the cocoon textile, a very low concentration (5 ppm) of HCl vapor can be detected by reading the decrease in the fluorescence intensity. At a lethal concentration (3000 ppm), an instantaneous fluorescence response is obtained. Additionally, the fluorescent pigment in PS can respond to temperature and can be extracted using ethanol, indicating that PS exhibits temperature and ethanol-sensing capabilities. The findings of this study prove that natural PS can be used in bio-optical applications.

A Study on Migrated Silk Entrepreneurs for Economic Impact with Special Reference to Kancheepuram

This research paper delves into the economic impacts of migrated silk entrepreneurs in Kancheepuram, a region synonymous with silk production in India. The study's primary objective is to uncover the contributions, challenges, and opportunities that migrated entrepreneurs bring to the traditional silk industry and to assess their role in the economic development of Kancheepuram. Employing a qualitative research design, the methodology hinges on semi-structured interviews with 30 migrated silk entrepreneurs, analysed through thematic analysis using NVivo 12 to identify recurring themes. Key findings reveal that migrated entrepreneurs significantly contribute to job creation, innovation, and market expansion in Kancheepuram's silk industry. They face considerable challenges, including market competition, access to capital, and regulatory hurdles, yet identify notable opportunities in technological advancements, sustainability, and global market integration. The study fills a crucial gap in the literature by offering detailed insights into the complex dynamics between migration, entrepreneurship, and economic development in a traditional industry context. The implications of this research are manifold, highlighting the need for supportive policy frameworks that recognize the unique needs and potential of entrepreneurs in traditional sectors. Furthermore, it underscores the importance of fostering an environment conducive to innovation and sustainability, thereby enhancing the global competitiveness of traditional industries like silk production.

Investigating parameters affecting the real and virtual drapability of silk fabrics for traditional Hanbok

This paper presents research into the parameters affecting the real and virtual drapability of silk fabrics for traditional Hanbok. The KES-FB (Kawabata evaluation system of fabric) and the CLO (3D fashion design software) fabric kit system were used to evaluate the physical properties. The relationships between physical properties and the drape coefficient of silk fabrics were statistically analyzed. It was determined whether the objectified real fabric data could be used and applied as a database when implementing virtual clothing using a 3D virtual clothing program. The KES-FB properties and CLO fabric kit results indicated that the bending property and weight were significantly correlated with the drape coefficient. The bending rigidity and weight per unit area were influential parameters of the drape coefficient. The regression analysis results of both the KES-FB and the CLO fabric kit revealed that bending rigidity and thickness were statistically significantly correlated with the drape coefficient. The bending property was the most determining parameter for the drape coefficient of silk fabrics. A statistically significant difference between the real and virtual drape coefficients of stiffer silk fabrics was found. In the CLO 7.1 program, the accuracy of drape implementation of virtual fabrics was found to be useful when the bending stiffness of the actual fabric was less than 0.089 gf·cm2/cm and the elasticity was more than 1.03%. The results revealed that more research on the program modeling method considering the mechanical and physical properties of the real fabric and its structure is needed.

Application of Nanotechnology in Sericulture: A Review

Nanoparticles (NPs) have emerged as promising tools for enhancing mulberry cultivation and the performance of silkworms, crucial for silk production. Mulberry, a vital plant for silk production, demands proper nutrient management for optimal growth and leaf production. Application of NPs, particularly zinc oxide and iron oxide, has shown significant improvements in mulberry growth parameters. Furthermore, NPs have demonstrated positive effects on silkworm larvae, enhancing feed efficiency and growth parameters, leading to better cocoon traits. Silkworms fed with NPs-treated mulberry leaves exhibited increased body weight, cocoon weight, and silk filament characteristics. Additionally, NPs have shown promise in enhancing silkworm reproduction and fecundity while conferring resistance against diseases like BmNPV. Various NPs, including TiO2, silver and chitosan, have exhibited antibacterial properties against silkworm pathogens, thereby contributing to disease prevention. Overall, NPs offer a sustainable and effective approach to enhance mulberry cultivation, improve silkworm performance and mitigate disease risks, thus potentially revolutionizing silk production practices.

