Natural and synthetic polymers for wounds and burns dressing

Biodegradable polymers, encompassing both natural and synthetic polymers, have demonstrated efficacy as carriers for synthetic drugs, natural bioactive molecules, and inorganic metals. This is due to their ability to control the release of these substances. As a result, various advanced materials, such as nanoparticle- loaded hydrogels, nanofibrous scaffolds, and nanocomposites, have been developed. These materials have shown promise in enhancing processes, such as cell proliferation, vascular angiogenesis, hair growth, and wound healing management. Natural polymers, including hyaluronic acid, collagen, chitosan, gelatin, and alginate, as well as synthetic polymers like polylactic acid, polyglycolic acid, polylactic co-glycolic acid, and PCA, have significant potential for promoting wound healing. This study examines the advancements in biodegradable polymers for wound healing, specifically focusing on each polymer and its distinctive formulations. It also discusses the in vitro experiments conducted using different cell lines, as well as the in vivo studies that explore the numerous uses of these polymers in wound healing. The discussion also included the exploration of modifications or combinations of several polymers, as well as surface changes, in order to produce synergistic effects and address the limitations of individual polymers. The goal was to expedite the healing process of different chronic wounds. Due to this, there have been notable advancements in the technological use of polymeric mixes, including biodegradable polymer-based scaffolds, which have accelerated the process of wound healing.

Natural and synthetic polymers are a versatile platform for developing biomaterials in the biomedical and environmental fields. Natural polymers are organic compounds that are found in nature. The most common natural polymers include polysaccharides, such as alginate, hyaluronic acid, and starch, proteins, e.g., collagen, silk, and fibrin, and bacterial polyesters. Natural polymers have already been applied in numerous sectors, such as carriers for drug delivery, tissue engineering, stem cell morphogenesis, wound healing, regenerative medicine, food packaging, etc. Various synthetic polymers, including poly(lactic acid), poly(acrylic acid), poly(vinyl alcohol), polyethylene glycol, etc., are biocompatible and biodegradable; therefore, they are studied and applied in controlled drug release systems, nano-carriers, tissue engineering, dispersion of bacterial biofilms, gene delivery systems, bio-ink in 3D-printing, textiles in medicine, agriculture, heavy metals removal, and food packaging. In the following review, recent advancements in polymer chemistry, which enable the imparting of specific biomedical functions of polymers, will be discussed in detail, including antiviral, anticancer, and antimicrobial activities. This work contains the authors' experimental contributions to biomedical and environmental polymer applications. This review is a vast overview of natural and synthetic polymers used in biomedical and environmental fields, polymer synthesis, and isolation methods, critically assessessing their advantages, limitations, and prospects.

In recent years, there has been a significant focus on bioactive dressings suitable for treating chronic and acute wounds. Electrospinning nanofibers are considered advanced dressing options due to their high porosity and permeability to air and water, effective barrier properties against external pathogens, and excellent resemblance to the extracellular matrix for wound healing and skin regeneration. This article reviews the recent advancements in the application of electrospinning nanofibers for bioactive wound healing. The review begins with an overview of the wound healing process and electrospinning methods. It then explores the advantages and disadvantages of different synthetic and natural polymers used in the preparation of electrospinning wound dressings. The natural polymers discussed in this review include collagen, gelatin, silk fibroin, chitosan, hyaluronic acid, and sodium alginate. Additionally, the review delves into commonly used synthetic polymers like polyvinyl alcohol, polyvinyl chloride, polyethylene lactone, polylactide, and polyurethane for wound dressing applications. Furthermore, the review examines the blending of natural and synthetic polymers to create high‐performance wound dressings. It also explores the incorporation of functional additives, such as antimicrobial agents, growth factors, and natural extracts, into electrospinning nanofibers to expedite wound healing and tissue repair. In conclusion, electrospinning is an emerging technology that provides unique opportunities for designing more effective wound dressings and care products.

