Identifying the components in eggshell membrane responsible for reducing the heat resistance of bacterial pathogens

Recent advancements and perspectives on processable natural biopolymers: Cellulose, chitosan, eggshell membrane, and silk fibroin

With the rapid development of the global economy and the continuous consumption of fossil resources, sustainable and biodegradable natural biomass has garnered extensive attention as a promising substitute for synthetic polymers. Due to their hierarchical and nanoscale structures, natural biopolymers exhibit remarkable mechanical properties, along with excellent innate biocompatibility and biodegradability, demonstrating significant potential in various application scenarios. Among these biopolymers, proteins and polysaccharides are the most commonly studied due to their low cost, abundance, and ease of use. However, the direct processing/conversion of proteins and polysaccharides into their final products has been a long-standing challenge due to their natural morphology and compositions. In this review, we emphasize the importance of processing natural biopolymers into high-value-added products through sustainable and cost-effective methods. We begin with the extraction of four types of natural biopolymers: cellulose, chitosan, eggshell membrane, and silk fibroin. The processing and post-functionalization strategies for these natural biopolymers are then highlighted. Alongside their unique structures, the versatile potential applications of these processable natural biopolymers in biomedical engineering, biosensors, environmental engineering, and energy applications are illustrated. Finally, we provide a summary and future outlook on processable natural biopolymers, underscoring the significance of converting natural biopolymers into valuable biomaterial platforms.

Bioactive glass-based fibrous wound dressings

Since the discovery of silicate bioactive glass (BG) by Larry Hench in 1969, different classes of BGs have been researched over decades mainly for bone regeneration. More recently, validating the beneficial influence of BGs with tailored compositions on angiogenesis, immunogenicity and bacterial infection, the applicability of BGs has been extended to soft tissue repair and wound healing. Particularly, fibrous wound dressings comprising BG particle reinforced polymer nanofibers and cotton-candy-like BG fibers have been proven to be successful for wound healing applications. Such fibrous dressing materials imitate the physical structure of skin's extracellular matrix and release biologically active ions e.g. regenerative, pro-angiogenic and antibacterial ions, e.g. borate, copper, zinc, etc., that can provoke cellular activities to regenerate the lost skin tissue and to induce new vessels formation, while keeping an anti-infection environment. In the current review, we discuss different BG fibrous materials meant for wound healing applications and cover the relevant literature in the past decade. The production methods for BG-containing fibers are explained and as fibrous wound dressing materials, their wound healing and bactericidal mechanisms, depending on the ions they release, are discussed. The present gaps in this research area are highlighted and new strategies to address them are suggested.

The eggshell membrane: A potential biomaterial for corneal wound healing

The eggshell membrane (ESM) is an abundant resource with innate complex structure and composition provided by nature. With at least 60 million tonnes of hen eggs produced globally per annum, utilisation of this waste resource is highly attractive in positively impacting sustainability worldwide. Given the morphology and mechanical properties of this membrane, it has great potential as a biomaterials for wound dressing. However, to date, no studies have demonstrated nor reported this application. As such, the objective of this investigation was to identify and optimise a reproducible extraction protocol of the ESM and to assess the physical, chemical, mechanical and biological properties of the substrate with a view to use as a wound dressing. ESM samples were isolated by either manual peeling (ESM-strip) or via extraction using acetic acid [ESM-A0.5] or ethylenediaminetetraacetic acid, EDTA [ESM-E0.9]. Energy dispersive X-ray spectroscopy (EDS) confirmed that there were no traces of calcium residues from the extraction process. Fourier transform infrared (FTIR) spectroscopy revealed that the extraction method (acetic acid and EDTA) did not alter the chemical structures of the ESM and also clarified the composition of the fibrous proteins of the ESM. Scanning electron microscopy (SEM) analyses revealed a three-layer composite structure of the ESM: an inner layer as continuous, dense and non-fibrous (limiting membrane), a middle layer with a network of fibres (inner shell membrane) and the outer layer (outer shell membrane) of larger fibres. Material properties including optical transparency, porosity, fluid absorption/uptake, thermal stability, mechanical profiling of the ESM samples were performed and demonstrated suitable profiles for translational applications. Biological in vitro studies using SV40 immortalised corneal epithelial cells (ihCEC) and corneal mesenchymal stromal cells (C-MSC) demonstrated excellent biocompatibility. Taken together, these results document the development of a novel sustainable biomaterial that may be used for ophthalmic wounds and/or other biomedical therapies.

