Biomedical nanotechnology offers superior potential for diagnostic imaging of malignancy at the microscopic level. In addition to current research focused on dual-imaging and therapeutic applications in vivo, these novel particles may also prove useful for obtaining immediate diagnostic results in vitro at the patient bedside. However, translating the use of nanoparticles for cancer detection to point-of-care applications requires that conditions be optimized such that minimal time is needed for diagnostic results to become available. Thus far, no reports have been published on minimizing the time needed to achieve acceptable optical contrast of cancer cells incubated with nanoparticles. In this study, we demonstrate the use of gold nanoshells targeted to anti-HER2 antibodies that produce sufficient optical contrast with HER2-overexpressing SK-BR-3 breast cancer cells in only 5 min. This work validates the proof of concept that nanoshells targeted to extracellular biomarkers can be used to enhance cancer diagnostic imaging for use in point-of-care applications.