Measurement and analysis of the shape recovery process of each erythrocyte for estimation of its deformability using the microchannel technique: the influence of the softness of the cell membrane and viscosity of the hemoglobin solution inside the cell

2012 ◽  
Vol 27 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Tsutomu Tajikawa ◽  
Yuya Imamura ◽  
Takaya Ohno ◽  
Fumiya Muranishi ◽  
Maki Kubota ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Shape Recovery ◽  
Recovery Process ◽  
Hemoglobin Solution ◽  
Measurement And Analysis

scholarly journals Control of the erythrocyte membrane shape: recovery from the effect of crenating agents.

1981 ◽  
Vol 91 (3) ◽  
pp. 884-888 ◽  
Author(s):  
E Alhanaty ◽  
M P Sheetz
Keyword(s):  
Energy Source ◽  
Cell Membrane ◽  
Shape Control ◽  
Shape Recovery ◽  
Recovery Process ◽  
Shape Preservation ◽  
Erythrocyte Shape ◽  
Membrane Components ◽  
Membrane Shape ◽  
Membrane Responsiveness

Intact erythrocytes become immediately crenated upon addition of 2,4-dinitrophenol (DNP) or pyrenebutyric acid (PBA). However, when cells are incubated at 37 degrees C in the presence of the crenating agents with glucose, they gradually (4--8 h) recover the normal biconcave disc form. The recovery process does not reflect a gradual inactivation of DNP or PBA since fresh cells are equally crenated by the supernatant from the recovered cells. Further, after recovery and removal of the crenating agents, cells are found to be desensitized to the readdition of DNP as well as to the addition of PBA, but they are more sensitive to cupping by chlorpromazine. This alteration in the cell membrane responsiveness was reversible upon further incubation in the absence of DNP. Recovery is dependent upon cellular metabolic state since an energy source is needed and incubation with guanosine but not adenosine will accelerate conversion to the disc shape. It is suggested that the conversion of cells from crenated to disc shape in the presence of the crenators, represents an alteration or rearrangement of membrane components rather than a redistribution of the crenators within the membrane. This shape recovery process may be important for erythrocyte shape preservation as well as shape control in other cells.

Investigate of Electrical Conductivity of Shape-Memory Polymer Filled with Carbon Black

2008 ◽  
Vol 47-50 ◽  
pp. 714-717 ◽  
Author(s):  
Xin Lan ◽  
Jin Song Leng ◽  
Yan Ju Liu ◽  
Shan Yi Du
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Shape Memory ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Recovery Process ◽  
Thermomechanical Properties ◽  
Electrically Conductive ◽  
New System

A new system of thermoset styrene-based shape-memory polymer (SMP) filled with carbon black (CB) is investigated. To realize the electroactive stimuli of SMP, the electrical conductivity of SMP filled with various amounts of CB is characterized. The percolation threshold of electrically conductive SMP filled with CB is about 3% (volume fraction of CB), which is much lower than many other electrically conductive polymers. When applying a voltage of 30V, the shape recovery process of SMP/CB(10 vol%) can be realized in about 100s. In addition, the thermomechanical properties are also characterized by differential scanning calorimetery (DSC).

scholarly journals Cell membrane shape control--effects of chloromethyl ketone peptides

Blood ◽  
1984 ◽  
Vol 63 (5) ◽  
pp. 1203-1208 ◽  
Author(s):  
E Alhanaty ◽  
MP Sheetz
Keyword(s):  
Shape Control ◽  
Shape Recovery ◽  
Cultured Cells ◽  
Shape Change ◽  
Lactic Acid Production ◽  
Recovery Process ◽  
Chloromethyl Ketone ◽  
Membrane Shape

Abstract The shape of the human erythrocyte is normally maintained in vivo as a biconcave disc for 120 days. In vitro, the cell shape can be altered readily by amphipathic compounds; however, given time and an energy source, the cells can recover the discoid morphology. An active shape control mechanism is postulated to regulate erythrocyte shape. The shape recovery process is a necessary element in reversing perturbations of shape and is basic to our understanding of how membrane shape is altered. We report here that the process of shape recovery from crenation is dramatically accelerated upon pretreatment of the cells with micromolar (20–100 microM) concentrations of chloromethyl ketone peptides [such as N-alpha-tosyl-L-phenylalanine- chloromethyl ketone (tos-pheCH2Cl)]. Such pretreatments do not appear to affect cellular viability, as judged by their normal biconcave disc shape, their sensitivity to crenators, their lactic acid production, or the ATP-dependent shape change of the purified membranes. Treatment with high concentrations of tos-pheCH2Cl does cause normal cells to become stomatocytic by an energy-requiring process, i.e., it requires glucose, incubation at 37 degrees C, and will not occur in ATP-depleted cells. We suggest that the chloromethyl ketone peptides affect a metabolic process that is associated with the hexose monophosphate (HMP) shunt. Through the alteration of the HMP shunt metabolism, they modify an active stomatocytic process in the erythrocyte that can correct for the perturbation caused by crenators. Implications of these findings for analogous phenomena in cultured cells are discussed.

