Current Trends in Advanced Alginate-Based Wound Dressings for Chronic Wounds

Fabrication and characterization of silver nanowire-coated porous alginate wet-laid webs for wound dressing applications

Wound care presents an imposed financial burden for healthcare organizations, prompting the need for novel and cost-efficient dressings. In this study, we address this challenge by introducing a novel approach to fabricate antibacterial alginate-based fibrous materials using a combination of wet spinning and the wet-laying method, which offer advantages including structural and functional properties such as breathability, nontoxicity, biocompatibility, and cost-effectiveness. The wet spinning method was employed to develop porous and non-porous Ca-alginate fibers with diameters of 100 ± 4.3 nm and 132 ± 1.2 nm, respectively. Porous Ca-alginate fibers were fabricated with the utilization of polyvinyl alcohol (PVA) as a pore-forming polymer. Obtained fibers were cut into 1-2 cm lengths to fabricate wet-laid webs. Finally, silver nanowires (AgNWs) were synthesized and then coated on the wet-laid webs at concentrations of 1 % and 3 % to impart antibacterial properties. FTIR analyses confirmed the successful removal of PVA, and swelling tests demonstrated that both porous and non-porous samples exhibit high swelling ability. The porous wet-laid materials swelled 12 times their initial weight, while this amount was 5 times their initial weight in non-porous wet-laid materials at a 60-min timepiece. SEM analysis verified fiber integrity, and MTT assays showed excellent cytocompatibility. Additionally, in vitro tests highlighted the scaffold's potential to support cell attachment and proliferation. The results demonstrate that wet-laid alginate-based fibrous dressings have low cytotoxicity, superior swelling capacity, antibacterial activity, and biocompatibility. This study underscores the potential of the silver nanowires-coated wet-laid webs as a novel and effective approach for producing multifunctional wound care materials.

Investigating the efficacy of gellan gum hydrogel films infused with Acacia stingless bee honey in wound healing

Effective wound healing requires biocompatible and functional wound dressings. This study explores the synergistic potential of gellan gum (GG), known for its exceptional gel-forming abilities, and acacia stingless bee honey (SBH), for its potent antioxidant properties, in developing advanced wound care solutions. GG hydrogel films incorporated with varying concentrations of SBH (v/v) at 10 % (GGSBH10), 15 % (GGSBH15), and 20 % (GGSBH20) were characterized. The incorporation of SBH into the GG matrix resulted in distinctive spectral peaks of ATR-FTIR associated with SBH, particularly evident in GGSBH20. Among the formulations, GGSBH20 demonstrated an impressive water vapor transmission rate of 1149 ± 11 g m-2 d-1 and a swelling ratio of 169 ± 7 %. Disk diffusion revealed that E. coli was susceptible to GGSBH. Cytotoxicity assessments (MTT and scratch assays) on 3 T3-L1 cells confirmed the biocompatibility of GGSBH, which showed no cytotoxic effects up to 72 h of incubation, and improved cell viability. Notably, GGSBH20 displayed the highest wound closure rate, significantly enhancing cell migration and proliferation. Overall, our findings underscore the promising healing properties of GG hydrogel films when enriched with acacia SBH, highlighting their potential as effective and innovative wound dressing materials.

Involvement of macromolecules in 3D printing for wound healing management: A narrative review

Wound healing comprises four overlapping stages involving complex biochemical and cellular processes. Any lapse in this procedure causes irregular healing, which generates clinical and financial burdens for the health system. Personalized treatment is preferred to overcome the limitations of classical as well as modern methods of wound healing. This review discusses recently developed 3D printing models for personalized treatment with varying degrees of success. It is an effective approach for treating wounds by developing custom dressings tailored to the patient's needs and reducing incidents of infections. Additionally, incorporating natural or synthetic polymers can further enhance their effectiveness. Macromolecular polymers, laminin, cellulose, collagen, gelatin, etc. that make up the bulk of 3D printable bio-inks, have been essential in diverse 3D bioprinting technologies throughout the layered 3D manufacturing processes. The polymers need to be tailored for the specific requirements of printing and effector functions in cancer treatment, dental & oral care, biosensors, and muscle repair. We have explored how 3D printing can be utilized to fasten the process of wound healing at each of the four stages. The benefits as well as the future prospects are also discussed in this article.

Brown algae biomass for fucoxanthin, fucoidan and alginate; update review on structure, biosynthesis, biological activities and extraction valorisation

Natural compounds promoting human health are the main focus of research nowadays. Fucoxanthin, fucoidan and alginate are such bioactive compounds that are extracted from marine brown algae. Extracting these 3 compounds through successive extraction enhances the commercial value of the brown algae biomass. There are studies on successive extraction of fucoidan and alginate but not with fucoxanthin which displays various biological bioactivities. Alginate, a polysaccharide presents 45 % in the cell wall of brown algae. Fucoidan, a sulphated polysaccharide proved showing various bioactivities. These bioproducts yield are vary depending on the species. Dictyota species recorded high fucoxanthin content of 7 %. Ascophyllum nodosum was found with high fucoidan of 16.08 % by direct extraction. Maximum alginate of 45.79 % was recorded from the brown alga Sargassum cymosum and by successive extraction 44 % was recorded from Ecklonia radiata. Fucoxanthin exits in two isomers as trans and cis forms. Based on linkage, fucoidan structure is found in 3 forms as 1,3- or 1,4- or alternating 1,3- and 1,4-linked fucose in the polysaccharide residues. Fucoidan composition varys depending on the degree of sulphation, composition of monosaccharides and location of collection. In alginate, its property relies on the mannuronic acid and guluronic acid composition. Biosynthesis of these 3 compounds is not much explored. Keeping this view which signify sequential extraction towards biomass valorisation, fucoxanthin, fucoidan and alginate extracted from the brown algae species focusing yield, extraction, characterisation, biosynthesis and biological activities were compiled and critically analysed and discussed in this review.

Natural biopolymer-based hydrogels: an advanced material for diabetic wound healing

A diabetic foot ulcer (DFU) is an open sore or wound that typically develops on the bottom of the foot. Almost 15% of people with diabetes are suffering from delayed wound healing worldwide. The main vehicle for the development of ulcers in the diabetic population is poor circulation and peripheral neuropathy. Chronic injuries from diabetes frequently lead to traumatic lower leg amputations. Hydrogels are three-dimensional gels that can be fabricated from natural polymers and synthetic polymers. Biopolymers are flexible, elastic, or fibrous materials that come from a natural source, such as plants, animals, bacteria, or other living things. Some of the naturally occurring polymers that are frequently employed in wound dressing applications include polysaccharides and proteins. These polymers can be employed for many therapeutic applications because of their inherent biocompatibility, low immunogenicity, non-toxicity, and biodegradability. They represent a tuneable platform for enhancing skin healing. Therefore, this review paper interprets how natural biopolymers and their various hydrogel forms can be potentially used for diabetic wound healing.

The emerging role of nanoscaffolds in chronic diabetic wound healing: a new horizon for advanced therapeutics

Non-healing or chronic wounds in extremities that lead to amputations in patients with Type II diabetes (hyperglycemia) are among the most serious and common health problems in the modern world. Over the past decade, more efficient solutions for diabetic ulcers have been developed. Nanofibers and/or composite materials capable of drug delivery, moisture control, and antibacterial effectiveness are increasingly utilized in the formulation of wound dressings, with a particular focus on the biofunctionalization of polymeric and hydrogel materials. Natural products, including plant extracts, honey, antibacterial agents, nanozymes, and metal nanoparticles, are now commonly and effectively implemented to enhance the functionality of wound dressings. Due to the complicated and dysfunctional physiological structure of the chronic wound sites in the extremities of diabetic patients, formulated nanoscaffold or hydrogel components are becoming more intricate and versatile. This study aimed to investigate the development of wound dressing materials over the years while demonstrating their progressively enhanced complexity in effectively targeting, treating, and managing chronic wounds. The mechanisms of action and bio-functionality of wound dressing technologies were elucidated based on findings from 290 studies conducted over the last decade. A notable observation that emerged from these studies is the evolution of wound dressing development technology, which has led to significant advancements in the operational range of smart systems. These include, but are not limited to, self-healing, self-oxygenation, and adaptable mimicry of human tissue.

