Extraction and antioxidant activity of sericin, a protein from silk

Peptides: Emerging Candidates for the Prevention and Treatment of Skin Senescence: A Review

One class of cosmetic compounds that have raised interest of many experts is peptides. The search for ingredients with good biocompatibility and bioactivity has led to the use of peptides in cosmetic products. Peptides are novel active ingredients that improve collagen synthesis, enhance skin cell proliferation, or decrease inflammation. Based on their mechanism of action, they can be classified into signal peptides, carrier peptides, neurotransmitter inhibitor peptides, and enzyme inhibitor peptides. This review focuses on the main types of peptides and their application in the cosmetic field, underlining their main limitations. One of the most significant drawbacks of cosmetic peptides is their poor permeability through membranes, which limits their delivery and effectiveness. As a result, this review follows the methods used for improving permeability through the stratum corneum. Increasing peptide bioavailability and stability for enhanced delivery to the desired site of action and visible effects have become central points for the latest research due to their promising features. For this purpose, several methods have been identified and described. Physical techniques include thermal ablation (radiofrequency and laser), electrical methods (electroporation, iontophoresis), mechanical approach (microneedles), and ultrasounds. As an alternative, innovative formulations have been developed in nano-systems such as liposomes, niosomes, ethosomes, nanoemulsions, and other nanomaterials to reduce skin irritation and improve product effectiveness. The purpose of this review is to provide the latest information regarding these noteworthy molecules and the reasoning behind their use in cosmetic formulations.

Comparison of Chondrocyte Behaviors Between Silk Microfibers and Polycaprolactone Microfibers in Tissue Engineering and Regenerative Medicine Applications

Silk and polycaprolactone (PCL), derived from natural and synthetic sources, respectively, are suture materials commonly used in surgery. Beyond their application in sutures, they are also compelling subjects in regenerative medicine and tissue engineering. This study evaluated the effects of degummed silk microfibers compared to electrospun PCL microfibers of a similar diameter on chondrocyte behavior. The two types of microfibers were analyzed using scanning electron microscopy (SEM), real-time PCR, Western blotting, and DMMB analysis. The results demonstrated that the silk microfibers exhibited a higher proliferative cell rate over time compared to the PCL microfibers. Additionally, the expression of chondrogenic phenotypes was significantly upregulated, while the marker for hypertrophic chondrocytes-type X collagen-was downregulated in cell-laden silk microfibers compared to cell-laden PCL microfibers. These findings suggest that natural degummed silk microfibers may be a viable option for repairing damaged cartilage in the future of orthopedic surgery and bioengineering.

Oral Toxicity and Hypotensive Influence of Sericin-Derived Oligopeptides (SDOs) from Yellow Silk Cocoons of Bombyx mori in Rodent Studies

Sericin-derived oligopeptides (SDOs) from yellow silk cocoons exhibit antihypertensive and hypoglycemic properties in both in vitro and in vivo studies. This study investigated the acute toxicity of SDOs as a novel food for human consumption using female ICR mice and Wistar rats, as well as the chronic toxicity test on both sexes of Wistar rats. Clinical chemistry, hematology, and histopathological studies revealed that SDOs were safe for a single dose of 2000 mg kg-1 body weight (BW) and daily oral administration of 50, 100, and 200 mg kg-1 BW for six months. The chronic toxicity study additionally measured the rats' systolic blood pressure (SBP) and blood sugar monthly as they slowly aged. In the 2nd month for male rats and the 4th month for both sexes, SDOs had a significant hypotensive effect on Wistar rats' blood pressure, lowering it from 130 mmHg to a plateau at 110-115 mmHg. In contrast, the blood pressure of the control rats exceeded 140 mmHg after five months. Nonetheless, the hypoglycemic effect was not observed. Measurements of SBP and blood glucose in aged rats during chronic toxicity tests yielded insights beyond ordinary toxicity, including the health and fitness of the lab rats, perhaps resulting in novel discoveries or areas of study that justify the sacrifice of the animals' lives.

