The need to understand cellular trafficking in vivo in situ requires the development and application of novel methodologies for cellular labeling and cell tracking. Here we applied new technologies associated with advances in molecular imaging to demonstrate the feasibility of labeling primary immune cells. We demonstrate the utility of fluorescently tagged polystyrene microspheres, MRI susceptible emulsions and cell entry peptoids. The adaptation of these labeling agents will permit cell specific delivery, diagnostic sensing and the delivery of therapeutic agents to sites of inflammation and infection.