Low Cost Oxygen-sensing Films For Clinical Wound Healing Monitoring
D. Naveed Tavako, Samantha Schwager, Lindsay Jeffries, Anthony Bruce, Christopher DeRosa, Cassandra Fraser, Shayn M. Peirce, Patrick S. Cottler.
University of Virginia, Charlottesville, VA, USA.
BACKGROUND: Oxygen delivery is essential for wound healing, therefore, a noninvasive and inexpensive tool to map wound oxygen has clinical significance. Assessment of healing typically relies on qualitative and subjective analysis, while oxygen monitoring can be expensive, highly variable, or only provide indirect measurements. We have developed an easy-to-use, thin film capable of monitoring wound oxygenation.
METHODS: The flexible dual-layer film utilizes novel boron oxygen-sensing nanoparticles (BNPs) capable of monitoring changes in wound oxygen via the oxygen-permeable layer (chitosan-polycaprolactone with BNPs), while isolating the wound through an oxygen-impermeable layer (alginate). The BNPs are a dual emissive difluoroboron β-diketonate dye incorporated into a poly(lactic acid) matrix (BF2bdkPLA) that demonstrate emissions of a standard fluorescent peak and a phosphorescence peak that quenches with increasing oxygen. The ratio of fluorescence to phosphorescence (F/P) provides normalized values directly proportional to oxygen.
RESULTS: In vitro utility of the films was demonstrated through F/P analysis documenting the film’s capability to isolate a hypoxic environment from ambient oxygen through the oxygen-permeable and impermeable layers (p<0.05, n=3). The oxygen sensitivity of the BNPs in films was also shown to be equivalent to BNPs in solution in a mouse wounds (p=0.43, n=3). Additionally, wound related angiogenesis led to F/P ratios increasing by 22%, while total wound area decreased 45% during the initial 3 days of healing.
CONCLUSIONS: BNPs in solution have documented utility, but present application and removal challenges. These results present a promising solution to directly map oxygen levels in wounds in a clinically relevant film formulation. Clinical use of the films has the potential to monitor chronic wounds healing trajectory, guiding care decisions.
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