Mutual interaction of red blood cells assessed by optical tweezers and scanning electron microscopy imaging

Abstract

The adhesion of red blood cells (RBC) has been studied extensively in frame of cell-to-cell interaction induced by dextran macromolecules, whereas the data are lacking for native plasma solution. We apply optical tweezers to investigate the induced adhesion of RBC in plasma and in dextran solution. Two hypotheses, cross-bridges and depletion layer, are typically used to describe the mechanism of cell interaction; however, both mechanisms need to be confirmed experimentally. These interactions in fact are very much dependent on the size and concentration of dextran and proteins in plasma. The results show that in different dextran solutions, the interaction of adhering RBC agrees well with the quantitative predictions obtained based on the depletion-induced cells adhesion model, whereas the migrating cross-bridges model is more appropriate for plasma. Despite the different mechanisms of RBC interaction in a mixture of dextran with the size ranges and volume fraction proportional to plasma proteins, the dependence of RBC adhering tends to be close to the cross-bridges model. The induced aggregation of RBC in the dextran solutions and in native plasma are observed by direct visualization utilizing scanning electron microscopy.

Impact of Nanocapsules on Red Blood Cells Interplay Jointly Assessed by Optical Tweezers and Microscopy

“…This dependence is typical for the so called "cross-bridges" model, assuming the accumulation of "cross-bridges" formed by plasma proteins between the interacting RBCs. RBCs interaction energy always increases upon cell disaggregation, as it was confirmed before in our studies [50,55,56]. Here, RBCs in presence of all the types of NCs demonstrate the same dependency, suggesting no difference in the interaction mechanism between the cells.…”

“…Measurements were performed as in our previous studies of mutual interaction of RBCs [50]. The aggregation force Fa of RBC is the minimum force required to stop two RBCs from overlapping.…”

Influence of interaction time on the red blood cell (dis)aggregation dynamics in vitro studied by optical tweezers

“…Traditional methods for RBC aggregation analysis, including measuring the extent and rate of aggregates formation by optical transmission or reflection properties of the suspension, are generally based on an average response of a large number of cells; detailed information about individual cell-cell interactions cannot be revealed. During the last few decades, with the creation of optical tweezers (OT) as a significant achievement of laser physics 4 , and with the introduction of OT into biological sciences by Nobel laureate Arthur Ashkin 5 , the investigation of intercellular interactions has been rapidly developed at a single-cell level [6][7][8] . OT has become a vital and indispensable tool in studying cellular and molecular interactions.…”

Optical Tweezers in Studies of Red Blood Cells

“…The role of macromolecule absorption in altering RBC mechanical properties and hence in influencing aggregation dynamics has been studied in detail with the same HOTs integrated with a fluorescence microscopy [150]. Recent works from our group have visualized the membrane morphologies of RBCs that adhered to each other by scanning electron microscopy (SEM) as shown in Figure 12 and evaluated the adhering strength in dextran solutions of different molecular weights (70 kDa, 150 kDa and 500 kDa) by conventional dual-beam OTs [151,152]. The SEM visualization of RBCs in mutual interactions has enabled the direct observation of the cilia on the cell surface, and the calculated cilia density is in good agreement with the deduced cross-bridges density in the "cross-bridging" model.…”

“…(a) RBC visualization by SEM reveals discrete cilia on the cell surface. (b) Enlarged detail of the inner part of the white rectangle in (a) indicates the cilia density as 1/3600 nm2 [151].…”