Biological cell morphology studies by scanning electrochemical microscopy imagery at constant height: Contrast enhancement using biocompatible conductive substrates

Abstract

Scanning ElectroChemical Microscopy (SECM) has emerged as a very attractive method to image living cells activity due to its non invasive character and to the possibility of concomitant electro- and physico-chemical measurements. One of the difficulties when studying morphology of living cells in real time by SECM, using classical constant height mode, is the low contrast of the obtained images due to the insulating character of both the cells and of the underlying substrates. We propose here a technical approach to improve the contrast of SECM imagery obtained at constant height in the feedback mode without the need of Faraday cage. To this aim, a piece of biocompatible transparent conductive substrate (indium tin oxide, ITO coated PET) was attached into the bottom of cell culture well over which the cells were cultured. The transparency of ITO is intended to perform simultaneously SECM and optical microscopy measurements. The concept was applied to the study of endothelial cells, EA.hy926, whose morphology may be altered via an antivascular treatment. Our results show that the differences in the conductivity of the substrate and of the cells enhance the contrast of SECM image in feedback mode at constant height using highly charged redox mediator. In addition, differences in cell morphology are significantly observed by SECM after cell treatment with Combretastatin A4 antivascular agent.