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Fibroin has been extensively applied in the medicine, therapy, cosmetic, and food fields. Functional modification is a common route way to expand the application potential. Tyrosinase is versatile for enzymatic functionalization of fibroin by oxidizing tyrosine residues into dopaquinone. However, grafting of functional molecules to the protein-bound dopaquinone suffers from self-crosslinking due to competitive aryl coupling or addition with other nucleophile in protein. Herein, bioinspired from pheomelanin synthesis, a new approach with superior grafting efficiency and reaction rate for enzymatic grafting of protein was developed. The high reactivity of Michael addition between thiol and dopaquinone was utilized to promote the efficiency for grafting of PEG onto fibroin. The grafting of PEG with thiol group was superior to that with amine group. It demonstrated a superior efficacy for thiol group over amino group on enzymatic functionalization. This research firstly established an effective biomimetic approach for enzymatic functionalization of protein without the unexpected self-crosslinking. It could emerged to serve as the strategy of protein functionalization. [Display omitted] • Bioinspiration from pheomelanin due to preference over eumelanin. • Strong competition against self-crosslinking. • Higher reactivity of thiols to dopaquinone than amines. • Superior grafting efficiency and reaction rate. • Versatile application extended to functionalization of protein. [ABSTRACT FROM AUTHOR]

Diabetes causes complications like delayed wound healing for a long time. Fibroin, aloe vera, and ginger extracts along with their combinations are used for diabetic wound healing. After induction of diabetes, The wound healing effects of fibroin (50 mg/ml), aloe vera gel (50 mg/ml), and ginger extract (30 mg/ml), individually and in combination, were assessed. The pro-inflammatory cytokines including tumor narcosis factor-α (TNF-α) interleukin (IL-6, IL-8, IL-1β), matrix metalloproteinases (MMP 2, MMP7, MMP 9), vascular endothelial growth factor (VEGF) and tissue inhibitors of metalloproteinases (TIMPs) levels were analyzed in the serum. A combination of fibroin + aloe vera gel + ginger extract (Fi + Al + Gi) healed the wounds in 11 days via wound contraction of 98.5 ± 0.9 % as compared to diabetic control (58.2 ± 0.7 %) and positive control (73.3 ± 0.6 %) groups. However, the wounds of the Polyfax and the diabetic control groups were healed in 17 and 19 days, corresponding to a contraction of: 96.7 ± 1.4 % and 96.3 ± 1.1 %. The histological assay showed that the Fi + Al + Gi group indicated an increased growth of collagen fibers, fibroblasts, keratinocytes and blood vessels with lessened inflammation. The Fi + Al + Gi group alleviated the serum level of TNF-α (12.7 ± 0.9 pg/ml), IL-6 (9.6 ± 0.9 pg/ml), IL-8 (19.6 ± 1.0 pg/ml), MMP2 (217.0 ± 9.2 pg/ml), MMP7 (279.0 ± 9.8 pg/ml), and MMP9 (156.0 ± 11.6 pg/ml) significantly as compared to the diabetic control (P ≤ 0.05). TIMP serum level (202.0 ± 6.9 pg/ml) was significantly elevated as compared to the diabetes control group. The present study concludes that the biomaterials in their combinations possess high regenerative and healing abilities. • Three biomaterials fibroin, aloe vera, and ginger were used either individually or in combination form to enhance the diabetic wound healing process • Quantification analysis of four inflammatory markers (TNF-α, IL-6 IL-1β and IL-8), was performed to understand the healing process. • Histopathological examinations of wounded skin demonstrated the elevated number of keratinocytes, fibroblasts, collagen fibers, and blood vessels. • Quantification values of five markers (MMP 2, MMP7, MMP 9), TIMPs), and VEGF evaluate new blood vessel formation and healing process were analyzed [ABSTRACT FROM AUTHOR]

In this work, the effect of incorporating silk fibroin, a fibrous biocompatible protein, into physically cross-linked agarose hydrogels was investigated as a simple model study to examine how supramolecular fibrous structures influence the properties of the hydrogels. The rheological and transport properties were studied. Fibroin did not change the general viscoelastic properties of the investigated hydrogels but changed the viscoelastic moduli values and also the mesh size, as calculated from rheometry data. Fibroin influenced the mechanical properties depending on its concentration: at lower concentrations, it increased the mesh size, while at higher concentrations, it acted as a filler, decreasing the mesh size. Similarly, the storage and loss moduli were affected, either increasing or decreasing based on the fibroin concentration. The fibroin effect on the diffusion of two dyes differing in their charge was the result of a combination of structural effects, responsible also for changes in the rheological properties, and a result of electrostatic interactions between the charged groups. For positively charged methylene blue, low fibroin concentrations accelerated diffusion, while higher concentrations slowed it by filling network vacancies. In contrast, for negatively charged eosin-B, fibroin strongly impeded diffusion at all concentrations due to electrostatic repulsion, leading to its accumulation at the hydrogel interface. The findings of this work may contribute to an understanding of the behavior of the extracellular matrix or soft tissues as well as to the development of the tailored design of hydrogel materials. [ABSTRACT FROM AUTHOR]

BACKGROUND: A large number of studies have confirmed that tissue engineering scaffolds can almost completely repair osteochondral defects. However, when osteochondral defects are complicated with infection, even after thorough debridement in the early stage, the repair effect of simple osteochondral tissue engineering scaffolds is often unsatisfactory. OBJECTIVE: To prepare fibroin/chitosan/nano-hydroxyapatite scaffold loaded with vancomycin hydrochloride sustained release microspheres, and to investigate the repair effect on infected osteochondral defect in distal femur of rabbit. METHODS: (1) Vancomycin hydrochloride sustained release microspheres were prepared by emulsified solvent evaporation method. The sustained-release microspheres of different weights (7.5, 10, and 12.5 mg) were mixed with fibroin protein-chitosan nanohydroxyapatite solution, and the scaffolds of fibroin protein/chitosan/nano-hydroxyapatite were prepared by chemical crosslinking method. The porosity, water absorption and expansion rate, hot water loss rate of the scaffolds, and drug sustained-release in vitro were characterized. (2) Forty-five New Zealand white rabbits were randomly divided into blank group, control group, and experimental group, with 15 rabbits in each group. The osteochondral defect and infection model of the distal femur of the right hind limb was established in both groups. The blank group was not treated, and the control group was implanted with fibroin protein-chitosan-nano-hydroxyapatite scaffold. Vancomycin hydrochloride sustained-release microspheres (10 mg) of fibroin/chitosan/nano-hydroxyapatite scaffold were implanted in the defect of the experimental group. The levels of C-reactive protein and leukocytes in blood samples were detected 1 week after operation. At 4, 8 and 12 weeks after operation, the tissue of the operative area was taken for gross observation and pathological observation. RESULTS AND CONCLUSION: (1) With the increase of sustained-release microspheres content, the porosity of scaffolds decreased, and there was significant difference among groups (P < 0.05). There were no significant differences in the pore size, water absorption expansion rate and hot water loss rate among the three groups (P > 0.05). Vancomycin hydrochloride was released sustainably in vitro for more than 30 days in all three groups of scaffolds. (2) The levels of C-reactive protein and leukocytes in blood samples of the experimental group were lower than those of the blank group and control group (P < 0.05). The repair of gross cartilage in the experimental group was significantly better than that in the blank group and the control group. Hematoxylin-eosin, Masson, Alcian blue and type II collagen immunohistochemical stainings showed that the osteochondral repair effect of the experimental group was significantly better than that of the blank group and the control group at each time point. (3) The results showed that fibroin/chitosan/nano-hydroxyapatite scaffolds loaded with vancomycin hydrochloride sustained-release microspheres could effectively promote the repair of open osteochondral defects. [ABSTRACT FROM AUTHOR]

