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Tumor necrosis factor-α (TNFα) is a representative marker for inflammation. Silk sericin is known as mild TNFα inducer. The purpose of this study was to compare the level of TNFα among different fractions of silk sericin. Silk sericin was extracted from cocoon and separated it by molecular weight. Each fraction was applied to RAW264.7 cells. The level of TNFα was evaluated by western blot and ELISA assay. In results, the level of TNFα was increased as time-dependent manner. Higher molecular weight fraction of sericin induced higher amount of TNFα than lower molecular weight fraction. In conclusion, different molecular weight fraction of sericin induced TNFα differently. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the last decade, many researchers demonstrated the biological activities of native Bombyx mori silk sericin (SS), and its use is widespread in the cosmetic and biomedical field. However, SS is a polluting material from the silk fibroin textile industry. This paper aims to demonstrate that the industrial wastewater‐derived SS has many biological properties, and can be used as an eco‐friendly product for cosmetic/pharmaceutical purposes with an important impact on the circular economy. RESULTS: We focused on the SS derived from an ad hoc extraction process or industrial degumming wastewater. Both products were preserved with three different methods: lyophilization, spray‐drying and sterilization. All SS were characterized in terms of amino acid content, molecular weight, physical–chemical properties, morphology and size distribution; then we evaluated the biological properties, the cytocompatibility/cytoprotective profile, and the immunomodulatory abilities of SS. Free radical scavenging, anti‐tyrosinase, and anti‐elastase activities of waste SS were confirmed. Waste and standard SS were cytocompatible on human fibroblasts; all SS samples inhibited the proliferation of stimulated peripheral blood mononuclear cells in a dose‐dependent manner. Waste SS showed a significant effect on tumor necrosis factor α and interleukin 10 release. CONCLUSIONS: These results pave the way for using textile wastewater‐derived SS to obtain high‐value‐added products for cosmetic and/or pharmaceutical purposes. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Objective: Silk sericin is a natural polymer with potential utility in biomedical and biotechnological applications. Recombinantly expressed sericin ensures a source of pure protein with no contamination and with multiple properties when expressed as a fusion protein. Hence, the present paper aims to recombinantly express a functional silk sericin fusion protein. Results: In order to develop a more effective sericin protein, we have attempted to recombinantly express a part of sericin sequence, which represents a highly conserved and internally repetitive unit of the sericin1 protein, and its fusion with cecropin B, a potent antimicrobial peptide. Both difficult-to-express proteins were expressed in Escherichia coli and purified by nickel-charged affinity resin. Further, functional assay demonstrated that both proteins were individually active against Gram-positive and negative bacteria, with enhanced bactericidal activity observed in sericin-cecropin B fusion protein. Conclusions: To our knowledge, this is the first report not only on the recombinant expression of sericin as a fusion protein but also the bactericidal possibility of the 38-amino acid serine-rich motif of sericin protein. We also discuss the potential biomedical and biotechnological applications of this sericin hybrid protein. [ABSTRACT FROM AUTHOR]

• Silk sericin, a biomacromolecule, is recovered from silk processing-waste. • Silk sericin is used as an additive in cell culture, cosmetic and health food. • Oral sericin evidently enhanced antioxidation and anti-inflammation. • Sericin improves blood glucose levels & insulin resistance via PI3K/P-AKT/AMPK pathways. • Sericin protein is a potentially functional additive for hypoglycaemic food. The sericin protein from silk-processing waste added to the normal diet at 0.8% (g%) level was administered orally to type 2 diabetic (T2D) mice to investigate its hypoglycaemic effects and mechanism. The oral protein is in the form of silk sericin hydrolysate, obtained from a boiling treatment of 0.025% calcium hydroxide solution. The protein significantly decreased fasting blood glucose, fasting plasma insulin, and glycosylated serum protein levels; improved oral glucose tolerance and insulin tolerance, and enhanced antioxidative activities. The protein could ameliorate the pathological damage in pancreatic β-cells and the liver tissue. It enhanced the expression of key proteins and enzymes, including insulin receptor, insulin receptor substrate, PI3K, phosphorylated-AKT, hepatic kinase, GLUT4, glycogen synthase, GSK3β, GLK, PFK1, PKM2, and AMPKα, which are related to insulin metabolism and glycolysis. The protein also reduced the expression of G6Pase, PCK, and ACC, which are related to gluconeogenesis and lipid metabolism in the liver, and decreased the expression of TNF-α, IL-6, P65, and IKKβ related to inflammation. In general, sericin could maintain normal glucose levels and regulate insulin secretion, insulin and lipid metabolism, and inhibition of inflammation. Therefore, sericin protein could be developed into a novel functional health food with significantly hypoglycaemic effect. [ABSTRACT FROM AUTHOR]

