Analysis Of The Materials For Wound Healing Application
Wound healing is the process of which the skin and the tissues restore itself after a trauma or an injury. In an intact skin, the epidermis, surface layer and the dermis, deeper layer creates a protective barrier against the external conditions. When the protective barrier is broken, a directed arrangement of biochemical events is set into motion to repair the damage. Wound healing, as an organic process within the material body, is achieved through four exactly and extremely programmed phases. In the 4-phases concept, there are the hemostasis phase, the inflammatory phase, the proliferation phase, and the remodeling phase. In the 3-phases approach, the hemostasis phase is contained within the inflammatory phase. In the human body as a normal biological process of wound healing is achieved through highly programmed phases and precisely: hemostasis, inflammation, proliferation, and remodeling. A speedy recovery with minimal scarring and maximal function is the main aim of wound healing. The selection of materials is very important from wound healing application point of views.
According to the Medline (2017), skin’s the body's largest organ. It is the first and best defense against external aggressors. The skin provides us with many beneficial functions such as: protection, sensation, regulation of temperature, immunological surveillance, prevention of dehydration, and synthesis of vitamin D3. However, traumas or injuries may cause in variation of skin defects. Wounds are injuries that break the outer layer of skin or other body tissues. Wounds include cuts, scrapes, scratches, and punctured skin. Wounds often happen because of an accident, but surgery, sutures, and stitches. Wounds cause infections and if worsen, it might lead to some serious diseases. Human skin generally needs to be covered with dressings immediately after it is damaged. There are a number of precautions to take which help to prevent wound infections developing. In most cases wound infections can be cured with an antibiotic cream medicine, and wound dressing.
An injury is a physical trauma or damage caused to the body by an external force. It is result from physical, chemical, mechanical and/or thermal damages that interferes with the natural recuperating process of the skin when progressed and constant. The treatment of skin injuries might be a critical issue in healthcare. More often than not, the treatment for skin loss is old autografts and allografts. As the tissue engineering is rising, it has emerged as an alternative treatment for excessive skin loss. Wound dressing materials have altered unendingly and significantly all through the previous years. Nowadays many polymers, and also natural materials, synthetic materials and combinations of types, nanoparticles immobilized synthetic compound or polymer materials are utilized for the applying of skin recovery. The fundamental point of wound healing is a speedy recuperation with insignificant scarring and maximal capacity. Modern dressings should not only increase patients’ comfort, but mostly they are designed to create appropriate environment around a wound that facilitates and participates in its healing.
The selection of materials is essential from wound healing application point of views. Developing of biodegradable plastic materials is required by using natural resources such as starch, cellulose and chitosan. Winter (1962) has announced the first generation of wound dressing polymeric materials and showed optimal environments for wound repair. This awareness mindfulness has altered the ways to wound dressing and made ready for the development of wound dressing from passive to active material and functionalized ones. The desirable wound dressing materials should ought to satisfy the accompanying conditions: maintain a local moist environment, protect the wound from side-infection, absorb the wound fluids and exudates, minimize the wound surface necrosis, prevent the wound dryness, stimulate the growth rate, and be elastic, non-toxic, non-antigenic, biocompatible and biodegradable dressing materials. Chitosan, a copolymer of glucosamine and N-acetylglucosamine units connected by-1,4-glycosidic linkages and great biodegradability, nontoxicity, biocompatibility and antifungal movement and its subsidiaries have been generally utilized as a part of the fields of prescription, beauty care products, agri-culture, biochemical partition frameworks, tissue designing et cetera.
Chitosan consists of β-(1 → 4)-linked 2-acetamido-2-deoxy-d-glucopyranose and 2-amino-2-deoxy-d-glucopyranose units. This is generally obtained by alkaline deacetylation of chitin, which is the main component of the exoskeleton of crustaceans, such as shrimps. Chitin is the main component and the second most abundant biopolymer in nature after cellulose. Chitosan is widely used in the field of biomedicine, food package, water treatment and so on due to its unique structure and property. Chitin is a normally rich mucopolysaccharide and is second to cellulose regarding the sum created annually by biosynthesis. Chitin is a typical constituent of the exoskeleton in animals, particularly in crustaceans, mollusks and insects. Deacetylation of chitin yields chitosan, which is a generally responsive compound and is produced in various forms, such as powder, glue, film and fiber. Chitosan is soluble in dilute aqueous acetic, lactic, malic, formic and succinic acids. Much attention has been paid to chitosan based biomedical materials, in light of its unique properties, such as, biodegradability, non-toxicity, anti-bacterial and biocompatibility. Chitosan is an advantage to wound recuperating because it stimulates homeostasis and quickens tissue recovery. A natural product is preferred to be used for biomedical research because these materials are more biocompatible than synthetic materials. Chitosan is biodegradable hence, it is metabolized by human enzymes such as lysozomes. It is an attractive material for a tissue engineering scaffold because it has structural similarities to glycosaminoglycans and is hydrophilic. Chitosan's monomeric unit, N-acetylglucosamine, occurs in hyaluronic acid, an extracellular macromolecule that is important in wound repair. Chitosan advances surface prompted thrombosis and blood coagulation and quickens coagulation in vivo by impacting the enactment of platelets. Chitosan is a major component of crustacean outer skeletons. This material is known in the wound management field for its haemostatic properties. It also possesses other biological activities and affects macrophage function that helps to accelerate the wound healing.
