These point-of-care diagnostic tools employ high-sensitivity fluorescence to perform rapid and accurate assessment of protease presence and activity in a wound, thereby facilitating administration of optimal wound therapy. Protease imbalances are often responsible for the development of a range of medical pathologies, such as cancer cell metastasis or the spread of infectious diseases. High protease levels also can suppress pro-healing factors and destroy nascent tissue in chronic wounds, the treatment of which accounts for the largest share of the global wound care market, projected to exceed $22 billion by 2022. Available protease activity assays are generally for laboratory settings rather than point-of-care wound assessment by non-technical personnel, and many point-of-care diagnostic tools lack the analytical sensitivity needed to minimize testing time for more rapid and effective treatment of chronic wounds.
Researchers at the University of Florida have developed rapid, point-of-care protease detection assays that enable physicians to provide better treatment for chronic wounds. The devices are easy to use, completing their testing all within the same unit. They also exhibit very high analytical sensitivity that shortens overall testing time for more efficient chronic wound therapy.
Simple point-of-care diagnostic device to rapidly quantify protease levels or activity in wound tissue samples
These diagnostic tools utilize fluorescence resonance energy transfer (FRET) and colorimetric assay formats operating on a high-sensitivity substrate-cleaving mechanism to detect or quantify the activity of matrix metalloproteinase (MMP), a protease that indicates the chronic status of a wound when present in elevated amounts. A peptide substrate contains both a fluorescing dye molecule and a second molecule that quenches the fluorescence of the fluorescing dye. The substrate is specifically cleavable only by the MMPs. Therefore, if elevated protease levels exist in the sample, then quenching of the fluorescing dye ceases, and its fluorescence indicates the protease activity in the wound. This mechanism empowers multiple assay devices, including straw and swab-based testing tools as well as thin film substrates able to portray visually the spatial distribution of protease activity across the surface of a wound bed.