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 24h 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 24h 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.