The organic electronic ion pump (OEIP) is an electrically controlled polymerbased device that has the capability to interact with biological systems down to a single cell level by mimicking neural signalling. This is accomplished by translation of an electrical signal into a chemical output, such as ions and neurotransmitters. Because of the combined spatial and temporal precision, this is a technology with a promising future as an advanced therapeutic device. Depending on the application, the OEIP requires different geometries. Implants that will be used to control on a single cell level require very small dimensions, while for example extracorporeal mounted OIEPs, with only the delivery channel penetrating the skin, require much longer channels. Despite the application, it is necessary to have a good knowledge about the transport and delivery properties and how they change due to the geometry. These properties have been observed as very varying and unstable in early unpublished results, and these findings motivate this project. This project includes photolithographic fabrication and investigation of transport and delivery properties such as effective resistance, efficiency and stability of OEIPs with varying delivery channel lengths and widths. Shorter delivery channels show a consistent but relatively low efficiency. Delamination between different layers of the device is suspected as the cause. Initially, the longer delivery channels show a low functionality, most probably due to poor encapsulation. It is suggested that a soft, water-permeable plastic best encapsulates OEIPs that will be used as a medical implant, while a material impermeable to water, for example a metal, could successfully encapsulate OEIPs operating in air.