Manipulation and Assessment of Human Red Blood Cells with Tunable “Tug-of-War” Optical Tweezers

Abstract

Optical trapping is important in assessing the deformability of red blood cells (RBCs), providing quick, noncontact force measurement in liquid medium with piconewton resolution. Traditional techniques, though, can involve complicated processes or cause photodamage. This study employs ``tug-of-war'' (TOW) optical tweezers with object-adapted optical potentials, to simply and stably trap, stretch, and squeeze a single RBC under different osmotic conditions, thus enabling the assessment of RBC deformability. The large forces of the TOW tweezers can cause larger deformations than traditional dual-trap tweezers at the same power conditions, which can greatly reduce photodamage.