Polymer scaffolds are increasingly ubiquitous in the field of tissue engineering in improving the repair and regeneration of damaged tissue. Natural polymers exhibit better cellular adhesion and proliferation than biodegradable synthetics but exhibit inferior mechanical properties, among other disadvantages. Synthetic polymers are highly tunable but lack key binding motifs that are present in natural polymers. Using collagen and poly(lactic acid) (PLA) as models for natural and synthetic polymers, respectively, an evaluation of the cellular response of embryonic mouse fibroblasts (NIH 3T3 line) to the different polymer types was conducted. The samples were analyzed using LIVE/DEAD™, alamarBlue™, and phalloidin staining to compare cell proliferation on, interaction with, and adhesion to the scaffolds. The results indicated that NIH3T3 cells prefer collagen-based scaffolds. PLA samples had adhesion at the initial seeding but failed to sustain long-term adhesion, indicating an unsuitable microenvironment. Structural differences between collagen and PLA are responsible for this difference. Incorporating cellular binding mechanisms (i.e., peptide motifs) utilized by natural polymers into biodegradable synthetics offers a promising direction for biomaterials to become biomimetic by combining the advantages of synthetic and natural polymers while minimizing their disadvantages.

A noticeable focus in recent years has been on creating bioactive dressings that are tailored to meet the requirements of wounds that are both acute and chronic. Because of these exceptional properties, electrospinning nanofibers stand out as a potential choice among the creative solutions being investigated. Among these are very high porosity and superior permeability to water and air, both of which are essential for promoting wound healing conditions. Moreover, these nanofibers’ ability to ward against foreign infections makes them an attractive option for improving wound care protocols. It is particularly notable because they closely mimic the extracellular matrix since this property can greatly enhance the efficacy of skin regeneration and wound healing processes. The present study aimed to explore the use of electrospinning nanofibers for bioactive dressings and wound healing. Extensive literature search was performed and relevant articles were collected from various databases like Google scholar, Taylor and Francis, Science direct, Springer, Embase, and Willey. Electrospinning nanofiber applications for the bioactive healing of wounds. The investigation begins with a comprehensive review of the wound healing procedure and the several electrospinning techniques used here. The many natural and synthetic polymers that are used to make electrospinning wound dressings are discussed in more detail. Prominent natural polymers, including hyaluronic acid, collagen, gelatin, silk fibroin, chitosan, and sodium alginate, are emphasized due to their special qualities and possible advantages in wound treatment. Furthermore, the paper explores the wide application of artificial polymers such as polyvinyl alcohol, polyvinyl chloride, polyethylene lactone, polylactide, and polyurethane, providing insight into their roles in the advancement of sophisticated wound dressings. In conclusion, the development of electrospinning technology offers promising prospects for creating improved wound care products and dressings that have the potential to completely transform the wound management industry.

Mechanical properties of the hybrids of natural (alginate, collagen, chitin, cellulose, gelatin, chitosan, silk, and keratin) and synthetic electrospun nanofibers: A review.

Ancient fibrous biomaterials from silkworm protein fibroin and spider silk blends: Biomechanical patterns

6 - Nanoengineered polymeric biomaterials for drug delivery system

Fibroblasts are important for the successful healing of deep wounds. However, the influence exerted by Cuticell, a natural polymer on fibroblasts and by the synthetic polymer, Suprathel, made of poly-L-lactic acid, is not sufficiently characterised. This study compared the survival and growth characteristics of human juvenile and adult dermal fibroblasts as well as murine fibroblast cell line L929, on a natural polymer with those of a synthetic polymer using different culture models. Murine, juvenile and adult human fibroblasts were seeded on both the natural and synthetic polymers using statical slide culture or the medium air interface and dynamical rotatory culture. Cell adherence, viability, morphology and actin cytoskeleton architecture were monitored for 1-7 days. Biomaterial permeability was checked with a previously established diffusion chamber. The majority of the murine and adult human fibroblasts survived in slide and rotatory cultures on both wound dressings. The fibroblasts seeded on the synthetic polymer exhibited phenotypically a typical spread shape with multiple cell adhesion sites earlier than those on the natural polymer. The highest survival rates in all tested fibroblast species over the entire observation time were detected in rotatory culture (mean: >70%). Nevertheless, it led to cell-cluster formation on both materials. In the medium air interface culture, few adult fibroblasts adhered and survived until the seventh day of culture on both the natural and synthetic polymers, and no viable juvenile and L929 fibroblasts could be found by day seven. Apart from a significant higher survival rate of L929 in slide culture on the natural polymer compared with the synthetic polymer at the end of the culturing period (p<0.0001), and a higher cell survival of L929 on the natural polymer in medium air interface culture, only minor differences between both materials were evident. This suggested a comparable cytocompatibility of both materials. Permeability testing revealed slightly higher permeance of the natural polymer compared with the synthetic polymer. Cell survival rates depended on the culture system and the fibroblast source. Nevertheless, the juvenile skin fibroblasts were the most sensitive. This observation suggests that wound dressings used in treating children should be tested beforehand with juvenile fibroblasts to ensure the dressing does not compromise wound healing. Future experiments should also include the response of compromised fibroblasts, for example, from burn patients.