Advances in nucleic acid delivery strategies for diabetic wound therapy

In recent years, the prevalence of diabetic wounds has significantly increased, posing a substantial medical challenge due to their propensity for infection and delayed healing. These wounds not only increase mortality rates but also lead to amputations and severe mobility issues. To address this, advancements in bioactive molecules such as genes, growth factors, proteins, peptides, stem cells, and exosomes into targeted gene therapies have emerged as a preferred strategy among researchers. Additionally, the integration of photothermal therapy (PTT), nucleic acid, and gene therapy, along with 3D printing technology and the layer-by-layer (LBL) self-assembly approach, shows promise in diabetic wound treatment. Effective delivery of small interfering RNA (siRNA) relies on gene vectors. This review provides an in-depth exploration of the pathophysiological characteristics observed in diabetic wounds, encompassing diminished angiogenesis, heightened levels of reactive oxygen species, and impaired immune function. It further examines advancements in nucleic acid delivery, targeted gene therapy, advanced drug delivery systems, layer-by-layer (LBL) techniques, negative pressure wound therapy (NPWT), 3D printing, hyperbaric oxygen therapy, and ongoing clinical trials. Through the integration of recent research insights, this review presents innovative strategies aimed at augmenting the multifaceted management of diabetic wounds, thus paving the way for enhanced therapeutic outcomes in the future.

In Vitro Biological Evaluation of an Alginate-Based Hydrogel Loaded with Rifampicin for Wound Care

We report a biocompatible hydrogel dressing based on sodium alginate-grafted poly(N-vinylcaprolactam) prepared by encapsulation of Rifampicin as an antimicrobial drug and stabilizing the matrix through the repeated freeze-thawing method. The hydrogel structure and polymer-drug compatibility were confirmed by FTIR, and a series of hydrogen-bond-based interactions between alginate and Rifampicin were identified. A concentration of 0.69% Rifampicin was found in the polymeric matrix using HPLC analysis and spectrophotometric UV-Vis methods. The hydrogel's morphology was evaluated by scanning electron microscopy, and various sizes and shapes of pores, ranging from almost spherical geometries to irregular ones, with a smooth surface of the pore walls and high interconnectivity in the presence of the drug, were identified. The hydrogels are bioadhesive, and the adhesion strength increased after Rifampicin was encapsulated into the polymeric matrix, which suggests that these compositions are suitable for wound dressings. Antimicrobial activity against S. aureus and MRSA, with an increased effect in the presence of the drug, was also found in the newly prepared hydrogels. In vitro biological evaluation demonstrated the cytocompatibility of the hydrogels and their ability to stimulate cell multiplication and mutual cell communication. The in vitro scratch assay demonstrated the drug-loaded alginate-grafted poly(N-vinylcaprolactam) hydrogel's ability to stimulate cell migration and wound closure. All of these results suggest that the prepared hydrogels can be used as antimicrobial materials for wound healing and care applications.

Electrospun Composites of Chitosan with Cerium Oxide Nanoparticles for Wound Healing Applications: Characterization and Biocompatibility Evaluation In Vitro and In Vivo

Cerium oxide nanoparticles (CeONPs), as part of tissue regeneration matrices, can protect cells from reactive oxygen species and oxidative stress. In addition, they can influence the properties of the scaffold, including its electrospinnability and mechanical strength. In this work, we prepared electrospun fiber mats from a chitosan and polyethylene oxide blend (CS-PEO) with the addition of ceria nanoparticles (CS-PEO-CeONP). The addition of CeONPs resulted in a smaller fiber diameter and higher swelling compared to CS-PEO fiber mats. CeONP-modified fiber mats also had a higher Young's modulus due to the reinforcing effect of the nanoparticles. Both mats had comparable adhesion and cytocompatibility to mesenchymal stem cells, which had a more rounded morphology on CS-PEO-CeONP compared to elongated cells on the CS-PEO mats. Biocompatibility in an in vivo rat model showed no acute toxicity, no septic or allergic inflammation, and no rough scar tissue formation. The degradation of both mats passed the stage of matrix swelling. CS-PEO-CeONP showed significantly slower biodegradation, with most of the matrix remaining in the tissue after 90 days. The reactive inflammation was aseptic in nature with the involvement of multinucleated foreign-body type giant cells and was significantly reduced by day 90. CeONPs induced the formation of the implant's connective tissue capsule. Thus, the introduction of CeONPs influenced the physicochemical properties and biological activity of CS-PEO nanofiber mats.

Calcium Peroxide-Based Hydrogel Patch with Sustainable Oxygenation for Diabetic Wound Healing

Nonhealing diabetic wounds are predominantly attributed to the inhibition of angiogenesis, re-epithelialization, and extracellular matrix (ECM) synthesis caused by hypoxia. Although oxygen therapy has demonstrated efficacy in promoting healing, its therapeutic impact remains suboptimal due to unsustainable oxygenation. Here, this work proposes an oxygen-releasing hydrogel patch embedded with polyethylene glycol-modified calcium peroxide microparticles, which sustainably releases oxygen for 7 days without requiring any supplementary conditions. The released oxygen effectively promotes cell migration and angiogenesis under hypoxic conditions as validated in vitro. The in vivo tests in diabetic mice models show that the sustainably released oxygen significantly facilitates the synthesis of ECM, induces angiogenesis, and decreases the expression of inflammatory cytokines, achieving a diabetic wound healing rate of 84.2% on day 7, outperforming the existing oxygen-releasing approaches. Moreover, the proposed hydrogel patch is designed with porous, soft, antibacterial, biodegradable, and storage stability for 15 days. The proposed hydrogel patch is expected to be promising in clinics treating diabetic wounds.

Cerium oxide nanoparticles in wound care: a review of mechanisms and therapeutic applications

Skin wound healing is a complex and tightly regulated process. The frequent occurrence and reoccurrence of acute and chronic wounds cause significant skin damage to patients and impose socioeconomic burdens. Therefore, there is an urgent requirement to promote interdisciplinary development in the fields of material science and medicine to investigate novel mechanisms for wound healing. Cerium oxide nanoparticles (CeO2 NPs) are a type of nanomaterials that possess distinct properties and have broad application prospects. They are recognized for their capabilities in enhancing wound closure, minimizing scarring, mitigating inflammation, and exerting antibacterial effects, which has led to their prominence in wound care research. In this paper, the distinctive physicochemical properties of CeO2 NPs and their most recent synthesis approaches are discussed. It further investigates the therapeutic mechanisms of CeO2 NPs in the process of wound healing. Following that, this review critically examines previous studies focusing on the effects of CeO2 NPs on wound healing. Finally, it suggests the potential application of cerium oxide as an innovative nanomaterial in diverse fields and discusses its prospects for future advancements.