Effects of Cell Lysis on the Rheological Behavior of Red Blood Cell Suspensions

1990 ◽  
Vol 112 (3) ◽  
pp. 257-262 ◽  
Author(s):  
Roger Tran-Son-Tay ◽  
B. B. Beaty ◽  
B. E. Coffey
Keyword(s):  
Cell Membrane ◽  
Intact Cell ◽  
Cell Suspensions ◽  
Hemoglobin Solution ◽  
Freeze Thaw ◽  
Complete Destruction ◽  
Thaw Cycle ◽  
Lower Viscosity ◽  
Freeze Thaw Cycle ◽  
Detrimental Impact

Rheological studies of lysed cell suspensions are performed with a magneto acoustic ball microrheometer. Two methods for lysing the cells are developed in order to provide cell volume concentrations identical to control intact cell suspensions. The first uses a freeze-thaw technique and the second uses sonication. It is found that cell suspensions disrupted by sonication have a lower viscosity than intact suspensions, whereas cell suspensions lysed by the freeze-thaw method exhibit a higher viscosity. Sonication is discovered to have a detrimental impact on the cell membrane, and to cause complete destruction of the cell membrane structure. Measurements of the steady state viscosity show that indeed the presence of the membrane is not detected, and that what is measured is mainly the viscosity of the hemoglobin solution. On the other hand, freeze-thaw results indicate that at least two phenomena occur. The first phenomemon, occurring during the first freeze-thaw cycle, produces an increase in viscosity and in viscoelasticity. The second one, taking place after subsequent freeze-thaw cycles, induces a decrease in the bulk rheological properties. Several possible mechanisms are presented to explain the observed phenomena.

626 Experiments in vitro on behavior and deformability of RBC in Microchannel : Effect of its Deformability on Shape Recovery Process

2006 ◽  
Vol 2006.5 (0) ◽  
pp. 173-174
Author(s):  
Takaya OHNO ◽  
Chihiro SAKAKIBARA ◽  
Tsutomu TAJIKAWA ◽  
Kenkichi OHBA
Keyword(s):  
Shape Recovery ◽  
Recovery Process

Programmable Shape Recovery Process of Water-Responsive Shape-Memory Poly(vinyl alcohol) by Wettability Contrast Strategy

2017 ◽  
Vol 9 (6) ◽  
pp. 5495-5502 ◽  
Author(s):  
Zhiqiang Fang ◽  
Yudi Kuang ◽  
Panpan Zhou ◽  
Siyi Ming ◽  
Penghui Zhu ◽  
...  
Keyword(s):  
Shape Memory ◽  
Vinyl Alcohol ◽  
Shape Recovery ◽  
Recovery Process ◽  
Poly Vinyl Alcohol

Shape Recovery Characteristics of 3D Printed Soft Polymers and Their Composites

2016 ◽  
Author(s):  
Wenbo Liu ◽  
Nan Wu ◽  
Kishore Pochiraju
Keyword(s):  
High Resolution ◽  
Shape Memory ◽  
Recovery Time ◽  
Shape Recovery ◽  
Recovery Process ◽  
Hot Water ◽  
Recovery Ratio ◽  
3D Printed ◽  
Term Creep

Shape memory polymers can be triggered to assume memorized shapes from temporarily deformed forms using thermal stimuli. This paper focuses on the characterization of the shape memory behaviors observed in selected 3D printable photo-cured polymer parts and filament with specified fillers. The shape recovery ratio and recovery time were analyzed using 3D printed specimens with 90° bends. Parts with the mixture of selected commercially available polymers — a rigid polymer (RP) and two digitally mixed polymer blends (DB-A and DB-B) were 3D-printed on a multi-material 3D printer capable of producing digital materials with variable mix ratios. The recovery ratios were determined after thermal triggering and after long-term creep (self-recovery) without thermal triggering. The 3D printed parts were heated to above their glass transaction temperature to train temporary shapes and the recovery of original shapes after a thermal trigger was monitored using a high-resolution camera. Long-term self-recovery (non-triggered) was also studied by observing the parts after temporary shape has been trained, as the try to regain their original shape over several days of slow recovery. The recovery of bending angles was quantitatively recorded from the images taken during the shape recovery process. The recovery due to thermal triggers was monitored under a high resolution microscope by reheating with hot water at 90°C. Experiments of long-term self-recovery at room temperature included monitoring of several parts by taking periodic images of the specimens using a resolution camera. The effect of inclusion of fillers on the shape recovery characteristics was also investigated. Silicon Carbide (SiC) with different weight fractions were mixed into PLA powders. Continuous filaments were extruded using a single screw extruder. The recovery time of thermal activation recovery was then characterized to determine the effect of addition of the fillers. The effect of material-mix ratio, initial printed orientation, filler type on the recovery ratio and recovery time are described in this paper.

scholarly journals On the Size Effect of Additives in Amorphous Shape Memory Polymers

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 327
Author(s):  
Elias M. Zirdehi ◽  
Hakan Dumlu ◽  
Gunther Eggeler ◽  
Fathollah Varnik
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Recovery Process ◽  
Size Ratio ◽  
Additive Concentration ◽  
Effect Of Additives ◽  
Dynamics Simulations ◽  
Small Additive

Small additive molecules often enhance structural relaxation in polymers. We explore this effect in a thermoplastic shape memory polymer via molecular dynamics simulations. The additive-to-monomer size ratio is shown to play a key role here. While the effect of additive-concentration on the rate of shape recovery is found to be monotonic in the investigated range, a non-monotonic dependence on the size-ratio emerges at temperatures close to the glass transition. This work thus identifies the additives’ size to be a qualitatively novel parameter for controlling the recovery process in polymer-based shape memory materials.

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