In this work, a kind of amine-type PET fibers was synthesized by reacting hexamethylenediamine (HMDA) with methacrylic acid-g-poly(ethylene terephthalate) (PET-g-MAA) fibers for the adsorption of silk sericin-capped silver nanoparticles (S-AgNPs) to produce antimicrobial fibers. Firstly, PET fibers were grafted MAA by using free radical polymerization technique and HMDA was covalently connected to the grafted PET fibers. Then, for S-AgNPs synthesis, 10 mL of AgNO3 solution (1 mM, 5 mM and 10 mM) was mixed with 10 mL of 1% sericin solution at pH 11. The obtained solution was stirred at room temperature for 24 h. The color change from transparent to yellow–brown indicated the formation of S-AgNPs. AgNPs formation was also determined by measuring the absorbance spectra of S-AgNPs between 300 and 600 nm using UV–Vis spectrophotometer. To determine the antimicrobial properties of S-AgNPs, agar-well diffusion tests were performed. 5 mM and 10 mM S-AgNPs groups showed antimicrobial activity on Escherichia coli and Staphylococcus aureus. After characterization of the synthesized S-AgNPs with UV–Vis spectrophotometer, Zetasizer, FTIR and TEM, the modified PET fibers were coated with S-AgNPs (5 mM and 10 mM). The S-AgNPs coated PET fibers were characterized by FTIR, SEM and X-ray fluorescence spectroscopy. The antimicrobial activities of the obtained PET fibers were investigated on S. aureus and E. coli bacteria by using disk diffusion test. It was found that the S-AgNPs coated modified PET fibers exhibited antimicrobial activities toward both gram-positive and gram-negative bacteria. The resulting polymeric PET fibers containing nano-silver can be used as an antimicrobial surface for many applications such as wound dressing. [ABSTRACT FROM AUTHOR]

Sericin has been used for the treatment of burn wound. The purpose of this study was to compare the wound healing between sericin plus 4-hexylresorcinol (4HR) ointment (SE+4HR) and base only ointment. Total 12 mice were included in this study. SE+4HR group showed significantly smaller wound size than base only group at 3 wk (P<0.05). Surface temperature was higher in SE+4HR group. In conclusion, SE+4HR group showed better wound healing than base only group. [ABSTRACT FROM AUTHOR]

Silk sericin (SS) is derived from natural Bombyx mori silk fibers, and it has the unique biological properties like good biocompatibility and low immunogenicity. However, pure SS material exhibits poor mechanical properties and high water solubility, which greatly reduces the formability of SS material and limits its wide range of applications. In this study, a transglutaminase (TGase) was combinedly used with two custom peptides of GQGEGQG (p-Q) and KKKK (p-K), containing exogenous glutamine and lysine residues, respectively, for facilitating the enzymatic crosslinking of sericin proteins. The efficacy of enzymatic incubation was assessed by the means of SDS-PAGE, size exclusion chromatography chromatogram, and determination of the quantitative changes in amino groups. Properties of the obtained SS membranes based on different treatments were also examined. The results revealed that incubating of SS with TGase and glutamine-containing peptide led to a noticeable increase in the molecular weight compared with others. TGase-mediated treatments had detectable impact on the conformational structures of SS, the obtained formability and mechanical property for the TGase/p-Q treated SS membrane were evidently improved compared to others. The suggestive alternative, based on the combination use of TGase and p-Q has the potential applications for preparation of the sericin-based biomaterials. [ABSTRACT FROM AUTHOR]

The synthesis of lipopeptides from silk sericin was realized in two steps: enzymatic hydrolysis of protein with Alcalase enzyme and the grafting of lipid chain (C 10 , C 12 or C 14) following the Schotten-Baumann reaction. The influence of experimental conditions on the degree of hydrolysis (DH) and the acylation rate (AR) was investigated. Then, equilibrium surface adsorption properties of lipopeptides at air/water interface were studied. The effect of lipopeptide structure, in particular the size of peptide and of the hydrophobic chain, was characterized. Lipopeptides obtained with DH from 20 % to 45 % and AR from 27 % to 41 % were successfully produced. The obtained results demonstrated that sericin peptides have poor amphiphilic properties, whereas lipopeptides efficiently decreased air/water surface tension up to 30.9 mN/m. The surface activity of lipopeptides seem to be closely related to their structure. Sericin lipopeptides show surface properties comparable to those of commercial surfactants, which emphasize the interest of these biomass-derived amphiphilic molecules for potential replacement of petroleum-based surfactants. [Display omitted] • Amphiphilic lipopeptides were obtained from silk sericin. • Hydrophilic peptides were produced by enzymatic hydrolysis of sericin. • Sericin peptides were functionalized with C10, C12 and C14 lipid chains. • The influence of the hydrophilic and the hydrophobic part was investigated. • Silk lipopeptides efficiently decrease surface tension up to 30.9 mN/m. [ABSTRACT FROM AUTHOR]