Exploring the Impact of Neo-Confucianism on Material Art Through the Artistic Characteristics of Kesi in Song Dynasty

The Song Dynasty was a period of great development in ancient Chinese art, including material art. Kesi, a type of material art is taken as an instance to explore how Neo-Confucianism influenced the development of art during the Song dynasty, a period marked by new developments in thought and culture. Neo-Confucianism impacted not only the political realm but also the art of painting, and further had a significant influence on the composition, coloring, and techniques of silk textile. The ornamental kesi taperstry paintings of the Song dynasty as a material artistry, similar with the style of flower and bird paintings of the period, focused on the realistic depiction of objects, using silk as a substitute for the brush. With image analysis, historical document research, and the corroboration between documents and physical objects, this article elucidates the artistic characteristics of kesi (silk tapestry) under the influence of the "investigation of things to extend knowledge" philosophy in Song dynasty.

Environmental Dyeing and Functionalization of Silk Fabrics with Natural Dye Extracted from Lac.

Most traditional synthetic dyes and functional reagents used in silk fabrics are not biodegradable and lack green environmental protection. Natural dyes have attracted more and more attention because of their coloring, functionalization effects, and environmental benefits. In this study, natural dyes were extracted from lac and used for coloring and functionalization in silk fabrics without any other harmful dyes. The extraction conditions were studied and analyzed by the univariate method. The optimal extraction process was that the volume ratio of ethanol to water was 60:40 with a solid-liquid ratio of 1:10, and reacting under the neutrality condition for 1 h at 70 °C. Silk fabric can be dyed dark owing to the certain lifting property of lac. After being dyed by Al3+ post-medium, the levels of the washing fastness, light fastness, and friction fastness of silk fabric are all above four with excellent fastness. The results show that the dyed silk fabrics have good UV protection, antioxidation, and antibacterial properties. The UV protection coefficient UPF is 42.68, the antioxidant property is 98.57%, and the antibacterial property can reach more than 80%. Therefore, the dyeing and functionalization of silk fabrics by utilizing naturally lac dyes show broad prospects in terms of the application of green sustainable dyeing and functionalization.

COLOR STRENGTH AND COLOR DIFFERENCE OF COTTON AND SILK FABRICS DYED WITH EXTRACTS FROM BUTTERFLY PEA FLOWERS

Natural dyes have always been of interest due to their non-toxicity and environmental benefits. In this work, cotton and silk fabrics were dyed with extracts from butterfly pea (BP) flowers. Accordingly, the effects of pH value, liquor ratio, dyeing concentration, temperature, exhausting time and mordanting agents on the color strength (K/S) and the color difference (E) of cotton and silk fabrics dyed with BP extracts were investigated. The experimental results showed that the K/S and E values of dyed cotton fabrics were much higher than those of dyed silk fabrics. The research also established the most suitable conditions for dyeing cotton and silk fabrics with BP extracts as being the following: pH of 6.0, liquor ratio of 1:5, dyeing time of 60 min, at 70 °C for cotton and 60 °C for silk. Notably, four different types of mordants, including potassium aluminium sulfate (KAl(SO4)2.12.H2O), copper sulfate (CuSO4.5H2O), ferrous sulfate (FeSO4.7H2O) and tannin, were used to enhance dyeability of cotton and silk fabrics with BP extracts. There were slight differences in the E values of mordanted and unmordanted samples, while the K/S values improved significantly, especially in the samples mordanted with tannins. Color fastness and color staining to washing and rubbing were also examined, indicating that treated silk fabrics achieved higher values than treated cotton fabrics.