The main antioxidant polyphenol compounds in the mango (Mangifera indica L.) leaf extract are susceptible to environmental degradations. Thus, in biomedical applications, the mango leaf extract is commonly encapsulated in a carrier. However, most studies employed the synthetic carrier materials that could affect the human health, and the complicated formulation procedure that could hinder the scalability. Therefore, this work, for the first time, explored the use of silk fibroin (an FDA-approved biomaterial), in nanoparticles platform, to encapsulate and deliver the mango leaf extract, utilizing the simple coacervation preparation method. Initially, the mango leaf ethanolic extract was obtained through maceration, resulting in a total phenolic content of 76.39 ± 0.14 mg GAE/g DPW and a notably high antioxidant activity (IC50 = 6.872 ± 0.512 µg/mL). Subsequently, silk fibroin nanoparticles loaded with the extract were developed by the coacervation technique. Depending on the fibroin content, these nanoparticles exhibited an appropriate size range of 500-800 nm with narrow size distributions, a spherical shape with smooth surfaces, a dominant silk-II crystalline structure, a drug entrapment efficiency exceeding 70%, and retained the main biomarker mangiferin. Moreover, the phenolic-compounds release profiles from the particles followed the three-step process, the first burstrelease step, the second sustained-release step, and the third degradation step. The particles were also non-toxic to the erythrocytes and the human embryonic kidney HEK-293 cell line. Lastly, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay demonstrated that the antioxidant activity of the mango leaf extract was preserved within the extract-loaded nanoparticles. The results suggested that the silk fibroin nanoparticles could be a potential platform to effectively encapsulate and deliver the mango leaf extract for biomedical purposes. [ABSTRACT FROM AUTHOR]

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We present the first long-read de novo assembly and annotation of the luna moth (Actias luna) and provide the full characterization of heavy chain fibroin (h-fibroin), a long and highly repetitive gene (>20 kb) essential in silk fiber production. There are >160,000 described species of moths and butterflies (Lepidoptera), but only within the last 5 years have we begun to recover high-quality annotated whole genomes across the order that capture h-fibroin. Using PacBio HiFi reads, we produce the first high-quality long-read reference genome for this species. The assembled genome has a length of 532 Mb, a contig N50 of 16.8 Mb, an L50 of 14 contigs, and 99.4% completeness (BUSCO). Our annotation using Bombyx mori protein and A. luna RNAseq evidence captured a total of 20,866 genes at 98.9% completeness with 10,267 functionally annotated proteins and a full-length h-fibroin annotation of 2,679 amino acid residues. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polymethyl methacrylate (PMMA) is a commonly used denture base material, but susceptibility to fracture under functional loading remains a challenge. OBJECTIVE: This preliminary screening study aims to investigate the potential of sericin and fibroin as reinforcing agents in the PMMA denture base material. METHODS: The flexural and impact strengths of PMMA incorporated with 0.01% sericin, and 0.01% each of sericin and fibroin, were evaluated. The control group consisted of PMMA without any additives. The maximum load and energy required to break the samples were measured. Statistical analysis was performed using one-way ANOVA test and Scheffe Post Hoc tests to compare mean values between subgroups. RESULTS: The results indicated significant improvement in the flexural and impact strengths of PMMA with the addition of sericin and fibroin. The subgroups with 0.01% sericin, and 0.01% each of sericin and fibroin, demonstrated higher mean values in load and energy measurements compared to the control group. The statistical analysis confirmed the significance of these findings. CONCLUSION: The addition of 0.01% sericin and 0.01% each of sericin and fibroin to PMMA denture-based resin material significantly increases its flexural and impact strengths. These preliminary findings suggest the potential of sericin and fibroin as effective reinforcing agents in PMMA denture base materials, thereby enhancing their biomechanical properties. [ABSTRACT FROM AUTHOR]

We previously showed through clinical trials that one plant-derived lactic acid bacteria (LAB) can improve constipation. We preliminarily found that the plant-derived LAB Lactococcus lactis BM32-1 can grow in a mixture of sericin and fibroin, which are extracted from silk and have been reported to help promote health. Thus, in the present study, we evaluated the favorable effect of a sericin/fibroin mixture (S/F-M), which was extracted from silk prepared from cocoons reared in an aseptic rearing system using an artificial diet, fermented with the BM32-1 strain through a clinical trial. The trial was conducted at Hiroshima University from June to October 2022 as a double-blind, placebo-controlled, randomized parallel-group comparative study with 50 eligible subjects (aged 23-71) who had an average defecation frequency of less than 5 times per week. The subjects were instructed to drink 100 mL of fermented S/F-M or placebo every day. After the 12 weeks of the clinical trial period, the average defecation frequency increased significantly--1.4 times higher than that at baseline in the test group-- as compared with the placebo group. Furthermore, the fecal microbiota was also compared before and after treatment, revealing that intake of the fermented S/F-M significantly multiplied the relative abundance of the genera Enterococcus and Clostridium, which have been reported to contribute to the amelioration of constipation by improving the gut microbiota and producing butyric acid, respectively. In conclusion, the S/F-M fermented using the BM32-1 strain improves defecation frequency through alteration of the gut microbiota. [ABSTRACT FROM AUTHOR]

Abstract Caddisfly larvae produce silk containing heavy and light fibroins, similar to the silk of Lepidoptera, for the construction of underwater structures. We analyzed the silk of Limnephilus lunatus belonging to the case-forming suborder Integripalpia. We analyzed the transcriptome, mapped the transcripts to a reference genome and identified over 80 proteins using proteomic methods, and checked the specificity of their expression. For comparison, we also analyzed the transcriptome and silk proteome of Limnephilus flavicornis. Our results show that fibroins and adhesives are produced together in the middle and posterior parts of the silk glands, while the anterior part produces enzymes and an unknown protein AT24. The number of silk proteins of L. lunatus far exceeds that of the web-spinning Plectrocnemia conspersa, a previously described species from the suborder Annulipalpia. Our results support the idea of increasing the structural complexity of silk in rigid case builders compared to trap web builders.