The main purpose was to elucidate the potential anti-aging impact of sericin, due to its anti-oxidant potential in D-galactose induced mice model. To induce natural aging in mice, a solution of 0.9 % saline containing D-galactose (250 mg/kg b.w.) was injected intraperitoneally for a period of 60 days. In this experiment, 56 male mice were arbitrarily categorized into 8 groups (1: control; 2: D-Galactose (250 mg/kg b.w), Group 3: Sericin (150 mg/kg b.w), Group 4: Metformin (150 mg/kg), Group 5: sericin (P), Group 6; sericin (T), Group 7; Met (P), Group 8; Met (T). The level of Glutathione reductase (2.1 ± 0.2 µmol/L), CAT (0.5 ± 0.0 mmol/mL), Superoxide dismutase (65.4 ± 1.7 U/mL), GSHPx (69.2 ± 1.7 U/l), T3 (3.1 ± 0.7 ng/mL), IL-2 (68.8 ± 1.5 Pg/mL), IL-4 (71.4 ± 4.2 Pg/mL), IgG (0.6 ± 0.0 mg/mL) and IgM (0.6 ± 0.0 mg/mL) were significantly (P < 0.05) decreased whereas the cortisol (22.0 ± 1.5 µg/L), and total cholesterol (229.4 ± 4.2 mg/dL)) were significantly elevated in D-galactose-treated /aged mice. However, administration of sericin significantly reduced the level of oxidative stress in aged mice. Real-time qPCR data showed that the level of telomere length- gene TERT significantly downregulated (10.43 ± 0.1) in the D-Gal-treated mice with respect to control (21.97 ± 0.5). The highest significant upregulation was found in the TERT gene when D-Gal-induced aged mice were treated with sericin (24.74 ± 0.3). Our outcomes showed that sericin gradually recovered the organ indices, and improved the histological changes of the brain, kidney, and liver in D-Gal-induced aging mice. Therefore, concluded that sericin possesses anti-aging effect against D-Gal-induced aging by diminishing oxidative stress, restoring the immune system, and enhancing the antioxidant defense system. [ABSTRACT FROM AUTHOR]

In this paper, Bombyx mori silk sericin nanocarriers with a very low size range were obtained by nanoprecipitation. Sericin nanoparticles were loaded with doxorubicin, and they were considered a promising tool for breast cancer therapy. The chemistry, structure, morphology, and size distribution of nanocarriers were investigated by Fourier transformed infrared spectroscopy (FTIR–ATR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and dynamic light scattering (DLS). Morphological investigation and DLS showed the formation of sericin nanoparticles in the 25–40 nm range. FTIR chemical characterization showed specific interactions of protein–doxorubicin–enzymes with a high influence on the drug delivery process and release behavior. The biological investigation via breast cancer cell line revealed a high activity of nanocarriers in cancer cells by inducing significant DNA damage.

In this work, a novel semi-interpenetrating polymer network (semi-IPN) hydrogel scaffold based on silk sericin (SS) and poly(N-hydroxyethyl acrylamide) (PHEA) was successfully fabricated via conventional free-radical polymerization. The porous structure of the scaffolds was introduced using a lyophilization technique and the effect of cross-linker (XL) on morphology, gelation time and physical properties of hydrogel scaffold was first studied. The results show that using low cross-linker content (0.125, 0.25 and 0.5 wt% XL) produced flexible scaffolds and appropriate gelation times for fabricating the scaffold. Therefore, the polymerization system with a constant percentage of XL at 0.5 wt% was chosen to study further the effect of SS on the physical properties and cell culture of the scaffolds. It was observed that the hydrogel scaffold of PHEA without SS (PHEA/SS-0) had no cell proliferation, whereas hydrogel scaffolds with SS enhanced cell viability when compared to the positive control. The sample of PHEA/SS at 1.25 wt% of SS and 0.5 wt% of cross-linker was the most suitable for HFF-1 cells to migrate and cell proliferation due to possessing a connective porous structure, along with silk sericin. The results proved that this novel porous semi-IPN hydrogel has the potential to be used as dermal reconstruction scaffold.

Ulcerative colitis is a chronic inflammatory bowel disease with a high recurrence rate. Natural phytochemical compounds are increasingly being considered as preventative and supportive treatments for this condition. However, the poor water solubility and stability of many of these compounds limit their effectiveness in vivo. To address this issue, fisetin (FT), a natural phytochemical with poor solubility, is stabilized using silk sericin (SS) to create a composite (SS/FT). The therapeutic potential of the SS/FT on ulcerative colitis is extensively investigated, and the results showed that it effectively alleviated the body weight loss and colon length shortening induced by dextran sulfate sodium. Notably, SS/FT downregulated the immune response, decreased colonic histopathological lesions, and reduced the cGAS/STING signal activation. This suggests that SS/FT may offer a promising therapy for treating ulcerative colitis., (© 2023 Wiley-VCH GmbH.)

The quest for an ideal wound dressing material has been a strong motivation for researchers to explore novel biomaterials for this purpose. Such explorations have led to the extensive use of silk fibroin (SF) as a suitable polymer for several applications over the years. Unfortunately, another major silk protein-sericin has not received its due attention yet in spite of having favorable biological properties. In this study, we report an approach of blending SF and silk sericin (SS) without the usage of chemical crosslinkers is made possible by the usage of formic acid which evaporates to induce β -sheets formation to form cytocompatible films. Raman spectroscopy confirms the presence of SF/SS components in blend and formation of β -sheet in films. In situ , gelation kinetics studies were conducted to understand the change in gelation properties with addition of sericin into SF. Methyl thiazolyl tetrazolium and live/dead assays were performed to study cellular attachment, viability and proliferation on SF/SS films. The antibacterial properties of SF/SS films were tested using Gram-negative and Gram-positive bacteria. The re-structured SF/SS films were stable, transparent, show good mechanical properties, antibacterial activity and cytocompatibility, therefore can serve as suitable biomaterial candidates for skin regeneration applications., (© 2024 IOP Publishing Ltd.)