Standardization and optimization of concentration of different mordants on the dyeing efficiency of Lawsonia inermis (Henna) on silk fibre

The natural dye henna usually being recognized as lawsone is a red-orange pigment that has long been used for the coloration of skin and hair as well as textile materials. This natural colorant garners the attention of researchers throughout the globe for the coloration of textile materials due to the fact that its color can easily be harmonized with nature. In the current study, concentration of different mordants (ferrous sulphate, alum, copper sulphate, and citric acid) were standardized on silk fibre using henna dye. To obtain the results, the study was divided into two experiments. The dyed fibre samples were analyzed for absorbance, color coordinates color strength, and color fastness properties. In experiment-I, standardization of different mordants at different concentrations were done while dye percentage was kept constant at 15%. Based on colour and acceptability results, ferrous sulphate at 2 and 4% was selected. In experiment II, optimization of the level of ferrous sulphate at 2, 3, and 4% was used along with 15% henna dye. Based on the results, it was concluded that 15% of henna dye along with 3% of ferrous sulphate gave better results on silk fibre.

Cocoon Care : Transformative Monitoring For Sericulture

Sericulture is the process of cultivating silkworms and extracting silk from them. The caterpillars of the domestic silk moth (also called „Bombyx Mori‟) are the most commonly used silkworm species in sericulture. Other types of silkworms (such as Eri, Muga, and Tasar) are also cultivated for the production of „wild silks‟. Silk is known as the queen of textiles due to its softness, durability, and luster. Furthermore, the silk fibers provide characteristics that are superior toany other type of fiber (e.g., water absorbency, heat resistance, dyeing efficiency, and luster). This textile is obtained from cocoons spun by larvae known as silkworm (Bombyx mori), which were discovered in China between 2600 and 2700 BC. The process of silk production is known as sericulture, beginning with the rearing of the silkworm1

Comparative Study on Dyeing Behaviours of Tasar and Tasar Blended Silk Fabrics

Tasar silk is widely sought after because to its natural beauty, durability, sustainability, and cultural relevance. Despite the long-standing yearning for Tasar textiles in their natural colour, weavers can only manufacture a limited number of different designs and types of the silk.It has become necessary to dye the Tasar fabric a different colour since the younger generation requires 100% Tasar cloths in a range of styles and colour combinations.Some manufacturers are now dyeing Tasar fabrics in smaller quantities, but their processing quality is subpar due to non-compliance with correct procedures for color concentration, time intervals, and warm washing, resulting in uneven dyeing, inconsistent hues, and poor fastness attributes.However, considering the current circumstances, it is essential that the Tasar Silk Industry understands how both pure Tasar fabrics and Tasar-blended fabrics are endowed with the fastness properties of Lanaset, Acid, and Reactive dyes.In this article, a comperative study was carried out to understand the dyeing behaviour of Acid, Lanaset and Reactive dye on Tasar x Tasar fabrics and Tasar x Mulberry fabrics. The fabric samples were prepared accordingly to evaluate the tensile properties, colour fastness to rubbing, perspiration, washing & light and colour strength. According to the findings, reactive dyeing had a larger percentage of strength loss than Lanaset and acid dyeing. Relative to other materials, acid-dyed fabrics required less washing, according to fastness data. However, reactive dyed fabrics did not perform well when it came to perspiration fastness. Lanaset dyed fabrics reacted faster to light than other types due to the presence of metal ions. The studies also showed that materials colored reactively had stronger color retention. This attempt shall provide the blue print for the industry to emulate in the future.

Unveiling the Use of Natural and Early Synthetic Dyes in Indonesian Historical Silk Textiles

Unveiling the Use of Natural and Early Synthetic Dyes in Indonesian Historical Silk Textiles

Green-process preparation and characterizations of optically transparent, thermally stable and mechanically superior regenerated silk-hyaluronate composite films

