Tailoring the drug loading capacity of polypyrrole films for use in intraocular biomicrorobots

Preliminary results concerning impregnation of polypyrrole (Ppy) films with rhodamine B (Rh-B) are presented. The films are envisioned to be functional surface coatings on biomicrorobots for controlled drug delivery. The polypyrrole films were obtained on gold substrates by anodic oxidation of pyrrole in aqueous solutions containing sodium dodecylbenzenesulfonate (SDBS) as doping agent. The influence of the sodium doping level on the wettability of the Ppy surfaces, and the loading capacity of Rh-B is systematically analyzed. The undoping of the films results in the formation of surface microcracks and tends to make the surface hydrophobic in nature, which subsequently leads to an increase of the adsorption capacity of Rh-B on the Ppy deposit. This controllable increase in adsorption capacity provides an opportunity to tailor the drug loading capacity of Ppy films.