A novel conductive microtubule hydrogel for electrical stimulation of chronic wounds based on biological electrical wires

Electrical stimulation (ES) is considered a promising therapy for chronic wounds via conductive dressing. However, the lack of a clinically suitable conductive dressing is a serious challenge. In this study, a suitable conductive biomaterial with favorable biocompatibility and conductivity was screened by means of an inherent structure derived from the body based on electrical conduction in vivo. Ions condensed around the surface of the microtubules (MTs) derived from the cell's cytoskeleton are allowed to flow in the presence of potential differences, effectively forming a network of biological electrical wires, which is essential to the bioelectrical communication of cells. We hypothesized that MT dressing could improve chronic wound healing via the conductivity of MTs applied by ES. We first developed an MT-MAA hydrogel by a double cross-linking method using UV and calcium chloride to improve chronic wound healing by ES. In vitro studies showed good conductivity, mechanical properties, biocompatibility, and biodegradability of the MT-MAA hydrogel, as well as an elevated secretion of growth factors with enhanced cell proliferation and migration ability in response to ES. The in vivo experimental results from a full-thickness diabetic wound model revealed rapid wound closure within 7d in C57BL/6J mice, and the wound bed dressed by the MT-MAA hydrogel was shown to have promoted re-epithelization, enhanced angiogenesis, accelerated nerve growth, limited inflammation phases, and improved antibacterial effect under the ES treatment. These preclinical findings suggest that the MT-MAA hydrogel may be an ideal conductive dressing for chronic wound healing. Furthermore, biomaterials based on MTs may be also promising for treating other diseases.

Therapeutic Potential of Nanocarrier Mediated Delivery of Peptides for Wound Healing: Current Status, Challenges and Future Prospective

Wound healing presents a complex physiological process that involves a sequence of events orchestrated by various cellular and molecular mechanisms. In recent years, there has been growing interest in leveraging nanomaterials and peptides to enhance wound healing outcomes. Nanocarriers offer unique properties such as high surface area-to-volume ratio, tunable physicochemical characteristics, and the ability to deliver therapeutic agents in a controlled manner. Similarly, peptides, with their diverse biological activities and low immunogenicity, hold great promise as therapeutics in wound healing applications. In this review, authors explore the potential of peptides as bioactive components in wound healing formulations, focusing on their antimicrobial, anti-inflammatory, and pro-regenerative properties. Despite the significant progress made in this field, several challenges remain, including the need for standardized characterization methods, optimization of biocompatibility and safety profiles, and translation from bench to bedside. Furthermore, developing multifunctional nanomaterial-peptide hybrid systems represents promising avenues for future research. Overall, the integration of nanomaterials made up of natural or synthetic polymers with peptide-based formulations holds tremendous therapeutic potential in advancing the field of wound healing and improving clinical outcomes for patients with acute and chronic wounds.

Effective antibacterial agents in modern wound dressings: a review

Wound infections are a significant concern in healthcare, leading to long healing times. Traditional approaches for managing wound infections rely heavily on systemic antibiotics, which are associated with the emergence of antibiotic-resistant bacteria. Therefore, the development of alternative antibacterial materials for wound care has gained considerable attention. In today's world, new generations of wound dressing are commonly used to heal wounds. These new dressings keep the wound and the area around it moist to improve wound healing. However, this moist environment can also foster an environment that is favorable for the growth of bacteria. Excessive antibiotic use poses a significant threat to human health and causes bacterial resistance, so new-generation wound dressings must be designed and developed to reduce the risk of infection. Wound dressings using antimicrobial compounds minimize wound bacterial colonization, making them the best way to avoid open wound infection. We aim to provide readers with a comprehensive understanding of the latest advancements in antibacterial materials for wound management.

Assessing the efficacy of curcumin-loaded alginate hydrogel on skin wound healing: A gene expression analysis

Skin tissue engineering has gained significant attention as a promising alternative to traditional treatments for skin injuries. In this study, we developed 3D hydrogel-based scaffolds, Alginate, incorporating different concentrations of Curcumin and evaluated their properties, including morphology, swelling behavior, weight loss, as well as hemo- and cytocompatibility. Furthermore, we investigated the therapeutic potential of Alginate hydrogel containing different amounts of Curcumin using an in vitro wound healing model. The prepared hydrogels exhibited remarkable characteristics, SEM showed that the pore size of hydrogels was 134.64 μm with interconnected pores, making it conducive for cellular infiltration and nutrient exchange. Moreover, hydrogels demonstrated excellent biodegradability, losing 63.5% of its weight over 14 days. In addition, the prepared hydrogels had a stable release of curcumin for 3 days. The results also show the hemocompatibility of prepared hydrogels and a low amount of blood clotting. To assess the efficacy of the developed hydrogels, 3T3 fibroblast growth was examined during various incubation times. The results indicated that the inclusion of Curcumin at a concentration of 0.1 mg/mL positively influenced cellular behavior. The animal study showed that Alginate hydrogel containing 0.1 mg/mL curcumin had high wound closure(more than 80%) after 14 days. In addition, it showed up-regulation of essential wound healing genes, including TGFβ1 and VEGF, promoting tissue repair and angiogenesis. Furthermore, the treated group exhibited down-regulation of MMP9 gene expression, indicating a reduction in matrix degradation and inflammation. The observed cellular responses and gene expression changes substantiate the therapeutic efficacy of prepared hydrogels. Consequently, our study showed the healing effect of alginate-based hydrogel containing Curcumin on skin injuries.

Antibacterial Micelles-Loaded Carboxymethyl Chitosan/Oxidized Konjac Glucomannan Composite Hydrogels for Enhanced Wound Repairing

Antibacterial hydrogels have emerged as a promising approach for effective wound treatment. However, despite extensive research on the fabrication of antibacterial hydrogels, it remains challenging to develop injectable, biocompatible, transparent, and mass-producible hydrogels with antibacterial properties. In this study, we successfully fabricated an antibacterial drug-loaded composite hydrogel, named CC45/OKG40/HS, through a Schiff base reaction between carboxymethyl chitosan (CC) and oxidized konjac glucomannan (OKG), followed by the encapsulation of stevioside-stabilized honokiol (HS) micelles. The CC45/OKG40/HS hydrogel exhibited several favorable properties, including a short gel time (<10 min), high water content (>92%), injectability, good adhesiveness, self-healing ability, and high transparency. In vitro experiments confirmed its excellent antibacterial properties, antioxidant activities, and high biocompatibility (no cytotoxicity, hemolysis ratio <5%). Furthermore, in vivo evaluation demonstrated that the CC45/OKG40/HS0.5 hydrogel accelerated wound healing by relieving inflammatory responses and enhancing re-epithelization. Given its feasibility for mass production, the findings showed that the CC45/OKG40/HS hydrogel has the potential as an advanced antibacterial wound dressing for commercial use.

Combining Alginate/PVPI-Based Film with Frequency Rhythmic Electrical Modulation System (FREMS) Technology as an Advanced Strategy for Diabetic Wounds

Diabetes is rising as one of the most diffused diseases of the century with the related urgent necessity to face its systemic and local effects on the patients, such as cardiovascular problems, degeneration of limbs, and dysfunction of the wound healing process. The diffusion of leg ulcers has been estimated to be 1.51 for 1000 population, and these non-resolved wounds can produce several social, economic, and mental health issues in diabetic patients. At the same time, these people experience neuropathic pain that causes morbidity and a further decrease in their quality of life. Here, a new study is presented where asodium alginate/Polyvinylpyrrolidone-Iodine complex (PVPI)-based wound dressing is combined with the Frequency Rhythmic Electrical Modulation System (FREMS) technology, an established medical device for the treatment of neuropathic pain and diabetic ulcers. The produced Alginate/PVPI-based films are characterized in terms of morphology, chemistry, wettability, bio-/hemo-compatibility, and clotting capacity. Next, the Alginate/PVPI-based films are used together with FREMS technology in diabetic mice models, and synergism of their action in the wound closure rate and anti-inflammatory properties is found. Hence, how the combination of electrical neurostimulation devices and advanced wound dressings can be a new approach to improve chronic wound treatment is demonstrated.