Conductive ink deposited on flexible substrates through simple methods such as dyeing or printing is one of the most promising approaches for scalable fabrication of wearable electronics. However, excessive chemical additives or a complex preparation process has limited the practical applications of conductive inks. Herein, a highly stable and antibacterial AgNPs/CNT/rGO (SACR) conductive ink with the only assistance of sustainable silk sericin (SS) is developed through a green one-step strategy. SS functions as not only the reductant of silver ions and GO by donating electrons but also the dispersant and stabilizer of CNTs through strong noncovalent interactions. The universality of SACR ink is demonstrated by depositing on various flexible substrates through handwriting, screen-printing, and dyeing techniques; meanwhile, the mechanical reliability between SACR ink and substrates is validated by peeling, bending, and twisting measurements. In addition, the synergistic effects of the multilevel hierarchical 0D/1D/2D structure and abundant interfacial interactions in SACR ink are advantageous to enhancing sensing performance. An SACR ink-based strain sensor and hydrogen peroxide (H 2 O 2 ) sensor are fabricated to detect physical and biochemical indicators, demonstrating the enormous potential of SACR ink in intelligent wearables for active health monitoring in early care.

Silk sericin (SS) has been extensively used to fabricate scaffolds for tissue engineering. However, due to its inferior mechanical properties, it has been found to be a poor choice of material when being electrospun into nanofibrous scaffolds. Here, SS has been combined with poly(vinyl alcohol) (PVA) and electrospun to create scaffolds with enhanced physical properties. Crucially, these SS/PVA nanofibrous scaffolds were created using only distilled water as a solvent with no added crosslinker in an environmentally friendly process. Temperature has been shown to have a marked effect on the formation of the SS sol–gel transition and thus influence the final formation of fibers. Heating the spinning solutions to 70 °C delivered nanofibers with enhanced morphology, water stability and mechanical properties. This is due to the transition of SS from β‐sheets into random coils that enables enhanced molecular interactions between SS and PVA. The most applicable SS/PVA weight ratios for the formation of nanofibers with the desired properties were found to be 7.5/1.5 and 10.0/1.5. The fibers had diameters ranging from 60 to 500 nm, where higher PVA and SS concentrations promoted larger diameters. The crystallinity within the fibers could be controlled by manipulation of the balance between PVA and SS loadings. In vitro degradation (in phosphate buffer solution, pH 7.4 at 37 °C) was 30–50% within 42 days and fibers were shown to be nontoxic to skin fibroblast cells. This work demonstrates a new green route for incorporating SS into nanofibrous fabrics, with potential use in biomedical applications. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

As a first step towards the production of functional cell sheets applicable for the regeneration of gut muscle layer, microstructured bacterial cellulose (mBC) was assessed for its ability to support the growth of enteric nervous system (ENS) and gut smooth muscle cells (SMCs). To improve the cellular response, mBC was modified with silk sericin (SS) which has renowned abilities in supporting tissue regeneration. While SS did not impair the line structures imparted to BC by PDMS templates, similarly to the patterns, it affected its physical properties, ultimately leading to variations in the behavior of cells cultured onto these substrates. Enabled by the stripes on mBC, both SMCs and ENS cells were aligned in vitro , presenting the in vivo -like morphology essential for peristalsis and gut function. Interestingly, cell growth and differentiation remarkably enhanced upon SS addition to the samples, indicating the promise of the mBC-SS constructs as biomaterial not only for gut engineering, but also for tissues where cellular alignment is required for function, namely the heart, blood vessels, and similars. Unlabelled Image • Patterned bacterial cellulose scaffolds incorporating silk sericin were prepared. • Intestinal smooth muscle and enteric nervous system cells aligned on these substrates. • Silk sericin enhanced cell growth on the structured bacterial cellulose. [ABSTRACT FROM AUTHOR]

In this study, 4 different types of GBR membrane were undergone for bio-degradability test; Silk mat from silkworm cocoon (TDI), silk mat from flatwise-spun (FS), collagen membrane (OssGuide), and dPTFE membrane (Cytoplast). Each material was segmented in 10.00 mm length and 0.3 mm thickness. The samples were put into the normal saline at 37°C for 2 weeks. After that, yield strength and tensile strain were measured and compared them with those of before treatment. The morphology of the membranes was observed by SEM. Tensile strain of FS was significantly increased at 2 weeks' normal saline treatment (P=0.018). When compared to OssGuide, TDI and FS showed significantly higher tensile strain at 2 weeks' normal saline treatment (P<0.05). In the SEM images, there were no significant changes in Cytoplast, TDI, and FS after 2 weeks' treatment. However, OssGuide showed damaged surface after 2 weeks' treatment. In conclusion, both TDI and FS did not have any evidence of biodegradability at 2 weeks' observation in normal saline treatment. However, OssGuide showed more than 20 % decrease in yield strength and tensile strain. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Sericin is cross-linked with DCMC through Schiff's base reaction. • Cross-linking of sericin with DCMC reinforces sericin film properties. • DCMC/SS film has excellent hydrophilicity and biocompatibility. Abstract Developing biomaterials based on the natural biomacromolecule silk sericin from Bombyx mori cocoon is of great interest for biomedical application. Dialdehyde carboxymethyl cellulose (DCMC) is derived from periodate oxidation of carboxy- methyl cellulose. Here, we developed a novel strategy of cross-linking of sericin with DCMC via the Schiff's base reaction. Fourier transform infrared spectroscopy and scanning electron microscopy indicated the formation of Schiff's base via the blending of sericin and DCMC. The mechanical properties tests suggested the covalent cross-linking effectively enhanced the tensile strength of sericin. The swelling test and water contact angle indicated the DCMC/SS film had excellent hydrophilicity, swellability. Additionally, we demonstrated the DCMC/SS film had excellent blood compatibility, cytocompatibility and promoting cell proliferation activity by the hemolysis ratio analysis, cell adhesion, cells viability and proliferation assays. The prepared DCMC/SS film has shown great promise in biomedical applications such as wound dressing, artificial skin and tissue engineering. [ABSTRACT FROM AUTHOR]

