Nmr device for detection of analytes

Abstract

This invention relates generally to detection devices having one or more small wells each surrounded by, or in close proximity to, an NMR micro coil, each well containing a liquid sample with magnetic nanoparticles that self-assemble or disperse in the presence of a target analyte, thereby altering the measured NMR properties of the liquid sample. The device may be used, for example, as a portable unit for point of care diagnosis and/or field use, or the device may be implanted for continuous or intermittent monitoring of one or more biological species of interest in a patient.

1 . A portable device comprising:
 (a) a permanent magnet defining a magnetic field;   (b) an RF excitation coil for transmitting an RF excitation to a plurality of liquid samples; and   (c) a support defining a plurality of wells, each of the wells having a volume of less than about 500 μL, for holding the plurality of liquid samples, and for each of the wells: an RF coil disposed about the well and configured to detect an NMR relaxation response produced by exposing a liquid sample within the well to a bias magnetic field created using the permanent magnet and the RF excitation.   
     
     
         2 . The portable device of  claim 1 , further comprising a removable cartridge sized for convenient insertion into and removal from a housing containing the permanent magnet and the RF excitation coil, wherein the plurality of wells for holding the plurality of liquid samples are contained within the removable cartridge. 
     
     
         3 . The portable device of  claim 2 , wherein, for each of the wells, the RF coil disposed about the well is contained within the removable cartridge. 
     
     
         4 . The portable device of  claim 2 , wherein, for each of the wells, the RF coil disposed about the well is not contained within the removable cartridge. 
     
     
         5 . The portable device of any one of  claims 1 , wherein for each of the wells, the RF coil disposed about the well has a characteristic dimension from about 10 μm to about 1000 μm. 
     
     
         6 . A method for measuring a change in a physical property of a liquid sample, the method comprising:
 (a) placing the liquid sample in a device of any of the preceding claims;   (b) exposing the liquid sample to an RF excitation in the presence of a magnetic field;   (c) following step (b), detecting an NMR relaxation response produced by the protons in the liquid sample; and   (d) on the basis of step (c), measuring a change in a physical property of the liquid sample.   
     
     
         7 . The method of  claim 6 , comprising measuring the change in the viscosity of the liquid sample. 
     
     
         8 . The method of  claim 6 , comprising measuring the change in the gellation of the liquid sample.