High-performance regenerated silk-hyaluronate composite films prepared by an environment-friendly process were highly desirable for medical dressing base material. In this study, sericin was removed from silk by steam treatment without using any chemical reagent, and a low concentration solution of Na2CO3 was used as a green process to dissolve silk fibers. Then the obtained silk fibroin was physically blended with sodium hyaluronate to generate optically transparent, thermally stable and mechanically superior regenerated silk-hyaluronate films. The results of structural characterizations and property tests showed that the insoluble silk short fibers prepared by the dissolution of Na2CO3 were dominated by a β-sheet crystalline structure while the soluble silk fibroins by an amorphous structure. Moreover, both insoluble silk short fibers and soluble silk fibroins could form uniform composite films with a low coefficient of thermal expansion after being blended with sodium hyaluronate, which were named as insoluble silk film (ISH) and soluble silk film (SSH), respectively. The tensile strength of ISH could reach 138.8 MPa and SSH reached 153.9 MPa, which were 65.7 % and 30.5 % higher than that of the commercial control insoluble fibroin film (83.8 MPa) and commercial control soluble fibroin film (117.9 MPa), and 173.2 % and 203.0 % higher than that of pure hyaluronate film (50.8 MPa), respectively. Also, ISH and SSH had a modulus higher than 3 GPa. In this study, the low-concentration Na2CO3 method provides a simple and green technique for the preparation of high performance silk-hyaluronate composite materials.

Superstrong and tough silk fibers cross-linked with functionalized graphene

Natural silkworm silks with an intriguing integration of good strength, modulus, toughness and biocompatibility, have been widely used in textile and medical industry. However, the strength of silkworm silks is inferior to that of spider dragline silks, which are the strongest natural silks but extremely low yield. Herein, we develop a feasible strategy to continuously produce superstrong and tough regenerated silk fibers (RSFs) through the reconstruction of hierarchical and cross-linked architectures. Amine functionalized graphene (NH2-G) has been introduced to improve the content of β-sheet and crystalline orientation, and glutaraldehyde (GA) has been used to bridge NH2-G and silk micro/nanofibrils (SNFs) to form a highly interconnected and closely packed network, resulting in the remarkably improvement of mechanical properties. The resultant fibers exhibit an excellent tensile strength of 1029.6 ± 144.8 MPa, a Young's modulus of 16.8 ± 1.5 GPa, and a toughness of 277.4 ± 17.0 MJ/m3, exceeding those of the natural silkworm silks, spider dragline silks and most other previously reported regenerated silk fibers. We believe that the high-performance silk-based fibers are promising applications in lightweight and advanced structural materials.

Diffusion properties of silk-derived laser-induced graphene

Direct laser writing is an efficient method for producing graphene on a substrate. This study investigated the formation of laser-induced graphene on silk fibers using molecular dynamics simulation and ReaxFF. The use of natural substrates such as silk fibers in laser-induced graphene has significant advantages in the industry due to their biodegradability and recyclability, making silk a preferred component in biomaterials and wearable biosensors. The study also looked into the diffusion coefficient of silk-derived laser-induced graphene using the MSD method and ReaxFF approach at varying temperatures and lengths. The simulation results showed that there is a non-linear relationship between the diffusion coefficient and temperature, while a linear relationship exists between the diffusion coefficient and graphene size. Interestingly, larger graphene structures exhibited a lower diffusion coefficient.

Polydopamine/SWCNT Ink Functionalization of Silk Fabric to Obtain Electroconductivity at a Low Percolation Threshold.

This study presents the functionalization of silk fabric with SWCNT ink. The first step was the formation of a polydopamine (PDA) thin coating on the silk fabric to allow for effective bonding of SWCNTs. PDA formation was carried out directly on the fabric by means of polymerization of dopamine in alkali conditions. The Silk/PDA fabric was functionalized with SWCNT ink of different SWCNT concentrations by using the dip-coating method. IR and Raman analyses show that the dominant β-sheet structure of silk fibroin after the functionalization process remains unchanged. The heat resistance is even slightly improved. The hydrophobic silk fabric becomes hydrophilic after functionalization due to the influence of PDA and the surfactant in SWCNT ink. The ink significantly changes the electrical properties of the silk fabric, from insulating to conductive. The volume resistance changes by nine orders of magnitude, from 2.4 × 1012 Ω to 2.3 × 103 Ω for 0.12 wt.% of SWCNTs. The surface resistance changes by seven orders of magnitude, from 2.1 × 1012 Ω to 2.4 × 105 Ω for 0.17 wt.% of SWCNTs. The volume and surface resistance thresholds are determined to be about 0.05 wt.% and 0.06 wt.%, respectively. The low value of the percolation threshold indicates efficient functionalization, with high-quality ink facilitating the formation of percolation paths through SWCNTs and the influence of the PDA linker.

