The electrochemical polymerization of polypyrrole films onto magnetically immobilized hydrophilic microbeads was carried out. Poly(pyrrole-pyrene)-microbeads coatings display thus higher permeability in water towards the diffusion of ferrocyanide than a pure poly(pyrrole-pyrene) film. In addition, the modulation of this permeability through an applied magnetic field that attracts the microbeads on the electrode surface or pushes back them was shown. Moreover, a glucose biosensor was prepared by adsorbing and electropolymerizing on a platinum electrode, an aqueous mixture containing glucose oxidase, amphiphilic pyrrole monomer and microbeads attracted by a magnet. The presence of microbeads inside the biocoating, markedly increases the biosensor performance.