Rational Design of Ag/ZnO Hybrid Nanoparticles on Sericin/Agarose Composite Film for Enhanced Antimicrobial Applications

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.

Fabrication of bimetallic Ag@ZnO nanocomposite and its anti-cancer activity on cervical cancer via impeding PI3K/AKT/mTOR pathway

INTRODUCTION

Bimetallic nanoparticles, specifically Zinc oxide (ZnO) and Silver (Ag), continue to much outperform other nanoparticles investigated for a variety of biological uses in the field of cancer therapy. This study introduces biosynthesis of bimetallic silver/zinc oxide nanocomposites (Ag@ZnO NCs) using the Crocus sativus extract and evaluates their anti-cancer properties against cervical cancer.

METHODS

The process of generating bimetallic nanoparticles (NPs), namely Ag@ZnO NCs, through the utilization of Crocus sativus extract proved to be uncomplicated and eco-friendly. Various methods, such as UV-vis, DLS, FTIR, EDX, and SEM analyses, were utilized to characterize the generated Ag@ZnO NCs. The MTT assay was employed to assess the cytotoxic properties of biosynthesized bimetallic Ag@ZnO NCs against the HeLa cervical cancer cell line. Moreover, the impact of Ag@ZnO NCs on HeLa cells was assessed by examining cell survival, ROS production, MMP levels, and induced apoptosis. Through western blot analysis, the expression levels of the PI3K, AKT, mTOR, Cyclin D, and CDK proteins seemed to be ascertained. Using flow cytometry, the cancer cells' progression through necrosis and apoptosis, in addition to the cell cycle analysis, were investigated.

RESULTS

Bimetallic Ag@ZnO NCs that were biosynthesized showed a high degree of stability, as demonstrated by the physicochemical assessments. The median size of the particles in these NCs was approximately 80-90 nm, and their zeta potential was -14.70 mV. AgNPs and ZnO were found, according to EDX data. Further, Ag@ZnO NCs hold promise as a potential treatment for cervical cancer. After 24 hours of treatment, a dosage of 5 µg/mL or higher resulted in a maximum inhibitory effect of 58 ± 2.9. The concurrent application of Ag/ZnO NPs to HeLa cells resulted in elevated apoptotic signals and a significant generation of reactive oxygen species (ROS). As a result, the bimettalic Ag@ZnO NCs treatment has been recognized as a chemotherapeutic intervention by inhibiting the production of PI3K, AKT, and mTOR-mediated regulation of propagation and cell cycle-regulating proteins.

CONCLUSIONS

The research yielded important insights into the cytotoxic etiology of biosynthesized bimetallic Ag@ZnO NCs against HeLa cells. The biosynthesized bimetallic Ag@ZnO NCs have a significant antitumor potential, which appears to be associated with the development of oxidative stress, which inhibits the development of the cell cycle and the proliferation of cells. Therefore, in the future, biosynthesized bimetallic Ag@ZnO NCs may be used as a powerful anticancer drug to treat cervical cancer.

Silk Sericin and Its Composite Materials with Antibacterial Properties to Enhance Wound Healing: A Review

Wound infections may disrupt the normal wound-healing process. Large amounts of antibiotics are frequently used to prevent pathogenic infections; however, this can lead to resistance development. Biomaterials possessing antimicrobial properties have promising applications for reducing antibiotic usage and promoting wound healing. Silk sericin (SS) has been increasingly explored for skin wound healing applications owing to its excellent biocompatibility and antioxidant, antimicrobial, and ultraviolet-resistant properties. In recent years, SS-based composite biomaterials with a broader antimicrobial spectrum have been extensively investigated and demonstrated favorable efficacy in promoting wound healing. This review summarizes various antimicrobial agents, including metal nanoparticles, natural extracts, and antibiotics, that have been incorporated into SS composites for wound healing and elucidates their mechanisms of action. It has been revealed that SS-based biomaterials can achieve sustained antimicrobial activity by slow-release-loaded antimicrobial agents. The antimicrobial-loaded SS composites may promote wound healing through anti-infection, anti-inflammation, hemostasis, angiogenesis, and collagen deposition. The manufacturing methods, benefits, and limitations of antimicrobial-loaded SS materials are briefly discussed. This review aims to enhance the understanding of new advances and directions in SS-based antimicrobial composites and guide future biomedical research.

