In situ calibrating optical tweezers with sinusoidal-wave drag force method*
Li Dia), Zhou Jin-Huaa), Hu Xin-Yaoa), Zhong Min-Chenga), Gong Leia), Wang Zi-Qianga), Wang Hao-Weia), Li Yin-Meia),b)
       
The force–extension relationship for a single double-stranded DNA molecule. Left, the colored solid lines are the experimental data of stretching DNA, which is computed with mean trapping stiffness and CF. The black dashed line is the theoretical result of the worm-like chain model. Right, the colored solid lines are the experimental data of stretching DNA, which is computed with the respective trapping stiffness and CF of every bead. The black dashed line is the theoretical result of the worm-like chain model with the same parameters of that in the left.