Peripheral nerve injuries account for 4 % of all injuries, and the consequences of trauma are a major medical and social problem, since they are characterized by a significant and long-term decline in limb function, and a high level of disability in patients. According to our data, up to 40% of patients sought specialized care for more than 6 months after the injury, and 19.9% were treated conservatively for an unreasonably long period of time. It led to an increase in the portion of unsatisfactory treatment results, since the prognosis of the further functional and useful degree of nerve recovery worsens with increasing time after injury. The main objective was to select the optimal option of biocompatible material for implementation in practice in case of traumatic peripheral nerve damage. Materials and methods. The analysis of medical literature for 2015–2020 was conducted. First of all, it should be noted that modern non-biological resorbable tubes are made of polyglycolic and polylactic acids. Non-resorbable tubes, including silicone, have shown undesirable effects, including axon compression during regeneration and the reaction of a fibrous foreign body. Hollow cylindrical tubes can be manufactured in several ways, such as electrospinning, crosslinking, physical film rolling, injection molding, melt extrusion, and braiding. Adequate surgical treatment of peripheral nerve injuries requires that the surgeon, in addition to an accurate knowledge of the anatomical details of the affected area, would also be familiar with microsurgical methods and had necessary equipment to operate. The main procedure in peripheral nerve surgery is the restoration of nerve continuity, which can be obtained by direct coaptation between the two ends of a severed nerve or by the introduction of nerve grafts to replace a defect in nerve tissue. Polyester is the most common synthetic material used in neural tissue engineering, along with polylactic acid, polycaprolactone, and polyglycolic acid. In combination with mesenchymal stem cells of the bone marrow, polylactic acid showed better results and accelerated the recovery of peripheral nerves. Polylactic acid directed the migration of Schwann's cells and induced the formation of a normal nervous structure. It was proved that the polycaprolactone material had an effect similar to that of autografts in nerve repair, and its characteristics were better than in a polylactic acid tube. Polyglycolic acid also possesses sufficient mechanical properties and can be used to repair a nerve defect. Artificial synthetic materials have good biocompatibility and biodegradability with minimal toxicity. For the production of high-purity polymer monomers, which are necessary for the manufacture of the frame, much time and financial costs are required. Moreover, the elasticity and hardness of such materials are imperfect. Three main natural biomaterials are used in tissue repair: collagen, silk, and gelatin. Collagen tube is the most widely used biological material in clinical practice. Silk materials with the protein fibroin, which promote the release of certain substrates, such as nerve growth factor particles, and provide more nutrients and a more favorable microenvironment for nerve repair, are worth noticing. Silk fibroin has good compatibility with the neurons of the dorsal root ganglia and supports cell growth. Gelatin materials are preferred due to the reduction of micromanipulation during nerve recovery. Natural biomaterials are easy to obtain in sufficient quantities; they have good biocompatibility and biodegradability and are easily absorbed by the body. However, each natural biomaterial has its drawbacks. Some of them are brittle or break down in a humid environment. Some natural materials are insoluble in water and traditional organic solvents, which limits their use. One of the most widely used biopolymers of natural origin is chitosan. Chitosan, derived by chitin deacetylation, plays a supporting, protective, and guiding role in the early stage of recovery of peripheral nerves and can provide a relatively stable, localized microenvironment during regeneration. Chitosan is absorbed and gradually decomposed in the late phase of recovery and regeneration of the nervous system. Issues regarding graphene-based nanomaterials use are considered. Graphene is a two-dimensional carbon nanomaterial with good optical, electrical and mechanical properties. It should be noted that when graphene nanoparticles incorporate into a chitosan or gelatin frame and are used to repair peripheral nerve damage in rats, this has contributed to the regeneration of the damaged nerve more quickly. Graphene also reduced the inflammatory response and accelerated the migration of endogenous neuroblasts. Hence, the use of these materials is not well understood due to the significant duration of recovery of the denervated proximal end of the nerve, so further research is needed to identify the advantages or disadvantages of their use.