Stimuli-responsive polysaccharide-based smart hydrogels for diabetic wound healing: Design aspects, preparation methods and regulatory perspectives

Diabetes adversely affects wound-healing responses, leading to the development of chronic infected wounds. Such wound microenvironment is characterized by hyperglycaemia, hyperinflammation, hypoxia, variable pH, upregulation of matrix metalloproteinases, oxidative stress, and bacterial colonization. These pathological conditions pose challenges for the effective wound healing. Therefore, there is a paradigm shift in diabetic wound care management wherein abnormal pathological conditions of the wound microenvironment is used as a trigger for controlling the drug release or to improve properties of wound dressings. Hydrogels composed of natural polysaccharides showed tremendous potential as wound dressings as well as stimuli-responsive materials due to their unique properties such as biocompatibility, biodegradability, hydrophilicity, porosity, stimuli-responsiveness etc. Hence, polysaccharide-based hydrogels have emerged as advanced healthcare materials for diabetic wounds. In this review, we presented important aspects for the design of hydrogel-based wound dressings with an emphasis on biocompatibility, biodegradability, entrapment of therapeutic agents, moisturizing ability, swelling, and mechanical properties. Further, various crosslinking methods that enable desirable properties and stimuli responsiveness to the hydrogels have been mentioned. Subsequently, state-of-the-art developments in mono- and multi- stimuli-responsive hydrogels have been presented along with the case studies. Finally regulatory perspectives, challenges for the clinical translation and future prospects have been discussed.

Microfluidic Preparation of pH-Responsive Microsphere Fibers and Their Controlled Drug Release Properties

In this study, a capillary microfluidic device was constructed, and sodium alginate solution and a pH-sensitive hydrophobic polymer (p(BMA-co-DAMA-co-MMA)) solution were introduced into the device for the preparation of hydrogel fibers loaded with polymer microspheres. The structure of the microsphere fiber, including the size and spacing of the microspheres, could be controlled by flow rate, and the microspheres were able to degrade and release cargo responding to acidic pH conditions. By modification with carboxymethylcellulose (CMC), alginate hydrogel exhibited enhanced pH sensitivity (shrunk in acidic while swollen in basic condition). This led to an impact on the diffusion rate of the molecules released from the inner microspheres. The microsphere fiber showed dramatic and negligible degradation and drug release in tumor cell (i.e., A431 and A549 cells) and normal cell environments, respectively. These results indicated that the microsphere fiber prepared in this study showed selective drug release in acidic environments, such as tumor and inflammation sites, which could be applied as a smart surgical dressing with normal tissue protective properties.

Using chitosan, hyaluronic acid, alginate, and gelatin-based smart biological hydrogels for drug delivery in oral mucosal lesions: A review

AIMS

Oral mucosal diseases can lead to pain, difficulty speaking and eating, psychological distress, and cancer. Topical drug delivery using biological macromolecules, specifically hydrogels, is gaining interest due to the drawbacks of conventional treatments for oral mucosal lesions.

SCOPE

Biological hydrogels made from natural polymers and their derivatives, such as chitosan, hyaluronic acid, alginate, and gelatin, represent promising alternatives to conventional oral medication delivery methods. Topical drug delivery is beneficial for oral mucosal lesions as it can directly target the affected area, especially with the development of smart stimuli-responsive hydrogels, which allow for more controlled drug release. Biological hydrogels have already been used to deliver drugs like lidocaine and nystatin. This review summarizes the current research on applying smart natural polymer-based hydrogels for drug delivery in oral mucosal lesions.

CONCLUSION

Smart biological hydrogels show great promise as topical drug delivery systems for oral mucosal lesions, offering sustained drug release, increased therapeutic efficacy, and minimized systemic complications. Technological advancement is expected to lead to the development of more effective and safer drug delivery systems. The potential benefits of biological polymer-based hydrogels make them an exciting area of research for oral mucosal lesion treatment.

The emerging progress on wound dressings and their application in clinic wound management

BACKGROUND

In addition to its barrier function, the skin plays a crucial role in maintaining the stability of the body's internal environment and normal physiological functions. When the skin is damaged, it is important to select proper dressings as temporary barriers to cover the wound, which can exert significant effects on defence against microbial infection, maintaining normal tissue/cell functions, and coordinating the process of wound repair and regeneration. It now forms an important approach in clinic practice to facilitate wound repair.

SEARCH STRATEGIES

We conducted a comprehensive literature search using online databases including PubMed, Web of Science, MEDLINE, ScienceDirect, Wiley Online Library, CNKI, and Wanfang Data. In addition, information was obtained from local and foreign books on biomaterials science and traumatology.

RESULTS

This review focuses on the efficacy and principles of functional dressings for anti-bacteria, anti-infection, anti-inflammation, anti-oxidation, hemostasis, and wound healing facilitation; and analyses the research progress of dressings carrying living cells such as fibroblasts, keratinocytes, skin appendage cells, and stem cells from different origins. We also summarize the recent advances in intelligent wound dressings with respect to real-time monitoring, automatic drug delivery, and precise adjustment according to the actual wound microenvironment. In addition, this review explores and compares the characteristics, advantages and disadvantages, mechanisms of actions, and application scopes of dressings made from different materials.

CONCLUSION

The real-time and dynamic acquisition and analysis of wound conditions are crucial for wound management and prognostic evaluation. Therefore, the development of modern dressings that integrate multiple functions, have high similarity to the skin, and are highly intelligent will be the focus of future research, which could drive efficient wound management and personalized medicine, and ultimately facilitate the translation of health monitoring into clinical practice.

Blood Coagulation Activities of Cotton-Alginate-Copper Composites

Alginate-based materials have gained significant attention in the medical industry due to their biochemical properties. In this article, we aimed to synthesize Cotton-Alginate-Copper Composite Materials (COT-Alg(-)Cu(2+)). The main purpose of this study was to assess the biochemical properties of new composites in the area of blood plasma coagulation processes, including activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT). This study also involved in vitro antimicrobial activity evaluation of materials against representative colonies of Gram-positive and Gram-negative bacteria and antifungal susceptibility tests. The materials were prepared by immersing cotton fibers in an aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the fibers with Cu(II) ions to yield antimicrobial activity. The results showed that the obtained cotton-alginate-copper composites were promising materials to be used in biomedical applications, e.g., wound dressing.

Versatile click alginate hydrogels with protease-sensitive domains as cell responsive/instructive 3D microenvironments

Alginate (ALG) is a widely used biomaterial to create artificial extracellular matrices (ECM) for tissue engineering. Since it does not degrade in the human body, imparting proteolytic sensitivity to ALG hydrogels leverages their properties as ECM-mimics. Herein, we explored the strain-promoted azide-alkyne cycloaddition (SPAAC) as a biocompatible and bio-orthogonal click-chemistry to graft cyclooctyne-modified alginate (ALG-K) with bi-azide-functionalized PVGLIG peptides. These are sensitive to matrix metalloproteinase (MMP) and may act as crosslinkers. The ALG-K-PVGLIG conjugates (50, 125, and 250 μM PVGLIG) were characterized for peptide incorporation, crosslinking ability (double-end grafting), and enzymatic liability. For producing cell-permissive multifunctional 3D matrices for dermal fibroblast culture, oxidized ALG-K was grafted with PVGLIG and with RGD peptides for cell-adhesion. SPAAC reactions were performed immediately before cell-laden hydrogel formation by secondary ionic-crosslinking, considerably reducing the steps and time of preparation. Hydrogels with intermediate PVGLIG concentration (125 μM) presented slightly higher stiffness while promoting extensive cell spreading and higher degree of cell-cell interconnections, likely favored by cell-driven proteolytic remodeling of the network. The hydrogel-embedded cells were able to produce their own pericellular ECM, expressed MMP-2 and 14, and secreted PVGLIG-degrading enzymes. By recapitulating key ECM-like features, these hydrogels provide biologically relevant 3D matrices for soft tissue regeneration.

