An active-nucleus sensor or a functionalized active-nucleus complex sensor is utilized in a method for detecting conformational change and binding event information in a targeted molecule, wherein the sensor does not participate in the conformational change or binding event. The method directly or indirectly detects the occurrence, deletion, shift, or any measurable change in a magnetic resonance signal with a unique magnetic resonance property from the active-nuclei, frequently hyperpolarized .sup.129Xe.
 This invention was made with Government support under Contract No. DE-AC03-76SF00098 awarded by the Department of Energy, Grant No. RR02305 awarded by National Institutes of Health, and Contract No. N0001498F0402 MDI-II awarded by the Office of Naval Research. The Government has certain rights in this invention.