A new bioremediation method for removal of wastewater containing oils with high oleic acid composition: Acinetobacter haemolyticus lipase immobilized on eggshell membrane with improved stabilities

As a result of the increasing demand for edible oils, which are an important part of human nutrition, in recent years, serious environmental problems may arise both during the production and after consumption of these oils.

Development of an antibacterial nanobiomaterial for wound-care based on the absorption of AgNPs on the eggshell membrane

To develop a promising antibacterial agent for wound-care dressing, a series of silver nanoparticles (AgNPs) and eggshell membrane (ESM) composites (AgNPs/ESM) were prepared. AgNPs were prepared using a chemical reduction method and their characteristics were determined. Various pH and processing time combinations were tested to find the optimal conditions for preparing AgNPs/ESM composites. To obtain the optimal nontoxic-level silver release, the AgNPs stock solution was diluted to 2 times, 4 times, 6 times, 8 times and 10 times with water and the concentration of silver released by the composites was also tested. All the prepared composites showed antibacterial activity, but the activity was the strongest when the stock AgNPs solution was diluted to four times (a concentration of silver was 2.41 mg/L). The addition of AgNPs changed the ESM from hydrophobic to hydrophilic by lowering the water contact angles from 105° to 75°, which is important for the wound-healing process. And the AgNPs/ESM composites had a higher surface area (159.08 m²/g) than the natural ESM (24.32 m²/g) and a suitable pore size (10.92 nm) as well, endowing with better absorption and antibacterial abilities. These findings suggested that the AgNPs/ESM composites are promising candidates for the development of antimicrobial agent for biomedical devices and therapeutic applications, such as wound-healing agent.

Water-soluble egg membrane enhances the immunoactivating properties of an Aloe vera-based extract of Nerium oleander leaves

Objective

To evaluate a blend of two natural ingredients on immune parameters relevant for their current topical use and potential support of microcirculation in skin tissue.

Materials and methods

A blend (BL) of Aloe vera-based Nerium oleander extract (NAE-8i, oleandrin-free) and hydrolyzed water-soluble egg membrane (WSEM) was applied to human whole-blood cultures for 24 hours, with each separate ingredient serving as a control. Immune-cell subsets were analyzed for expression levels of the activation markers CD69 and CD25. Culture supernatants were analyzed for cytokines, chemokines, and immunoregulating peptides.

Results

BL increased CD69 expression on lymphocytes, monocytes, and CD3^–CD56⁺ natural killer cells, and CD25 expression on natural killer cells. The number of CD69⁺CD25⁺ lymphocytes increased in cultures treated with BL and the separate ingredients. BL triggered production of multiple cytokines and chemokines, where CC chemokines MIP1α and MIP3α, as well as cytokines involved in wound healing – Groα, Groβ, ENA78, and fractalkine – reached levels manyfold above treatment with either NAE-8i or WSEM alone.

Conclusion

Data on BL showed that WSEM strongly enhanced NAE-8i’s effects on immunoactivation in vitro. This has potential relevance for support of immunity in skin tissue, including antibacterial and antiviral defense mechanisms, wrinkle reduction, and wound care.

Reduction of facial wrinkles by hydrolyzed water-soluble egg membrane associated with reduction of free radical stress and support of matrix production by dermal fibroblasts

Objective

The aim of this study was to evaluate the effects of water-soluble egg membrane (WSEM) on wrinkle reduction in a clinical pilot study and to elucidate specific mechanisms of action using primary human immune and dermal cell-based bioassays.

Methods

To evaluate the effects of topical application of WSEM (8%) on human skin, an open-label 8-week study was performed involving 20 healthy females between the age of 45 years and 65 years. High-resolution photography and digital analysis were used to evaluate the wrinkle depth in the facial skin areas beside the eye (crow’s feet). WSEM was tested for total antioxidant capacity and effects on the formation of reactive oxygen species by human polymorphonuclear cells. Human keratinocytes (HaCaT cells) were used for quantitative polymerase chain reaction analysis of the antioxidant response element genes Nqo1, Gclm, Gclc, and Hmox1. Evaluation of effects on human primary dermal fibroblasts in vitro included cellular viability and production of the matrix components collagen and elastin.

