, Stephen Dodd, Alan Koretsky
Fluorescent and plasmonic probes have proven invaluable in the life sciences, but function poorly in optically inaccessible regions. Here we present radio-frequency addressable analogs that afford sensing opportunities similar to those of fluorescent sensors, but that are readable with standard NMR equipment. The sensors comprise magnetic nano-assemblies that reversibly reconfigure in response to chosen stimuli, yielding novel, geometry-dependent, dynamic NMR spectral signatures. Using such sensors, we demonstrate pH sensing, ionic strength mapping, cell metabolism tracking, and sensor multiplexing. The shape-changing sensors can be made from biocompatible materials, are detectable down to low femtomolar concentrations, and offer potential NMR spectral shifts a million-fold greater than those of traditional magnetic resonance spectroscopies. Inherent adaptability should allow the same sensing platform to measure numerous environmental and physiological indicators.
NMR, MRI, Magnetic resonance imaging, nanosensor, radio-frequency sensor, fluorescent sensor, plasmonic sensor, pH, magnetic particles