Enhancing the Production of Eco-Friendly Silk Fabrics through the Application of Nonthermal Plasma Wettability Techniques.

The combination of the effects of nonthermal plasma using atmospheric pressure of plasma jet and the photocatalytic effects of titanium dioxide nanoparticles was used to study the plasma flow modes, electrical characteristics, nonthermal characteristics, antimicrobial measurements, and surface modifications. Using different wettabilities of argon discharges in a laminar flow: (i) wet I, wettability with 2.4 slm argon mixture with oxygen ratio O2, equivalent to 15 mslm (Ar/O2), and (ii) wet II, wettability (Ar/O2) mixture combined with titanium dioxide, to accelerate the inactivation process on the nonwoven fabric surface. For wet 0, wet I, and wet II discharges, the average rate of heat transfer to the nonwoven silk fabric increased significantly. Specifically, it goes from 104.6 to 118.6 and then to 241.7 mW, respectively. The kinetic deactivation rate of Escherichia coli increases starting at 0.20, then going up to 0.32, and finally reaching 0.57 min-1. The increased wettability of the TiO2 photocatalyst results in an enhanced bactericidal rate, which is caused by both the heat impact from the nonthermal jet and potentially photocatalytic disinfection, leading to the generation of active species. The mechanical parameters owing to different wettabilities and plasma interactions with the fabric membrane were tested for the treated samples, such as stiffness, ultimate yield strength, tensile strength, strain, hardening, elongation, resilience, and toughness.

Rapid identification of silk products by attenuated total reflection–mid-infrared spectroscopy and extreme learning machines

Silk is a high-quality fiber of natural protein and its amino acid composition is close to that of the human skin. The texture of pure silk is elegant, soft and comfortable to wear, with good breathability and hygroscopicity, as well as excel dirt absorption and sterilization. It is essential to identify natural pure silk products and various non-silk and adulterated silk products with other fibers. The work focuses on exploring the feasibility of combining attenuated total reflection–mid-infrared (ATR-MIR) spectroscopy feature selection, extreme learning machines (ELM), and ensemble and for rapid identification of silk products. A dataset consisting of 70 silk samples and 83 other fiber samples was prepared. The dataset is split evenly into training and test sets for building and validating predictive models. Simulated annealing (SA) was used for pre feature selection. A total four kinds of ELM models including full-spectrum, subspace and ensemble models were developed and compared. The optimized local model and the ensemble model achieve the best and most stable performance, i.e., with 100% accuracy. It seems that SA, ELM combined with ATR-MIR technique may be a potential alternative to traditional analytical methods of silk identification, which can avoid time-consuming and labor-intensive chemical analysis.

A prognostic and health management approach using colour fade to determine the condition of silk in a museum display environment

Silk is highly susceptible to fade, often resulting in colour loss to the fabric even when displayed in controlled museum environments. This study applies the engineering-inspired Prognostics and Health Management (PHM) approach to assess the remaining useful life (RUL) of silk fabric in a museum environment, focussing on predicting colour fade as an indicator of degradation. A novel mathematical model is developed to forecast cumulative colour fade of silk upholstery exhibited at the Great Gallery in The Wallace Collection, London. Unlike traditional accelerated aging methods, this model utilises naturally aged samples to estimate the rate of colour change over time. The main contribution of this work lies in the methodology and computational framework for model development using environmental data and conditions of silk in the museum environment. The proposed PHM methodology allows for continuous modifications of the colour fade model to improve accuracy by deploying new data from different silk collections and environments. The article demonstrates a model-based approach for informed decision making in museums regarding display and storage of silk upholstery.