Caddisfly larvae produce silk containing heavy and light fibroins, similar to the silk of Lepidoptera, for the construction of underwater structures. We analyzed the silk of Limnephilus lunatus belonging to the case-forming suborder Integripalpia. We analyzed the transcriptome, mapped the transcripts to a reference genome and identified over 80 proteins using proteomic methods, and checked the specificity of their expression. For comparison, we also analyzed the transcriptome and silk proteome of Limnephilus flavicornis. Our results show that fibroins and adhesives are produced together in the middle and posterior parts of the silk glands, while the anterior part produces enzymes and an unknown protein AT24. The number of silk proteins of L. lunatus far exceeds that of the web-spinning Plectrocnemia conspersa, a previously described species from the suborder Annulipalpia. Our results support the idea of increasing the structural complexity of silk in rigid case builders compared to trap web builders. [ABSTRACT FROM AUTHOR]

This report uses a low‐cost and straightforward technique to synthesize a highly active, magnetically separable, and optically active nano‐biocomposite. The nanocomposite was created by combining Fibroin, TiO2, and Fe3O4. The analyses confirmed the formation of a core‐shell structure of Fibroin and Fe3O4, which was then combined with titanium dioxide nanoparticles. The incorporation of nanoparticles reduced the band gap of the system from 3.2 eV in bare titanium oxide to 1.8 eV. This enhancement improved its light absorption and charge generation. Additionally, the nano‐biocomposite showed improved chemical stability and photocatalytic activity when compared to bare TiO2 in the oxidation of benzyl alcohol under visible light (With 99 % yield and over 99 % selectivity). These results suggest that our nano‐biocomposite is a promising catalyst for photocatalytic applications under visible light. [ABSTRACT FROM AUTHOR]

BACKGROUND: Combined radiation and wound injury appeared mainly in patients with tumor radiotherapy and nuclear radiation accidents. The radiation destroys the repair mechanism, resulting in delayed or prolonged wound healing. It still lacks an effective therapeutic strategy currently. OBJECTIVE: To prepare multifunctional wound dressings based on the multiple clinical symptoms of combined radiation and wound injury, which are designed to be antibacteria, promoted healing and analgesics. METHODS: Using levofloxacin, fibroin and lidocaine hydrochloride as raw materials, 3D bioprinting technology was applied to prepare the multifunctional wound dressing. (1) The multifunctional dressing was placed on a fixed culture plate coated with Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and incubated at 37 °C overnight to detect the diameter of the antibacterial zone. (2) 40 Kunming mice were randomly divided into trauma group, radiation and trauma model group, treatment group and positive drug group, with 10 mice in each group. Mice in the radiation and trauma model group, treatment group and positive drug group were irradiated by 60Co gamma rays. After 1 hour of radiation, a full-layer skin defect wound with a diameter of 1 cm was made on the back of each mouse in the four groups. Normal saline was applied to the wounds of the trauma group and the radiation and trauma model group. Trethanolamine cream was applied to the wounds of the positive drug group. Multifunctional dressing was applied to the wounds of the treatment group. The dressing was changed every 2 days, and the treatment was continued for 14 days. Wound healing rate and serum interleukin-6 level were measured at 3, 7 and 14 days after wound modeling. 14 days after the wound modeling, the skin tissue of the wound was obtained and received hematoxylin-eosin staining, Masson staining and cytokeratin-14 immunohistochemical staining. RESULTS AND CONCLUSION: (1) 3D-printed multifunctional wound dressing had good antibacterial activity. The antibacterial zone diameters against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were (4.15±0.09), (4.18±0.23) and (4.35±0.13) cm, respectively. (2) With the extension of modeling time, the wound healed gradually. The wound healing rate of the treatment group and the positive drug group was higher than that of the radiation and trauma model group at 3, 7 and 14 days after modeling (P < 0.01, P < 0.001). The wound healing rate of the treatment group was higher than that of the positive drug group. With the extension of modeling time, the serum interleukin level of mice increased first and then decreased. The serum interleukin level in the treatment group at 3, 7 and 14 days after modeling was lower than that in the radiation and trauma model group. Hematoxylin-eosin staining and Masson staining exhibited that inflammatory cells infiltrated the granuloma tissue in the trauma group, and the dermal collagen fibers were densely arranged. The normal structure of epidermis and dermis was destroyed and inflammatory cells were infiltrated in the radiation and trauma model group. In the treatment group, normal skin mucosal tissue was observed, the epidermis was arranged closely, and the sweat glands, hair follicles and dermal collagen fibers were arranged regularly. In the positive drug group, the arrangement of epidermal layer was tight, and the arrangement of sweat glands, hair follicles and dermal collagen fibers was regular. Cytokeratin-14 immunohistochemical staining displayed that the epidermal tissue thickness in the treatment group was lower than that in the other three groups (P < 0.01, P < 0.001). (3) The results confirm that the 3D-printed multifunctional dressing has multiple functions of local anesthesia, anti-infection and promoting healing. [ABSTRACT FROM AUTHOR]

In modern medicine, the issues of regeneration of damaged organs are quite relevant. Methods are being actively developed to simplify regeneration processes. The object of study is scaffolds, that is, structures of various materials that serve as a substrate for tissue regeneration. Tissue engineering is involved in the development of such structures. It combines the scientific achievements of cell biology, biochemistry, engineering and medicine. New methods for producing scaffolds are being developed. Thus, scaffolds are a polymer or other composite material that can imitate the structure of various tissues; it contains healing drugs. Scaffolds are cellular matrices, the main part of which is tissue regeneration. Next, this study provides a review of the literature on the benefits and practices of using scaffolds made of synthetic and various xenogeneic materials in regenerative medicine.

The search for novel antibiotic-loaded biomaterials that support the management of osteomyelitis has been extensive in current years. This study developed multifunctional hydrogel to enhance the performance of osteo-conduction and antimicrobial as supporting implant materials for osteomyelitis treatment and prevention. Ciprofloxacin-loaded thermosensitive hydrogels composed of silk fibroin and poloxamers were prepared using the cold method. F1, F2, and F3 formulations resulted in gelation time of within 3 min under 37°C. Physical evaluation showed that the formulations, especially F3, had a proper swelling ratio and 82.34% biodegradability within 14 days. Ciprofloxacin from formulations exhibited an initial burst release within 24 h and continuous delivery, with more than 84% release over 14 days. Released antibiotics showed efficacy against Staphylococcus aureus ATCC25923 and eradicating activity against biofilms. Moreover, hydrogels had no cytotoxic effect on MC3T3-E1 cells with 93–106% cell viability. This multifunctional hydrogel showed a promising approach for supporting osteomyelitis treatment and prevention.

