Our research focuses on the development and evaluation of metal-, polymer- or protein-based nanoparticles applicable in an imaging and/or therapeutic context. The idea is to conceptualize the nanoparticles not as merely tiny aggregates of molecules but rather as platforms with large surface-to-volume ratios. By harnessing the well developed surface chemistry, one can load a wide range of functionalities onto the particle surface. We adopt an interdisciplinary approach, taking advantage of the recent progress made in peptide/protein/materials chemistry, bioconjugation, molecule imaging, cell/molecular biology as well as clinical medicine, and integrating these merits, with rational design, into nanoscale gadgets. The resulted products, with unique physical properties, targeting profiles, or theranostic attributes, are emerging as a new generation of therapeutic/imaging formula and hold great promise to improve patient management and treatment outcomes in a wide range of diseases, especially cancer.