Fig. 5
From: Enhanced ion tolerance of electrokinetic locomotion in polyelectrolyte-coated microswimmer
Geometry optimization biocompatibility demonstration with the live human cell (acute promyelocytic leukemia NB4 and human blood cells). a The dependence of the geometry factor “a” on nanowire’s geometry. The three nanowire geometries in b are marked as the red star (short nanowire), orange star (medium nanowire), and blue star (long nanowire) respectively. b The representative ionic strength dependence of the normalized speed of the SPS coated nanowire microswimmer for short (red), medium (orange), and long (blue) nanowire microswimmers. The corresponding absolute velocity data is shown in Supplementary Fig. 13. The solid lines are calculated by Eq. (2) with measured SPS conductivity and the bands are the confidence interval at 95% confidence. The inset shows the linear relationship of the normalized reciprocal speed with the ionic strength. The dash lines are the expected relationships predicted by Eq. (2). The solid lines and corresponding color bands in the inset indicate the fitting plots with the confidence interval of the experimental data at 95% confidence level. c The Dukhin number to the ionic strength dependence for the SPS-coated microswimmers with different geometries. The red, orange, and blue curves are corresponding to the Du of the short, medium, and long nanowire with a = 0.74, 2.32, and 9.16 μm, respectively. d The relationship between EI50 and geometric factor “a”. The dots correspond to data from Table S5. The red line shows the theoretical curve based on Eq. (3). The inset shows the corresponding linear relationship between EI50 and a−1. The error bar of “a” and a−1reflects the size uncertainty obtained from the swimmers’ tracking videos; see details in Supplementary Note 15. e Demonstration of microswimmer operation in PBS buffer solution together with the live NB4 cell (scale bar is 20 μm). The inset shows the magnified view of the microswimmer with the trajectory of 2 s (scale bar of the inset is 5 μm). f The trajectory of the microswimmer operation in diluted human blood (scale bar is 10 μm)
