Electrospinning is a simple, low-cost, and highly efficient technique to generate nanometer to micrometer thick fibers from polymer solutions and is utilized in different fields. Silk fibroin (SF), a structural protein found in <i>Bombyx mori</i> cocoons, has attracted attention for various biomedical applications with characteristics such as biocompatibility and biodegradability. Indocyanine green (ICG), an FDA approved dye, is used in medical diagnostics due to its unique fluorescent and photothermal properties. Our previous work has shown that irradiation of ICG solution by an IR laser can induce quick thermal energy release. We propose that SF-ICG matrix can effectively absorb and clot blood toward hemorrhage control. In this study, SF and ICG were co-spun to generate flexible microfibers with high surface area to volume ratios; in response to IR irradiation, the fibrous matrix effectively harnessed thermal energy release to achieve blood clotting. However, as-spun fibers were unstable in aqueous solutions, causing ICG leaching. Post-treatment methods were explored to monitor ICG leaching. It was found that ethanol treatment induced β-sheet formation in SF and enhanced the SF-ICG interaction to reduce ICG leaching from the composite fibers. Ethanol vapor treated (EVT) SF-ICG fibers showed 50% less ICG leaching than liquid ethanol treated (LET) SF-ICG fibers indicating the efficacy of the EVT. With 14.9 W/cm<sup>2</sup> irradiation, the post-treated SF-ICG 3D fibrous ball of 2-3mg dry weight, solidified a drop of bovine blood in 6 to 50 s. In contrast, a single layer fiber matrix required 3 min to achieve the same clotting effect. The results suggest that a larger contact area of fibers is desirable for faster blood clotting, and EVT prompted better ICG retention in SF fibers. Additional studies are focusing on optimizing conditions to achieve bleeding control at various flow rates and blood pressures mimicking situations such as hemorrhage control of arterial bleeding.

Electrospun silk-indocyanine green composite fibers for hemorrhage control

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.