“…When blood flows on a superhydrophobic surface, the drag reduction effect of the surface increases the slip flow rate of the boundary layer, reduces the shear stress inside the fluid, and reduces the collision between platelets and the surface. [100][101][102] Pham et al [98] studied the shear stress and velocity distribution in flowing blood using a finite element simulation method, and The platelets adhesion on the microstructure substrate is significantly less than that on the flat substrate. b) The top of the microstructure has large wall shear stress.…”
Section: Compatibility Mechanisms Of Sbfrssmentioning
confidence: 99%
“…Therefore, a variety of methods, including chemical, 3D printing, and micropattern printing, have been developed to modify the surface of biomaterials with superhydrophobic blood-repellent properties, making them more suitable for implantation in vivo. [72,73,102,[127][128][129][130] Zhang et al [127] fabricated a superhydrophobic surface on a medical titanium surface with blood compatibility, which was evaluated with platelet-rich plasma and whole blood. Furthermore, the hollow tube with an inner supe-rhydrophobic surface was implanted into rabbits (Figure 9a), and the results suggested that the inner wall could effectively resist blood adhesion, aggregation, and thrombosis formation.…”
Section: Implant Materialsmentioning
confidence: 99%
“…Therefore, a variety of methods, including chemical, 3D printing, and micropattern printing, have been developed to modify the surface of biomaterials with superhydrophobic blood‐repellent properties, making them more suitable for implantation in vivo. [ 72,73,102,127–130 ] Zhang et al. [ 127 ] fabricated a superhydrophobic surface on a medical titanium surface with blood compatibility, which was evaluated with platelet‐rich plasma and whole blood.…”
Superhydrophobic biological fluid‐repellent surfaces (SBFRSs) have attracted great attention in the treatment of blood and urine‐related diseases because of their unique wettability and compatibility, which creates a new path for the development of medical apparatus and instruments, and are expected to create advances in various fields. Here, this review provides an up‐to‐date summary of research progress on the repellent mechanism and application of SBFRSs. The underlying physical and chemical principles for designing superhydrophobic surfaces are first introduced. Then, the dialectical influences of solid‐liquid interactions between superhydrophobic surfaces and biological fluids on the wettability and compatibility are emphatically expounded. Subsequently, attention is drawn to the recent applications of SBFRSs in biomedical fields, such as surgical medical apparatus, implant materials, extracorporeal circulation devices, and biological fluid detection. Finally, the outlook and challenges in terms of employing SBFRSs are also discussed. This review is expected to provide a comprehensive guidance for the preparation of SBFRSs with compatibility and long‐term superhydrophobic stability that is closely related to clinical applications.
“…When blood flows on a superhydrophobic surface, the drag reduction effect of the surface increases the slip flow rate of the boundary layer, reduces the shear stress inside the fluid, and reduces the collision between platelets and the surface. [100][101][102] Pham et al [98] studied the shear stress and velocity distribution in flowing blood using a finite element simulation method, and The platelets adhesion on the microstructure substrate is significantly less than that on the flat substrate. b) The top of the microstructure has large wall shear stress.…”
Section: Compatibility Mechanisms Of Sbfrssmentioning
confidence: 99%
“…Therefore, a variety of methods, including chemical, 3D printing, and micropattern printing, have been developed to modify the surface of biomaterials with superhydrophobic blood-repellent properties, making them more suitable for implantation in vivo. [72,73,102,[127][128][129][130] Zhang et al [127] fabricated a superhydrophobic surface on a medical titanium surface with blood compatibility, which was evaluated with platelet-rich plasma and whole blood. Furthermore, the hollow tube with an inner supe-rhydrophobic surface was implanted into rabbits (Figure 9a), and the results suggested that the inner wall could effectively resist blood adhesion, aggregation, and thrombosis formation.…”
Section: Implant Materialsmentioning
confidence: 99%
“…Therefore, a variety of methods, including chemical, 3D printing, and micropattern printing, have been developed to modify the surface of biomaterials with superhydrophobic blood‐repellent properties, making them more suitable for implantation in vivo. [ 72,73,102,127–130 ] Zhang et al. [ 127 ] fabricated a superhydrophobic surface on a medical titanium surface with blood compatibility, which was evaluated with platelet‐rich plasma and whole blood.…”
Superhydrophobic biological fluid‐repellent surfaces (SBFRSs) have attracted great attention in the treatment of blood and urine‐related diseases because of their unique wettability and compatibility, which creates a new path for the development of medical apparatus and instruments, and are expected to create advances in various fields. Here, this review provides an up‐to‐date summary of research progress on the repellent mechanism and application of SBFRSs. The underlying physical and chemical principles for designing superhydrophobic surfaces are first introduced. Then, the dialectical influences of solid‐liquid interactions between superhydrophobic surfaces and biological fluids on the wettability and compatibility are emphatically expounded. Subsequently, attention is drawn to the recent applications of SBFRSs in biomedical fields, such as surgical medical apparatus, implant materials, extracorporeal circulation devices, and biological fluid detection. Finally, the outlook and challenges in terms of employing SBFRSs are also discussed. This review is expected to provide a comprehensive guidance for the preparation of SBFRSs with compatibility and long‐term superhydrophobic stability that is closely related to clinical applications.
“…It is therefore beneficial to improve the flow in BMHVs, perhaps through design modifications, to mitigate the risk of blood clotting and stroke. Recent efforts in this area include passive control via deploying vortex generators (Hatoum & Dasi 2019) or superhydrophobic surfaces (Hatoum et al 2020) on the valve leaflets, both with the goal of reducing the intensity of turbulent flow downstream of the valve.…”
Section: Physiological Backgroundmentioning
confidence: 99%
“…Recent efforts in this area include passive control via deploying vortex generators (Hatoum & Dasi 2019) or superhydrophobic surfaces (Hatoum et al. 2020) on the valve leaflets, both with the goal of reducing the intensity of turbulent flow downstream of the valve. Figure 1.( a ) Leading-edge view of a Regent mechanical valve (https://www.structuralheartsolutions.com).…”
Bileaflet mechanical heart valves (BMHV) create unphysiological turbulent flow. Such turbulent flow involves multiple instability mechanisms interacting with one another in a confined geometry. For instance, an impinging leading-edge vortex (ILEV) instability creates disturbances at the leading edge of the valve leaflets, while potentially promoting turbulence downstream of the BMHV (Zolfaghari and Obrist, Phys. Rev. Fluids, vol. 4, 2019). In this article, we use adjoint-based methods to study the structural sensitivity of the ILEV instability in the BMHV, and to quantify the role of this instability in the maximum disturbance energy growth in the wake of the BMHV. We first present a direct numerical simulation to show the effect of the ILEV instability on the turbulent flow in the wake of the valve. Second, we perform a modal linear stability analysis on a two-dimensional subdomain attached to the leading edge of one leaflet. We investigate the sensitivity of the global modes associated with this flow using their adjoints, and then show a passive control scenario using a local feedback source. This results in a partial improvement in the flow oscillations downstream of the leaflets. We finally present a non-modal approach to identify the optimal initial conditions for achieving maximum energy growth at arbitrary locations. We show that, for sufficiently large times, the optimal initial condition for highest energy growth in the wake points at the leading edge, which includes the ILEV instability. Our study illustrates that an improved leading-edge shape can effectively reduce turbulence in the wake of the BMHV.
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