Advances of regenerated and functionalized silk biomaterials and application in skin wound healing

The cocoon silk of silkworms (Bombyx mori) has multiple potential applications in biomedicine due to its good biocompatibility, mechanical properties, degradability, and plasticity. Numerous studies have confirmed that silk material dressings are more effective than traditional ones in the skin wound healing process. Silk material research has recently moved toward functionalized biomaterials and achieved remarkable results. Herein, we summarize the recent advances in functionalized silk materials and their efficacy in skin wound healing. In particular, transgenic technology has realized the specific expression of human growth factors in the silk glands of the silkworms, which lays the foundation for fabricating novel and low-cost functionalized materials. Without a green and safe preparation process, the best raw silk materials cannot be made into medically safe products. Therefore, we provide an overview of green and gentle approaches for silk degumming and silk sericin (SS) extraction. Moreover, we summarize and discuss the processing methods of silk fibroin (SF) and SS materials and their potential applications, such as burns, diabetic wounds, and other wounds. This review aims to enhance our understanding of new advances and directions in silk materials and guide future biomedical research.

Bio-based antimicrobial food packaging films based on hydroxypropyl starch/polyvinyl alcohol loaded with the biosynthesized zinc oxide nanoparticles

In the last decades, bio-based active food packaging materials have received much attention. It is known that the utilization of traditional materials for food packaging applications lack some critical characteristics such as resistance to the harmful microbes that cause a damage to the preserved foods. Therefore, the current study aimed to find an alternative packaging films comprises an efficient biopolymers. This research work was designed to prepare film mats using hydroxypropyl starch (HPS), polyvinyl alcohol (PVA), palmitic acid (PA) and biosynthesized zinc oxide nanoparticles (ZnONPs). The fabricated films were coded as 1H, 2H, 3H and 4H based on the utilized concentration of ZnONPs. The biosynthesized ZnONPs and the bio-based films loaded with ZnONPs were characterized. The results revealed that ZnONPs exhibited nearly spherical shape and size ∼40 nm. The surface structure of the produced bioactive packaging films exhibited smooth with homogeneous features, excellent mechanical and thermal stability properties. The prepared bioactive packaging film loaded with ZnONPs (4H) exhibited superior antibacterial activity among other films against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 with inhibition zones 15.1 ± 0.76 and 12.1 ± 0.71 mm respectively. Correspondingly, packing film 4H exhibited potential antifungal activity toward Aspergillus niger RCMB 02724, A. flavus RCMB 02782, Penicillium expansum IMI 89372 and Fusarium oxysporum RCMB 001004 with inhibition zones (16 ± 1.0, 22 ± 0.90, 18.0 ± 1.1 and12.3 ± 0.57 mm respectively). Moreover, all prepared films did not show cytotoxicity on the normal cell line (Wi38) and recorded biodegradability properties that reached around 85 % after four weeks in soil. Based on these results, the antimicrobial films comprising HPS/PVA and loaded with the biosynthesized ZnONPs can be considered as a suitable film for food packaging purposes.