Nano-sized biomaterials are innovative drug carriers with nanometric dimensions. Designed with biocompatibility in mind, they enable precise drug delivery while minimizing side effects. Controlled release of therapeutic substances enhances efficacy, opening new possibilities for treating neurological and oncological diseases. Integrated diagnostic-therapeutic nanosystems allow real-time monitoring of treatment effectiveness, which is crucial for therapy personalization. Utilizing biomaterials as nano-sized carriers in conjunction with drugs represents a promising direction that could revolutionize the field of pharmaceutical therapy. Such carriers represent groundbreaking drug delivery systems on a nanometric scale, designed with biocompatibility in mind, enabling precise drug delivery while minimizing side effects. Using biomaterials in synergy with drugs demonstrates significant potential for a revolutionary impact on pharmaceutical therapy. Conclusions drawn from the review indicate that nano-sized biomaterials constitute an innovative tool that can significantly improve therapy effectiveness and safety, especially in treating neurological and oncological diseases. These findings should guide researchers towards further studies to refine nano-sized biomaterials, assess their effectiveness under various pathological conditions, and explore diagnostic-therapeutic applications. Ultimately, these results underscore the promising nature of nano-sized biomaterials as advanced drug carriers, ushering in a new era in nanomedical therapy. [ABSTRACT FROM AUTHOR]

Protein extraction from silk is a unique area of research and the foremost need is the efficient extraction of the silk proteins namely fibroin and sericin from the silk fibres, which is conventionally done using chemicals. In this work, we show that Ionic liquids (ILs) can be employed as a green and alternative method for degumming sericin from both mulberry (B. mori) and non‐mulberry (A. assamensis and P. ricini) silk. Six different ILs with varying tail lengths were studied for their degumming efficiencies. The interaction between silk proteins and IL ions involves a complex ionic disruption of hydrogen bonds, non‐polar interactions, and electrostatic effects. We have found that 1‐Butyl‐3‐methylimidazolium chloride (BMIM.Cl), 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIM.BF4) and Tetraethylammonium bromide (TEAB) bring in higher weight loss % in silk fibres compared to other ILs, indicating that it can be used in better sericin removal without significant damage to the silk fibre. TEAB emerged as a potential candidate for sericin extraction due to its promotion of protein destabilization. Additionally, no drastic changes in the structure of the extracted silk protein sericin were observed, as evident from the FTIR spectra and SEM images. This work highlights for the first time, the use of ILs for extraction of non‐mulberry silk sericin and also proves that ILs can be a potential green solvent for sericin extraction. [ABSTRACT FROM AUTHOR]

Understanding how native silk spinning occurs is crucial for designing artificial spinning systems. One often overlooked factor in Bombyx mori is the secretion of sericin proteins. Herein, we investigate the variation in amino acid content at different locations in the middle silk gland (MSG) of B. mori. This variation corresponds to an increase in sericin content when moving towards the anterior region of the MSG, while the posterior region predominantly contains fibroin. We estimate the mass ratio of sericin to fibroin to be ~25/75 wt% in the anterior MSG, depending on the fitting method. Then, we demonstrate that the improvement in the extensional behavior of the silk dope in the MSG correlates with the increase in sericin content. The addition of sericin may decrease the viscosity of the silk dope, a factor associated with an increase in the spinnability of silk. We further discuss whether this effect could also result from other known physicochemical changes within the MSG. [ABSTRACT FROM AUTHOR]

The golden rule in tissue engineering is the creation of a synthetic device that simulates the native tissue, thus leading to the proper restoration of its anatomical and functional integrity, avoiding the limitations related to approaches based on autografts and allografts. The emergence of synthetic biocompatible materials has led to the production of innovative scaffolds that, if combined with cells and/or bioactive molecules, can improve tissue regeneration. In the last decade, silk fibroin (SF) has gained attention as a promising biomaterial in regenerative medicine due to its enhanced bio/cytocompatibility, chemical stability, and mechanical properties. Moreover, the possibility to produce advanced medical tools such as films, fibers, hydrogels, 3D porous scaffolds, non-woven scaffolds, particles or composite materials from a raw aqueous solution emphasizes the versatility of SF. Such devices are capable of meeting the most diverse tissue needs; hence, they represent an innovative clinical solution for the treatment of bone/cartilage, the cardiovascular system, neural, skin, and pancreatic tissue regeneration, as well as for many other biomedical applications. The present narrative review encompasses topics such as (i) the most interesting features of SF-based biomaterials, bare SF's biological nature and structural features, and comprehending the related chemo-physical properties and techniques used to produce the desired formulations of SF; (ii) the different applications of SF-based biomaterials and their related composite structures, discussing their biocompatibility and effectiveness in the medical field. Particularly, applications in regenerative medicine are also analyzed herein to highlight the different therapeutic strategies applied to various body sectors. [ABSTRACT FROM AUTHOR]

Caddisworms (Trichoptera) spin adhesive silks to construct a variety of underwater composite structures. Many studies have focused on the fibroin heavy chain of caddisworm silk and found that it contains heavy phosphorylation to maintain a stable secondary structure. Besides fibroins, recent studies have also identified some new silk proteins within caddisworm silk. To better understand the silk composition and its secretion process, this study reports the silk gland proteome of a retreat‐building caddisworm, Stenopsyche angustata Martynov (Trichoptera, Stenopsychidae). Using liquid chromatography tandem mass spectrometry (LC‐MS/MS), 2389 proteins were identified in the silk gland of S. angustata, among which 192 were predicted as secreted silk proteins. Twenty‐nine proteins were found to be enriched in the front silk gland, whereas 109 proteins were enriched in the caudal silk gland. The fibroin heavy chain and nine uncharacterized silk proteins were identified as phosphorylated proteins. By analysing the sequence of the fibroin heavy chain, we found that it contains 13 Gly/Thr/Pro‐rich regions, 12 Val/Ser/Arg‐rich regions and a Gly/Arg/Thr‐rich region. Three uncharacterized proteins were identified as sericin‐like proteins due to their larger molecular weights, signal peptides and repetitive motifs rich in serine. This study provides valuable information for further clarifying the secretion and adhesion of underwater caddisworm silk. [ABSTRACT FROM AUTHOR]

The domestic silkworm, Bombyx mori, has been widely used in silk production for centuries. It is also used as a bioreactor by the textile and pharmaceutical industries to mass produce recombinant bioactive proteins containing silk-based materials. Furthermore, silkworms are well-known as a source of food and have also been orally administered to prevent and treat several human disorders. In this study, we aimed to investigate the inherent bio-physicochemical properties of edible silkworms to accurately evaluate their clinical and nutritional potential. We prepared raw powder from whole larvae of silkworm. The yield rate of the powder derived from dried larvae was almost 100% (98.1–99.1% in replicates). As “percentage yield” translates to “Budomari” in Japanese, this raw powder was named “B100rw.” We further prepared B100dn that was denatured through autoclaving. Thereafter, we examined whether B100rw sustained the original bio-physicochemical properties by comparing it with B100dn. There was no significant difference in nutritional content between B100rw and B100dn. B100rw contained proteins derived from silkworm larvae and mulberry leaves, whereas the proteins of B100dn were mostly degraded. On measuring the enzymatic activity of both powders using trehalase as an indicator enzyme, B100rw was found to maintain trehalase activity. B100rw also maintained a random coil conformation, similar to that of liquid silk. This suggested that B100rw sustained the unique bio-physicochemical properties of living larvae. These findings may facilitate the development of novel food products or orally administered vaccines.

