Magnetically modulated optical nanoprobes

We have developed magnetically modulated optical nanoprobes (MagMOONs) to magnetically modulate the signal from fluorescent probes and thus separate it from autofluorescence, electronic offsets, and other background signals. These micro- and nanosized particles emit fluorescence signals, indicating chemical concentrations, and blink in response to rotating magnetic fields. Demodulating the signal dramatically enhances the probe's signal to background ratio. The probes and methods promise to improve immunoassays, intracellular chemical sensing, and fundamental biochemical research. (C) 2003 American Institute of Physics.