Real-Time Dual Optical-Electrochemical Monitoring of Cell Adhesive Response

DIEGO PALLAROLA

Buenos Aires

Simposio; Frontiers in Physical Sciences; 2016

Max-Planck-Gesellschaft, International Center for Advanced Studies, Alexander von Humboldt Foundation

Cell-cell and cell-extracellular matrix recognition and adhesion are central processes of the cell?ssensory machinery[1] and are mediated by transmembrane adhesion receptors of the integrinfamily[2]. These processes play a crucial role in most fundamental cellular events includingmotility, proliferation, differentiation, and apoptosis[3].Electrical-impedance-based sensors have emerged as a powerful tool to investigate celladhesion[4]. These devices are based on impedance measurements using weak and non-invasive ACsignals and have been successfully employed to study cellular events such as cell attachment,spreading and motility through monitoring changes in the impedance signal in a label-free,instantaneous and non-destructive manner[5]. However, most of these studies are limited toinvestigating continuous adherent coatings, nanomaterial-polymer composites or surfaces patternedwith mixtures of bioactive and unsubstituted molecules. All of these studies suffer from a nonhomogeneousligand distribution on a molecular scale, which represents a major drawback.Our approach aims at creating sensors that efficiently utilize both the improved signaltransduction of nanomaterials and the binding-precision of nanopatterns with a precise spatialdistribution of adhesive ligands. Gold nanoparticles were deposited at defined interparticle distancesonto transparent conductive substrates, such as indium-tin oxide. The geometrically controlled goldnanoparticles positioning locates adhesive ligands with nanometer resolution, while maintaining thesuperior sensitivity of nanostructured materials towards electrical transduction of surface events.The use of transparent electrodes allows for simultaneous and real-time monitoring of cell adhesionusing electrochemical and optical microscopy techniques. Particularly, this approach was applied tostudy the response of epithelial cells to cyclic pentapeptide ligands with different binding affinitiesto integrins alphavbeta3 and alpha5beta1.