Abstract Purpose Post-interventional hemorrhage can result in serious complications, especially in patients with hemostatic disorders. Identification of safe and efficient local hemostatic agents is important, particularly in the context of an ageing society and the emergence of new oral anticoagulants. The aim of this in vitro study was to investigate the potential of silk fibroin membranes coated with the inorganic polymer polyphosphate (polyP) as a novel hemostatic device in oral surgery. Methods Cocoons of the silkworm Bombyx mori were degummed and dissolved. Varying amounts of long-chain polyP (2–2000 µg/mm2) were adsorbed to the surface of silk fibroin membranes. Analysis of the procoagulant effect of polyP-coated silk membranes was performed using real-time thrombin generation assays in human plasma. Increasing concentrations of polyP (0.15–500 µg/ml) served as a positive control, while uncoated silk fibroin membranes were used as negative control. Results PolyP-coated silk fibroin membranes triggered coagulation when compared to plasma samples and pure silk fibroin membranes. A polyP-dose-dependent effect of thrombin generation could be found with a maximum (ETP = 1525.7 nM⋅min, peak thrombin = 310.1 nM, time to peak = 9.8 min, lag time = 7.6 min.) at 200 µg/mm2 of polymer loading on the silk fibroin membrane surface. Conclusions In this study, it was demonstrated that silk fibroin membranes coated with polyP have the potential to act as a promising novel hemostatic device. Graphical Abstract

In this work, the effect of incorporating silk fibroin, a fibrous biocompatible protein, into physically cross-linked agarose hydrogels was investigated as a simple model study to examine how supramolecular fibrous structures influence the properties of the hydrogels. The rheological and transport properties were studied. Fibroin did not change the general viscoelastic properties of the investigated hydrogels but changed the viscoelastic moduli values and also the mesh size, as calculated from rheometry data. Fibroin influenced the mechanical properties depending on its concentration: at lower concentrations, it increased the mesh size, while at higher concentrations, it acted as a filler, decreasing the mesh size. Similarly, the storage and loss moduli were affected, either increasing or decreasing based on the fibroin concentration. The fibroin effect on the diffusion of two dyes differing in their charge was the result of a combination of structural effects, responsible also for changes in the rheological properties, and a result of electrostatic interactions between the charged groups. For positively charged methylene blue, low fibroin concentrations accelerated diffusion, while higher concentrations slowed it by filling network vacancies. In contrast, for negatively charged eosin-B, fibroin strongly impeded diffusion at all concentrations due to electrostatic repulsion, leading to its accumulation at the hydrogel interface. The findings of this work may contribute to an understanding of the behavior of the extracellular matrix or soft tissues as well as to the development of the tailored design of hydrogel materials.

This study aimed to develop a film dressing prepared by incorporating a complex of cannabidiol and 2-hydroxypropyl-β-cyclodextrin (CBD/HP-β-CD) into a fibroin-based film and to investigate its wound healing capabilities. The fibroin from silkworm cocoons exhibited a total protein content of 96.34 ± 0.14% w/w and a molecular weight range of 25 to 245 kDa. Fourier-transform infrared spectroscopy (FTIR) revealed the presence of characteristic amide peaks (I, II, and III) in the isolated fibroin. The CBD/HP-β-CD complex, prepared with a molar ratio of 1:2 (CBD to HP-β-CD), had 81.5 ± 1.2% w/w CBD content, as determined by high-performance liquid chromatography (HPLC). X-ray diffraction (XRD) and FTIR analyses demonstrated successful encapsulation of CBD's hydrophobic aromatic rings by HP-β-CD. Blending the fibroin solution with the CBD/HP-β-CD complex produced a transparent, slightly yellowish film. Mechanical testing revealed a tensile strength of 48.67 ± 2.57 MPa and a % elongation at a break of 1.71 ± 0.21%. XRD and FTIR analyses showed distinctive crystalline and chemical structures of the film. In subsequent in vitro experiments with normal human dermal fibroblasts, the film demonstrated potential for wound healing. An increase in cell division (G2/M phase) was observed compared to the fibroin film without the CBD/HP-β-CD complex. Additionally, fibroblasts treated with the film exhibited enhanced cell migration in a scratch assay and increased expression of vascular endothelial growth factor protein compared to the control group. Overall, these findings underscore the film's potential for enhancing wound healing outcomes. [ABSTRACT FROM AUTHOR]

Silk has been used in China for thousands of years and is the only natural filament fiber in nature that can be mass-produced, which is of great significance in the textile industry. In recent years, protein films, a derivative material of silk, have attracted much attention and are widely used in the fields of antimicrobial dressings, bone repair scaffolds, slow-release carriers and biosensors, and have become a high-tech material with a promising future. Despite the superior mechanical properties of native silk, the strength and toughness of regenerated silk-protein membranes are unsatisfactory, which greatly hinders their wide application. To enhance the mechanical strength of regenerated sericin materials, some scholars have enhanced the mechanical strength of regenerated sericin materials by mixing natural proteins, such as wool keratin and spider silk protein, and also improved the softness and ductility of regenerated sericin materials by adding non-protein components, such as glycerol and polyvinyl alcohol, of which glycerol can also promote the interactions between the molecules of sericin and the water molecules to improve the hydrophilicity of sericin. Both protein and non-protein addition methods are often accompanied by problems such as complex dissolution, cumbersome process, waste of resources and environmental pollution. Wool keratin-associated proteins (KAPs) are fibrous proteins rich in cysteine, capable of forming disulphide bonds upon oxidation. These bonds, along with hydrophobic interactions and van der Waals forces, contribute to the high mechanical strength and structural stability of keratin. In this study, KAP-incorporated silk was generated through transgenic methods and used as the material. Silk protein membranes were then obtained by gradually removing water from the silk protein solution and shaping it accordingly. Furthermore, 1% glycerol was added to the silk solution to modify the protein membrane. We tested the secondary structure, physicochemical properties, and mechanical properties of ordinary sericin protein membranes, KAP-incorporated sericin protein membranes, and glycerol-plasticized protein membranes, and then analyzed the improvement of sericin protein membranes by the incorporation of KAP. In this study, we used the KAP-incorporated silk obtained by transgenic transfer of the wool keratin gene into the silkworm, Bombyx mori, to produce performance-enhanced hybrid silk-protein membranes. Compared with the tedious process of dissolving silk and wool separately and then mixing them in the traditional method of making hybrid protein membranes, this method has the advantages of relative simplicity and higher efficiency, and provides a new way and idea for the research and utilisation of natural proteins such as silk and wool. The KAP-incorporated sericin protein membranes produced were tested, and it was found that the incorporation of KAP protein could increase the secondary structure of the stability of silk fibroin membranes and improve the mechanical properties of the membranes, and the adding of glycerol could also significantly improve the tensile properties and hydrophilicity of the KAP sericin membranes. The production of silk/wool keratin mixed protein films through transgenic methods has the characteristics of simplicity, zero pollution, and excellent performance, which can provide new ideas for the research and application of natural silk materials. [ABSTRACT FROM AUTHOR]

