Nonwetting Nanostructured Hemostatic Material for Bleeding Control with Minimal Adhesion

Abstract

clotting speed by promoting coagulation reactions. [6,7] However, the commonly used hydrophilic hemostatic materials have the following drawbacks. [7,8] First, they are not effective in bleeding control. As clotting passively depends on the coagulation process, bleeding through the hydrophilic material will not stop until the formation of a strong clot to seal the wound. Second, after clot solidification, the hydrophilic dressing soaked blood would form a composite that strongly adheres on the wound, making it difficult to remove the dressing for subsequent wound care; forced peeling would cause tear, secondary bleeding and infection. [9,10] To deal with these problems, hemostatic materials based on new strategies for clot formation have been developed. [6,7,[11][12][13][14][15] Inspired by the fibrin meshwork generated during clot formation, modified chitosan with hydrophobic functional groups was developed; the hydrophobic groups can insert to the membrane of red blood cells, forming a cell-spanning network to seal the wound; [13] but the network may be disturbed by running blood, resulting in blood loss. Under a similar framework, thin layers of peptide were coated on normal hemostatic materials; upon contact with blood, peptides could self-assemble and form nanofiber structures, trapping red blood cells and generating a clot independent of body's coagulation mechanism, which would be beneficial for people with coagulation disorders. [14] Adhesive hydrogel with strong adhesion on wet tissue was also developed for hemostatic applications. [16] Biomacromolecule hydrogel mimicking the extracellular matrix could crosslink under UV irradiation to seal the wound; [15] dry tissue adhesive could absorb water and form physical and covalent cross-links with the wet tissue to seal the bleeding wound. [17] However, the peptide material or the adhesive hydrogel would have strong adhesion and prevent gauze removal for subsequent wound treatment.To address these limitations, surface hydrophobicity and detachable hydrogel was leveraged to enhance the hemostatic performance and to reduce wound adhesion. [7,8,18] A hydrophobic coating prepared on the external surface of cotton dressing could function as a permeation barrier to prevent blood seepage and reduce blood loss. [7] Detachable tissue adhesive was also developed for bleeding control; [19] the bioadhesive applied on a bleeding wound could be removed by cleaving the physical and chemical cross-links at the

Superhydrophobic Biological Fluid‐Repellent Surfaces: Mechanisms and Applications

“…Reproduced with permission. [ 108 ] Copyright 2021, John Wiley and Sons. b) Illustration and SEM images of fibrin fibers and blood clot formation from blood on a superhydrophobic CNF surface.…”

“…Recently, they also reported another superhydrophobic hemostatic dressing that was prepared by a two‐step spray coating process. [ 108 ] First, the hydrophobic component, beeswax, was sprayed on the surface of the CNFs to form a superhydrophobic nanofibrous structure, and then kaolin particles were decorated on the nanostructure to create a coagulation effect. This superhydrophobic hemostatic dressing exhibited a similar effect as the blood‐repellent CNF/PDMS coating dressing.…”

“…For example, Toes et al [107] pointed out that a superhydrophobic modified polytetrafluoroethylene artificial blood vessel did not improve the anticoagulant performance in vivo, instead causing more platelet deposition in an extracorporeal circulation test. More interestingly, Li et al [35,108] found that a superhydrophobic carbon nanofiber (CNF) composite could act as a rapid hemostatic material because the surface promoted the rapid growth of fibrin after contact with EDTA-containing blood, thereby triggering rapid coagulation. The blood sliding experiment was conducted on the surface of superhydrophobic CNF (blood contact angle: 151.2 ± 4.1°, n = 3), and it was observed that abundant fibers were generated on the backward side of blood rolling, and the residual fibrin fibers on the surface could still be found after the blood droplets completely fell off (Figure 5a).…”

“…Blood-repellent dressings are an ideal choice for wound dressings. [35,61,108,133] Li et al [35] illustrated a super blood-repellent surface with immobilized CNFs/PDMS using normal cotton gauze. After modification by CNF/PDMS, the initial normal cotton gauze with superhydrophilic blood absorption became superhydrophobic to blood (Figure 10a).…”

Multifunctional 3D platforms for rapid hemostasis and wound healing: Structural and functional prospects at biointerfaces

“…Further in vivo assessments demonstrated the gelatin nanofiber sponge’s ability to rapidly induce stabilization of blood clots, thereby leading to the least amount of blood loss compared to other commercialized products currently in use, thus proving its advantage as a hemostatic agent [ 7 ] . Other studies on nanofiber composites have also demonstrated the ability of these structures to promote rapid hemostasis and incur minimal secondary damage due to the composites’ intrinsic property of super-hydrophobicity and high user tunability [ 37 , 83 ] .…”