Nanofibrous Mats: Harnessing Bioactivity for Advanced Wound Care

By Samantha Greene

The book "Nanofibrous Mats: Harnessing Bioactivity for Advanced Wound Care" by Samantha Greene is a complete guide to making and studying electrospun nanofibrous mats for use as wound dressings. There is a lot of information in this book about the qualities and uses of these materials, such as their bioactivity, biocompatibility, and ability to heal wounds.

Samantha Greene's study looks into the different ways that electrospun nanofiber mats can be made, including electrospinning, electrospinning with coaxial nozzles, and freeze-drying. The book also talks about how to describe these materials using different scientific methods, such as SEM, TEM, XRD, FTIR, and DSC.

While the book talks about how important bioactive nanofiber mats are for wound healing, it talks about how they can help cells stick together and grow, as well as their antibacterial qualities. It also looks at how these materials might be used in tissue engineering and restorative medicine.

Many thanks for sharing "Nanofibrous Mats: Harnessing Bioactivity for Advanced Wound Care." It is a great resource for people who study biomaterials, wound healing, tissue engineering, and regenerative medicine. The book gives a thorough explanation of how to make and identify electrospun nanofiber mats, as well as how they might be used to help wounds heal and tissues grow back.

• Language: English
• Publisher: NajeebAhmed
• Release date: Mar 28, 2024
• ISBN: 9798224636877

Book preview

1.  Introduction

1.1.  Overview

This thesis aims to provide a general perspective of nanofibrous mats and their uses for wound dressings. A wound dressing is a protective barrier helps in many aspects of the healing process [1]. An ideal wound dressing material should mimic the biologically and physically active extracellular architectures that can eventually induce repairing and regeneration of the human tissues across the wound site [2]. Recently, natural and synthetic polymeric mats have been developed for skin tissue regeneration [3]. In particular, electrospun polymeric nanofibrous mats can serve as a wound dressing material, providing mechanical support for the cellular activities and protection of the wound from bacterial penetration and dehydration [4-6]. Non-woven nanofibrous mats produced via electrospinning technology possess a high surface area and interconnectivity with nanometric diameters in order to imitate the properties of the extracellular matrix (ECM) [7, 8]. These characteristics are well-suited for usage in regenerative medicine. Furthermore, nanofibrous mats have excellent porosity, which is essential for better fibroblast attachment, cell proliferation, migration and nutrient exchange at the wound surface without any fluid absorption [9, 10].

Until now, metal/metal oxide nanostructures have grabbed the attention of biomedical and pharmaceutical industries for their distinctive physical properties such as large surface to volume ratio, high porosity and tunable mechanical strength [11, 12]. They can be readily functionalized with therapeutic delivery agents such as essential oils, vitamins, amino acids and antibiotics for accelerating the wound healing process [13-15].

1.2.  Structure of the skin

Skin is the largest multi-functional organ of the human body has many crucial functions [16, 17]. It also helps regulate the body temperature, serves as the primary defense system against the external environment and plays an active role in the immune system to protect the body from chemical, mechanical, thermal forces and infection from micro- organisms [18-20]. The integument is made up of three layers: the epidermis composed of stratified squamous epithelium and the dermis, made up of connective tissue and fibroblasts in ECM [21-23]. The hypodermis or subcutaneous-tissue lies below the dermis (Scheme 1.1) comprises of mesenchymally derived adipose tissue [24, 25].

Scheme 1.1. Schematic representation of the structure of human skin.

Skin injuries are a major burden of the health care system in the entire world [26-28]. The wound-care management is a natural therapeutic response of rejuvenating dermal and epidermal tissues in the shortest time to prevent infection, minimize pain and reduce scarring.

However, human skin cannot heal a deep injury such as diabetic ulcers, pressure damage and burn injuries [29, 30]. In full thickness wounds, there is no source of cells remaining for regeneration, except the wound edges. As a result, complete re-epithelialization takes the form of a scar while accelerating the wound healing process. This demands the need for fabricating a skin substitute, which would regenerate the native tissue and restore all of its functions after a healthy healing process [31, 32].

