Examples of several multiplexed nanoparticles used as an imaging contrast agent, as a drug delivery vehicle, and/or for image-guided therapy. (a)_SEM image of hollow nanocages used to contain therapy products. Reproduced with permission from Skrabalak SE, Chen J, Sun Y, et al. Gold nanocages: synthesis, properties, and applications. Acc Chem Res 2008 Dec;41(12):1587–95 [86] (b) Gold nanoshells for use in photothermal applications. Reproduced with permission from Loo C, Lowery A, Halas N, et al. Immunotargeted Nanoshells for Integrated Cancer Imaging and Therapy. Nano Letters 2005;5(4):709–11. [87]. (c) Diagram demonstrating a multifunctional nanosystem platform utilizing a silver cage with a silica core. Reproduced with permission from Homan K, Shah J, Gomez S, et al. Silver nanosystems for photoacoustic imaging and image-guided therapy. J Biomed Opt 2010 Mar-Apr;15(2):021316 [92]. (d) Silver coated PLGA as a carrier for imaging contrast agents. Image courtesy of K.A. Homan. All figures used with permission.