Structure/function relations of chronic wound dressings and emerging concepts on the interface of nanocellulosic sensors

Authors: Fontenot, Krystal; Edwards, Judson - Vince; HALDANE, DAVID - Innovatech-Engineering; PIRCHER, NICOLE - University Of Natural Resources & Applied Life Sciences - Austria; LIEBNER, FALK - University Of Natural Resources & Applied Life Sciences - Austria; Nam, Sunghyun; Condon, Brian

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/10/2017
Publication Date: 3/15/2020
Citation: Fontenot, K.R., Edwards, J.V., Haldane, D., Pircher, N., Liebner, F., Nam, S., Condon, B.D. 2020. Structure/function relations of chronic wound dressings and emerging concepts on the interface of nanocellulosic sensors. In: Flipponen, I., Peresin, M.S. Nypelo, T., editors. Lignocellulosics: Renewable Feedstock for (Tailored) Functional Materials and Nanotechnology. 1st edition. New York, NY:Elsevier Inc. p. 249-278.
DOI: https://doi.org/10.1016/B978-0-12-804077-5.00014-2

Interpretive Summary: Chronic or non-healing wounds continue to affect 7 million patients in the United States and have a rising cost of $4 billion by 2019. Hence, the need of specialized point of care diagnostic or theranostic wound dressings. Here we discuss passive/active, interactive, bioactive, and intelligent dressings based on content, mode of action, the types of wounds to which dressings are best suited with and an application with a view to recent advances. We also propose nanocellulosic materials as a transducer surface for the generation of a protease biosensor layer as an interface for multilayered semiocclusive intelligent chronic wound dressing that not only detects but also sequester proteases. The cellulose print cloth (control) and nanocellulosic materials (nanocrystals, nanocellulose composites, and nanocellulosic aerogels) were selected due to their structural and biophysical similarities to commercially available dressings whether gauze, film, or hydrogel. In addition to this, the nanocellulosic materials offer characteristic properties (SSA, permeability, wettability, and surface charge) as a function of a biosensor layer. Conjugation of the nanocellulosic materials to a tripeptide or tetrapeptide substrates will provide the ideal selectivity and sensitivity needed for detecting HNE and serving as an effective biosensor layer of a multilayered dressing. Therefore, interfacing a nanocellulosic biosensor with a semiocclusive dressing is a paradigm adaptable for the detection of other markers of clinical interest as well, through substitution of the biomolecule needed for the desired point of care diagnostics or theranostic interest.

Technical Abstract: It is estimated that chronic wounds affect around 7 million patients in the United States alone 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 dressings and discuss recent advances based on polysaccharide-based materials. Dressings may be categorized as passive or active, interactive, bioactive, and intelligent. Here we discuss these categories in the context of materials that are designed for moist wound healing based on material content, mode of action and application with a view to recent advances. Intelligent dressings, which are defined as multifunctional and/or sensor-interfaced are based on the incorporation of sensor motifs and functional alignment to treat specific pathological issues of the chronic wound at a molecular level. Excessive protease levels is given as an example of a detectable pathology. Point of care diagnostics for wound care has ushered in a variety of novel biosensor approaches to wound care. Biosensors incorporate a sensor biomolecule and a transducer surface wherein the biomolecule constitutes the ‘sensing element’. Effective biosensors require sensitivity and selectivity in order to elicit a valid detection signal. Here we address nanocellulosic-based biosensors as functionally robust sensors and interfaced to different types of intelligent dressing motifs designed for protease point of care diagnostics. Nanocellulosic materials such as nanocrystals, nanocellulose composites, and nanocellulosic aerogels prepared from cotton or wood offer ideal properties including biodegradability, biocompatibility, functionality, and a high specific surface area as a favorable transducer surface for a biosensor. A protease peptide substrate which provides the fluorescent signal of detection is utilized as the ‘sensing element’ of the target protease, human neutrophil elastase, a biomarker for chronic wound point of care diagnostics and a therapeutic target for other inflammatory diseases. As a model, the nanocellulose-based biosensors are discussed in terms of substrate loading, specific surface area, porosity, surface charge, and sensitivity to proteases as a putative functional paradigm for incorporation into semiocclusive dressings.