Comparison of the effects of RBC manipulation with optical tweezers and with photonic nanojet

Abstract

Red blood cells (RBCs) govern the blood microrheology, and influence blood viscosity and vascular resistance through their aggregation, deformability and interaction with endothelial cells. Alterations in these properties are linked to diseases such as type 2 diabetes, hypertension, and sickle cell anemia. Optical tweezers can be used to study RBC aggregation and deformability, but thermal damage must be avoided. We show that a 1064 nm Nd:YAG trap causes no significant cell damage within 30 minutes at powers below 30 mW, whereas 80–150 mW visibly damages the membrane in 1–3 minutes. At a trapping power of 22 mW, periodic force application causes the hysteresis effect, which increases the membrane rigidity after 14–16 trapping-relaxation cycles. Another approach to manipulate RBCs is the photonic nanojet (PNJ) formed by microobject itself. The liquid molecules inside the nanojet are heated up, and the expansion of the liquid molecules results in a backward force on the microobject. With this concept, we demonstrate the parallel manipulation of RBCs in large scale. With video microscopy and drag force measurements, the backaction force and the velocity for individual RBCs can be evaluated. We have measured the backaction force on RBCs and found that the backaction force exhibits hysteresis during the change of the injection laser power. In this paper, we compare the peculiarities of the techniques mentioned that allow for measuring the RBC properties, which could be markers of different pathologies.
This research was funded by the Russian Science Foundation Grant No. 25-15-00172 and the National Natural Science Foundation of China Grant No. 62475047.

Speaker

Andrei E. Lugovtsov
Faculty of Physics, M.V. Lomonosov Moscow State University
Russia

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