Current technologies for cell stimulation suffer from a variety of drawbacks. Indeed, precise, localized, and minimally disruptive machine-to-cell interfacing is difficult to achieve. Here we present the organic electronic ion pump (OEIP), a polymer-based delivery system exhibiting high spatial, temporal, and dosage precision. Based on electrophoretic transport of positively charged species, the OEIP can deliver - with high precision - an array of biologically relevant substances without fluid flow, thus eliminating convective disturbance of the target system's environment. We discuss our results to date, including oscillatory delivery profiles and stimulation of neuronal cells in vitro, as well as our ongoing work.