Sericin Protein: Structure, Properties, and Applications

Silk sericin, the glue protein binding fibroin fibers together, is present in the Bombyx mori silkworms' cocoons. In recent years, sericin has gained attention for its wide range of properties and possible opportunities for various applications, as evidenced by the meta-analysis conducted in this review. Sericin extraction methods have evolved over the years to become more efficient and environmentally friendly, preserving its structure. Due to its biocompatibility, biodegradability, anti-inflammatory, antibacterial, antioxidant, UV-protective, anti-tyrosinase, anti-aging, and anti-cancer properties, sericin is increasingly used in biomedical fields like drug delivery, tissue engineering, and serum-free cell culture media. Beyond healthcare, sericin shows promise in industries such as textiles, cosmetics, and food packaging. This review aims to highlight recent advancements in sericin extraction, research, and applications, while also summarizing key findings from earlier studies.

Enhancing Wound Healing: A Comprehensive Review of Sericin and Chelidonium majus L. as Potential Dressings

Wound healing, a complex physiological process orchestrating intricate cellular and molecular events, seeks to restore tissue integrity. The burgeoning interest in leveraging the therapeutic potential of natural substances for advanced wound dressings is a recent phenomenon. Notably, Sericin, a silk-derived protein, and Chelidonium majus L. (C. majus), a botanical agent, have emerged as compelling candidates, providing a unique combination of natural elements that may revolutionize conventional wound care approaches. Sericin, renowned for its diverse properties, displays unique properties that accelerate the wound healing process. Simultaneously, C. majus, with its diverse pharmacological compounds, shows promise in reducing inflammation and promoting tissue regeneration. As the demand for innovative wound care solutions increases, understanding the therapeutic potential of natural products becomes imperative. This review synthesizes current knowledge on Sericin and C. majus, envisioning their future roles in advancing wound management strategies. The exploration of these natural substances as constituents of wound dressings provides a promising avenue for developing sustainable, effective, and biocompatible materials that could significantly impact the field of wound healing.

Expanding the boundaries of silk sericin biomaterials in biomedical applications

Silk sericin (SS) has a long history as a by-product of the textile industry. SS has emerged as a sustainable material for biomedical engineering due to its material properties including water solubility, diverse impact on biological activities including antibacterial and antioxidant properties, and ability to promote cell adhesion and proliferation. This review addresses the origin, structure, properties, extraction, and underlying functions of this protein. An overview of the growing research studies and market evolution is presented, along with highlights of the most common fabrication matrices (hydrogels, bioinks, porous and fibrous scaffolds) and tissue engineering applications. Finally, the future trends with this protein as a multifaceted toolbox for bioengineering are explored, along with the challenges with SS. Overall, the present review can serve as a foundation for the creation of innovative biomaterials utilizing SS as a fundamental building block that hold market potential.

Enhancing Cisplatin Efficacy with Low Toxicity in Solid Breast Cancer Cells Using pH-Charge-Reversal Sericin-Based Nanocarriers: Development, Characterization, and In Vitro Biological Assessment

