MINI-REVIEW Wound dressings for a proteolytic-rich environment Andreia Vasconcelos & Artur Cavaco-Paulo Received: 30 November 2010 / Revised: 17 January 2011 / Accepted: 17 January 2011 / Published online: 1 March 2011 # Springer-Verlag 2011 Abstract Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin. The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of healing process will be reviewed. Keywords Wound healing . Silk fibroin . Collagen . Elastin . Keratin Introduction In the past, traditional dressings such as plant fibers, honey and animal fat were used to cover the wound, keeping it dry by allowing the evaporation of wound exudate and preventing the entry of harmful bacteria into the wound. Nowadays, the development of new biopolymers and fabrication techniques creates wound dressings with im- proved properties that enhance the healing process. Effective wound management requires the understanding of the type of wound and healing process. The physical, mechanical and chemical properties of the dressing must also be taken into consideration. The new biomaterials to be applied as wound dressings should create a moist environment around the wound, effective oxygen circulation, cellular guidance and low bacterial load. This review discusses the basic principles of wound healing, type of wounds and the type of wound dressings. An overview will be given on the properties of fibrous proteins and their characteristics as wound dressings. Wounds and wound healing process A wound, according to the Wound Healing Society, is the result of “disruption of normal anatomic structure and function” (Lazarus et al. 1994). Based on the nature of the repair process, wounds can be classified in acute wounds and chronic wounds. Acute wounds usually heal complete- ly within 8–12 weeks with minimal scarring (Nicholas 2002). The primary causes of acute wounds include mechanical injuries and burns. Chronic wounds fail to heal in the expected time frame and persist beyond 12 weeks, with the possibility to reoccur (Harding et al. 2002). A chronic wound does not heal properly because the orderly sequence of events is disrupted at one or more stages of the healing. The factors that inhibited or negatively influence the healing can be divided into systemic and local (Table 1). A chronic wound is usually a permanent inflammatory state comprising a high and constant proteolytic activity. This will diminish the recognition and subsequent removal of cells by macro- A. Vasconcelos : A. Cavaco-Paulo (*) Departamento de Engenharia Têxtil, Campus de Azurém, Universidade do Minho, 4800-058 Guimarães, Portugal e-mail: artur@det.uminho.pt Appl Microbiol Biotechnol (2011) 90:445–460 DOI 10.1007/s00253-011-3135-4