Herein, fibroin, polylactide (PLA), and carbon are investigated for their suitability as biocompatible and biodegradable materials for amperometric biosensors. For this purpose, screen‐printed carbon electrodes on the biodegradable substrates fibroin and PLA are modified with a glucose oxidase membrane and then encapsulated with the biocompatible material Ecoflex. The influence of different curing parameters of the carbon electrodes on the resulting biosensor characteristics is studied. The morphology of the electrodes is investigated by scanning electron microscopy, and the biosensor performance is examined by amperometric measurements of glucose (0.5–10 mM) in phosphate buffer solution, pH 7.4, at an applied potential of 1.2 V versus a Ag/AgCl reference electrode. Instead of Ecoflex, fibroin, PLA, and wound adhesive are tested as alternative encapsulation compounds: a series of swelling tests with different fibroin compositions, PLA, and Ecoflex has been performed before characterizing the most promising candidates by chronoamperometry. Therefore, the carbon electrodes are completely covered with the particular encapsulation material. Chronoamperometric measurements with H2O2 concentrations between 0.5 and 10 mM enable studying the leakage current behavior. [ABSTRACT FROM AUTHOR]

Purpose: Post-interventional hemorrhage can result in serious complications, especially in patients with hemostatic disorders. Identification of safe and efficient local hemostatic agents is important, particularly in the context of an ageing society and the emergence of new oral anticoagulants. The aim of this in vitro study was to investigate the potential of silk fibroin membranes coated with the inorganic polymer polyphosphate (polyP) as a novel hemostatic device in oral surgery. Methods: Cocoons of the silkworm Bombyx mori were degummed and dissolved. Varying amounts of long-chain polyP (2–2000 µg/mm2) were adsorbed to the surface of silk fibroin membranes. Analysis of the procoagulant effect of polyP-coated silk membranes was performed using real-time thrombin generation assays in human plasma. Increasing concentrations of polyP (0.15–500 µg/ml) served as a positive control, while uncoated silk fibroin membranes were used as negative control. Results: PolyP-coated silk fibroin membranes triggered coagulation when compared to plasma samples and pure silk fibroin membranes. A polyP-dose-dependent effect of thrombin generation could be found with a maximum (ETP = 1525.7 nM⋅min, peak thrombin = 310.1 nM, time to peak = 9.8 min, lag time = 7.6 min.) at 200 µg/mm2 of polymer loading on the silk fibroin membrane surface. Conclusions: In this study, it was demonstrated that silk fibroin membranes coated with polyP have the potential to act as a promising novel hemostatic device. [ABSTRACT FROM AUTHOR]

Silk has a long history as an exclusive textile, but also as a suture thread in medicine; nowadays, diverse cell carriers are manufactured from silk. Its advantages are manifold, including high biocompatibility, biomechanical strength and processability (approved for nearly all manufacturing techniques). Silk's limitations, such as scarcity and batch to batch variations, are overcome by gene technology, which allows for the upscaled production of recombinant "designed" silk proteins. For processing thin fibroin filaments, the sericin component is generally removed (degumming). In contrast to many synthetic biomaterials, fibroin allows for superior cell adherence and growth. In addition, silk grafts demonstrate superior mechanical performance and long-term stability, making them attractive for anterior cruciate ligament (ACL) tissue engineering. Looking at these promising properties, this review focusses on the responses of cell types to silk variants, as well as their biomechanical properties, which are relevant for ACL tissue engineering. Meanwhile, sericin has also attracted increasing interest and has been proposed as a bioactive biomaterial with antimicrobial properties. But so far, fibroin was exclusively used for experimental ACL tissue engineering approaches, and fibroin from spider silk also seems not to have been applied. To improve the bone integration of ACL grafts, silk scaffolds with osteogenic functionalization, silk-based tunnel fillers and interference screws have been developed. Nevertheless, signaling pathways stimulated by silk components remain barely elucidated, but need to be considered during the development of optimized silk cell carriers for ACL tissue engineering. [ABSTRACT FROM AUTHOR]

Duy Toan Pham,1 Quoc Cuong Huynh,1 Ruby Lieu,2 Viet Bach Nguyen,3 Van De Tran,4 Bui Thi Phuong Thuy5 1Department of Chemistry, College of Natural Sciences, Can Tho University, Can Tho, 900000, Vietnam; 2Faculty of Commerce, Van Lang University, Ho Chi Minh City, Vietnam; 3Faculty of Chemical Engineering, College of Engineering, Can Tho University, Can Tho, 900000, Vietnam; 4Department of Health Organization and Management, Can Tho University of Medicine and Pharmacy, Can Tho, 900000, Vietnam; 5Faculty of Fundamental Sciences, Van Lang University, Ho Chi Minh City, VietnamCorrespondence: Bui Thi Phuong Thuy, Faculty of Fundamental Sciences, Van Lang University, 69/68 Dang Thuy Tram Street, Ward 13, Binh Thanh District, Ho Chi Minh City, Vietnam, Email thuy.btp@vlu.edu.vnBackground: Wedelia trilobata L. (WT), a common herbal plant in Vietnam, is popularly used as a strong antioxidant in Vietnamese folk medicine. However, limited studies have reported the application of WT flower in cosmeceutical area.Purpose: This study explored the potentials of WT loaded fibroin microparticles (FMPs-WT) as a novel anti-aging cosmeceutical product.Methods: The WT flower was firstly extracted by maceration with methanol, ethanol 60%, and ethanol 96%, and its chemical compositions and total polyphenol content were investigated. Then, the FMPs-WT were developed by desolvation method and physicochemically characterized. Finally, the product antioxidant activities were in-vitro determined using DPPH assay.Results: The optimal WT extract was the ethanol 60% extract, which contains polyphenols, alkaloids, flavonoids, saponins, glycosides, and organic acids; with a total polyphenol content of 46.47 ± 2.32 mg GAE/g plant powder. The FMPs-WT were successfully formulated, with a distinct silk-II polymorph; varied sizes of 0.592 to 9.820 μm, depending on the fibroin concentrations and the WT extraction solvent; high entrapment efficiencies of > 65%; and sustained-release patterns of polyphenol in pH 7.4 for > 6 h. Regarding the antioxidant activity, the pure WT flower extracts possessed high scavenging actions with IC50 of 7.98 ± 0.40 μg/mL, comparable with the standard ascorbic acid (IC50 = 4.23 ± 0.21 μg/mL). Moreover, the FMPs-WT could retain the extract antioxidant capacity, and exert the effects in a timely manner, corresponding to its release profile.Conclusion: The FMPs-WT could be further investigated to become a potential anti-aging cosmeceutical product in the market.Keywords: Wedelia trilobata L., silk, fibroin, microparticles, antioxidant, DPPH

Featured Application: For heritage science purposes, especially to preserve silk artifacts. This study investigates the degradation mechanism of silk fibroin through Fourier-transformed infrared spectroscopy (FTIR) analysis. The secondary structure of silk fibroin-based materials is monitored using FTIR, and various estimators are calculated to assess the impact of degradation conditions and aging time. The oxidation estimator shows consistent growth, indicating peptide bond oxidation from the early stages of artificial aging, regardless of the conditions. The environment influences the hydrolysis estimator, with water introduction leading to significant changes. The crystallinity estimator reflects the overall degradation level, affected by oxidation and hydrolysis. XRD and FTIR analysis of historical silk banners up to 500 years old demonstrate a decrease in crystallinity and an increase in hydrolysis and oxidation. The presence of water accelerates the oxidation process, while crystallinity changes are primarily driven by oxidation. Fibroin degradation affects both antiparallel and parallel regions, with water playing a crucial role in accelerating hydrolysis and causing structural shifts. This study enhances our understanding of silk fibroin degradation and provides valuable insights for preserving historical silk artifacts. [ABSTRACT FROM AUTHOR]

