Innovations in Drug Delivery for Chronic Wound Healing.

Wound healing is a varied and complex process designed to restore normal skin structure, function, and appearance in a timely manner. To achieve this goal, different immune and biological systems participate in coordination through four separate steps, including homeostasis, inflammation, proliferation, and regeneration. Each step involves the function of different cells, cytokines, and growth factors. However, chronic ulcers, which are classified into three types of ulcers, namely vascular ulcers, diabetic ulcers, and pressure ulcers, are not able to heal through the mentioned natural stages. This, in turn, causes mental and physical problems for these people and, as a result, imposes high economic and social costs on the society. In this regard, using a system that can accelerate the healing process of such chronic wounds, as an urgent need in society, should be considered. Therefore, in this study, the innovations of drug delivery systems for the healing of chronic wounds using hydrogels, nanomaterials, and membranes are discussed and reviewed.