Embodiments of the present invention are generally directed to compositions comprising a class of molecular probes for detecting the presence of anionic cell surfaces. Embodiments include compositions that are enriched for these compositions and preparations, particularly preparations suitable for use as laboratory/clinical reagents and diagnostic indicators, either alone or as part of a kit. An embodiment of the invention provides for a highly selective agent useful in the discernment and identification of dead or dying cells, such as apoptotic cells, in a relatively calcium-free environment. An embodiment of the invention provides a selective agent for the identification of bacteria in a mixed population of bacterial cells and nonbacterial cells.
GOVERNMENT INTEREST STATEMENT
 The United States Government owns rights in the present invention as research relevant to the development of the invention was supported by United States federal funds from the National Institutes of Health, Grant Number RO1 GM 059078 and from the United States Department of Energy's National Nuclear Security Administration contract DE-AC04-94AL8500.