Novel Amoxicillin-Loaded Sericin Biopolymeric Nanoparticles: Synthesis, Optimization, Antibacterial and Wound Healing Activities

Silk Sericin and Its Effect on Skin Wound Healing: A State of the Art

Despite the significant progress in wound healing, chronic skin wounds remain a challenge for today's medicine. Due to the growing popularity of natural materials, silk protein-based dressings are gaining more attention in this field. Most studies refer to silk fibroin because sericin has been considered a waste product for years. However, sericin is also worth noting. Sericin-based dressings are mainly studied in cell cultures or animals. Sericin is the dressings' main component or can be included in more complex, advanced biomaterials. Recent studies highlight sericin's important role, noting its biocompatibility, biodegradability, and beneficial effects in skin wound healing, such as antibacterial activity, antioxidant and anti-inflammatory effects, or angiogenic properties. Developing sericin-based biomaterials is often simple, free of toxic by-products, and inexpensive, requiring no highly sophisticated apparatus. As a result, sericin-based dressings can be widely used in wound healing and have low environmental impact. However, the literature in this area is further limited. The following review collects and describes recent studies showing silk sericin's influence on skin wound healing.

Therapeutic potential of silkworm sericin in wound healing applications

Chronic wounds are characterised by an imbalance between pro and anti-inflammatory signals, which result in permanent inflammation and delayed re-epithelialization, consequently hindering wound healing. They are associated with bacterial infections, tissue hypoxia, local ischemia, reduced vascularization, and MMP-9 upregulation. The global prevalence of chronic wounds has been estimated at 40 million in the adult population, with an alarming annual growth rate of 6.6%, making it an increasingly significant clinical problem. Sericin is a natural hydrophilic protein obtained from the silkworm cocoon. Due to its biocompatibility, biodegradability, non-immunogenicity, and oxidation resistance, coupled with its excellent affinity for target biomolecules, it holds great potential in wound healing applications. The silk industry discards 50,000 tonnes of sericin annually, making it a readily available material. Sericin increases cell union sites and promotes cell proliferation in fibroblasts and keratinocytes, thanks to its cytoprotective and mitogenic effects. Additionally, it stimulates macrophages to release more therapeutic cytokines, thus improving vascularization. This review focuses on the biological properties of sericin that contribute towards enhanced wound healing process and its mechanism of interaction with important biological targets involved in wound healing. Emphasis is placed on diverse wound dressing products that are sericin based and the utilisation of nanotechnology to design sericin nanoparticles that aid in chronic wound management.

Correction: Diad et al. Novel Amoxicillin-Loaded Sericin Biopolymeric Nanoparticles: Synthesis, Optimization, Antibacterial and Wound Healing Activities. Int. J. Mol. Sci. 2022, 23, 11654

In the original publication [...].

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.

Biopolymer based nanoparticles and their therapeutic potential in wound healing - A review

Nanoparticles (NPs) have been extensively investigated for their potential in nanomedicine. There is a significant level of enthusiasm about the potential of NPs to bring out a transformative impact on modern healthcare. NPs can serve as effective wound dressings or delivery vehicles due to their antibacterial and pro-wound-healing properties. Biopolymer-based NPs can be manufactured using various food-grade biopolymers, such as proteins, polysaccharides, and synthetic polymers, each offering distinct properties suitable for different applications which include collagen, polycaprolactone, chitosan, alginate, and polylactic acid, etc. Their biodegradable and biocompatible nature renders them ideal nanomaterials for applications in wound healing. Additionally, the nanofibers containing biopolymer-based NPs have shown excellent anti-bacterial and wound healing activity like silver NPs. These NPs represent a paradigm shift in wound healing therapies, offering targeted and personalized solutions for enhanced tissue regeneration and accelerated wound closure. The current review focuses on biopolymer NPs with their applications in wound healing.

In vitro and in vivo anti-colorectal cancer effect of the newly synthesized sericin/propolis/fluorouracil nanoplatform through modulation of PI3K/AKT/mTOR pathway

The present work aimed to assess the potential effect of sericin/propolis/fluorouracil nanoformula against colorectal cancer (CRC) (the fourth most common cause of cancer-related mortalities). A novel anti-cancerous formula of the synthesized sericin/propolis nanoparticles was developed and tested both in vitro (using Caco-2 cell line) and in vivo (in experimentally induced colorectal cancer animal models). The combination index of the prepared nanoformula proved that the combination between sericin/propolis nanoparticles and 5-fluorouracil demonstrated the highest synergistic effect (0.86), with dose reduction index (DRI) of the chemotherapeutic drug reaching 1.49. The mechanism of action of the prepared nanoformula revealed that it acts through the inhibition of the PI3K/AKT/mTOR signaling pathway and consequently inhibiting cancerous cells proliferation. Treatment and prophylactic studies of both sericin and propolis showed increased TBARS (Thiobarbituric Acid Reactive Substance) formation, downregulated BCL2 (B-cell lymphoma 2) and activated BAX, Caspase 9 and Caspase 3 expression. The prepared nanoformula decreased the ROS (Reactive Oxygen Species) production in vivo owing to PI3K/AKT/mTOR pathway inhibition and FOXO-1 (Forkhead Box O1) activation that resulted in autophagy/apoptosis processes stimulation. The potent anticancer effect of the prepared nanoformula was further emphasized through the in vivo histopathological studies of experimentally induced tumors. The newly formulated sericin/propolis/fluorouracil nanoparticles exhibited clear-cut cytotoxic effects toward tumor cells with provided evidence for the prophylactic effect.