Oral gargling solution has been used for the control of halitosis. The purpose of this study was to compare the level of hydrogen sulphide concentration between silk oral gargling solution and commercially available oral gargling solution. Total 21 volunteers were included in this study. The relative level of hydrogen sulphide concentration was calculated to the baseline level. In terms of the primary endpoint of the trial, relative level of hydrogen sulphide concentration was 50.84 ± 33.19% with silk group, versus 71.07 ± 21.83% with Listerine group (Pnon-inferiority =0.003). In conclusion, the results of oral gargling with a silk protein for healthy individual were non-inferior to oral gargling with Listerine for hydrogen sulphide concentration reduction. [ABSTRACT FROM AUTHOR]

Abstract Pro-oxidative stress induced by dietary polyphenols elevates reactive oxygen species (ROS) production in cancer cells, which subsequently leads to oxidative stress-mediated apoptosis. Sericin, a principal component of silk is associated with a mixture of polyphenols and flavonoids, possesses various biomedical attributes including anticancer activity. In the present study, we have evaluated the pro-oxidative effect of Bombyx mori sericin (BMS), Antheraea assamensis sericin (AAS), and Philosamia ricini sericin (PRS) against different cancer cells. Cytotoxicity of silk sericin (SS) evaluated using A431, SAS, and MCF-7 cells showed ≥50% reduction in their viability at 4 mg/mL. Intracellular ROS levels, cell cycle arrest, and apoptosis assessed using flow cytometry corroborated that SS treatment elevated the intracellular ROS levels, caused cell cycle arrest at the sub-G1 phase and resulted in apoptotic cell death. SS treated A431 and SAS cells showed upregulation of p53 and dysregulation of Bax and Bcl-2 gene expression. Whereas, AAS treated MCF-7 cells showed upregulation of Bax and downregulation of Bcl-2 gene expression. AAS treated MCF-7 and SAS cells showed downregulation of Bcl-2 protein expression in comparison to their control cells. Thus, the present study demonstrates that the pro-oxidative effect induced by SS suppresses the cancer growth indicating its potential anticancer activity. Graphical abstract Image 1 Highlights • SS induced 50% growth inhibition in cancer cells. • SS induced redox imbalance in cancer cells. • AAS decrease SOD activity in cancer cells. • AAS treatment cause depletion of mitochondrial membrane potential in MCF-7 cells. • SS induced apoptosis in MCF-7, SAS and A431 cells. [ABSTRACT FROM AUTHOR]

Silk sericin (SS) produced by Bombyx mori is normally discarded as waste in manufacturing processes, which causes environmental pollution. Therefore, investigating the use of silk sericin has economic and environmental benefits. As a three-dimensional structure, the sericin-derived hydrogel was explored in different applications. However, many developed gelation procedures raise concerns regarding safety, cost, and duration of gelation time. In this work, “thiol-ene” click chemistry was used to quickly and controllably prepare an SS-derived hydrogel to resolve these early concerns. Then, berberine was loaded and used as a model for investigating the drug-release profiles of the prepared hydrogel. The experimental results revealed that this hydrogel is eligible for a long-term release of berberine. Throughout the antibacterial experiments, the released berberine maintained its antibacterial activity. Our work expands the application of SS in biomedical industries in an eco-friendly way. Furthermore, the discussed strategy could provide a reference for the subsequent development of SS-derived materials.

[Display omitted] • Harnessed the bioactive silk sericin to encapsulate anthocyanins. • Enhanced stability and multifunctional bioactivity of anthocyanins. • A hairpin structure between phenylalanine, tyrosine and anthocyanins. • Silk sericin and anthocyanins formulation evinced ROS-triggered wound healing. Anthocyanins, a class of polyphenols possessing potent antioxidant properties, are limited in their applicability in biomedical industries owing to their low stability. This study harnessed the bioactive silk sericin to encapsulate anthocyanins and thereby conferred enhanced stability and multifunctional bioactivity. Meanwhile, experimental and computational methods were used to systematically probe the interaction between silk sericin and anthocyanins. The hydrogel formulation of silk sericin displayed higher encapsulation efficiency and concomitant improvements in stability under diverse conditions such as pH, metals, and temperature. Molecular simulations revealed that the amino acids, phenylalanine and tyrosine, with a hairpin structure were pivotal in the interaction between the two components, culminating in the formation of nanocomposites, a finding corroborated by the experimental results using various spectroscopic techniques. Significantly, the encapsulated anthocyanins exhibited enhanced bioactivity, particularly in their reactive oxygen species (ROS) scavenging ability. Leveraging the potent antioxidant properties of silk sericin and anthocyanins, the formulation evinced ROS-triggered wound healing functions by modulating factors such as TGF-β, IL-1β, TNF-α, IL-10, and VEGF. This study highlights the potential of utilizing two bioactive components derived from the same sericultural system to enhance stability and regulate bioactivity in tissue engineering applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Aloe vera, chitosan, and silk sericin have been investigated for their physicochemical properties as well as functional characteristics such as antibacterial, antioxidant, and UV resistance. Aloe vera was extracted by methanol as a solvent. Silk sericin was prepared from a boiled water solution of silk cocoons through ethanol precipitation, while chitosan was synthesized by deacetylation of chitin. FT-IR, TGA, DSC, EDX, UV–vis, and XRD were used to characterize the extracted Aloe vera, chitosan, and sericin. Antibacterial activity, antioxidant activity and UV protection factors were also investigated. The TGA graph revealed that the significant weight loss at 400 °C was 39%, 51%, and 52%. for Aloe vera, chitosan, and sericin, respectively. For E. coli , Aloe vera, chitosan, and silk sericin, the zones of inhibition were 2.5 mm, 3 mm, and 1 mm, respectively, whereas for S. aureus, the zones of inhibition were 4 mm, 5 mm, and 1.5 mm. The free radical scavenging activity of 10 mg/ml Aloe vera, chitosan and sericin was 93%, 53% and 52%, respectively. All three UV radiation zones were absorbed by an Aloe vera solution. Chitosan and silk sericin solution exclusively absorbed UV-C rays. These almost priceless natural resources can contribute to health-related beneficial issues. [ABSTRACT FROM AUTHOR]