Platinum-based chemotherapeutic agents are widely employed in cancer treatment because of their effectiveness in targeting DNA. However, this indiscriminate action often affects both cancerous and normal cells, leading to severe side effects and highlighting the need for innovative approaches in achieving precise drug delivery. Nanotechnology presents a promising avenue for addressing these challenges. Protein-based nanocarriers exhibit promising capabilities in the realm of cancer drug delivery with silk sericin nanoparticles standing out as a leading contender. This investigation focuses on creating a sericin-based nanocarrier (SNC) featuring surface charge reversal designed to effectively transport cisplatin (Cispt-SNC) into MCF-7 breast cancer cells. Utilizing AutoDock4.2, our molecular docking analyses identified key amino acids and revealed distinctive conformational clusters, providing insights into the drug-protein interaction landscape and highlighting the potential of sericin as a carrier for controlled drug release. The careful optimization and fabrication of sericin as the carrier material were achieved through flash nanoprecipitation, a straightforward and reproducible method that is devoid of intricate equipment. The physicochemical properties of SNCs and Cispt-SNCs, particularly concerning size, surface charge, and morphology, were evaluated using dynamic light scattering (DLS) and scanning electron microscopy (SEM). Chemical and conformational analyses of the nanocarriers were conducted using Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD), and elemental composition analysis was performed through energy-dispersive X-ray spectroscopy (EDX). This approach aimed to achieve the smallest nanoparticle size for Cispt-SNCs (180 nm) and high drug encapsulation efficiency (84%) at an optimal sericin concentration of 0.1% (w/v), maintaining a negative net charge at a physiological pH (7.4). Cellular uptake and cytotoxicity were investigated in MCF-7 breast cancer cells. SNCs demonstrated stability and exhibited a pH-dependent drug release behavior, aligning with the mildly acidic tumor microenvironment (pH 6.0-7.0). Efficient cellular uptake of Cispt-SNC, along with DNA fragmentation and chromatin condensation, was found at pH 6, leading to cell apoptosis. These results collectively indicate the potential of SNCs for achieving controlled drug release in a tumor-specific context. Our in vitro studies reveal the cytotoxicity of both cisplatin and Cispt-SNCs on MCF-7 cells. Cisplatin significantly reduced cell viability at 10 μM concentration (IC50), and the unique combination of sericin and cisplatin showcased enhanced cell viability compared to cisplatin alone, suggesting that controlled drug release is indicated by a gradient decrease in cell viability and highlighting SNCs as promising carriers. The study underscores the promise of protein-based nanocarriers in advancing targeted drug delivery for cancer therapy.

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

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

Codelivery of resveratrol melatonin utilizing pH responsive sericin based nanocarriers inhibits the proliferation of breast cancer cell line at the different pH

Protein-based nanocarriers have demonstrated good potential for cancer drug delivery. Silk sericin nano-particle is arguably one of the best in this field. In this study, we developed a surface charge reversal sericin-based nanocarrier to co-deliver resveratrol and melatonin (MR-SNC) to MCF-7 breast cancer cells as combination therapy. MR-SNC was fabricated with various sericin concentrations via flash-nanoprecipitation as a simple and reproducible method without complicated equipment. The nanoparticles were subsequently characterized for their size, charge, morphology and shape by dynamic light scattering (DLS) and scanning electron microscope (SEM). Nanocarriers chemical and conformational analysis were done by fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) respectively. In vitro drug release was determined at different pH values (7.45, 6.5 and 6). The cellular uptake and cytotoxicity were studies using breast cancer MCF-7 cells. MR-SNC fabricated with the lowest sericin concentration (0.1%), showed a desirable 127 nm size, with a net negative charge at physiological pH. Sericin structure was preserved entirely in the form of nano-particles. Among the three pH values we applied, the maximum in vitro drug release was at pH 6, 6.5, and 7.4, respectively. This pH dependency showed the charge reversal property of our smart nanocarrier via changing the surface charge from negative to positive in mildly acidic pH, destructing the electrostatic interactions between sericin surface amino acids. Cell viability studies demonstrated the significant toxicity of MR-SNC in MCF-7 cells at all pH values after 48 h, suggesting a synergistic effect of combination therapy with the two antioxidants. The efficient cellular uptake of MR-SNC, DNA fragmentation and chromatin condensation was found at pH 6. Nutshell, our result indicated proficient release of the entrapped drug combination from MR-SNC in an acidic environment leading to cell apoptosis. This work introduces a smart pH-responsive nano-platform for anti-breast cancer drug delivery.

