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Therapeutic Nanostructures for Improved Wound Healing
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Lalduhsanga Pachuau, Pranab Jyoti Das, Bhaskar Mazumder
The incidence of chronic wounds is on the rise due to increasing diabetic and peripheral circulation disorders (Lai et al., 2014). Impaired angiogenesis and cellular migration in such cases results in increased wound healing time. This often necessitates the external supply of angiogenic factors such as VEGF that help in the formation of new blood vessels for complete regeneration at the wound site. Nanoconstruct fiber mats are a promising delivery system for growth factors as they can also function as skin substitutes, with similar tensile strength and Young’s modulus. Growth factors can be delivered in a controlled manner to effect dermal re-epithelialization and reconstruction. Delivery of rhEGF through poly (ε-caprolactone) (PCL)-PEG nanofibers was also reported to enhance the expression of EGF receptors and significantly increase wound closure in diabetic animals (Choi et al., 2008).
Computational Modeling of Transepithelial Endogenous Electric Signals
Published in Ben Greenebaum, Frank Barnes, Biological and Medical Aspects of Electromagnetic Fields, 2018
Somen Baidya, Ahmed M. Hassan, Min Zhao
While the wound healing mechanism consists of a complex combination of several overlapping events in a precise order, it is also prone to interruptions in any of its stages. An interruption in one of the stages may lead to a nonhealing or a chronic wound, which is defined as a wound that fails to heal through in an orderly and timely manner [14]. According to the Wound Healing Foundation, approximately 6.5 million patients suffer from chronic wounds, which are wounds that heal in an abnormal or a longer than usual manner [15]. The annual economic impact of these chronic wounds is estimated to be $39 billion, which indicates to the importance of finding an effective treatment modality to accelerate the healing of chronic wounds [15]. It is important to emphasize that many factors contribute to wound healing such as antibiotic-resistant biofilm, blood circulation, and chemical stimulus from growth factors [16]. For example, several experiments have demonstrated the significant relationship between the oxygen supply to the wound center and new capillary development [17]. Other studies focused on the effect of the mechanical forces in the wound’s environment on its healing rate [18]. In this chapter, we are concentrating on investigating the role of electrical signals, whether they are naturally generated or applied externally, as one of the promising approaches for accelerating the healing of chronic wounds [3,19,20].
Polyurethanes in Biomedical Applications
Published in Nina M. K. Lamba, Kimberly A. Woodhouse, Stuart L. Cooper, Polyurethanes in Biomedical Applications, 2017
Nina M. K. Lamba, Kimberly A. Woodhouse, Stuart L. Cooper
Wounds can be divided into acute and chronic, and partial thickness and full thickness. Acute wounds heal rapidly. Chronic wounds are considered to be wounds of long duration that fail to heal within a reasonable time period,202,203 although the definition of reasonable varies depending on the wound, site, and patient. Chronic wounds may involve the epidermis (erosion) only or with increasing severity, both the epidermal and dermal layers (ulcer).203 At present, wound, dressings for chronic leg ulcers are frequently occlusive and impregnated with different agents. These agents include glycerine, zinc, dermis, collagen and a host of others. The progress of chronic wounds towards healing is frequently inconsistent. Excellent media for bacteria, chronic wounds are commonly associated with peripheral vascular disease and arterial insufficiency although the etiology of these wounds is not well understood.202,203
Sodium carboxymethyl cellulose hydrogels containing reduced graphene oxide (rGO) as a functional antibiofilm wound dressing
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Nor Hazwan Ali, Mohd Cairul Iqbal Mohd Amin, Shiow-Fern Ng
Wound infections are responsible for morbidity and significantly contribute to increasing health care costs [1]. Chronic wounds are usually tissue injuries that heal slowly due to repeated tissue insults or underlying physiological conditions such as diabetes and malignancies, persistent infections, poor primary treatment and other factors related to the patient [2]. In chronic wounds, bacterial infection and colonization are important factors that affect the process of wound healing. Additionally, the inflammatory response will continue if the virulent microbes exist at the wound site, thus enabling persistent host injury and delaying the healing process [3]. Inadequate management of infected wounds can prolong treatment periods, increase resource use, lead to major amputation and, in the worst case, result in life-threatening conditions such as septicaemia and bacteraemia [1].