Results

Topical use of a WSEM-containing facial cream for 8 weeks resulted in a significant reduction of wrinkle depth (P<0.05). WSEM contained antioxidants and reduced the formation of reactive oxygen species by inflammatory cells in vitro. Despite lack of a quantifiable effect on Nrf2, WSEM induced the gene expression of downstream Nqo1, Gclm, Gclc, and Hmox1 in human keratinocytes. Human dermal fibroblasts treated with WSEM produced more collagen and elastin than untreated cells or cells treated with dbcAMP control. The increase in collagen production was statistically significant (P<0.05).

Conclusion

The topical use of WSEM on facial skin significantly reduced the wrinkle depth. The underlying mechanisms of this effect may be related to protection from free radical damage at the cellular level and induction of several antioxidant response elements, combined with stimulation of human dermal fibroblasts to secrete high levels of matrix components.

Support of Joint Function, Range of Motion, and Physical Activity Levels by Consumption of a Water-Soluble Egg Membrane Hydrolyzate

This study evaluated the effects of consumption of hydrolyzed water-soluble egg membrane (WSEM) on joint function in an otherwise healthy population experiencing chronic pain. A randomized, double-blind, placebo-controlled crossover study included two 4-week periods of placebo and WSEM consumption, separated by a 4-week washout period. Twenty-five study participants were randomized to either the “placebo-first” or “WSEM first” sequence in the crossover trial, and 22 participants completed the study requirements. Range of motion (ROM) was assessed using digital inclinometry for joints associated with vertical weight bearing from neck to knees and for shoulders. Pain at rest and when physically active was scored for the same anatomical areas using visual analog scales (VAS). Physical functioning was tracked using questionnaires with VAS. Consumption of WSEM was associated with improved ROM for neck, spine, hips, and knees, with ROM for the neck and right knee being significantly improved during WSEM consumption compared to placebo (P < .05). ROM improvement for the dominant shoulder was highly significant during WSEM consumption (P < .01). Physical activity levels were significantly higher after WSEM than after placebo consumption (P < .05). Many aspects of physical functioning as part of daily living improved. Subgroup analysis showed rapid improvement of lower back pain after 5 days of WSEM consumption compared to placebo consumption (P < .05) in subjects who participated in the study during the winter season. Daily consumption of 450 mg WSEM was associated with improved joint function, comfort during daily activities, and increased physical activity.

Preparation of copper-containing bioactive glass/eggshell membrane nanocomposites for improving angiogenesis, antibacterial activity and wound healing

Effectively stimulating angiogenesis and avoiding wound infection are great challenges in wound care management. Designing new healing dressings with requisite angiogenic capacity and antibacterial performance is of particular significance. In order to achieve this aim, we prepared a copper (Cu)-containing bioactive glass nanocoating (40-50nm) with uniform nanostructure on natural eggshell membrane (Cu-BG/ESM) by the pulsed laser deposition (PLD) technique. The surface physicochemical properties including hydrophilicity and hardness of ESM were significantly improved after depositing Cu-BG nanocoatings. Meanwhile, 5Cu-BG/ESM films containing 5mol% Cu stimulated proangiogenesis by improving vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1α protein secretion as well as angiogenesis-related gene expression (VEGF, HIF-1α, VEGF receptor 2 (KDR) and endothelial nitric oxide (eNos)) of human umbilical vein endothelial cells (HUVECs). When used to treat full-thickness skin defects in mice, 5Cu-BG/ESM films enhanced the healing quality as confirmed by the significantly improved angiogenesis (as indicated by CD31 expression) and formation of continuous and uniform epidermis layer in vivo. Furthermore, 5Cu-BG/ESM films could maintain a sustained release of Cu(2+) ions and distinctly inhibited the viability of bacteria (Escherichia coli). The results indicate that Cu(2+) ions released from Cu-BG/ESM nanocomposite films play an important role for improving both angiogenesis and antibacterial activity and the prepared nanocomposite films combined Cu-containing BG nanocoatings with ESM are a promising biomaterial for wound healing application.

STATEMENT OF SIGNIFICANCE

Designing new healing dressings with requisite angiogenic capacity and antibacterial performance is of particular significance in wound care management. In our study, we successfully prepared copper-containing bioactive glass/eggshell membrane (Cu-BG/ESM) nanocomposites with uniform bioactive glass nanocoatings by using pulsed laser deposition (PLD) technology. Due to the deposited Cu-BG nanocoatings on the surface of ESM, Cu-BG/ESM nanocomposites possessed significantly improved physicochemical and biological properties, including surface hydrophilicity, hardness, antibacterial ability, angiogenesis rate in vitro and wound healing quality in vivo as compared to pure ESM and BG/ESM films. Our study showed that prepared nanocoatings on Cu-BG/ESM nanocomposites offer a beneficial carrier for sustained release of Cu(2+) ions which played a key role for improving both angiogenesis and antibacterial activity. The prepared nanocomposites combined Cu-containing BG nanocoatings with ESM are a promising biomaterial for wound healing application.