Evaluation of Antibacterial Mechanism of Action, Tyrosinase Inhibition, and Photocatalytic Degradation Potential of Sericin-Based Gold Nanoparticles

In recent times, numerous natural materials have been used for the fabrication of gold nanoparticles (AuNPs). Natural resources used for the synthesis of AuNPs are more environment friendly than chemical resources. Sericin is a silk protein that is discarded during the degumming process for obtaining silk. The current research used sericin silk protein waste materials as the reducing agent for the manufacture of gold nanoparticles (SGNPs) by a one-pot green synthesis method. Further, the antibacterial effect and antibacterial mechanism of action, tyrosinase inhibition, and photocatalytic degradation potential of these SGNPs were evaluated. The SGNPs displayed positive antibacterial activity (8.45-9.58 mm zone of inhibition at 50 μg/disc) against all six tested foodborne pathogenic bacteria, namely, Enterococcus feacium DB01, Staphylococcus aureus ATCC 13565, Listeria monocytogenes ATCC 33090, Escherichia coli O157:H7 ATCC 23514, Aeromonas hydrophila ATCC 7966, and Pseudomonas aeruginosa ATCC 27583. The SGNPs also exhibited promising tyrosinase inhibition potential, with 32.83% inhibition at 100 μg/mL concentration as compared to 52.4% by Kojic acid, taken as a reference standard compound. The SGNPs also displayed significant photocatalytic degradation effects, with 44.87% methylene blue dye degradation after 5 h of incubation. Moreover, the antibacterial mode of action of the SGNPs was also investigated against E. coli and E. feacium, and the results show that due to the small size of the nanomaterials, they could have adhered to the surface of the bacterial pathogens, and could have released more ions and dispersed in the bacterial cell wall surrounding environment, thereby disrupting the cell membrane and ROS production, and subsequently penetrating the bacterial cells, resulting in lysis or damage to the cell by the process of structural damage to the membrane, oxidative stress, and damage to the DNA and bacterial proteins. The overall outcome of the current investigation concludes the positive effects of the obtained SGNPs and their prospective applications as a natural antibacterial agent in cosmetics, environmental, and foodstuff industries, and for the management of environmental contagion.

Silk Sericin Protein Materials: Characteristics and Applications in Food-Sector Industries

There is growing concern about the use of plastic in packaging for food materials, as this results in increased plastic waste materials in the environment. To counter this, alternative sources of packaging materials that are natural and based on eco-friendly materials and proteins have been widely investigated for their potential application in food packaging and other industries of the food sector. Sericin, a silk protein that is usually discarded in large quantities by the sericulture and textile industries during the degumming process of manufacturing silk from silk cocoons, can be explored for its application in food packaging and in other food sectors as a functional food and component of food items. Hence, its repurposing can result in reduced economic costs and environmental waste. Sericin extracted from silk cocoon possesses several useful amino acids, such as aspartic acid, glycine, and serine. Likewise, sericin is strongly hydrophilic, a property that confers effective biological and biocompatible characteristics, including antibacterial, antioxidant, anticancer, and anti-tyrosinase properties. When used in combination with other biomaterials, sericin has proved to be effective in the manufacture of films or coating or packaging materials. In this review, the characteristics of sericin materials and their potential application in food-sector industries are discussed in detail.

Synergistic Effect of Silk Sericin and Curcumin to Treat an Inflammatory Condition

Inflammation-related diseases are recognized as the major cause of morbidity around the globe. In this study, the anti-inflammatory potential of sericin, curcumin, and their mixture was investigated in vivo and in vitro. Edema was induced via 1% carrageenan and then sericin (0.03, 0.06, 0.09 mg/ml), curcumin (1%, 2%, 3%), and their mixture doses were applied topically. The paw circumference and thickness were measured after 1-, 2-, 3-, 4-, 5-, and 6-hour post-carrageenan injection. The levels of IL-4 and IL-10 were measured from the serum. In mice fibroblast cells, sericin (20, 40, 60 μg/ml), curcumin (5, 10, 20 μM), and mixture concentrations were applied and then stimulated with lipopolysaccharide (LPS). Afterward, the cells were used for the analysis of gene expression, and the supernatant was collected for protein expression of IL-1β, IL-4, and IL-10. Our results demonstrated that sericin and curcumin caused a dose-dependent reduction in edema, whereas the mixture-treated group reduced the paw thickness and circumference most significantly (p = .0001). Furthermore, the mixture treatment of carrageenan-inflicted group increased the levels of anti-inflammatory cytokines, IL-4 (650.87 pg/ml) and IL-10 (183.14 pg/ml), in comparison to the carrageenan control. The in vitro data revealed that among all the treatment doses, the mixture-treated group has effectively reduced the gene (1.13-fold) and protein (51.9 pg/ml) expression of IL-1β in comparison to McCoy cells stimulated with LPS. Moreover, mixture treatment elevated the expression of IL-4 and IL-10 at genes (4.3-fold and 3.7-fold, respectively) and protein levels (169.33 and 141.83 pg/ml, respectively). The current study reports the enhanced anti-inflammatory effects of the mixture of curcumin and sericin through modulating expressions of interleukins in vitro and in vivo. Thus, natural products (curcumin and sericin)-based formulations have greater potential for clinical investigations.

