Their medicinal value has been explored [19] and they have also been used as substrates for the production of fungal biomass [20]. Another application includes their use in the adsorption of heavymetals from water [21]. In this study, we report a novel ‘green’ biological route for the synthesis of nanoparticles and also demonstrate their assembly into microcubes and microwires (due to the coffee ring phenomenon) by using the banana peel extract (BPE) powder as a reducingmaterial. The structures have been char- 0927-7765/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2010.05.029 46 A. Bankar et al. / Colloids and Surfaces B: Biointerfaces 80 (2010) 45–50 acterized by using UV–vis spectroscopy, SEM-EDS, XRD and FTIR analysis. In addition, an application (antimicrobial activity) of the synthesized nanoparticles has also been demonstrated.