Post doctoral scholar Terasaki institute for biomedical innovation LOS ANGELES, California, United States
Introduction:: Introduction: Untreated hemorrhage results in diverse complications and fatality. However, timely diagnosis and management of blood loss using hemostatic agents can be life-saving. Herein, we developed a biocompatible and biodegradable theranostic device that can detect hemorrhage and simultaneously stop bleeding. The device is composed of a silk fibroin (SF) sponge sandwiched between silver nanowire (AgNW) electrodes that function as a capacitive sensor to detect bleeding and distinguish blood from other bodily fluids. Taking advantage of the hemostatic property of natural SF, the device facilitates blood clotting. Additionally, the AgNW electrodes endow anti-bacterial properties to the device.
Materials and Methods:: Materials and Methods: Shape-memory SF sponges containing different concentrations of SF (3, 4, and 5% w/v) were developed by distributing SF dispersions in 48-well plates, followed by overnight freezing at -20 °C and freeze-drying. Subsequently, the samples were crystallized with methanol and freeze-dried to form porous sponges. A conductive layer of AgNWs was deposited on SF sponges by vacuum filtration to develop AgNW-SF theranostic device. Physical, mechanical, hemostatic, hemorrhage detection ability and antibacterial properties of the device were characterized.
Results, Conclusions, and Discussions:: Results and Discussion:Fig. 1A shows all-in-one AgNW-SF theranostic device consists of functional components, including the top and bottom AgNW layers for conducting electrodes and antibacterial agents and the middle silk sponge for efficient hemostasis. The device serves as a sandwiched capacitive sensor for hemorrhage detection. Fig.1B shows the real picture of the device and SEM view of the device, displaying a porous structure of SF sponge and a thin layer of AgNW electrode which is ~15 μm thick and located on the sponge's surface. Figure 1C shows a distinction in capacitance change between blood and serum or water, which could help identify the possible interruptions made by other fluids in the final collected signal, enabling the accurate detection of the onset of the hemorrhage. Hemostatic efficacy of the devices was tested in a rat liver bleeding model (Figure 1D). As shown in Figure 1E, the total bleeding after treatment with AgNW-SF was significantly lower than that for Dengen® (commercial hemostat) and the hemostatic time was significantly reduced from ~ 127 s for the injury group to ~ 70 s for in the experimental groups (Figure 1F). In addition, we observed that activated platelets clumped together and became trapped under the fibrin network, as an indication of a blood clot (Figure 1G).
Acknowledgements (Optional): : Acknowledgments: The authors acknowledge funding from the National Institutes of Health (AR074234, AR073135, HL140618, HL137193, GM126571, GM126831).
