e., a more positive potential represents a more reducing state, whereas a more negative potential represents a more oxidising www.selleckchem.com/products/MG132.html state. This Inhibitors,Modulators,Libraries enables us to attribute the changes in OCP observed definitively, hence a reduction in OCP now equates to a ��loss�� of signal. Despite this change, the principal of the biosensor system remains the same; variations in the OCP of adherent cells on the gold sensors reflect changes in cell behaviour.2.2. Electrochemical Monitoring of Cell BehaviourUnlike conventional sensors, in whole cell biosensors such Inhibitors,Modulators,Libraries as the Oncoprobe system the cells form the active sensing layer. This provides the opportunity to not only assay cells from an individual against certain treatments, e.g.
, in chemosensitivity or drug resistance testing, but also for Inhibitors,Modulators,Libraries drug discovery or toxicology applications, whereby Inhibitors,Modulators,Libraries a target cell type or line could have candidate compounds screened against it.Figure 4a shows the real-time monitoring of confluent layers of fibroblasts over 18h with and without treatments of cycloheximide or IL-1��/TNF��. Exposure to the latter is known to stimulate cellular activity and the OCP value is shown to be elevated over that of the control untreated cells. By contrast, cycloheximide (a known inhibitor of protein synthesis) is seen to suppress the OCP value of the cells. Thus, the electrochemical monitoring clearly discriminates between ��activated�� and ��compromised�� cells relative to the untreated controls.
Carfilzomib Confirmation that the treatments used in Figure 4a were non-toxic and cells remained adherent is demonstrated by the photomicrographs in Figure 4b; the cellular morphology observed for some cells exposed to TNF��/IL-1�� showing a typical dendritic/stellate appearance (B in Figure 4b) compared to control and cycloheximide-treated cells.Figure 4.(a) Real-time monitoring of the OCP of rheumatoid synovial fibroblasts showing the effects of cycloheximide and TNF��/IL-1�� (mean values from 6 sensors for each treatment). (b) Photomicrographs showing the morphology of control (A), TNF��/IL-1�� …To demonstrate that this electrochemical technology is applicable to different adherent cell types, OCP values have been monitored in experiments involving a variety of cell lines. Figure 5a shows the OCP profile for the human hepatocyte cell line, HepG2, and its response to camptothecin, a cytotoxic quinoline alkaloid that inhibits DNA topoisomerase I and induces apoptosis .
For a comparative study, the same cell line and camptothecin concentrations were examined by the conventional MTT assay after 24 h (Figure 5b). Both assays demonstrate the effects of camptothecin exposure, but while the end-point MTT assay shows the effect of the compound selleck kinase inhibitor after 24h, the real-time bioelectrochemical monitoring of Figure 5a shows behavioural changes throughout the time course; with adherent cells present beyond 24 h (data not shown).Figure 5.