The N-acetyl glucosamine (NAG) present in chitin and chitosan is a noteworthy part of dermal tissue which is fundamental for repair of scar tissues. Chitosan's positive surface charge enables it to effectively support cell development. Chitosan has a few favorable circumstances over other kind of disinfectants since it has a higher antibacterial movement, a more extensive range of action, a higher executing rate and a lower lethality toward mammalian cells. Its antibacterial and quickening of wounds makes it as wound healing material various forms like globules, powders, gels, wipes, tubes, strands and movies. One-dimensional nanoparticles with hollow nanotubular structure are Halloysite nanotubes (HNTs). It is belong to the kaolin group of minerals mined from natural deposits. Halloysite are natural inorganic nanomaterials with an empirical formula of Al2Si2O5 (OH)4nH2O. Halloysite nanotubes are unique and versatile nanomaterials that composed of double layer of aluminium, silicon, hydrogen and oxygen. The length of HNTs is in the range of 0.2–1.5 mm, while the inner diameter and the outer diameter oftubes are in the ranges of 10–40 nm and 40–70 nm, respectively. Halloysite nanotubes are formed as a result of strain caused by lattice mismatch between adjacent silicon dioxide and aluminium oxide layers. HNTs are novel 1D natural nanomaterials with a unique combination of tubular nanostructure, large aspect ratio, natural availability, rich functionality, good biocompatibility, and high mechanical strength. Halloysite is a natural nanotubular clay mineral (HNTs, Halloysite Nano Tubes) chemically indistinguishable to kaolinite and because of its great biocompatibility, is an alluring nanomaterial for a huge range of biological. As tube-like regular nanomaterials, halloysite nanotubes (HNTs) have potential applications in wound healing because of their high mechanical quality, great biocompatibility, hemostatic property, and wound mending capacity.
HNTs are cytocompatible and possible to be used in tissue engineering as movable materials according to recent study. Halloysite (with a Chinese traditional name “Chishizhi”) was usually used as a recuperating material in traditional Chinese medicine in a pulverized form which has been verified by the effectiveness of hemostasis and wound healing. The role of HNTs as a biocompatible and viable candidate for biomaterial applications has been verified. Polyvinyl Alcohol (PVA) is a synthetic polymer that is soluble in water. It is effective in film forming, emulsifying, and has an adhesive quality, has no odor, is not toxic, and is resistant to grease, oils, and solvents. It is ductile but strong, flexible, and functions as a high oxygen and aroma barrier. Hermann and Haehnel (1994) first prepared Polyvinyl Alcohol by hydrolyzing polyvinyl acetate in ethanol with potassium hydroxide. Polyvinyl Alcohol (PVA) has drawn much consideration for wound dressing applications; its various wonderful biomedical properties have been portrayed well. An artificial polymer PVA that has been used during the first half of the 20th century worldwide. It has been applied in the medical, commercial, industrial, food sectors that has been used to produce many end products, such as lacquers, surgical threads, and food packaging materials. It is a biodegradable imitation used in paper coating and textile sizing of natural polymers. It is widely used by blending with others polymer compounds and other polymers with hydrophilic properties. For various industrial applications it is utilized to enhance the mechanical properties of films because of its structure and hydrophilic properties.
At present, PVA is a standout amongst the most continuous and the most seasoned engineered polymer hydrogels that because of its great biocompatibility has been connected in a few progressed biomedical applications e.g. wound dressing and wound management. However, its application in hydrogel frame is restricted for transcutaneous injury dressings because of its poor attachment property, unbiased trademark, generally low water take-up, and exceptionally crystalline areas that are impermeable to oxygen dispersion. A water-soluble synthetic polymer PVA, possess an excellent bio reactor properties in wound dressing has known to be used as a stabilizer in nanoparticles synthesis having less toxicity. It has a good biocompatibility and for many years that has been applied as a biomaterial or additive to drug compositions. The individual characteristics of chitosan, PVA, HNT nanoparticles encouraged the researchers from synthesizing these polymers to make a feasible material for wound healing application.