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.

Nano-Chitosan/Eucalyptus Oil/Cellulose Acetate Nanofibers: Manufacturing, Antibacterial and Wound Healing Activities

Accelerated wound healing in infected skin is still one of the areas where current therapeutic tactics fall short, which highlights the critical necessity for the exploration of new therapeutic approaches. The present study aimed to encapsulate Eucalyptus oil in a nano-drug carrier to enhance its antimicrobial activity. Furthermore, in vitro, and in vivo wound healing studies of the novel nano-chitosan/Eucalyptus oil/cellulose acetate electrospun nanofibers were investigated. Eucalyptus oil showed a potent antimicrobial activity against the tested pathogens and the highest inhibition zone diameter, MIC, and MBC (15.3 mm, 16.0 μg/mL, and 256 μg/mL, respectively) were recorded against Staphylococcus aureus. Data indicated a three-fold increase in the antimicrobial activity of Eucalyptus oil encapsulated chitosan nanoparticle (43 mm inhibition zone diameter against S. aureus). The biosynthesized nanoparticles had a 48.26 nm particle size, 19.0 mV zeta potential, and 0.45 PDI. Electrospinning of nano-chitosan/Eucalyptus oil/cellulose acetate nanofibers was conducted, and the physico-chemical and biological properties revealed that the synthesized nanofibers were homogenous, with a thin diameter (98.0 nm) and a significantly high antimicrobial activity. The in vitro cytotoxic effect in a human normal melanocyte cell line (HFB4) proved an 80% cell viability using 1.5 mg/mL of nano-chitosan/Eucalyptus oil/cellulose acetate nanofibers. In vitro and in vivo wound healing studies revealed that nano-chitosan/Eucalyptus oil/cellulose acetate nanofibers were safe and efficiently enhanced the wound-healing process through enhancing TGF-β, type I and type III collagen production. As a conclusion, the manufactured nano-chitosan/Eucalyptus oil/cellulose acetate nanofiber showed effective potentiality for its use as a wound healing dressing.

Fungal Secondary Metabolites/Dicationic Pyridinium Iodide Combinations in Combat against Multi-Drug Resistant Microorganisms

The spread of antibiotic-resistant opportunistic microbes is a huge socioeconomic burden and a growing concern for global public health. In the current study, two endophytic fungal strains were isolated from Mangifera Indica roots and identified as Aspergillus niger MT597434.1 and Trichoderma lixii KU324798.1. Secondary metabolites produced by A. niger and T. lixii were extracted and tested for their antimicrobial activity. The highest activity was noticed against Staphylococcus aureus and E. coli treated with A. niger and T. lixii secondary metabolites, respectively. A. niger crude extract was mainly composed of Pentadecanoic acid, 14-methyl-, methyl ester and 9-Octadecenoic acid (Z)-, methyl ester (26.66 and 18.01%, respectively), while T. lixii crude extract's major components were 2,4-Decadienal, (E,E) and 9-Octadecenoic acid (Z)-, and methyl ester (10.69 and 10.32%, respectively). Moreover, a comparative study between the fungal extracts and dicationic pyridinium iodide showed that the combination of A. niger and T. lixii secondary metabolites with dicationic pyridinium iodide compound showed a synergistic effect against Klebsiella pneumoniae. The combined formulae inhibited the bacterial growth after 4 to 6 h through cell wall breakage and cells deformation, with intracellular components leakage and increased ROS production.

Nanomaterials-Functionalized Hydrogels for the Treatment of Cutaneous Wounds

Hydrogels have been utilized extensively in the field of cutaneous wound treatment. The introduction of nanomaterials (NMs), which are a big category of materials with diverse functionalities, can endow the hydrogels with additional and multiple functions to meet the demand for a comprehensive performance in wound dressings. Therefore, NMs-functionalized hydrogels (NMFHs) as wound dressings have drawn intensive attention recently. Herein, an overview of reports about NMFHs for the treatment of cutaneous wounds in the past five years is provided. Firstly, fabrication strategies, which are mainly divided into physical embedding and chemical synthesis of the NMFHs, are summarized and illustrated. Then, functions of the NMFHs brought by the NMs are reviewed, including hemostasis, antimicrobial activity, conductivity, regulation of reactive oxygen species (ROS) level, and stimulus responsiveness (pH responsiveness, photo-responsiveness, and magnetic responsiveness). Finally, current challenges and future perspectives in this field are discussed with the hope of inspiring additional ideas.