Surface-functionalized nanoparticle library yields probes for apoptotic cells.

We have developed techniques for the efficient synthesis and screening of small libraries of surface-functionalized nanoparticles for the recognition of specific types of cells. To illustrate this concept we describe the development of a nanoparticle that preferentially recognizes apoptotic Jurkat cells in a manner similar to the apoptosis-recognizing protein annexin V. The nanoparticle, which is detectable by fluorescence or NMR relaxometry, was analyzed for the ability to recognize normal and apoptotic cells by fluorescence-activated cell sorting (FACS) analysis and fluorescence microscopy. The capability to develop nanoparticles which interact with specific target cells could be applied to the design of materials for diverse applications including quantum dots, which serve as fluorescence tracers, colloidal gold, which serves as a tracer for electron micrographs, or the crystalline forms of drugs.