Rapid and simple purification of lysozyme from the egg shell membrane

Lysozyme (EC 3.2.1.17) is a hydrolytic enzyme that cleaves the β-(1,4)-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycan, a major bacterial cell wall polymer. In the food industry, lysozyme is used as an additive mainly in the production of wine and beer. Lysozyme was found to be localized in the egg shell membrane. In this study, we found that lysozyme was easily purified from the egg shell membrane and that the enzyme also had antibacterial activity. Furthermore, we found that the antibacterial activity of purified lysozyme from the egg shell membrane was lower than that of purified lysozyme from the egg white at alkaline pH. The method for rapid purification of lysozyme developed in this study should contribute to the food industry.

Sorption on eggshell waste--a review on ultrastructure, biomineralization and other applications

The structure, adsorption behavior and applications of eggshell waste materials have been reviewed. The ultrastructure of eggshell particles has been discussed to understand the pore structure as well as the surface geometry of the materials leading to its multifarious applicability. Besides, the ultrastructure studies give full information regarding the chemical constituents of egghell particles as well as eggshell membranes. The process of biomineralization in living organisms, their consequent effect of controlling the formation of inorganic-organic composites propelling their application in biomimetic designing of advanced composites with optimized novel properties leading to advances in materials design have been discussed. Utilization of eggshell waste materials for the removal of organic dyes and heavy inorganic ions has been reviewed with suitable models for understanding their adsorption quality and capacity. The applications of these materials in various fields of research have been extensively discussed.

Ethylenediaminetetraacetate and lysozyme improves antimicrobial activities of ovotransferrin against Escherichia coli O157:H7

The aim of this study was to evaluate the effect of EDTA, lysozyme, or the combination of EDTA and lysozyme on the antibacterial activity of ovotransferrin against Escherichia coli O157:H7. Ovotransferrin solutions (20 mg/mL) containing 100 mM NaHCO3 (OS) with added EDTA (2.0 or 2.5 mg/mL), lysozyme (1.0, 1.5, or 2.0 mg/mL), or both were prepared. The antibacterial activities of OS, OSE (OS+EDTA), or OSL (OS+lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. In addition, OSE, OSL, or OSEL (OS+EDTA+lysozyme) was applied to irradiated pork chops and commercial hams to determine whether the solutions had antibacterial activity on meat products. The effect of the initial cell population on the antibacterial activity of OSE, OSL, and OSEL was determined. Ethylenediaminetetraacetate at 2 mg/mL plus OS induced a reduction of approximately 3 to 4 log in viable E. coli O157:H7 cells in brain heart infusion broth media, and 1 mg/mL of lysozyme plus OS resulted in a reduction of approximately 0.5 to 1.0 log during a 36-h incubation at 35 degrees C. However, neither OSE nor OSEL showed a significant antibacterial effect on pork chops and hams during storage at 10 degrees C. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA have the potential to control E. coli O157:H7.

Antimicrobial activity of cuticle and outer eggshell protein extracts from three species of domestic birds

1. The eggshell cuticle is the proteinaceous outermost layer of the eggshell which regulates water exchange and protects against entry of micro-organisms. In this study, we investigated the hypothesis that the cuticle may also reduce microbial contamination by providing a chemical defence. 2. Outer eggshell and cuticle protein was extracted from domestic chicken (Gallus gallus), duck (Anas platyrhynchos) and goose (Anser anser) eggs by HCl and urea treatment, respectively. Antimicrobial activity of the extracts against Gram-positive and Gram-negative bacteria was evaluated. 3. C-type lysozyme, ovotransferrin and ovocalyxin-32 were identified in all extracts by Western blotting. All extracts from all species demonstrated lysozyme enzymatic activity. Immobilised c-type lysozyme retained some enzymatic activity. Protein extracts demonstrated activity against Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis suggesting the action of antimicrobial proteins in addition to lysozyme. 4. The results suggest that the antimicrobial outer eggshell and cuticle proteins present in a number of avian species may be a mechanism which enhances avian reproductive success.