Currently, there are vast numbers of wound dressing materials existing in the market for a rapid wound healing response. Thus, modern wound dressings should be able to exchange gas, maintaining balanced moisture at the wound interface, act as a barrier to microorganisms, as well as restores the structure and function of the healed tissue [33-35]. Especially, electrospun nanofibrous mats were recognized to serve as a promising wound dressing material to utilize natural ECM analog, which effectively promotes cell adhesion, proliferation and promote oxygen diffusion in and out of the injured tissue [36-38].

1.3.  Wounds

Wounds are injuries to the body that can occur in soft tissues like skin or intestine, as well as in hard tissue like bones or cartilage and can be provoked by exogenous (trauma, compression and burns) or endogenous causes (metabolic diseases). Skin wounds are generally classified into two categories [39-41]:

οΤ Acute wounds

οΤ Chronic wounds

1.3.1.  Acute wounds

Acute wounds are injuries to the skin that can result from mechanical factors (abrasions, lacerations, incisions and contusions), exposure to corrosive chemicals, radiation, electrical shock and thermal sources. They usually heal completely within a period of 8-12 weeks [42].

1.3.2.  Chronic wounds

Wounds that are arrested in a phase of healing is known as chronic wounds. Chronic non-healing wounds such as diabetic foot ulcers, pressure ulcers and venous leg ulcers exhibit a pathologically delayed healing process, usually lasting longer than weeks or months [43, 44]. Granulocytes and macrophage numbers decline early in the healing process in acute wounds. Normally chronic wounds are more difficult to cure because they deal with damage to the skin due to impaired efferocytosis or dead cell clearance and excessive pro- inflammatory cytokine production [45-47].

1.4.  Wound healing

Wound healing refers to the natural way of restoring devitalized tissue layers and cellular structures [48]. Molecular and cellular components are responsible for the degradation and repair of tissues that happen during healing [49, 50]. The aim of the wound healing process is not only the reconstruction of the damaged tissue but also the recovery of its complete functionality, with a minimum of scarring. Wound healing is caused by primary, secondary and tertiary intention [51-54].

1.4.1.  Primary intention healing

Primary intention healing is the fastest type of wound closure, which occurs where the tissue surfaces have been closed. Wounds that heal by first intention closure have a small; will occur directly by fibrous adhesion, without the formation of granulation tissue with very little tissue loss. This can be immediately sealed with simple suturing or staples or even with skin graft placement [55, 56].

1.4.2.  Secondary intention healing

Secondary intention healing involves considerable tissue loss, in which the wound edges cannot be closed. Generally, this type of closure requires more time and energy than primary intention, which will close by adhesion of granulating surfaces and contraction of the wound. This intention involves no active intent to seal the wound [57].

1.4.3.  Tertiary intention healing

Tertiary intention healing is also known as delayed primary closure. This type of wound contains a large degree of tissue damage [51, 58]. Examples of tertiary intention wounds that are closed in this way include traumatic injuries such as dog bites or lacerations involving foreign bodies. Wounds that heal by tertiary intention require more connective tissue than wounds that heal by secondary intention. Moreover, vacuum-assisted closure dressings and hemostatic bandages are used to provide soft tissue coverage in tertiary closure [59, 60].

1.5.  Phases of wound healing

Wound healing is a dynamic process can be realized by two mechanisms called regeneration and repair [61]. Regeneration is the specific substitution of damaged tissues by

identical cells in which the wound heals by scar formation. The major healing mechanism is repair where damaged tissues are replaced by connective tissue which then forms a scar [62, 63]. Independently from the tissue involved, the healing process always occurs through a series of molecular, biochemical and cellular events that can be grouped into four overlapping phases [49] (Scheme 1.2):

οΤ  Hemostasis

οΤ Inflammation

οΤ  Proliferation

οΤ  Remodeling

Scheme 1.2. Schematic representation of phases of wound healing.

1.5.1.  Hemostasis

Bleeding usually occurs when the skin is injured and serves to flush out bacteria or antigens from the wound. Hemostasis occurs immediately upon injury [64]. Hemostasis begins immediately after wounding with the coagulation process and development of a fibrin clot. Fibrinogen in