Colloids and Surfaces B: Biointerfaces 79 (2010) 365–371 Contents lists available at ScienceDirect Colloids and Surfaces B: Biointerfaces journal homepage: www.elsevier.com/locate/colsurfb Electrically controlling cell adhesion, growth and migration Michael Gabi a , Alexandre Larmagnac a , Petra Schulte b , Janos Vörös a,∗ a Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, University and ETH Zurich, ETZ F82, Gloriastrasse 35, CH-8092 Zurich, Switzerland b Forschungszentrum Jülich GmbH, Institut für Bio- und Nanosysteme, 52425 Jülich, Germany article info Article history: Received 29 January 2010 Received in revised form 20 April 2010 Accepted 21 April 2010 Available online 2 May 2010 Keywords: ITO electrode Neurite outgrowth Cell migration Electrochemically controlled surface chemistry Neuron PLL-g-PEG Myoblast abstract We have developed a neurochip to control the adhesion and outgrowth of individual neurons by electro- chemical removal of protein repellent molecules from transparent electrodes. The neurochip architecture is based on three parallel indium-tin-oxide (ITO) electrodes on a SiO 2 substrate and a photoresist struc- ture forming a landing spot for the neuron soma and two lateral outgrowth pathways for the neurites. The whole surface was turned protein and cell repellent with poly(ethylene glycol) grafted-poly(l-lysine) (PLL-g-PEG) before enabling neuron soma adhesion by selective PLL-g-PEG removal. After the neuron has settled down a potential was applied to the pathway electrodes to permit the neurite outgrowth along pathways formed by the SU8 structure. We also show the possibility to control cell migration by small pulsed currents. Myoblasts were therefore seeded on a chemical pattern of cell adhesive PLL and cell resistant PLL-g-PEG. The PLL-g-PEG was then removed electrochemically from the electrodes to permit migration onto the cell free electrodes. Electrodes without applied current were confluently overgrown within 24 h but a small pulsed current was able to inhibit cell growth on the bare ITO electrode for more than 72 h. With both techniques, cell adhesion, growth and migration can be controlled dynamically after the cells started to grow on the substrate. This opens new possibilities: we believe the key to control the development of topologically controlled neuron networks or more complex co-cultures is the combina- tion of passive surface modifications and active control over the surface properties at any time of the experiment. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Experimental techniques in biomedical engineering often involve the use of patterned substrates to study fundamental cellu- lar processes. The patterned surfaces are engineered to specifically influence cell adhesion, outgrowth, migration, organization and tis- sue development by providing alternating surface properties in the micrometer range. In principle the cells are seeded on pre- fabricated substrates patterned either with different materials e.g. metals, metal oxides or organic molecules which preferably do not change their properties during the experiment. Such passive substrates are patterned by normal photolithography techniques for spatial arrangements of different solid materials [1], protein- aqueous materials [1–5], polyelectrolytes [6,7] or self-assembled monolayers (SAMs) [8,9]. Photolithography in combination with laser ablation was also reported [10]. Another method, “-contact printing” developed by Whitesides et al., uses a microstruc- ∗ Corresponding author. Tel.: +41 44 632 59 03; fax: +41 44 632 11 93. E-mail addresses: gabi@biomed.ee.ethz.ch (M. Gabi), larmagnac@biomed.ee.ethz.ch (A. Larmagnac), petra.schulte@fz-juelich.de (P. Schulte), janos.voros@biomed.ee.ethz.ch, voros@ethz.ch (J. Vörös). tured stamp made of poly-(dimethylsiloxane) (PDMS) [11]. This printing technique is mostly used to transfer patterns of poly(l- lysine) (PLL) [12–17] or extracellular matrix proteins such as laminin, fibronectin to a flat substrate. Instead of proteins, synthetic molecules consisting of substrate binding sites and specific cell adhesive peptide sequences (e.g. RGD, IKVAV, etc.) can be printed onto solid materials [18–20]. Another approach for patterning cells is to provide a 3D structure on a surface were cells can attach and grow inside or along the structure. Merz and Fromherz used litho- graphically patterned SU8 polyester structures to guide individual snail neurons [21,22]. Topographical effects of smaller structures such as silicon pillars and micron-sized holes on neuron growth were also investigated [23,24]. There were also attempts to culture neurons in microfluidic platforms allowing directed growth of neu- rites from their cell bodies [25] or pattern them at low densities for further differentiation [26]. It has also been tried to trap the neu- rons mechanically in parylene cages positioned on electrode sites of a multielectrode array (MEA) chip. The cell body is hold in place by the cage, while the neurites are free to grow into the surrounding area [27]. All these methods provide a prefabricated passive patterned surface for cell cultures. Nowadays, the challenge shifts towards more complex structures built of different cell types or to 0927-7765/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2010.04.019