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

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

Extraction, Modification and Biomedical Application of Agarose Hydrogels: A Review

Numerous compounds present in the ocean are contributing to the development of the biomedical field. Agarose, a polysaccharide derived from marine red algae, plays a vital role in biomedical applications because of its reversible temperature-sensitive gelling behavior, excellent mechanical properties, and high biological activity. Natural agarose hydrogel has a single structural composition that prevents it from adapting to complex biological environments. Therefore, agarose can be developed into different forms through physical, biological, and chemical modifications, enabling it to perform optimally in different environments. Agarose biomaterials are being increasingly used for isolation, purification, drug delivery, and tissue engineering, but most are still far from clinical approval. This review classifies and discusses the preparation, modification, and biomedical applications of agarose, focusing on its applications in isolation and purification, wound dressings, drug delivery, tissue engineering, and 3D printing. In addition, it attempts to address the opportunities and challenges associated with the future development of agarose-based biomaterials in the biomedical field. It should help to rationalize the selection of the most suitable functionalized agarose hydrogels for specific applications in the biomedical industry.

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.

Balancing the antibacterial and osteogenic effects of double-layer TiO2 nanotubes loaded with silver nanoparticles for the osseointegration of implants

The improvement of Ag nanoparticles (AgNPs), in particular, loaded titania nanotubes, includes not only the antibacterial effect but also balancing the side effects from the antibacterial effect and osteogenesis properties, which can lead to an increased success rate of implants. Herein, based on the various needs of the graft to inhibit bacteria at different stages in vivo, we used a special osteogenic honeycomb-like "large tube over small tube" double-layered nanotube structure and created ultra-small-sized silver nanoparticles uniformly loaded on the surface and the interior of double-layer nanotubes by an optimized sputter coating method to ensure the time-dependent controllable release of antibacterial Ag ions from grafts and achieve the balance of the antibacterial effect and osteogenesis properties. The release of Ag⁺ from DNT-Ag8 was determined by inductively coupled plasma spectrometry. The release rate of Ag was slow; it was 30% on the first day and plateaued by the 19th day. Porphyromonas gingivalis adhesion and live bacteria were less abundant on the surface of DNT-Ag8, reaching an antibacterial efficiency of 55.6% in vitro. DNT-Ag8 shows a significantly higher antibacterial effect in a rat model infected with Staphylococcus aureus. An in vitro study demonstrated that DNT-Ag8 had no adverse effects on the adhesion, viability, proliferation, ALP staining, or activity assays of rat BMSCs. In contrast, it increased the expression of osteogenic genes. In vivo, DNT-Ag8 promoted bone-implant osseointegration in a beagle mandibular tooth loss model. This study demonstrated that the uniform loading of small-diameter silver nanoparticles using a honeycomb bilayer nanotube template structure is a promising method for modifying titanium surfaces to improve both bacteriostasis and osseointegration.

Silk sericin-based materials for biomedical applications

Silk sericin, a natural protein extracted from silkworm cocoons, has been extensively studied and utilized in the biomedical field because of its superior biological activities and controllable chemical-physical properties. Sericin is biocompatible and naturally cell adhesive, enabling cell attachment, proliferation, and differentiation in sericin-based materials. Moreover, its abundant functional groups from variable amino acids composition allow sericin to be chemically modified and cross-linked to form versatile constructs serving as alternative matrixes for biomedical applications. Recently, sericin has been constructed into various types of biomaterials for tissue engineering and regenerative medicine, including various bulk constructions (films, hydrogels, scaffolds, conduits, and devices) and micro-nano formulations. In this review, we systemically summarize the properties of silk sericin, introduce its different forms, and demonstrate their newly-developed as well as potential biomedical applications.

