Dual mode imaging and selective functionalization of multimaterial nanopyramids

AEI 40

Jeunghoon Lee, polyljh@gmail.com, Warefta Hasan, w-hasan@northwestern.edu, and Teri W. Odom, todom@northwestern.edu. Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208
Metal nanoparticles have attracted significant interest in potential applications such as biological detection, targeted delivery, and photothermal therapy because they possess unique optical properties and easily modifiable surfaces. In this paper, we demonstrate that nanopyramids composed of two different materials, gold and nickel, fabricated using a soft lithographic process, can function as optically and magnetically active nanoparticles. The ‘PEEL' technique used to fabricate the bilayer nanopyramids allows us to generate pyramidal nanoparticles composed of multiple materials easily. Using appropriate surface ligands, only part of the nanopyramids can be chemically and biologically functionalized. Also, nanopyramids functionalized with dye labeled DNA as fluorescent probe can be imaged under both dark field (DF) scattering and fluorescence mode. The nanopyramids display orientation dependent scattering behavior, and scattering spectra measured from the nanopyramid chains formed under magnetic field show strong polarization dependence, which suggest a possible plasmon coupling between nanopyramids.