Translational Challenges and Prospective Solutions in the Implementation of Biomimetic Delivery Systems

Biomimetic delivery systems (BDSs), inspired by the intricate designs of biological systems, have emerged as a groundbreaking paradigm in nanomedicine, offering unparalleled advantages in therapeutic delivery. These systems, encompassing platforms such as liposomes, protein-based nanoparticles, extracellular vesicles, and polysaccharides, are lauded for their targeted delivery, minimized side effects, and enhanced therapeutic outcomes. However, the translation of BDSs from research settings to clinical applications is fraught with challenges, including reproducibility concerns, physiological stability, and rigorous efficacy and safety evaluations. Furthermore, the innovative nature of BDSs demands the reevaluation and evolution of existing regulatory and ethical frameworks. This review provides an overview of BDSs and delves into the multifaceted translational challenges and present emerging solutions, underscored by real-world case studies. Emphasizing the potential of BDSs to redefine healthcare, we advocate for sustained interdisciplinary collaboration and research. As our understanding of biological systems deepens, the future of BDSs in clinical translation appears promising, with a focus on personalized medicine and refined patient-specific delivery systems.

Three-Dimensional Membranes of Natural Polymer Complex Nanoparticle for Potential Medical Applications

Skin wound healing is a complex biological process of tissue regeneration in which the wound dressing is crucial for rapid healing; it must protect the wound keep an adequate level of moisture and prevent infections. Alginate (AL), a polysaccharide from brown algae, has been extensively studied for wound treatment, and aloe vera gels (AVGs) have also been used in the treatment of skin. The AVG main bioactive polysaccharide was combined with AL for the preparation of membranes. Two-dimensional membranes were prepared by casting and, for comparison, transparent nanoparticle 3D membranes were produced by high-intensity ultrasonication followed by ionotropic crosslinking. The effects of the amount of AVG, ionotropic gelation, and the structure (2D or 3D) of the AL-AVG membranes were compared. Scanning electron microscopy (SEM) showed higher surface roughness on 3D membranes. Three-dimensional membranes showed a higher swelling ratio, and swelling increased with AVG content and decreased with higher calcium concentration and longer gelation times. The degradation of the membranes was evaluated with and without a lysozyme at pH 5.5, 7.5, and 8.5, to simulate different skin conditions; the results evidence that pH had a higher effect than the enzyme. The cytotoxicity of the membranes was evaluated with ATCC CCL 163 and ATCC CCL 81 cells, and an excellent biocompatibility of both cell types (>90% of cell viability after 48 h incubation) was observed for all AL-AVG membranes.

Perspectives on Scaffold Designs with Roles in Liver Cell Asymmetry and Medical and Industrial Applications by Using a New Type of Specialized 3D Bioprinter

Cellular asymmetry is an important element of efficiency in the compartmentalization of intracellular chemical reactions that ensure efficient tissue function. Improving the current 3D printing methods by using cellular asymmetry is essential in producing complex tissues and organs such as the liver. The use of cell spots containing at least two cells and basement membrane-like bio support materials allows cells to be tethered at two points on the basement membrane and with another cell in order to maintain cell asymmetry. Our model is a new type of 3D bioprinter that uses oriented multicellular complexes with cellular asymmetry. This novel approach is necessary to replace the sequential and slow processes of organogenesis with rapid methods of growth and 3D organ printing. The use of the extracellular matrix in the process of bioprinting with cells allows one to preserve the cellular asymmetry in the 3D printing process and thus preserve the compartmentalization of biological processes and metabolic efficiency.

Polysaccharide based transdermal patches for chronic wound healing: Recent advances and clinical perspective

Polysaccharides form a major class of natural polymers with diverse applications in biomedical science and tissue engineering. One of the key thrust areas for polysaccharide materials is skin tissue engineering and regeneration, whose market is estimated to reach around 31 billion USD globally by 2030, with a compounded annual growth rate of 10.46 %. Out of this, chronic wound healing and management is a major concern, especially for underdeveloped and developing nations, mainly due to poor access to medical interventions for such societies. Polysaccharide materials have shown promising results and clinical potential in recent decades with regard to chronic wound healing. Their low cost, ease of fabrication, biodegradability, and ability to form hydrogels make them ideal candidates for managing and healing such difficult-to-heal wounds. The present review presents a summary of the recently explored polysaccharide-based transdermal patches for managing and healing chronic wounds. Their efficacy and potency of healing both as active and passive wound dressings are evaluated in several in-vitro and in-vivo models. Finally, their clinical performances and future challenges are summarized to draw a road map towards their role in advanced wound care.

Modern Approaches in Wounds Management

Wound management represents a well-known continuous challenge and concern of the global healthcare systems worldwide. The challenge is on the one hand related to the accurate diagnosis, and on the other hand to establishing an effective treatment plan and choosing appropriate wound care products in order to maximize the healing outcome and minimize the financial cost. The market of wound dressings is a dynamic field which grows and evolves continuously as a result of extensive research on developing versatile formulations with innovative properties. Hydrogels are one of the most attractive wound care products which, in many aspects, are considered ideal for wound treatment and are widely exploited for extension of their advantages in healing process. Smart hydrogels (SHs) offer the opportunities of the modulation physico-chemical properties of hydrogels in response to external stimuli (light, pressure, pH variations, magnetic/electric field, etc.) in order to achieve innovative behavior of their three-dimensional matrix (gel-sol transitions, self-healing and self-adapting abilities, controlled release of drugs). The SHs response to different triggers depends on their composition, cross-linking method, and manufacturing process approach. Both native or functionalized natural and synthetic polymers may be used to develop stimuli-responsive matrices, while the mandatory characteristics of hydrogels (biocompatibility, water permeability, bioadhesion) are preserved. In this review, we briefly present the physiopathology and healing mechanisms of chronic wounds, as well as current therapeutic approaches. The rational of using traditional hydrogels and SHs in wound healing, as well as the current research directions for developing SHs with innovative features, are addressed and discussed along with their limitations and perspectives in industrial-scale manufacturing.

A systematic review of natural products for skin applications: Targeting inflammation, wound healing, and photo-aging

BACKGROUND

Every day the skin is constantly exposed to several harmful factors that induce oxidative stress. When the cells are incapable to maintain the balance between antioxidant defenses and reactive oxygen species, the skin no longer can keep its integrity and homeostasis. Chronic inflammation, premature skin aging, tissue damage, and immunosuppression are possible consequences induced by sustained exposure to environmental and endogenous reactive oxygen species. Skin immune and non-immune cells together with the microbiome are essential to efficiently trigger skin immune responses to stress. For this reason, an ever-increasing demand for novel molecules capable of modulating immune functions in the skin has risen the level of their development, particularly in the field of natural product-derived molecules.

PURPOSE

In this review, we explore different classes of molecules that showed evidence in modulate skin immune responses, as well as their target receptors and signaling pathways. Moreover, we describe the role of polyphenols, polysaccharides, fatty acids, peptides, and probiotics as possible treatments for skin conditions, including wound healing, infection, inflammation, allergies, and premature skin aging.

