Encapsulation of laccase in a conducting polymer matrix: A simple route towards polypyrrole microcontainers

The encapsulation of laccase dissolved in aqueous droplets adsorbed on glass or gold was studied. When the droplet-decorated substrate is placed in an organic solution containing a monomer (pyrrole), the enzymatic polymerization occurs at the droplet/solution interface yielding a polypyrrole shell. Due to the shape of the droplets, the polymeric hemispherical microcontainers that encapsulate the enzyme are produced on the substrate surface. The polymeric structures were investigated with several microscopy techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), conducting AFM and near-field scanning optical microscopy (NSOM). The chemical nature of the microcontainers was studied with infrared spectroscopy and cyclic voltammetry. The activity of the encapsulated laccase was probed spectrophotometrically. It was shown that the enzyme retains relatively high level of activity after encapsulation. (C) 2009 Elsevier B.V. All rights reserved.