Bioinspired Wound Dressing

"The innovations in chronic wound care have been inadequate, proving to be a significant challenge to treat successfully chronic wounds, due to their inability to heal quickly like acute wounds. Some chronic wounds never recover leading to sepsis or amputations. Patients with chronic wounds can require hospitalisation for long periods of time, which puts an increased strain on health care services.
Chronic wounds are not completely understood, there are important steps that are carried out in sequence within the body to heal wounds, these are: homeostasis, inflammation, proliferation and remodelling but chronic wounds do not progress beyond the inflammation stage.
Hydrogels
It has become recognised that chronic wounds heal better when maintained in a moist environment. Hydrogels are three-dimensional hydrophilic networks that can be synthetically designed to absorb ca. 1000 times their weight of water without solubilising. When swollen they are able to simulate biological tissue. They possess the majority of the ideal characteristics required of dressings, in particular that of managing the wound bed moisture, a cooling effect believed to considerably reduced the pain associated with the wound, enable gaseous exchange and can be removed without causing further trauma. For these reasons they are used as dressings for dry, sloughy, or necrotic wounds. One disadvantage, however, is that when swollen they lose structural integrity.
Interpenetrating network (IPN) hydrogels are hydrogels that contain two or more cross-linked polymeric units, which are structurally more favourable due to their increased strength and stability upon swelling. They are particularly interesting for biomedical use, as they share similarities with the extracellular matrix, due to cells containing many proteins, IPN can consist of many polymer units, these similarities make them an excellent candidate for wound dressings to aid in tissue regeneration.
Project aim
In this project we propose to design a dressing to stimulate extracellular matrix (ECM) synthesis to promote progress through the proliferation wound healing stage. The ECM is heterogeneous and in a healthy environment is constantly renewed. It consists of two main components glycoproteins (fibronectin, proteoglycans, laminin) and fibrous proteins (collagen, elastin). The ECM influences the differentiation as well as anchorage and attachment of connective tissue to enhance the healing process. The design of a wound dressing capable of regulating ECM activity is therefore a desirable objective. In this project, it is thus proposed that the design of hydrogel-based dressings consisting of polymeric networks with the potential to mimic the ECM are explored further.
The use of synthetic materials will provide the ability to tune the hydrogel, to produce a stronger wound dressing, that enables gaseous exchange and absorption of excess wound exudate, without losing structural integrity and enabling the wound to heal and progress beyond the inflammatory stage.
A cost-effective hydrogel will be developed that consists of an interpenetration network of crosslinked polymers, that provides adequate strength upon swelling. Appropriate monomer units, from natural or synthetic materials, will be selected to suit the healing of chronic wounds.
The polymerisation process will be optimised, the properties of the hydrogel that will be assessed are equilibrium water content (EWC), mechanical and peel strength, viscoelastic properties and water vapour sorption properties.
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