Differential adsorption of silver nanoparticles to the inner and outer surfaces of the Agave americana cuticle

Plant cuticular materials have been recently described as highly efficient natural sorbents for organic pollutants; however, their role as adsorption agent for metal ions and metallic particles is unknown. The objective was to study the adsorption and fabrication of silver ions and nanoparticles by the Agave americana cuticle and its structural components. The two sides of the A. americana cuticle exhibited different behavior with respect to the adsorption of silver nanoparticles produced by microwave-assisted polyol reduction. Only the outside of the cuticle was found to be coated with silver nanoparticles. A mechanistic investigation showed that the first step in this reaction is formation of the nanoparticles in solution. Then the metallic nanoparticles were adsorbed by the cuticle. Silver ions were not adsorbed by the cuticle. Our data suggest that cutin and cutan biopolymers are the major cuticular fractions responsible for adsorption of the silver nanoparticles.