zeta potential

[MissP.5_25]

Hi.

I am doing some experiment on finding the electrical characteristics (surface conductance specifically) of a particle which is then attached to different amount of DNAs. The whole aim of this experiment is actually to analyse the sensitivity of this new found method of detecting DNA, but I don't think I need to explain it in detail for this particular problem.

Now, this zeta potential is crucial because it's needed to calculate the crossover frequency of the DNA-attached particles. Crossover frequency is the frequency at which dielectrophoresis force is 0 (neither positive nor negative).

After measuring the zeta potential of the particles, it was found that the zeta potential didn't show a significant change despite changing the ratio of particle to DNA. The crossover frequency however, did show a change corresponding to the different ratios of particle to DNA. Why is this so? And that's what I need to figure out. I am not so good at math so I am helping someone could solve this question, please. I guess the answer could be found by analysing this equation.

 

The equation is attached.