AC Conductivity Measurements of Ultradilute Colloidal Suspensions in HEPES Buffer.

Impedance spectroscopy was used to probe the AC conductivity of extremely dilute colloidal suspensions (2.5 × 10 ≤ Φ ≤ 4.0 × 10) comprising of polystyrene microspheres (PS; κ ≫ 1 and ζ = -65 mV), gold nanoparticles (Au NPs; κ > 1 and ζ = -26 mV), and Au-coated PS metallodielectric particles (Au-PS) in HEPES buffer.