DUAL NANOPARTICLE ASSAY FOR DETECTION AND SEPARATION OF BIOLOGICAL SPECIES

摘要

The subject invention provides novel methods, kits, and compositions for use in detecting, quantifying, and/or separating target cells in a sample. In one embodiment, methods for the rapid collection and detection of leukemia cells are provided using a novel dual nanoparticle assay with aptamers as the molecular recognition element. Aptamer sequences are prepared using a cell based SELEX strategy, where the aptamers are specific for CCRF-CEM acute leukemia (AL) cells. Such aptamers preferably demonstrate a high degree of specificity or selectivity for AL cells in complex mixtures, including whole blood samples. According to one embodiment of the invention, aptamer modified magnetic nanoparticles are used for target cell extraction, while aptamer modified fluorescent nanoparticles are simultaneously added for sensitive cell detection. Combining two types of nanoparticle-based screening techniques allows for rapid, selective, and sensitive detection not possible by using either particle alone. In a related embodiment, fluorescent nanoparticles amplify the signal intensity corresponding to a single aptamer binding event, resulting in improved sensitivity over methods using individual dye labeled probes. In addition, aptamer modified magnetic nanoparticles allow for rapid extraction of target cells not possible with other separation methods. Fluorescent imaging and flow cytometry are used for cellular detection to demonstrate the application of this method for medical diagnostics.