Novel architectured porous Cu@Cu 2 O hybrid microspheres were successfully designed and synthesized using silk sericin (SS) as structure-director to firstly form the hierarchical Cu 2 O/SS microspheres by self-assembly, followed by a calcination process. A possible mechanism has been proposed based on the results of FESEM, TEM and XRD analysis. The photocatalytic performance of obtained porous Cu@Cu 2 O hybrid microspheres was investigated, and the synergistic effect of Cu and Cu 2 O phases contributed to improving the light absorption ability, electron-hole separation and transfer compared with pure Cu 2 O. Importantly, the photo-degradation ratio of Cu@Cu 2 O hybrid microspheres for methyl orange (MO) reached up to 99.9% after 110 min visible light irradiation, which is almost 1.3 times than that of pure Cu 2 O. Furthermore, Cu@Cu 2 O hybrid microspheres also exhibited outstanding reusability and stability because that its degradation efficiency for MO still maintained at 93.5% after five cycles. [ABSTRACT FROM AUTHOR]

As the interest in the recycling of byproducts and resources derived from agriculture has increased, research on the application of sericin abandoned in the silk industry has been continuously carried out, but there is a limit due to the weak mechanical properties. Recently, nanocellulose has been attracting attention as an optimal reinforcing material to improve the deficient physical properties of natural polymers. In the present study, bamboo-derived cellulose nanofibrils (B-CNFs) were prepared and used as a facile reinforcer to improve the mechanical properties of the sericin film. B-CNF was prepared via simple and eco-friendly ultrasonic treatment and whole bio-nanocomposite film fabrication process conducted under aqueous solution condition. The prepared B-CNF was well distributed into the glycerol-plasticized sericin matrix without agglomeration until 10 wt% B-CNF loading, while agglomerated cellulose nanofibrils appeared after 20 wt% B-CNF loading. This uniform distribution of B-CNF not only greatly improved the properties of the sericin film but also affected the hydrophilic properties of bio-nanocomposite film. Moreover, the prepared B-CNF reinforced bio-nanocomposite films had notable antioxidant activity without any additional antioxidant ingredients. These findings support the potential use of B-CNF reinforced sericin films in active food packaging, drug delivery carriers, and in wound dressing materials. Silk and bamboo-derived natural polymeric raw materials and aqueous solvent-based film manufacturing processes will strongly provide cost efficiency and environmental friendliness and can be a suitable replacement of petroleum-based polymer industry and its related application fields. [ABSTRACT FROM AUTHOR]

Abstract Silk sericin (SS), a globular and water-soluble protein, showed to in vitro sustain the proliferation of different mammalian cell lines, and to in vitro protect them from the oxidative stress because of its free-radical-scavenging activity. Also, platelet-derived products, such as platelet gel, platelet rich plasma or platelet lysate (PL) are used in cell cultures as a serum substitute due to their great content of growth factors. In the clinical practice, both SS and PL were employed for various reparative treatments and showed to sustain the wound repair process regulating fibroblast recruitment, migration, proliferation and differentiation. For these reasons, the combination of PL and SS could lead to effective and innovative products, either for the ex vivo cell expansion, or for the production of active wound healing advanced medications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Silk industry was an important mainstay of Asian textile industry. However, a large volume of filature wastewater is produced during the cocoon cooking step and it might lead to severe environment pollution without effective treatment. In fact, the wastewater contained an important and valuable protein, silk sericin. In this work, foam fractionation was purposed to recover silk sericin (SS) from the filature wastewater. A novel column with groined internal component (GIC) was developed for strengthening foam fractionation at room temperature. Compared with the control column, the collected foam from the experimental column possessed of a low liquid holdup because the low gas-liquid weakened the viscous effect caused by the rising velocity of the bubbles, when the rising foam passed through the corner channels creased by GIC. Under the suitable operating conditions of pH 4.0, length of GIC 400 mm, volumetric air flow rate 200 mL/min and pore diameter of gas distributor 180 μm, the enrichment ratio and the recovery percentage of SS reached 6.77 and 80.29%, respectively. This work is expected to provide a cost-effective technique to recover SS from the filature wastewater, and to facilitate the industrialization of foam fractionation in wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Silk sericin has excellent features of antioxidant ability and good cytocompatibility; however, high water solubility and poor mechanical properties have restricted its application in biomedical fields. In this study, aimed at improving the mechanical properties of a regenerated silk sericin, the primary hydroxy groups in silk sericin were enzymatically oxidized by using laccase and 2,2',6,6'‐tetramethylpiperidine‐N‐oxyl (TEMPO), and the generated reactive groups then reacted further with the amino groups in the sericin chains. The efficacy of the enzymatic cross‐linking was evaluated by means of determination of amino groups, SDS polyacrylamide gel electrophoresis, Fourier transform infrared (FTIR) spectroscopy, and size exclusion chromatography. The results indicated that either laccase/TEMPO incubation or laccase treatment alone incurred a noticeable increase in the molecular weight of the sericin. FTIR analysis revealed that there was small change in the structure of the silk sericin after laccase/TEMPO treatment, and the obtained air‐dried sericin membrane exhibited remarkably improved mechanical properties relative to those of the uncross‐linked sericin membrane. In addition, the biocompatibility of the sericin membrane was at an acceptable level according to the cell viability of NIH/3T3 cells. The present work provides a novel method for the preparation of sericin‐based biomaterials. [ABSTRACT FROM AUTHOR]