Burn wounds are complex and intricate injuries that have become a common cause of trauma leading to significant mortality and morbidity every year. Dressings are applied to burn wounds with the aim of promoting wound healing, preventing burn infection and restoring skin function. The dressing protects the injury and contributes to recovery of dermal and epidermal tissues. Polymer-based nanotherapeutics are increasingly being exploited as burn wound dressings. Natural polymers such as cellulose, chitin, alginate, collagen, gelatin and synthetic polymers like poly (lactic-co-glycolic acid), polycaprolactone, polyethylene glycol, and polyvinyl alcohol are being obtained as nanofibers by nanotechnological approaches like electrospinning and have shown wound healing and re-epithelialization properties. Their biocompatibility, biodegradability, sound mechanical properties and unique structures provide optimal microenvironment for cell proliferation, differentiation, and migration contributing to burn wound healing. The polymeric nanofibers mimic collagen fibers present in extracellular matrix and their high porosity and surface area to volume ratio enable increased interaction and sustained release of therapeutics at the site of thermal injury. This review is an attempt to compile all recent advances in the use of polymer-based nanotherapeutics for burn wounds. The various natural and synthetic polymers used have been discussed comprehensively and approaches being employed have been reported. With immense research effort that is currently being invested in this field and development of proper characterization and regulatory framework, future progress in burn treatment is expected to occur. Moreover, appropriate preclinical and clinical research will provide evidence for the great potential that polymer-based nanotherapeutics hold in the management of burn wounds.

Hydrogels are polymeric materials that possess a set of characteristics meeting various requirements of an ideal wound dressing, making them promising for wound care. These features include, among others, the ability to absorb and retain large amounts of water and the capacity to closely mimic native structures, such as the extracellular matrix, facilitating various cellular processes like proliferation and differentiation. The polymers used in hydrogel formulations exhibit a broad spectrum of properties, allowing them to be classified into two main categories: natural polymers like collagen and chitosan, and synthetic polymers such as polyurethane and polyethylene glycol. This review offers a comprehensive overview and critical analysis of the key polymers that can constitute hydrogels, beginning with a brief contextualization of the polymers. It delves into their function, origin, and chemical structure, highlighting key sources of extraction and obtaining. Additionally, this review encompasses the main intrinsic properties of these polymers and their roles in the wound healing process, accompanied, whenever available, by explanations of the underlying mechanisms of action. It also addresses limitations and describes some studies on the effectiveness of isolated polymers in promoting skin regeneration and wound healing. Subsequently, we briefly discuss some application strategies of hydrogels derived from their intrinsic potential to promote the wound healing process. This can be achieved due to their role in the stimulation of angiogenesis, for example, or through the incorporation of substances like growth factors or drugs, such as antimicrobials, imparting new properties to the hydrogels. In addition to substance incorporation, the potential of hydrogels is also related to their ability to serve as a three-dimensional matrix for cell culture, whether it involves loading cells into the hydrogel or recruiting cells to the wound site, where they proliferate on the scaffold to form new tissue. The latter strategy presupposes the incorporation of biosensors into the hydrogel for real-time monitoring of wound conditions, such as temperature and pH. Future prospects are then ultimately addressed. As far as we are aware, this manuscript represents the first comprehensive approach that brings together and critically analyzes fundamental aspects of both natural and synthetic polymers constituting hydrogels in the context of cutaneous wound healing. It will serve as a foundational point for future studies, aiming to contribute to the development of an effective and environmentally friendly dressing for wounds.

