A novel technique is proposed in which a nuclear magnetic resonance (NMR) spectrum or magnetic resonance image (MRI) is encoded and stored as spin polarization and is then moved to a different physical location to be detected. Remote detection allows the separate optimization of the encoding and detection steps, permitting the independent choice of experimental conditions, and excitation and detection methodologies. In the first experimental demonstration of this technique, we show that NMR signal can be amplified by taking diluted 129Xe from a porous sample placed inside a large encoding coil, and concentrating it into a smaller detection coil. In general, the study of NMR active molecules at low concentration that have low physical filling factor is facilitated by remote detection. In the second experiment, MRI information encoded in a very low field magnet (4-7mT) is transferred to a high field magnet (4.2 T) in order to be detected under optimized conditions. Furthermore, remote detection allows the utilization of ultra-sensitive optical or superconducting detection techniques, which broadens the horizon of NMR experimentation.

NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon chemical shift, which is a key requirement for being able to multiplex the biosensor.