Polymeric biomaterials for wound healing applications: a comprehensive review
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Ahmed Olanrewaju Ijaola, Damilola O. Akamo, Fouad Damiri, Cletus John Akisin, Emmanuel Anuoluwa Bamidele, Emmanuel Gboyega Ajiboye, Mohammed Berrada, Victor Onyebuchukwu Onyenokwe, Shang-You Yang, Eylem Asmatulu
In recent years, novel biomaterials have been fabricated to accelerate the healing process of acute and chronic wounds. These include hydrogels, nanofibrous, composite, foam/spongy, bilayered, and trilayered scaffolds. The most developed biomaterials in the literature are nanofibrous scaffolds, hydrogels, and composite scaffolds. Recently, the advances in nanotechnology has provided pathways for incorporating nanomaterials, especially nanoparticles into other polymeric biomaterials such as hydrogels and nanofibers to improve their mechanical strength, wettability, drug-release duration, bactericidal activity, cell attachment, and cell proliferation. Also, bilayered and trilayered scaffolds are a set of recent biomaterials gaining notable attention in the literature, but there are few studies of interest on this new class of biomaterials. Trilayered scaffolds mimic full-thickness skin, and they provide a dense superficial layer, bioactive layer, and porous lower layer. The average closure time for chronic wounds healed by recently developed biomaterials is between 5 and 30 days, based on the literature. Furthermore, hydrophilicity, biodegradability, excellent mechanical strength, high porosity, optimal gas permeability, and optimal water vapor transmission rate are desirable characteristics of biomaterials used for accelerating the healing of acute and chronic wounds. In general, individual therapies could be researched to effectively treat certain wound types as a result of improvements in biomedicine and tissue engineering technologies. Additionally, the development of innovative materials capable of being manipulated to imitate the skin's environment, circumstances, and structure is critical for the treatment and management of diverse wound types. Finally, the integration of bioactive components into biomaterial scaffolds could promote wound healing responses, hence enabling successful wound therapy and care.
Topical negative-pressure wound therapy: emerging devices and techniques
Published in Expert Review of Medical Devices, 2020
Raymund E. Horch, Ingo Ludolph, Wibke Müller-Seubert, Katharina Zetzmann, Theresa Hauck, Andreas Arkudas, Alexander Geierlehner
NPWT was initially invented to treat complex chronic wounds defined as usually heavily colonized wounds that do not heal within 3 months. However, from personal experience, it is often a matter of years rather than months during which people suffer from chronic wounds. The normal wound healing process can be seen as a complex interplay between certain molecular, cellular, and humoral processes. If disruption of those processes takes place wounds are prone to chronification [79]. The milieu of chronic wounds is markedly different from wounds undergoing a normal healing process. Chronic wounds are usually stuck in the inflammatory phase and highly susceptible to infection. Its underlying causes are manifold including but not limited to venous stasis, pressure necrosis, peripheral arterial disease, radiation, pyoderma gangrenosum, and diabetes (Figure 3) [25,60]. Up to 2% of the population suffers at least once from a chronic wound in the course of a lifetime [66]. Chronic wounds are usually accompanied with long hospital stays and emotional distress [80]. In addition, the patients’ disability and intensive medical care constitute a massive financial burden for the patient and health-care systems [81]. NPWT can also be applied to chronic wounds as temporary closure before definitive surgical closure such as skin grafting or tissue transfer. The rationale behind the bridging strategy in chronic wounds is to prepare the wound bed by reducing its bacterial load, removing harmful substances and debris, as well as stimulating delivery and production of various growth factors. Those effects can be of paramount importance especially in multimorbid patients potentially determining their overall long-term outcome. Lower leg ulcers are often accompanied by soft-tissue infection and severe peripheral vascular disorders. Poor vascularization of the lower limb can limit wound coverage to free tissue transfer in combination with vascular procedures. If a patient's general medical condition does not allow any complex reconstructive procedure under general anesthesia, lower limb amputation is often considered the only way to prevent systemic infection and save a patient’s life. However, NPWT combined with surgical debridement can reduce the complexity of the required surgical procedure such as skin grafting instead of pedicled or free tissue transfer [82,83]. This leads to the reduction of anesthesia time and increases the limb preservation rates in critically ill patients with lower leg defects [84].