Electrochemically switchable platform for the micro-patterning and release of heterotypic cell sheets
This article describes a dynamic platform in which the biointerfacial properties of micro-patterned domains can be switched electrochemically through the spatio-temporally controlled dissolution and adsorption of polyelectrolyte coatings. Insulating SU-8 micro-patterns created on a transparent indium tin oxide electrode by photolithography allowed for the local control over the electrochemical dissolution of polyelectrolyte mono- and multilayers, with polyelectrolytes shielded from the electrochemical treatment by the underlying photoresist stencil. The platform allowed for the creation of micro-patterned cell co-cultures through the electrochemical removal of a non-fouling polyelectrolyte coating and the localized adsorption of a cell adhesive one after attachment of the first cell population. In addition, the use of weak adhesive polyelectrolyte coatings on the photoresist domains allowed for the detachment of a contiguous heterotypic cell sheet upon electrochemical trigger. Cells grown on the ITO domains peeled off upon electrochemical dissolution of the sacrificial polyelectrolyte substrate, whereas adjacent cell areas on the insulated weakly adhesive substrate easily detached through the contractile force generated by neighboring cells. This electrochemical strategy for the micro-patterning and detachment of heterotypic cell sheets combines simplicity, precision and versatility, and presents great prospects for the creation of cellular constructs which mimic the cellular complexity of native tissues.
KeywordsIndium tin oxide electrode SU-8 photoresist Micro-patterning Photolithography Cell co-cultures Heterotypic cell sheet engineering
The authors thank Stephen Wheeler and Martin Lanz for technical assistance and the Competence Centre for Material Science and Technology (CCMX), ETH Zurich, the Marie Heim-Vögtlin grant No. PMPDP2_122997 from the Swiss National Science Foundation, and the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° NMP4-SL-2009-229292 (Find&Bind) for financial support.
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