Synthesis of Biogenic Gold Nanoparticles by Using Sericin Protein from Bombyx mori Silk Cocoon and Investigation of Its Wound Healing, Antioxidant, and Antibacterial Potentials

Introduction

A number of biological wastes and factory waste materials have been tested recently for the eco-friendly biosynthesis of nanoparticles. Sericin protein (SSP) is usually removed from the silk cocoon during the degumming process in the process of making the silk, and this sericin protein is normally thrown away by the sericulture industries as waste materials. It is found that this sericin protein possesses a number of biological properties.

Methods

Considering this, in the present study, an effort has been made to biosynthesize gold nanoparticles (SSP-AuNPs) using the waste sericin solution as the reducing and capping agent and investigate its biopotential in terms of its wound healing, antioxidant and antibacterial activities.

Results

The synthesis of SSP-AuNPs was perceived by the visual color change and confirmed by UV-Vis spectroscopy with absorption maxima at 522 nm. Further characterization of SSP-AuNPs was done by TEM, EDS, XRD, FTIR, DLS, zeta potential, TGA, AFM, etc. The size of SSP-AuNPs was found out to be 54.82 nm as per the particle size analyzer and the zeta potential is -19.8 mV. The SSP-AuNPs displayed promising wound healing potential of 70.96 and 69.76% wound closure rate at 5 and 10 µg/mL respectively as compared to 74.91% by the Centella asiatica taken as a positive control. It also exhibited promising antioxidant potential in terms of the DPPH, ABTS free radical scavenging, reducing power potential, and total antioxidant capacity. Besides, the SSP-AuNPs also displayed significant antibacterial activities against the tested pathogenic bacterial with the diameter of inhibition zones ranging between 12.10 and 14.96 mm as compared to the positive control cephalexin that displayed inhibition zones ranging between 12.08 and 13.24 mm.

Discussion

Taken together, SSP-AuNPs could serve as an interesting candidate for food, cosmetics, and biomedical fields in the applications of wound healing, cosmetics, antibacterial bandages, and ointments, etc.

Silk sericin as building blocks of bioactive materials for advanced therapeutics

Silk sericin is a class of protein biopolymers produced by silkworms. Increasing attention has been paid to silk sericin for biomedical applications in the last decade, not only because of its excellent biocompatibility and biodegradability but also due to the pharmacological activities stemming from its unique amino acid compositions. In this review, the biological properties of silk sericin, including curing specific diseases and promoting tissue regeneration, as well as underlying mechanisms are summarized. We consider the antioxidant activity of silk sericin as a fundamental property, which could account for partial biological activities, despite the exact mechanisms of silk sericin's effect remaining unknown. Based on the reactive groups on silk sericin, approaches of bottom-up fabrication of silk sericin-based biomaterials are highlighted, including non-covalent interactions and chemical reactions (reduction, crosslinking, bioconjugation, and polymerization). We then briefly present the cutting-edge advances of silk sericin-based biomaterials applied in tissue engineering and drug delivery. The challenges of silk sericin-based biomaterials are proposed. With more bioactivities and underlying mechanisms of silk sericin uncovered, it is going to boost the therapeutic potential of silk sericin-based biomaterials.

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

BACKGROUND

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

MAIN BODY

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

CONCLUSION

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