METHODS

Literature was searched, analyzed, and collected using databases, including PubMed, Science Direct, and Google Scholar. The search terms used included "Skin", "wound healing", "natural products", "skin microbiome", "immunomodulation", "anti-inflammatory", "antioxidant", "infection", "UV radiation", "polyphenols", "polysaccharides", "fatty acids", "plant oils", "peptides", "antimicrobial peptides", "probiotics", "atopic dermatitis", "psoriasis", "auto-immunity", "dry skin", "aging", etc., and several combinations of these keywords.

RESULTS

Natural products offer different solutions as possible treatments for several skin conditions. Significant antioxidant and anti-inflammatory activities were reported, followed by the ability to modulate immune functions in the skin. Several membrane-bound immune receptors in the skin recognize diverse types of natural-derived molecules, promoting different immune responses that can improve skin conditions.

CONCLUSION

Despite the increasing progress in drug discovery, several limiting factors need future clarification. Understanding the safety, biological activities, and precise mechanisms of action is a priority as well as the characterization of the active compounds responsible for that. This review provides directions for future studies in the development of new molecules with important pharmaceutical and cosmeceutical value.

No country for old antibiotics! Antimicrobial peptides (AMPs) as next-generation treatment for skin and soft tissue infection

In recent years, the unprecedented rise of bacterial antibiotic resistance together with the lack of adequate therapies have made the treatment of skin infections and chronic wounds challenging, urging the scientific community to focus on the development of new and more efficient treatment strategies. In this context, there is a growing interest in the use of natural molecules with antimicrobial features, capable of supporting wound healing i.e., antimicrobial peptides (AMPs), for the treatment of skin and soft tissue infections. In this review, we give a short overview of the bacterial skin infections as well as some of the classic treatments used for topical application. We then summarize the AMPs classes, stressing the importance of the appropriate selection of the peptides based on their characteristics and physicochemical properties in order to maximize the antibacterial efficacy of the therapeutic systems against multi-drug resistant pathogens. Additionally, the present paper provides a comprehensive and rigorous assessment of the latest clinical trials investigating the efficacy of AMPs in the treatment of skin and soft tissue infections, highlighting the relevant outcomes. Seeking to obtain novel and improved compounds with synergistic activity, while also decreasing some of the known side effects of AMPs, we present two employed strategies using AMPs: (i) AMPs-conjugated nanosystems for systemic and topical drug delivery systems and (ii) antibiotics-peptide conjugates as a strategy to overcome antibiotics resistance. Finally, an important property of some of the AMPs used in wound treatment is highlighted: their ability to help in wound healing by generally promoting cell proliferation and migration, and in some cases re-epithelialization and angiogenesis among others. Thus, as the pursuit of improvement is an ongoing effort, this work presents the advances made in the treatment of skin and soft tissue infections along with their advantages and limitations, while the still remaining challenges are addressed by providing future prospects and strategies to overcome them.

Innovative Functional Biomaterials as Therapeutic Wound Dressings for Chronic Diabetic Foot Ulcers

The imbalance of local and systemic factors in individuals with diabetes mellitus (DM) delays, or even interrupts, the highly complex and dynamic process of wound healing, leading to diabetic foot ulceration (DFU) in 15 to 25% of cases. DFU is the leading cause of non-traumatic amputations worldwide, posing a huge threat to the well-being of individuals with DM and the healthcare system. Moreover, despite all the latest efforts, the efficient management of DFUs still remains a clinical challenge, with limited success rates in treating severe infections. Biomaterial-based wound dressings have emerged as a therapeutic strategy with rising potential to handle the tricky macro and micro wound environments of individuals with DM. Indeed, biomaterials have long been related to unique versatility, biocompatibility, biodegradability, hydrophilicity, and wound healing properties, features that make them ideal candidates for therapeutic applications. Furthermore, biomaterials may be used as a local depot of biomolecules with anti-inflammatory, pro-angiogenic, and antimicrobial properties, further promoting adequate wound healing. Accordingly, this review aims to unravel the multiple functional properties of biomaterials as promising wound dressings for chronic wound healing, and to examine how these are currently being evaluated in research and clinical settings as cutting-edge wound dressings for DFU management.

How to Promote Skin Repair? In-Depth Look at Pharmaceutical and Cosmetic Strategies

Skin repair encompasses epidermal barrier repair and wound healing which involves multiple cellular and molecular stages. Therefore, many skin repair strategies have been proposed. In order to characterize the usage frequency of skin repair ingredients in cosmetics, medicines, and medical devices, commercialized in Portuguese pharmacies and parapharmacies, a comprehensive analysis of the products' composition was performed. A total of 120 cosmetic products, collected from national pharmacies online platforms, 21 topical medicines, and 46 medical devices, collected from INFARMED database, were included in the study, revealing the top 10 most used skin repair ingredients in these categories. A critical review regarding the effectiveness of the top ingredients was performed and an in-depth analysis focused on the top three skin repair ingredients pursued. Results demonstrated that top three most used cosmetic ingredients were metal salts and oxides (78.3%), vitamin E and its derivatives (54.2%), and Centella asiatica (L.) Urb. extract and actives (35.8%). Regarding medicines, metal salts and oxides were also the most used (47.4%) followed by vitamin B5 and derivatives (23.8%), and vitamin A and derivatives (26.3%). Silicones and derivatives were the most common skin repair ingredients in medical devices (33%), followed by petrolatum and derivatives (22%) and alginate (15%). This work provides an overview of the most used skin repair ingredients, highlighting their different mechanisms of action, aiming to provide an up-to-date tool to support health professionals' decisions.

Chitosan, alginate, hyaluronic acid and other novel multifunctional hydrogel dressings for wound healing: A review

Wound healing is a complex project, and effectively promoting skin repair is a huge clinical challenge. Hydrogels have great prospect in the field of wound dressings because their physical properties are very similar to those of living tissue and have excellent properties such as high water content, oxygen permeability and softness. However, the single performance of traditional hydrogels limits their application as wound dressings. Therefore, natural polymers such as chitosan, alginate and hyaluronic acid, which are non-toxic and biocompatible, are individually or combined with other polymer materials, and loaded with typical drugs, bioactive molecules or nanomaterials. Then, the development of novel multifunctional hydrogel dressings with good antibacterial, self-healing, injectable and multi-stimulation responsiveness by using advanced technologies such as 3D printing, electrospinning and stem cell therapy has become a hot topic of current research. This paper focuses on the functional properties of novel multifunctional hydrogel dressings such as chitosan, alginate and hyaluronic acid, which lays the foundation for the research of novel hydrogel dressings with better performance.

Alginate Ag/AgCl Nanoparticles Composite Films for Wound Dressings with Antibiofilm and Antimicrobial Activities

Recently, silver-based nanoparticles have been proposed as components of wound dressings due to their antimicrobial activity. Unfortunately, they are cytotoxic for keratinocytes and fibroblasts, and this limits their use. Less consideration has been given to the use of AgCl nanoparticles in wound dressings. In this paper, a sustainable preparation of alginate AgCl nanoparticles composite films by simultaneous alginate gelation and AgCl nanoparticle formation in the presence of CaCl₂ solution is proposed with the aim of obtaining films with antimicrobial and antibiofilm activities and low cytotoxicity. First, AgNO₃ alginate films were prepared, and then, gelation and nanoparticle formation were induced by film immersion in CaCl₂ solution. Films characterization revealed the presence of both AgCl and metallic silver nanoparticles, which resulted as quite homogeneously distributed, and good hydration properties. Finally, films were tested for their antimicrobial and antibiofilm activities against Staphylococcus epidermidis (ATCC 12228), Staphylococcus aureus (ATCC 29213), Pseudomonas aeruginosa (ATCC 15692), and the yeast Candida albicans. Composite films showed antibacterial and antibiofilm activities against the tested bacteria and resulted as less active towards Candida albicans. Film cytotoxicity was investigated towards human dermis fibroblasts (HuDe) and human skin keratinocytes (NCTC2544). Composite films showed low cytotoxicity, especially towards fibroblasts. Thus, the proposed sustainable approach allows to obtain composite films of Ag/AgCl alginate nanoparticles capable of preventing the onset of infections without showing high cytotoxicity for tissue cells.