In the last few years, wound healing and the development of "ideal" biomaterials that provide quick recovery and minimize scarring have represented one of the most important priorities of researchers. In this direction, silk fibroin (SF) scaffolds have gained substantial awareness, as a promising polymer owing to their increased biocompatibility, outstanding mechanical properties, and biodegradability, especially their tensile strength. Furthermore, SF is acknowledged to accelerate the wound healing process by encouraging cell growth and proliferation, and also the migration of different types of cells that are included in different stages of the healing process. Therefore, metal oxide nanoparticles (NPs), such as iron oxide (FeO), copper oxide (CuO), zinc oxide (ZnO), or magnesium oxide (MgO) NPs, have been extensively researched for their antimicrobial properties and ability to enhance tissue regeneration in addition to SF. When introduced within scaffolds, these NPs impart enhanced mechanical properties, including improved scaffold stability and durability. Moreover, the presence of the NPs could also increase the biocompatibility of scaffolds, facilitating cell proliferation, adhesion, and migration, ultimately promoting wound healing processes. The incorporation of metal oxide NPs and other natural polymers into SF scaffolds has thus emerged as a favorable method to enhance the properties and therapeutic potential of the developed biomaterial. This review aims to provide an overview of the advancements in SF scaffolds containing metal oxide NPs for wound healing applications.

Various nanomaterials have been studied for their biomedical application in recent years. Among them, nanocomposites have a prominent medical application in the prevention, diagnosis, and treatment of various diseases. Nanocomposites are made up of polymeric matrix layers composed of synthetic or natural polymers like chitosan, polyethylene glycol, etc. Polymer nanocomposites are inorganic nanoparticles dispersed in a polymer matrix. There are two types of polymeric nanocomposites which include natural and synthetic polymer nanocomposites. These nanocomposites have various biomedical applications, such as medical implants, wound healing, wound dressing, bone repair and replacement, and dental filling. Polymeric nanocomposites have a wide range of biomedical applications due to their high stability, non-immunogenic nature, sustained drug delivery, non-toxic, and can escape reticuloendothelial system uptake along with drug bioavailability improvement. In this review, we have discussed various types of natural and synthetic polymer nanocomposites and their biomedical applications.

Microparticle delivery system is accepted as are reliable. Mean to delivery the drug to the target site with specificity,. The drug should be delivered to specific target site at a rate and concentration that provides optimum therapeutic efficacy and reducing the side effect to minimum. Microspheres are empty spherical particles, the particle size is less than 200 mm. Microspheres are free flowing powder consisting of natural and synthetic polymers. They have the potential controlled release drug. Polymers are the most important things of pharmaceutical drug delivery. There are many kind of polymers which varying the properties available those days for use in different pharmaceutical applications. Polymers use in the preparation of microspheres is the synthetic and natural polymers. Synthetic polymers are acrolein, poly anhydrides, methyl meth acrylate, lactides, and glycosides. Natural polymers are albumin, gelatin, collagen, agarose, chitosan, carragenene. Microspheres are the free flowing powders consist of protein and synthetic polymers having a particle size ranging from 1 ? 1000 micrometer. Microspheres are prepared by several techniques but the choice of method depends upon the drug. The polymers used and duration of action required. The evaluation parameters of microspheres are micromeritic properties particle size and shape, swelling index, tapped density, drug loading efficiency. In coming days by combining numerous other sceniorio, we will find the microspheres in novel drug delivery. Specifically in disease cell sorting diagnostics, gene and genetic materials, safe targeted and effective in vivo delivery and supplements a tiny interpretation of diseased organ and tissue in the body. Keywords: Microencapsulation, novel drug delivery, synthetic and natural polymers, duration of action.