Membrane technology has recently been given extensive consideration for the treatment of effluent to remove suspended solids, organic compounds and inorganic contaminants such as heavy metals. The aim of this study was to prepare, characterize, and test membranes made of silk fibroin (SF) and polymethyl methacrylate (PMMA) blend with different wt% ratios (5%, 10%, and 15%), respectively. The membranes were prepared by phase inversion scheme using water as non‐solvent. Fourier transform infrared spectroscopy (FTIR) was performed to find chemical interactions between polymer matrix and fibroin. The mechanical property of synthesized membranes was also carried out. The surface roughness, and finger‐like pore geometry developed by impregnation of fibroin filler in membrane matrix were depicted by atomic force microscopy (AFM) and scanning electron microscope (SEM), respectively. Surface porosity improved from 4.5% ± 1.9% to 30.0% ± 2.8%, water contact angle reduced from 68° ± 3.0° to 38° ± 1.2°, and highest pure water permeation value (31 L m−2 h−1) was obtained with the addition of fibroin loading. The membrane showed a greater affinity for Cr(VI) in comparison with Pb(II). The highest % rejection was evaluated to be 83% and 56% for Cr(VI), and Pb(II) by utilizing 1.70 wt% fibroin filler in membrane composition, respectively. [ABSTRACT FROM AUTHOR]

Despite the availability of advanced treatments, cancer remains the second leading cause of death worldwide. This is due to the many challenges prevailing in the research field and cancer therapy. Resistance to therapy and side effects provide major hindrances to recovery from cancer. As a result, in addition to the aim of killing cancer cells, the focus should also be on reducing or preventing side effects of the treatment. To enhance the effectiveness of cancer treatment, many researchers are studying drug delivery systems based on silk proteins: fibroin and sericin. These proteins have high biocompatibility, biodegradability, and ease of modification. Consequently, many researchers have developed several formulations of silk proteins such as scaffolds, nanoparticles, and hydrogels by combining them with other materials or drugs. This review summarizes the use of silk proteins in various forms in cancer research and therapy. The use of silk proteins to study cancer cells, to deliver cancer drugs to a target site, in cancer thermal therapy, and as an anti-cancer agent is described here. [ABSTRACT FROM AUTHOR]

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Sericulture is associated primarily with the production of cocoons for textile purposes. However, the widespread availability of synthetic fibers caused a decline in interest in natural fabrics, including silk. Changing trends on the textile market made it necessary to find the new possibilities of using mulberry silkworm cocoons. Due to the, fact that the silk fiber is made mainly of two proteins – sericin and fibroin they began to be used in the cosmetics industry. Smoothing, moisturizing, nourishing and anti-wrinkle properties have made cosmetics based on silk proteins very popular. Research conducted among consumers shows that when choosing cosmetics, they are more and more often guided not only by the price, but also by the composition and origin of the ingredients. The fully organic rearing of the mulberry silkworm provides raw materials with valuable properties. The possibilities of using cocoons in cosmetics constitute an alternative to the use of cocoons in the textile industry. We examined the prospect of revitalizing the Polish silk industry in the view of testing whether silkworm farming in Poland may become a common and profitable activity.

Silk fibroin (SF) is a biomacromolecule composed of proteins with properties, such as biocompatibility, biodegradability, and low immunogenicity. Thus, Silk fibroin nanoparticles (FNps) overcome the disadvantages of non-degradable synthetic nanoparticles. We studied the structural and thermal properties of SF and FNps from Bombyx mori L. cross-breed Pilamo I cocoons. Raw fibroin (RF) was obtained using a sodium Na2CO3 solution as part of an experimental design to improve extraction, and FNps were obtained by denaturing RF with a ternary solution of CaCl2:H2O:CH3CH2OH, followed by precipitation using an anti-solvent method with propanol. Pilamo I cocoon, RF, and FNps were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and elemental chemical analysis of energy dispersive X-rays (EDS). The Light Scattering (DLS) and the thermal properties of RF and FNps were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The FTIR results showed that sericin-free raw fibroin was obtained, and the SEM results showed that the nanometer-sized particles had a globular structure and apparent porosity. The differences in the enthalpy of the crystallization peaks in the DSC and TGA curves showed that the FNps had higher thermal stability than RF fibers. This result furthers the development of alternative materials as vehicles of active compounds from natural extracts.

Membrane separation technology is an efficient and high‐performance technique. It is a thin flat sheet and acts like a delicate barrier for the selective transport of substances under the influence of pressure. Low cost and various applications in industry as well as in medical make it more important. The basic property of a dialysis membrane is the ability to remove toxic materials from blood in minimum time, and maximum protein rejection, and must have the ability to moderate the water flux. Protein deposition or adsorption on the surface of the membrane results in low flux and change of selectivity of membrane for low toxic removal. In this work we prepared cellulose acetate membrane through the phase inversion method. The effects of additives are characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infra‐Red (FT‐IR), and Contact Angle. The membrane performance is also studied in pure water flux, water uptakes, porosity, BSA rejection, and Urea clearance test. This membrane is modified by adding various types of organic and inorganic additives which will perform specific functions. M‐3 membrane showed excellent results its hydrophilicity is 133.33 %, leaching point is 2.08, pure water permeation flux 97.19 L/m2h, porosity is 13.97 nm, BSA rejection value is 91 % and Urea clearance is 92 %. These results show that M‐3 is excellent for dialysis operations. [ABSTRACT FROM AUTHOR]

Bombyx mori is an agriculturally important insect used extensively for silk production. India, especially the eastern regions, is mostly dependent on the multivoltine breeds of silkworm Bombyx mori and their hybrids/crossbreeds. The multivoltine breeds are indigenous and superior in survival and hardiness but are relatively inferior in terms of qualitative traits, typically the silk quality. Therefore, it is highly relevant to understand the mechanism of silk production in the multivoltine breeds to decipher the reasons for the inferior quality of silk produced by the multivoltine breeds and thus gain leads to improve the quality of silk production in multivoltine breeds. With this background, study was carried to identify differential expression of the major genes associated with silk proteins in the silk gland region of the popular multivoltine breeds. Our results indicated that although fib-L, fib-H, Sericins, and P25 are the major genes associated with silk filament, a few other genes associated with silk assembly, transport, and protection in the silk glands are the ones that largely contribute towards efficient silk production. The differential expression of these genes had a major effect on the movement of silk proteins within the silk gland and the efficiency of silk production as well. The Pearson correlation revealed a positive correlation amongst the genes dealt with in this study, indicating that the concurrent increase in expression of both the types of genes in the silk glands, significantly improves the silk production. [ABSTRACT FROM AUTHOR]

