Figure 2.

Washing step evaluation of magnetic beads to remove the electrically conductive solution (DPBS) from the samples with streptavidin-coated magnetic beads using 20% glycerol in grade water. Impedance magnitude (a) and phase (b) of the supernatant solution after each wash was measured at 1000 Hz and 1 V. “*” indicates statistically significant impedance magnitude change compared to all other groups. Statistical assessment on the results was performed using ANOVA with Tukey posthoc test for multiple comparisons. Statistical significance threshold was set at 0.05, p<0.05. Error bars represent standard error of the mean (n = 3). No significant difference between the impedance magnitude measured after the 4^th wash and the impedance magnitude measured after 5^th, 6^th, and 7^th washes was observed (n = 3, p<0.05). Based on these results, 4 washes were adequate to fully remove the electrically conductive DPBS from the magnetic bead solution, eliminating a potential conductive bias.