Over the last two decades, silk fibroin has been exploited as a versatile optical material in biological applications due to a combination of unique properties. Recently, protocols have been developed to produce a silk fibroin negative tone resist that is UV crosslinkable, thereby allowing micro and nanoscale patterning of the protein using traditional photolithographic tools. The same protocol has been applied to the silk protein sericin to develop a sericin resist. Despite the immense potential of these biomaterials to develop micro optical patterns on silicon and glass surfaces, as well as self-standing components, their refractive indexes are not well characterized. In this work, optimizing a method to obtain extremely smooth, thin films, the refractive index (RI) of fibroin and sericin proteins and resists were characterized using ellipsometry. The parameters of the Sellmeier and Cauchy dispersion laws have been determined to obtain the RI over a large wavelength range. A complete morphological study of the films has been conducted. In addition, the effect of solvent on the optical properties of silk fibroin and sericin thin films are reported, with differences in values explained by examining the change in the protein secondary structure. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) has been applied for wound dressing application. In this study, physical and biological properties of the BC dressing were improved by incorporation of silk sericin (SS), polyhexamethylene biguanide (PHMB), and glycerin. The glycerin incorporation reduced dehydration rate and wound adhesion of the BC dressing in a concentration-dependent manner. PHMB, an antiseptic agent, provided antibacterial activity against Gram-positive and Gram-negative bacteria. Meanwhile, SS would enhance collagen and tissue formation in wounds. Finally, we confirmed that the BC dressing incorporating SS, PHMB, and glycerin was safe to be used as a medical material according to ISO 10993-6 standard. [ABSTRACT FROM PUBLISHER]

High antibacterial and skin-like hydrogels have always been the perfect wound dressing for human to protect wound from infection. Here, based on silk sericin, we design a series of nanoclay lithium magnesium silicate hydrate (LMSH) cross-linked semi-IPN sericin/poly(NIPAm/LMSH) (HSP) nanocomposite hydrogels and demonstrate advantages in serving as antibacterial wound dressing in comparison with gauze. Firstly, the effect of mass ratios of sericin/(sericin + NIPAm) upon pore structure, feasibility of mechanics and gas permeability of HSP nanocomposite hydrogels were evaluated. Then, the relationship between nanocomposite hydrogel and histological/antimicrobial properties was systematically analyzed. It was found that, the introduction of sericin increased internal pore size, leading to obvious transition from honeycomb to layered structure. Furthermore, as mass ratio of sericin/(sericin + NIPAm) is 20%, the wound healing area treated with nanocomposite hydrogels at 6th day reached up to 83%, 3 times of gauze, and almost recovered at 13th day. Especially, antibacterial mechanism can be thought to be the results that the macromolecular sericin embedded in the nanocomposite hydrogel adsorbed bacteria by charge interaction and micromolecular sericin dissociating out from nanocomposite hydrogels can be adsorbed onto bacteria. [ABSTRACT FROM AUTHOR]

Some natural compounds have recently been widely employed in wound healing applications due to their biological properties. One such compound is sericin, which is produced by Bombix mori, while active polyphenols, polysaccharides and proteins are synthetized by Chlorella vulgaris and Arthrospira platensis microalgae. Our hypothesis was that sericin, as an optimal bioactive polymeric carrier for microencapsulation process, could also improve the regenerative effect of the microalgae. A solvent-free extraction method and spray drying technique were combined to obtain five formulations, based on algal extracts (C. vulgaris and A. platensis, Chl and Art, respectively) or silk sericin (Ser) or their mixtures (Chl-Ser and Art-Ser). The spray drying was a suitable method to produce microspheres with similar dimensions, characterized by collapsed morphology with a rough surface. Art and Art-Ser showed higher antioxidant properties than other formulations. All microspheres resulted in cytocompatibility on fibroblasts until 1.25 mg/mL and promoted cell migration and the complete wound closure; this positive effect was further highlighted after treatment with Art and Art-Ser. To our surprize the combination of sericin to Art did not improve the microalgae extract efficacy, at least in our experimental conditions. [ABSTRACT FROM AUTHOR]

