Electroaddressing agarose using Fmoc-phenylalanine as a temporary scaffold

Electroaddressing, the use of imposed electrical stimuli to guide assembly, is attractive because electrical stimuli can be conveniently applied with high spatial and temporal resolution. Several electroaddressing mechanisms have been reported in which electrode-induced pH gradients trigger stimuli-responsive materials to undergo localized sol-gel transitions to form hydrogel matrices. A common feature of existing hydrogel electrodeposition mechanisms is that the deposited matrix retains residual charged, acidic, or basic (macro)molecules. Here, we report that pH-responsive fluorenyl-9-methoxycarbonyl-phenylalanine (Fmoc-Phe) can be used to codeposit the neutral and thermally responsive polysaccharide agarose. Upon cooling, an agarose network is generated and Fmoc-Phe can be removed. The Fmoc-Phe-mediated codeposition of agarose is simple, rapid, spatially selective, and allows for the electroaddressing of a bioactive matrix.