The golden rule in tissue engineering is the creation of a synthetic device that simulates the native tissue, thus leading to the proper restoration of its anatomical and functional integrity, avoiding the limitations related to approaches based on autografts and allografts. The emergence of synthetic biocompatible materials has led to the production of innovative scaffolds that, if combined with cells and/or bioactive molecules, can improve tissue regeneration. In the last decade, silk fibroin (SF) has gained attention as a promising biomaterial in regenerative medicine due to its enhanced bio/cytocompatibility, chemical stability, and mechanical properties. Moreover, the possibility to produce advanced medical tools such as films, fibers, hydrogels, 3D porous scaffolds, non-woven scaffolds, particles or composite materials from a raw aqueous solution emphasizes the versatility of SF. Such devices are capable of meeting the most diverse tissue needs; hence, they represent an innovative clinical solution for the treatment of bone/cartilage, the cardiovascular system, neural, skin, and pancreatic tissue regeneration, as well as for many other biomedical applications. The present narrative review encompasses topics such as (i) the most interesting features of SF-based biomaterials, bare SF’s biological nature and structural features, and comprehending the related chemo-physical properties and techniques used to produce the desired formulations of SF; (ii) the different applications of SF-based biomaterials and their related composite structures, discussing their biocompatibility and effectiveness in the medical field. Particularly, applications in regenerative medicine are also analyzed herein to highlight the different therapeutic strategies applied to various body sectors.

Silk fibroin is a natural polymer with physicochemical properties heavily dependent on its silkworm sources and cultivation conditions. Hence, this study critically compared the characteristics and capacity to generate micro-/nanoparticles of fibroin extracted from the Thai silk and Vietnamese silk. Both Thai fibroin (SFT) and Vietnamese fibroin (SFV) were extracted and fabricated into micro-/nanoparticles using the same methods of desalination and condensation, respectively. Firstly, the amino acid compositions of SFT and SFV were determined and found to be similar, suggesting that the different cultivation conditions did not alter the fibroin chemical contents. Secondly, utilizing various analytical techniques, the SFT structure revealed less heavy chains, more light chains and P-25 glycoproteins, and lower crystallinity than those of SFV. Accordingly, compared to the particles formed by SFT, the SFV-based particles were significantly bigger (∼1700 nm vs. ∼150 nm), and possessed less drug (Amphotericin B) entrapment efficiency (64.3 ± 4.4% vs. 79.3 ± 5.1%), higher hemototoxicity, and less biostability in the blood. Conclusively, these differences add more insights for the appropriate applications of each fibroin kind to best promote its qualities and effectiveness.

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

[Display omitted] • Diet and strain affect silk gland gene expression in the late fifth instar silkworm. • Diet affects fibroin-related gene expression in the middle silk gland. • Artificial diet upregulates the sericin gene in the posterior silk gland. The silkworm (Bombyx mori) is a model organism for lepidopteran insects. It is an oligophagous insect that primarily feeds on mulberry leaves and has industrial use for the production of raw silk. The development of artificial diets has provided an alternative nutrient source for silkworms; however, one significant issue is that the production of cocoons is lower in silkworms reared on artificial diets compared with those reared on mulberry leaves. The differences in the silk gland in the late-stage fifth instar silkworm larvae, when silk synthesis is most active, between those raised on artificial diets and mulberry leaves, are unknown. In this study, we identified differences in the transcriptomes of the middle and posterior silk glands of fifth instar day five silkworm larvae reared on artificial diets compared with those reared on mulberry leaves using three strains: Daizo, Nichi01, and J137 × C146. We found that the silk-related genes fibrohexamerin (fhx), fibroin-light-chain (fibL), and fibroin-heavy-chain (fibH) in the middle silk gland, and ser1 in the posterior silk gland, were differentially expressed in a strain-dependent manner. In silkworms reared on artificial diets, fhx , fibL , and fibH in the middle silk gland were upregulated in Nichi01 and downregulated in J137 × C146, whereas ser1 in the posterior silk gland was upregulated in J137 × C146 compared with silkworms reared on mulberry leaves. Our results demonstrate that the diet and strain of silkworm larvae affect the expression of genes related to silk production in their silk glands during the late fifth instar stage. [ABSTRACT FROM AUTHOR]

This study aimed to develop a film dressing prepared by incorporating a complex of cannabidiol and 2-hydroxypropyl-β-cyclodextrin (CBD/HP-β-CD) into a fibroin-based film and to investigate its wound healing capabilities. The fibroin from silkworm cocoons exhibited a total protein content of 96.34 ± 0.14% w/w and a molecular weight range of 25 to 245 kDa. Fourier-transform infrared spectroscopy (FTIR) revealed the presence of characteristic amide peaks (I, II, and III) in the isolated fibroin. The CBD/HP-β-CD complex, prepared with a molar ratio of 1:2 (CBD to HP-β-CD), had 81.5 ± 1.2% w/w CBD content, as determined by high-performance liquid chromatography (HPLC). X-ray diffraction (XRD) and FTIR analyses demonstrated successful encapsulation of CBD’s hydrophobic aromatic rings by HP-β-CD. Blending the fibroin solution with the CBD/HP-β-CD complex produced a transparent, slightly yellowish film. Mechanical testing revealed a tensile strength of 48.67 ± 2.57 MPa and a % elongation at a break of 1.71 ± 0.21%. XRD and FTIR analyses showed distinctive crystalline and chemical structures of the film. In subsequent in vitro experiments with normal human dermal fibroblasts, the film demonstrated potential for wound healing. An increase in cell division (G2/M phase) was observed compared to the fibroin film without the CBD/HP-β-CD complex. Additionally, fibroblasts treated with the film exhibited enhanced cell migration in a scratch assay and increased expression of vascular endothelial growth factor protein compared to the control group. Overall, these findings underscore the film’s potential for enhancing wound healing outcomes.

Abstract Background Chromatin architecture is critical for gene expression during development. Matrix attachment regions (MARs) control and regulate chromatin dynamics. The position of MARs in the genome determines the expression of genes in the organism. In this study, we set out to elucidate how MARs temporally regulate the expression of the fibroin heavy chain (FIBH) gene during development. We addressed this by identifying MARs and studying their distribution and differentiation, in the posterior silk glands of Bombyx mori during 5th instar development. Results Of the MARs identified on three different days, 7.15% MARs were common to all 3 days, whereas, 1.41, 19.27 and 52.47% MARs were unique to day 1, day 5, and day 7, respectively highlighting the dynamic nature of the matrix associated DNA. The average chromatin loop length based on the chromosome wise distribution of MARs and the distances between these MAR regions decreased from day 1 (253.91 kb) to day 5 (73.54 kb) to day 7 (39.19 kb). Further significant changes in the MARs in the vicinity of the FIBH gene were found during different days of 5th instar development which implied their role in the regulation and expression of the FIBH gene. Conclusions The presence of MARs in the flanking regions of genes found to exhibit differential expression during 5th instar development indicates their possible role in the regulation of their expression. This reiterates the importance of MARs in the genomic functioning as regulators of the molecular mechanisms in the nucleus. This is the first study that takes into account the tissue specific genome-wide MAR association and the potential role of these MARs in developmentally regulated gene expression. The current study lays a foundation to understand the genome wide regulation of chromatin during development.