Acting force measurement of microbeads and hemocytes in different mediums using inverted-embedded optical tweezers system

The IR Laser was used to trap and manipulate particles and hemocytes in different medium, and the influence between the object and viscosity of medium can be measured. An “inverted-embedded optical tweezers system” that combined the laser and the inverted microscopy was installed, and it could observe and manipulate the objects simultaneously. The goal of this experiment is using the IR laser to manipulate hemocytes in blood (serum). Finally, the acting force can be measured and compared. It was obtained that the trapping force was 0.554pN and influence radius was 14.2μm when the 6μm bead suspended in water and power was 6.5mW. The trapping force was 0.368pN and influence radius was 6.51μm when the 9μm WBC (White Blood Cell) cell suspended in serum and power was 4.5mW. The trapping force was 0.168pN and influence radius was 12.61μm when the 12μm BCC (K562, Blood Cancer Cell) suspended in water and power was 4.5mW. The trapping force would be enhanced when the power was increased and the trapping force of the object suspended in serum would be larger than that suspended in water at the same conditions.