**1. Introduction**

The Wound Healing Society has defined the wound as the result of 'disruption of normal anatomic structure and function'. A wound can be also described as a defect or break in the skin, which results from physical or thermal damage, or from medical and physiological

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

conditions [1]. The wound healing is a dynamic process consisting of four continuous and precisely programmed phases, namely haemostasis, inflammation, proliferation and remodelling. Multiple factors, such as infections, stress, diabetes, smoking and obesity, can lead to impaired wound healing by interfering with one or more of these phases [2]. Once injured, the skin loses many of the protective defence mechanism of the intact skin and is colonized by the microorganisms on its surface. According to the replication status of the microorganisms, a wound can be classified as contaminated, colonized, locally infected and/or with spreading invasive infection [3]. The main bacterial mode of living in an infected wound is biofilm, which can be defined as a confluent community of adherent bacteria characterized by high cell densities and encased in an extracellular polymeric matrix that acts as physical barrier for biological and pharmaceutical antimicrobials [4, 5]. The presence of bacterial biofilm is associated with impaired epithelialization and granulation tissue formation and promotes a low-grade inflammatory response that interferes with wound healing [6]. The biofilm matrix plays an important role in the increased antibiotic resistance and has an enormous impact on medicine in terms of both therapeutic options and costs. Biofilm has been estimated to be associated with 65% of nosocomial infections, and the treatment costs associated with biofilm infection and chronic wounds have been estimated to be more than 1 billion USD annually in the United States [4, 7].

The increasing resistance of bacteria to antibiotics represents a huge concern, so that the World Health Organization recently has described the problem as 'so serious that it threatens the achievements of modern medicine' [8, 9]. Moreover, the large number of wound dressings and the limited guidelines available have induced an undesirable inconsistency in wound-care practice [10]. The local treatment of wounds is crucial for preventing infections, controlling exudates and providing the moist environment necessary for wound healing. At this purpose, efforts have been made by many research groups in the development of bioactive dressings, which can play an active role in wound protection and healing, and/or are able to release biomolecules and antimicrobials for prevention and treatment of wound infections [8, 11, 12]. A strategy for the treatment of infected wounds with increased resistance to traditional antibiotic therapy is the use of specific antibacterial agents immobilized on the surface of a material, thus providing a wide spectrum of activity in terms of bacterial toxicity and destructuration of the bacterial biofilm matrix [13].

This chapter aims to provide the reader with an overview of the most promising routes to develop advanced biomaterials with antimicrobial properties for the management of wound infections through nanotechnology approaches. The new generation and application of nanomaterials with novel properties are one of the century's key technology developments, which offer extraordinary opportunities in the pharmaceutical and medical field [14]. The great potential of nanometals such as zinc, copper and silver in wound dressing formulations and their use as antimicrobial agent in wound infections will be presented, along with the most recent efforts and results achieved by several research group in the definition of effective strategies for prevention of wound infection and for enhanced wound healing. Moreover, the most relevant results obtained by the authors of this chapter in the field of silver-based antibacterial treatments for wound-healing application will be presented and discussed.