Silver Nanoparticle-Loaded Gelatin-Based Nanocomposite Films toward Enhanced Mechanical Properties and Antibacterial Activity

Gelatin (GH) is a natural polymer material with unique physical, chemical, and biological properties that render it a good base material for biomedical material production. Herein, Ag nanoparticles (NPs) were loaded onto a waterborne polyurethane-GH composite (WPU-g-GH) to prepare a GH-based nanocomposite (AgNP/WPU-g-GH) films). The prepared nanocomposite films were characterized using several analyses including Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction, transmission emission microscopy, mechanical strength tests, and other analyses. The results demonstrated that the nanocomposite films had high mechanical strength, good thermal stability, and controllable biodegradability. In particular, when the AgNP loading content was 0.03%, the tensile strength, elongation at break, and average particle size of the nanocomposite film reached 45.13 MPa, 476.04%, and 13.02978 ± 1.64406 nm, respectively. Disk diffusion and cytotoxicity analyses revealed that the nanocomposite films exhibited significant antibacterial activity against Gram-negative and Gram-positive bacteria without affecting the cell viability of fibroblasts. These findings indicate that the nanocomposite films with high mechanical strength and antibacterial activity could be used for wound management, tissue adhesion, and biomaterial surface coating.

Novel Hydrophobic Nanostructured Antibacterial Coatings for Metallic Surface Protection

A simple and cost-efficient method to modify different surfaces in order to improve their bioactivity, corrosion and wear resistance proved to be sol-gel coatings. The silane layers have been shown to be effective in the protection of steel, aluminum or magnesium alloys and copper and copper alloys. Moreover, it has been found that the adding of different inorganic nanoparticles into silica films leads to increasing their performance regarding corrosion protection. In this study, we fabricated, a simple sol-gel method, transparent mono- and bi-layered hydrophobic coatings with simultaneous antibacterial, hydrophobic and anti-corrosive properties for the protection of metallic surfaces against the action of air pollutants or from biological attacks of pathogens. The first layer (the base) of the coating contains silver (Ag) or zinc oxide (ZnO) nanoparticles with an antibacterial effect. The second layer includes zinc oxide nanoparticles with flower-like morphology to increase the hydrophobicity of the coating and to improve corrosion-resistant properties. The second layer of the coating contains a fluorinated silica derivative, 1H,1H,2H,2H-perfluorooctyl triethoxysilane (PFOTES), which contributes to the hydrophobic properties of the final coating by means of its hydrophobic groups. The mono- and bi-layered coatings with micro/nano rough structures have been applied by brushing on various substrates, including metallic surfaces (copper, brass and mild steel) and glass (microscope slides). The as-prepared coatings showed improved hydrophobic properties (water CA > 90°) when compared with the untreated substrates while maintaining the transparent aspect. The corrosion resistance tests revealed significantly lower values of the corrosion rates recorded for all the protected metallic surfaces, with the lowest values being measured for the bi-layered coatings containing ZnO particles, both in the first and in the second layers of the coating. Considering the antibacterial activity, the most effective were the AOAg-II and AOZnO-II coatings, which exhibited the highest reduction of microbial growth.

Biogenic Silver Nanoparticles: Synthesis and Application as Antibacterial and Antifungal Agents

The importance and need for eco-oriented technologies has increased worldwide, which leads to an enhanced development of methods for the synthesis of nanoparticles using biological agents. This review de-scribes the current approaches to the preparation of biogenic silver nanoparticles, using plant extracts and filtrates of fungi and microorganisms. The peculiarities of the synthesis of particles depending on the source of biocomponents are considered as well as physico-morphological, antibacterial and antifungal properties of the resulting nanoparticles which are compared with such properties of silver nanoparticles obtained by chemical synthesis. Special attention is paid to the process of self-assembly of biogenic silver nanoparticles.

