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Single red blood cell dynamics in shear flow and its role in hemorheology
Published in Annie Viallat, Manouk Abkarian, Dynamics of Blood Cell Suspensions in Microflows, 2019
Three independent modes of deformation only are necessary to describe any static elastic state of the membrane since it is a thin structure (see Figure 5.2): isotropic stretching or compression, simple shear at constant surface area, and out of plane bending. Only three elastic moduli are therefore necessary to describe any instantaneous state of stress in the membrane: the stretching modulus Kα, the shear modulus Gs and the bending modulus B, respectively. However, unlike a uniform elastic thin sheet, the various elastic moduli are carried by different parts of the composite membrane of the cell. It is the lipid bilayer that mainly resists both bending and stretching deformations, while the underlying spectrin cytoskeleton bears the resistance to shear deformation (Figure 5.2).
The Cell as an Inspiration in Biomaterial Design
Published in Heather N. Hayenga, Helim Aranda-Espinoza, Biomaterial Mechanics, 2017
Helim Aranda-Espinoza, Katrina Adlerz
Alternatively, actin-related protein (ARP) complexes associate with the side of an already-assembled actin filament and nucleate actin monomers into a new filament there, resulting in a branched network of actin. Filamin is an actin-associated protein that holds together two actin filaments at right angles forming a loose, highly viscous active gel associated with lamellipodia used in cell migration. Alternatively, spectrin forms a hexagonal mesh binding actin filaments together into a stiff 3D web and is concentrated underneath the plasma membrane forming the actin cell cortex. Actin polymerization to form filaments and the filaments’ ability to form gels has captured the imagination of scientists to create interesting biomaterials like the reinforced liposomes and actin gels described here.
Red Blood Cell and Platelet Mechanics
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
The spectrin layer is a network of elongated proteins biochemically crosslinked with each other. This highly porous scaffold structure is relatively easy to deform by external forces, but as soon as the forces are removed, it moves back elastically and regains its original shape.
Recent advances in micro-sized oxygen carriers inspired by red blood cells
Published in Science and Technology of Advanced Materials, 2023
Qiming Zhang, Natsuko F. Inagaki, Taichi Ito
The human body contains a complex capillary network where blood flows constantly while carrying its vehicle components. Blood, as a non-Newtonian fluid, can flow steadily through complex microvascular structures owing to its shear-thinning behaviors [34]. The viscosity of the blood is dependent on various components such as hematocrit and plasma, as well as the viscoelastic properties of formed elements [35]. As RBCs comprise the most abundant formed elements in the blood, the viscosity of blood increases almost linearly with the hematocrit [36]. Even in the narrowest blood capillaries of 3–4 m, RBCs can still pass without impediment owing to the deformability given by the cell membrane as supported by the spectrin network on their surface (as mentioned in the earlier section). Owing to this deformability, RBCs are not constricted in their shape as they face high shear stresses and intracapillary resistance; they deform themselves into different shapes (including parachutes and slippers) at different velocities [37].
Curvatures of smectic liquid crystals and their applications
Published in Journal of Information Display, 2018
Curvatures of soft matters are of interest for both fundamental scientific research and a number of potential applications. Common examples of curvatures are found in cell membranes, organelles, proteins, block copolymers, and liquid crystals (LCs) [1–7]. Curvatures of soft matters are varied depending on intermolecular interactions and stimuli-responsive characteristics [8–13]. Generally, a curvature can be described by its mean curvature H and Gaussian curvature K, which are given by two principal radii of curvature, R1 and R2, as shown in Figure 1. Thus, curved surfaces of differential geometries in soft matters allow us to define the topological features and symmetry, and understand structural functions for practical applications. For example, the biconcave disc-like shape of a red blood cell, consisting of a phospholipid bilayer and the underlying two-dimensional network of spectrin molecules, plays a crucial role for the fast gas exchange between hemoglobin and the surrounding medium, enabling flexible migration into various vessels including capillary vessels of smaller size than the red blood cells [14]. Block copolymers are another example, being a material frequently used in the fabrication and engineering of nanostructures. These can show a variety of curvatures such as spheres, cylinders, and lamella are gyroids depending on the volume fraction of each block, which can be used in patterning applications [15–22].
Nonlinear dynamics of membrane skeleton in osteocyte
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Zhuang Han, Lian-Wen Sun, Xin-Tong Wu, Xiao Yang, Yu-Bo Fan
The membrane skeleton exists in a wide variety of cells, and plays an important role in mechanotransduction and structural supporting, which mainly consists of spectrin and located under the cell phospholipid bilayer membrane (Bennett and Baines 2001; He et al. 2016). The membrane skeleton is first found in red blood cells and the elasticity of membrane skeleton can affect their shapes, adhesion, and signal transduction. The interactions between membrane skeleton and myosin IIA can control the red blood cell membrane curvature and deformability and blood rheology (Smith et al. 2018). The dynamic structure of membrane skeleton can change the function and membrane stability of red blood cells all along the cell’s circulatory life (Gokhin and Fowler 2016; Minetti et al. 2018). Then the membrane skeleton is found in nerve cells and it is a dynamically regulated platform for mechanical reception (Unsain et al. 2018; Zhou et al. 2019). The membrane skeleton influences axonal diameter and signal transduction by regulating the relative position and activation state of non-muscle myosin II and actin rings (Costa et al. 2020). The disassembly of the actin-spectrin-based membrane skeleton causes the actin destabilization and then induces the trophic deprivation of neuronal axon and leads to the axonal degeneration (Jia et al. 2020). What’s more, the rearrangement of the membrane skeleton caused by mechanical compression injury leads to the disruption of ionic equilibrium and eventually triggers the apoptosis and necrosis of dorsal root ganglion neurons (Quan et al. 2014). Besides these, the membrane skeleton also influences other cells. For example, the changes of membrane skeleton can affect the intraflagellar transport, which breaks the formation of microtubules and then prevents the cilium formation of Caenorhabditis elegans cells (Jia et al. 2019). The polymerization of membrane skeleton maintains the invaginated membrane system maturation in murine megakaryocytes (Patel-Hett et al. 2011), and controls the diffusion dynamics and signaling of B cell receptor through Igβ (Treanor et al. 2010).