Structure/Function Relations of Chronic Wound Dressings and Emerging Concepts on the Interface of Nanocellulosic Sensors

Abstract Chronic wounds affect around 7 million patients in the United States and the wound management market is to reach a value of $4.4 billion in 2019. Thus, improvements in chronic wound dressings are a major issue in wound management resources. In this paper, we examine some of the basic categorical and characteristic differences of the dressings designed for moist wound healing based on material content and mode of action with respect to recent advances with polysaccharide-based materials. Dressings may be categorized as passive or active, interactive, bioactive, and intelligent. Intelligent dressings are multifunctional and/or sensor-interfaced based on the incorporation of sensor motifs and functional alignment to treat specific pathological issues at the molecular level, i.e., excessive protease levels of a chronic wound. Point of care diagnostics for wound care have ushered in a variety of novel biosensor approaches for wound healing. Biosensors incorporate a sensor biomolecule and a transducer surface wherein the biomolecule constitutes the “sensing element.” We propose nanocellulosic-based biosensors as functionally robust sensors interfaced with different intelligent dressing motifs for protease point of care diagnostics. Nanocellulosic materials such as nanocrystals, nanocellulose composites, and nanocellulosic aerogels offer ideal properties, i.e., biodegradability, biocompatibility, functionality, and a high specific surface area (SSA) as a favorable transducer surface to which the sensing element, a fluorescent protease peptide substrate, is conjugated. The substrate provides the selectivity needed for detecting the target protease, human neutrophil elastase, a biomarker for chronic wound point of care diagnostics. As a model, the nanocellulose-based biosensors are discussed in terms of porosity, pore size, wettability, SSA, and surface charge as a putative functional paradigm for incorporation into intelligent protease sequestrant dressings.