Impedance Spectroscopy for Silica Nanoparticle Detection in Caco-2 Cells

We present a feasibility study aiming at the detection of silica nanoparticles (NPs) in human intestinal epithelial cells. Caco-2 cells were maintained in cell culture medium (Dulbecco's Modified Eagle's Medium, DMEM) and differentiated for 21 days. To study the effect of silica NPs on the differentiated Caco-2 cell, cells were treated for 24 h with different doses. We measured the serum-free culture medium first, which was supplemented with different doses of silica NPs using a parallel-plate capacitor principle to demonstrate the sensitivity of the sensing principle to the particle concentration.In a next step we treated Caco-2 cells with serum-free culture medium containing silica NPs. After 24 h incubation time, culture medium was removed and cells were washed with PBS, so that topical adherent NPs should have been removed. We finally present the use of a second coplanar electrode design with eight single electrodes connectable in arbitrary combination to detect the silica NPs in cells.