Environmentally benign alginate extraction and fibres spinning from different European Brown algae species

Applications of natural fibres are expanding, and sustainable alternatives are needed to support this growing demand. We investigated the production of fibres using alginates from Saccharina latissima (SAC), Laminaria digitata (LAM), Sacchoriza polyschides (SACC), and Himanthalia spp. (HIM). After extraction (3 % w/v biomass) using a sustainable protocol based on citric acid, crude alginate represented 61-65 % of the biomass dry weight for SAC and LAM, and 34-41 % for SACC and HIM when experiments were performed at small scale (1.5 g of starting material). Interestingly, scaling-up extraction (60 g of starting material) decreased yields to 26-30 %. SAC and LAM alginates had the highest M/G (mannuronic acid/guluronic acid) ratios and molecular weights when compared to those from SACC and HIM (M/G:1.98 and 2.23, MW: 302 and 362 kDa, vs 1.83 and 1.86, 268 and 168 kDa). When the four types of alginates were tested for spinning fibres cross-linked with CaCl2, only SAC and LAM alginates produced fibres. These fibres showed no clumps or cracks under stretching action and presented a similar Young's modulus (2.4 and 2.0 GPa). We have demonstrated that alginate extracted from S. latissima and L. digitata can be successfully spun into functional fibres cross-linked with CaCl2.

Development of a photosynthetic hydrogel as potential wound dressing for the local delivery of oxygen and bioactive molecules

The development of biomaterials to improve wound healing is a critical clinical challenge and an active field of research. As it is well described that oxygen plays a critical role in almost each step of the wound healing process, in this work, an oxygen producing photosynthetic biomaterial was generated, characterized, and further modified to additionally release other bioactive molecules. Here, alginate hydrogels were loaded with the photosynthetic microalgae Chlamydomonas reinhardtii, showing high integration as well as immediate oxygen release upon illumination. Moreover, the photosynthetic hydrogel showed high biocompatibility in vitro and in vivo, and the capacity to sustain the metabolic oxygen requirements of zebrafish larvae and skin explants. In addition, the photosynthetic dressings were evaluated in 20 healthy human volunteers following the ISO-10993-10-2010 showing no skin irritation, mechanical stability of the dressings, and survival of the photosynthetic microalgae. Finally, hydrogels were also loaded with genetically engineered microalgae to release human VEGF, or pre-loaded with antibiotics, showing sustained release of both bioactive molecules. Overall, this work shows that photosynthetic hydrogels represent a feasible approach for the local delivery of oxygen and other bioactive molecules to promote wound healing. STATEMENT OF SIGNIFICANCE: As oxygen plays a key role in almost every step of the tissue regeneration process, the development of oxygen delivering therapies represents an active field of research, where photosynthetic biomaterials have risen as a promising approach for wound healing. Therefore, in this work a photosynthetic alginate hydrogel-based wound dressing containing C. reinhardtii microalgae was developed and validated in healthy skin of human volunteers. Moreover, hydrogels were modified to additionally release other bioactive molecules such as recombinant VEGF or antibiotics. The present study provides key scientific data to support the use of photosynthetic hydrogels as customizable dressings to promote wound healing.

In Vitro and In Vivo Characterization Methods for Evaluation of Modern Wound Dressings

Chronic wound management represents a major challenge in the healthcare sector owing to its delayed wound-healing process progression and huge financial burden. In this regard, wound dressings provide an appropriate platform for facilitating wound healing for several decades. However, adherent traditional wound dressings do not provide effective wound healing for highly exudating chronic wounds and need the development of newer and innovative wound dressings to facilitate accelerated wound healing. In addition, these dressings need frequent changing, resulting in more pain and discomfort. In order to overcome these issues, a wide range of affordable and innovative modern wound dressings have been developed and explored recently to accelerate and improve the wound healing process. However, a comprehensive understanding of various in vitro and in vivo characterization methods being utilized for the evaluation of different modern wound dressings is lacking. In this context, an overview of modern dressings and their complete in vitro and in vivo characterization methods for wound healing assessment is provided in this review. Herein, various emerging modern wound dressings with advantages and challenges have also been reviewed. Furthermore, different in vitro wound healing assays and in vivo wound models being utilized for the evaluation of wound healing progression and wound healing rate using wound dressings are discussed in detail. Finally, a summary of modern wound dressings with challenges and the future outlook is highlighted.

Role of Alginate Composition on Copper Ion Uptake in the Presence of Histidine or Beta-Amyloid

The anomalous interaction between metal ions and the peptide beta-amyloid is one of the hallmarks of Alzheimer's disease. Metal-binding biopolymers, including polysaccharides, can elucidate the fundamental aspects of metal ions' interactions with biological tissue and their interplay in Alzheimer's disease. This work focuses on the role of the alginate composition on Cu(II) adsorption in the presence of histidine or β-amyloid, the peptide associated with the progression of Alzheimer's disease. Alginate samples with different mannuronic/guluronic (M/G) ratios led to similar Cu(II) adsorption capacities, following the Langmuir isotherm and the pseudo-second-order adsorption kinetic models. Although the presence of histidine produced up to a 20% reduction in the copper adsorption capacity in guluronic-rich alginate samples (M/G~0.61), they presented stable bidentate chelation of the metallic ion. Chemical analyses (FTIR and XPS) demonstrated the role of hydroxyl and carboxyl groups in copper ion chelation, whereas both crystallinity and morphology analyses indicated the prevalence of histidine interaction with guluronic-rich alginate. Similar results were observed for Cu(II) adsorption in alginate beads in the presence of beta-amyloid and histidine, suggesting that the alginate/histidine system is a simple yet representative model to probe the application of biopolymers to metal ion uptake in the presence of biological competitors.

IMPACT OF THE NASAL VALVE SHAPE ON THE OLFACTORY FUNCTION AND SUBJECTIVE PERCEPTION OF THE NASAL BREATHING

OBJECTIVE

The aim: To study the impact of the internal nasal valve shape on respiratory and olfactory nose function as well as on quality of life.

PATIENTS AND METHODS

Materials and methods: The study involved 17 volunteers who noted satisfaction of nasal breathing in the absence of changes during endorhinoscopy. The study was con¬ducted in two stages: stage 1 involved assessing initial indicators of quality of life by the SNOT-22 questionnaire, performing active anterior rhinomanometry, and estimating the olfactory function (Sniffin' Sticks); stage 2 consisted in re-assessing the mentioned indicators after changing the shape and lumen of the internal nasal valve. The sodium alginate self-hardening gel was used for simulating the narrowing of the nasal valve. It was applied to the mucous in the upper part of the nasal valve area, obturating the diffuser above the level of attachment of the middle nasal turbinate to a depth of 3-4 mm from nasal vestibule.

RESULTS

Results: Air resistance did not change significantly after partial blockage of the internal nasal valve, although, 16 out of 17 patients showed signs of hyposmia with an average Sniffin' Sticks test score 8.68 ± 0.15.

CONCLUSION

Conclusions: The simulated partial blockage of the internal nasal valve lumen in its upper part in the area of the diffuser does not significantly affect the resistance of the air passing through the nasal passages, but the olfactory function is impaired, which is reflected the quality of life.