In this work, a novel semi-interpenetrating polymer network (semi-IPN) hydrogel scaffold based on silk sericin (SS) and poly(N-hydroxyethyl acrylamide) (PHEA) was successfully fabricated via conventional free-radical polymerization. The porous structure of the scaffolds was introduced using a lyophilization technique and the effect of cross-linker (XL) on morphology, gelation time and physical properties of hydrogel scaffold was first studied. The results show that using low cross-linker content (0.125, 0.25 and 0.5 wt% XL) produced flexible scaffolds and appropriate gelation times for fabricating the scaffold. Therefore, the polymerization system with a constant percentage of XL at 0.5 wt% was chosen to study further the effect of SS on the physical properties and cell culture of the scaffolds. It was observed that the hydrogel scaffold of PHEA without SS (PHEA/SS-0) had no cell proliferation, whereas hydrogel scaffolds with SS enhanced cell viability when compared to the positive control. The sample of PHEA/SS at 1.25 wt% of SS and 0.5 wt% of cross-linker was the most suitable for HFF-1 cells to migrate and cell proliferation due to possessing a connective porous structure, along with silk sericin. The results proved that this novel porous semi-IPN hydrogel has the potential to be used as dermal reconstruction scaffold. [ABSTRACT FROM AUTHOR]

Antimicrobial mixed dressings have traditionally been used to minimize bacterial infection of burns and other wounds. This study presents the advancement of biocompatible chitosan/silk sericin (CHT/SS) scaffolds combined with lauric acid (LA) and zinc oxide nanoparticles (nZnO) for the successful wound dressing applications. Antibacterial assay results showed that the diameters of the inhibition zone increased from 2 ± 0.4 to 7 ± 0.1 mm forEscherichia coli, as well as from 2.5 ± 0.2 to 6 ± 0.4 mm forStaphylococcus aureuswhile CHTS/SS/100nZnO compared to CHT/SS/0.01LA. The results not only showed excellent inhibition against Gram-positive and Gram-negative bacterial growth but also revealed improved proliferation and extended viability for HaCaT cells. [ABSTRACT FROM PUBLISHER]

This study reports drug-loaded silk sericin (SS)/silk fibroin (SF) blend microparticles being fabricated by the water-in-oil emulsion solvent diffusion of a SS/SF aqueous blend solution. Blue dextran was used as the water-soluble drug model. The influence of the SS/SF blend ratio on the characteristics and drug release behavior of the blend microparticles was investigated. The blend microparticles were analyzed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and UV-vis spectroscopy. The blend microparticles were nearly spherical in shape as determined from SEM micrographs. The FTIR and TG results demonstrated that interactions between SS and SF molecules had occurred. The blend microparticles showed very high drug loading efficiency (94–98%) for all blend ratios. Thein vitrodrug release significantly decreased with decreasing SS blend ratio. The results demonstrated that the SS/SF blend microparticles could be used as biocompatible and biodegradable microparticles for controlled release drug delivery applications. [ABSTRACT FROM PUBLISHER]

Wound healing is a natural process of body reaction to repair itself after injury. Nonetheless, many internal and external factors such as aging, comorbidity, stress, smoking, alcohol drinking, infections, malnutrition, or wound environment significantly affect the quality and speed of wound healing. The unsuitable conditions may delay wound healing process and cause chronic wound or scar formation. Therefore, many researches have attempted to search for agents that can accelerate wound healing with safety and biocompatibility to human body. Widely studied wound healing agents are those derived from either natural sources including plants and animals or chemical synthesis. The natural products seem to be safer and more biocompatible to human tissue. This review paper demonstrated various kinds of the animal-derived products including chitosan, collagen, honey, anabolic steroids, silk sericin, peptides, and proteoglycan in term of mechanisms of action, advantages, and disadvantages when applied as wound healing accelerator. The benefits of these animal-derived products are wound healing promotion, anti-inflammatory, antimicrobial activity, moisturizing effect, biocompatibility, and safety. However, the drawbacks such as allergy, low stability, batch-to-batch variability, and high extraction and purification costs could not be avoided in some products. [ABSTRACT FROM AUTHOR]

Cooked mature silkworms have received increasing attention as a new source of income for sericultural farms. Quality improvement of these worms as the end-product requires prevention of the following: inclusion of unfertilized silkworm eggs, mixing with impurities, producing undercooked or overcooked mature larvae, and mixing spewed silk substance. Preventing unfertilized eggs and impurities and reducing undercooked or overcooked mature larvae can be achieved by sericultural farms. However, the prevention of spewed silk substance requires the development of new techniques. This study developed new techniques for optimum cold storage temperature, soaking, and hydro-thermal treatment to minimize the spewing of mature larvae prior to steaming: when larvae mature after 7 days on the 5th instar, they should be soaked in water at room temperature of 25℃ immediately upon collection and stored at 8℃ for less than 3 days. They should be soaked in boiling water for approximately 10 s immediately before steaming to kill the larvae and cooked with steam. This method allows for the production of high-quality mature larvae without spewed silk substance. These new techniques will considerably improve the production of well-cooked quality mature larvae by minimizing silk substance spewed out from the larvae. [ABSTRACT FROM AUTHOR]