Development of theranostic wound dressings: harnessing the knowledge of biospecific interactions at the biomaterial interface to promote healing and identify biomarkers.

Chronic wounds are widely recognized as a global health challenge, but both our understanding of wound biology and the implementation of technological innovations for their treatment have made only limited progress in the last few decades [1]. Currently, the clinical assessment of the wound is based on the experience of the clinicians who follow recommendations taken from a range of available guidelines and choose commercially available wound dressings on the basis of their suitability to the wound conditions [2]. For example, the Wounds UK’s best practice statement on the management of chronic wounds recommends several criteria for the assessment of lesions that are mainly based on a subjective clinical inspection of the overall wound bed and peri-wound area status (e.g. inflammation), the exudate volume and viscosity, pain, and infectiongenerated malodor. Methods of wound size measurement provide quantitative data, but they suffer from limited intra-rater reliability. Likewise, the choice of the most suitable wound dressing is made with the aim of providing biological conditions favorable to healing. Despite the wide range available, wound dressings are all designed with two main characteristics: (i) an absorbent layer made of a polymeric porous hydrogel capable of absorbing excess exudate while keeping the wound moist and (ii) a film (e.g. silicon) protecting the wound from external contaminants and bacteria [3]. More advanced wound dressings include anti-microbial agents (e.g. silver nanoparticles) or growth factors known to promote healing [3]. The use of the latter is limited by their costs, need for refrigerated storage conditions, and debated healing properties. In this context, up to 42% of wounds do not heal within 6 months from the first presentation, often leading to severe complications [4]. Based on these premises, the quest for both healing-promoting wound dressings and objective parameters of wound evaluation is legitimately advocated. 2. Theranostic wound dressings