Biopolymer Composites with Sensors for Environmental and Medical Applications

One of the biggest economic and environmental sustainability problems is the over-reliance on petroleum chemicals in polymer production. This paper presents an overview of the current state of knowledge on biopolymers combined with biosensors in terms of properties, compounding methods and applications, with a focus on medical and environmental aspects. Therefore, this article is devoted to environmentally friendly polymer materials. The paper presents an overview of the current state of knowledge on biopolymers combined with biosensors in terms of properties, compounding methods and applications, with a special focus on medical and environmental aspects. The paper presents the current state of knowledge, as well as prospects. The article shows that biopolymers made from renewable raw materials are of great interest in various fields of science and industry. These materials not only replace existing polymers in many applications, but also provide new combinations of properties for new applications. Composite materials based on biopolymers are considered superior to traditional non-biodegradable materials due to their ability to degrade when exposed to environmental factors. The paper highlights the combination of polymers with nanomaterials which allows the preparation of chemical sensors, thus enabling their use in environmental or medical applications due to their biocompatibility and sensitivity. This review focuses on analyzing the state of research in the field of biopolymer-sensor composites.

The Discovery and Development of Natural-Based Biomaterials with Demonstrated Wound Healing Properties: A Reliable Approach in Clinical Trials

Current research across the globe still focuses strongly on naturally derived biomaterials in various fields, particularly wound care. There is a need for more effective therapies that will address the physiological deficiencies underlying chronic wound treatment. The use of moist bioactive scaffolds has significantly increased healing rates compared to local and traditional treatments. However, failure to heal or prolonging the wound healing process results in increased financial and social stress imposed on health institutions, caregivers, patients, and their families. The urgent need to identify practical, safe, and cost-effective wound healing scaffolding from natural-based biomaterials that can be introduced into clinical practice is unequivocal. Naturally derived products have long been used in wound healing; however, clinical trial evaluations of these therapies are still in their infancy. Additionally, further well-designed clinical trials are necessary to confirm the efficacy and safety of natural-based biomaterials in treating wounds. Thus, the focus of this review is to describe the current insight, the latest discoveries in selected natural-based wound healing implant products, the possible action mechanisms, and an approach to clinical studies. We explore several tested products undergoing clinical trials as a novel approach to counteract the debilitating effects of impaired wound healing.

Biofabricated macrophage and fibroblast membranes synergistically promote skin wound healing

Effective skin wound healing is a complex process involving anti-inflammation, fibrosis, matrix reconstruction, and angiogenesis. This work aimed to integrate the macrophage-mediated anti-inflammation and fibroblast-assisted matrix reconstruction for enhanced skin wound healing. Herein, we utilized the cytomembranes derived from repolarized M2 macrophages and fibroblasts to prepare the natural biologics. Results showed that the inflammatory M1 macrophages were repolarized to M2 phenotype by the M2 macrophage cytomembranes. As a consequence, the cytomembranes of M2 macrophage could facilitate the wound closure in mice. Furthermore, the addition of fibroblast membranes to the macrophage cytomembranes contributed to a better matrix reconstruction, neovascularization and angiogenesis. Next, we used a transforming growth factor-β (TGF-β) inhibitor to attenuate cutaneous scar formation. Therefore, our modality could promote skin wound healing and effectively suppress scar formation in the preclinical murine skin wounds. The cytomembrane biologics might provide a biocompatible and versatile tool for wound healing.

The Fabrication of Alginate–Carboxymethyl Cellulose-Based Composites and Drug Release Profiles

Recently, hydrogels based on natural water-soluble polysaccharides have attracted more and more attention due to their favorable characteristics. The high water-holding capacity, lack of toxicity, and biodegradability of such hydrogels make it possible to develop new materials on their basis for biotechnological, biomedical, pharmacological, and medical purposes. Sodium alginate is a non-toxic natural polysaccharide found in marine algae. It is capable of forming solid gels under the action of polyvalent cations that cross-link polysaccharide chains. Alginate-based products are popular in many industries, including food processing, pharmaceutical, and biomedical applications. Cellulose is the most abundant, renewable, and natural polymer on Earth, and it is used for various industrial and biomedical applications. Carboxymethyl cellulose (CMC) is useful in pharmaceutical, food, and non-food industries such as tablets, ice cream, drinks, toothpaste, and detergents. In this review, various methods for the preparation of the compositions based on sodium alginate and CMC using different crosslinking agents have been collected for the first time. Additionally, the drug release profile from such polymer matrixes was analyzed.

Carrageenan-Based Compounds as Wound Healing Materials

The following review is focused on carrageenan, a heteroglycan-based substance that is a very significant wound healing biomaterial. Every biomaterial has advantages and weaknesses of its own, but these drawbacks are typically outweighed by combining the material in various ways with other substances. Carrageenans' key benefits include their water solubility, which enables them to keep the wound and periwound damp and absorb the wound exudate. They have low cytotoxicity, antimicrobial and antioxidant qualities, do not stick to the wound bed, and hence do not cause pain when removed from the wounded region. When combined with other materials, they can aid in hemostasis. This review emphasizes the advantages of using carrageenan for wound healing, including the use of several mixes that improve its properties.

Fabrication, Property and Application of Calcium Alginate Fiber: A Review

As a natural linear polysaccharide, alginate can be gelled into calcium alginate fiber and exploited for functional material applications. Owing to its high hygroscopicity, biocompatibility, nontoxicity and non-flammability, calcium alginate fiber has found a variety of potential applications. This article gives a comprehensive overview of research on calcium alginate fiber, starting from the fabrication technique of wet spinning and microfluidic spinning, followed by a detailed description of the moisture absorption ability, biocompatibility and intrinsic fire-resistant performance of calcium alginate fiber, and briefly introduces its corresponding applications in biomaterials, fire-retardant and other advanced materials that have been extensively studied over the past decade. This review assists in better design and preparation of the alginate bio-based fiber and puts forward new perspectives for further study on alginate fiber, which can benefit the future development of the booming eco-friendly marine biomass polysaccharide fiber.

Novel Technologies in Chronic Wound Care

In Israel, 20% of wounds do not progress to full healing under treatment with conservative technologies of which 1 to 2% are eventually defined as chronic wounds. Chronic wounds are a complex health burden for patients and pose considerable therapeutic and budgetary burden on health systems. The causes of chronic wounds include systemic and local factors. Initial treatment involves the usual therapeutic means, but as healing does not progress, more advanced therapeutic technologies are used. Undoubtedly, advanced means, such as negative pressure systems, and advanced technologies, such as oxygen systems and micrografts, have vastly improved the treatment of chronic wounds. Our service specializes in treating ulcers and difficult-to-heal wounds while providing a multiprofessional medical response. Herein, we present our experience and protocols in treating chronic wounds using a variety of advanced dressings and technologies.

A More Biomimetic Cell Migration Assay with High Reliability and Its Applications

Cell migration refers to the directional movement of cells to the surrounding cell-free zone in response to chemical and mechanical stimuli. A cell migration assay is an essential device for studying pharmaceutical and medical problems. In this paper, we present a novel approach to a cell migration assay on a chip with two merits, namely (i) simultaneous creation of many cell samples on the same condition and (ii) cells migrating while being stressed in a fluidic environment. The first merit has addressed the problem of poor reproducibility in experimental studies for medical problems such as wound healing, and the second merit has made the cell migration device, which is an in vitro environment, more biomimetic. The two merits are attributed to a novel mechanical method to simultaneously create many cell-free zones and to the design of a microfluidic process to create shear stress in cells uniformly. Two applications were studied on our device to explore its effectiveness. The first application is regarding the combination chemotherapy of cisplatin and doxorubicin (Adriamycin) on cervical cancer cells (HeLa). The second application is regarding inhibiting the migration of endothelial cells (HUVEC) in the process of anti-angiogenesis.