Marine Polysaccharides for Wound Dressings Application: An Overview

Wound dressings have become a crucial treatment for wound healing due to their convenience, low cost, and prolonged wound management. As cutting-edge biomaterials, marine polysaccharides are divided from most marine organisms. It possesses various bioactivities, which allowing them to be processed into various forms of wound dressings. Therefore, a comprehensive understanding of the application of marine polysaccharides in wound dressings is particularly important for the studies of wound therapy. In this review, we first introduce the wound healing process and describe the characteristics of modern commonly used dressings. Then, the properties of various marine polysaccharides and their application in wound dressing development are outlined. Finally, strategies for developing and enhancing marine polysaccharide wound dressings are described, and an outlook of these dressings is given. The diverse bioactivities of marine polysaccharides including antibacterial, anti-inflammatory, haemostatic properties, etc., providing excellent wound management and accelerate wound healing. Meanwhile, these biomaterials have higher biocompatibility and biodegradability compared to synthetic ones. On the other hand, marine polysaccharides can be combined with copolymers and active substances to prepare various forms of dressings. Among them, emerging types of dressings such as nanofibers, smart hydrogels and injectable hydrogels are at the research frontier of their development. Therefore, marine polysaccharides are essential materials in wound dressings fabrication and have a promising future.

Bactericidal and Virucidal Activities of Biogenic Metal-Based Nanoparticles: Advances and Perspectives

Much progress has been achieved in the preparation and application of engineered nanoparticles (NPs) in the field of medicine, mainly for antibacterial and antiviral applications. In the war against bacteria and viruses, besides traditional antibiotics and antiviral drugs, metal-based nanoparticles, such as silver (AgNPs), copper (CuNPs), copper oxides (CuO-NPs), iron oxide (FeO-NPs), zinc oxide (ZnO-NPs), and titanium oxide (TiO2-NPs) have been used as potent antimicrobial agents. These nanoparticles can be synthesized by traditional methods, such as chemical and physical routes, or more recently by biogenic processes. A great variety of macro and microorganisms can be successfully used as reducing agents of metal salt precursors in the biogenic synthesis of metal-based NPs for antimicrobial activity. Depending on the nature of the biological agent, NPs with different sizes, aggregation states, morphology, surface coatings and charges can be obtained, leading to different antimicrobial effects. Considering the drug resistance to traditional therapies, the development of versatile nanomaterials with potent antimicrobial effects is under intensive investigation. In this sense, this review presents and discusses the recent progress in the preparation and application of metal-based nanoparticles biogenically synthesized for antibacterial and antivirus applications. The strength and limitations are critically discussed.

Recent breakthroughs of antibacterial and antiviral protective polymeric materials during COVID-19 pandemic and after pandemic: Coating, packaging, and textile applications

The global epidemic owing to COVID-19 has generated awareness to ensuring best practices for avoiding the microorganism spread. Indeed, because of the increase in infections caused by bacteria and viruses such as SARS-CoV-2, the global demand for antimicrobial materials is growing. New technologies by using polymeric systems are of great interest. Virus transmission by contaminated surfaces leads to the spread of infectious diseases, so antimicrobial coatings are significant in this regard. Moreover, antimicrobial food packaging is beneficial to prevent the spread of microorganisms during food processing and transportation. Furthermore, antimicrobial textiles show an effective role. We aim to provide a review of prepared antimicrobial polymeric materials for use in coating, food packaging, and textile during the COVID-19 pandemic and after pandemic.

Inorganic Nanoparticles and Composite Films for Antimicrobial Therapies

The development of drug-resistant microorganisms has become a critical issue for modern medicine and drug discovery and development with severe socio-economic and ecological implications. Since standard and conventional treatment options are generally inefficient, leading to infection persistence and spreading, novel strategies are fundamentally necessary in order to avoid serious global health problems. In this regard, both metal and metal oxide nanoparticles (NPs) demonstrated increased effectiveness as nanobiocides due to intrinsic antimicrobial properties and as nanocarriers for antimicrobial drugs. Among them, gold, silver, copper, zinc oxide, titanium oxide, magnesium oxide, and iron oxide NPs are the most preferred, owing to their proven antimicrobial mechanisms and bio/cytocompatibility. Furthermore, inorganic NPs can be incorporated or attached to organic/inorganic films, thus broadening their application within implant or catheter coatings and wound dressings. In this context, this paper aims to provide an up-to-date overview of the most recent studies investigating inorganic NPs and their integration into composite films designed for antimicrobial therapies.