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.

What is claimed is: 
     
         1 . A device for the detection of one or more analytes in a sample from a subject suspected of having sepsis or septic shock, the device comprising:
 (a) a permanent magnet defining a magnetic field;   (b) a support defining a well for holding a liquid sample comprising magnetic particles and the one or more analytes and having an RF coil disposed about the well, the RF coil configured to detect an echo response produced by exposing the liquid sample to a bias magnetic field created using the permanent magnet and an RF excitation;   (c) an electrical element in communication with the RF coil, the electrical element configured to amplify, rectify, transmit, and/or digitize the signal corresponding to the echo response; and   (d) a removable cartridge sized for convenient insertion into and removal from the device and having a compartment comprising one or more populations of magnetic particles having binding moieties on their surfaces, wherein the binding moieties are operative to alter an aggregation of the magnetic particles in the presence of the one or more analytes; and   wherein at least one of the binding moieties is operative to bind to at least one of the following: (i) the one or more analytes; (ii) another of the binding moieties; and (iii) an aggregation-inducing molecule in the liquid sample, thereby producing an aggregate of multiply-linked magnetic particles as a function of the presence or concentration of the one or more analytes in the liquid sample.   
     
     
         2 . The device of  claim 1 , wherein the well and the RF coil are configured to provide a filling factor of at least about 0.1. 
     
     
         3 . The device of  claim 1 , wherein the well has a volume of less than about 300 μL. 
     
     
         4 . The device of  claim 1 , wherein the well and the RF coil are configured such that the volume circumscribed by the RF coil is less than about 300 μL. 
     
     
         5 . The device of  claim 1 , wherein the RF coil has a characteristic dimension from about 10 μm to about 1000 μm. 
     
     
         6 . The device of  claim 1 , further comprising a tube for holding the liquid sample, the tube having a varying cross section. 
     
     
         7 . The device of  claim 1 , wherein an aggregate of multiply-linked magnetic particles is disaggregated as a function of the presence or concentration of the one or more analytes in the liquid sample. 
     
     
         8 . The device of  claim 1 , wherein the removable cartridge comprises an array of compartments, and wherein magnetic particles having different binding moieties are disposed in different compartments for detection of the one or more analytes, the different binding moieties promoting aggregation or disaggregation of the magnetic particles in the presence of the one or more analytes. 
     
     
         9 . The device of  claim 8 , wherein magnetic particles having different binding moieties are disposed in different compartments for detection of multiple analytes. 
     
     
         10 . The device of  claim 8 , wherein magnetic particles having the same binding moieties are disposed in different compartments for replicate measurements. 
     
     
         11 . The device of  claim 8 , wherein magnetic particles having the same binding moieties are disposed in different compartments for detection of varying analyte concentrations in the liquid sample. 
     
     
         12 . The device of  claim 8 , wherein for each of the wells, the RF coil disposed about the well is contained within the removable cartridge. 
     
     
         13 . The device of  claim 1 , wherein the liquid sample comprises blood. 
     
     
         14 . The device of  claim 1 , wherein one of the one or more analytes is a biologically active substance. 
     
     
         15 . The device of  claim 14 , wherein the biologically active substance is selected from a protein, a peptide, a polypeptide, an amino acid, a nucleic acid, an oligonucleotide, a therapeutic agent, a metabolite of a therapeutic agent, RNA, DNA, an antibody, a carbohydrate, a polysaccharide, glucose, a lipid, a gas, an electrolyte, a lipoprotein, cholesterol, a fatty acid, a glycoprotein, a proteoglycan, and a lipopolysaccharide. 
     
     
         16 . The device of  claim 15 , wherein one of the one or more analytes is a protein. 
     
     
         17 . The device of  claim 16 , wherein the protein is TNF-alpha. 
     
     
         18 . The device of  claim 16 , wherein the protein is an interleukin. 
     
     
         19 . The device of  claim 16 , wherein the protein is G-CSF. 
     
     
         20 . The device of  claim 16 , wherein the protein is a complement protein. 
     
     
         21 . The device of  claim 16 , wherein the protein is troponin. 
     
     
         22 . A method for detecting one or more analytes in a liquid sample from a subject suspected or known to have sepsis or septic shock, the method comprising:
 (a) placing the liquid sample in a device of  claim 1 , the device comprising (i) a permanent magnet defining a magnetic field, (ii) a support defining a well for holding a liquid sample comprising magnetic particles and the one or more analytes and having an RF coil disposed about the well, the RF coil configured to detect an echo response produced by exposing the liquid sample to a bias magnetic field created using the permanent magnet and an RF excitation, (iii) an electrical element in communication with the RF coil, the electrical element configured to amplify, rectify, transmit, and/or digitize the signal corresponding to the echo response, and (iv) a removable cartridge sized for convenient insertion into and removal from the device and having a compartment comprising one or more populations of magnetic particles having binding moieties on their surfaces, wherein the binding moieties are operative to alter an aggregation of the magnetic particles in the presence of the one or more analytes;   (b) contacting the liquid sample with the magnetic particles in the presence of the bias magnetic field;   (c) exposing the sample to an RF excitation;   (d) following step (c), detecting an echo response produced by the liquid sample; and   (e) on the basis of the result of step (d), detecting the one or more analytes.   
     
     
         23 . The method of  claim 22 , further comprising using the result of step (e) to diagnose sepsis or septic shock. 
     
     
         24 . A method of monitoring one or more analytes in a liquid sample for the diagnosis, management, or treatment of sepsis or septic shock in a patient, the method comprising:
 (a) placing the liquid sample in a device of  claim 1 , the device comprising (i) a permanent magnet defining a magnetic field, (ii) a support defining a well for holding a liquid sample comprising magnetic particles and the one or more analytes and having an RF coil disposed about the well, the RF coil configured to detect an echo response produced by exposing the liquid sample to a bias magnetic field created using the permanent magnet and an RF excitation, (iii) an electrical element in communication with the RF coil, the electrical element configured to amplify, rectify, transmit, and/or digitize the signal corresponding to the echo response, and (iv) a removable cartridge sized for convenient insertion into and removal from the device and having a compartment comprising one or more populations of magnetic particles having binding moieties on their surfaces, wherein the binding moieties are operative to alter an aggregation of the magnetic particles in the presence of the one or more analytes;   (b) contacting the liquid sample with the magnetic particles in the presence of the bias magnetic field;   (c) exposing the sample to an RF excitation;   (d) following step (c), detecting an echo response produced by the liquid sample;   (e) on the basis of the result of step (d), detecting the one or more analytes; and   (f) using the result of step (e) to diagnose, manage, or treat sepsis or septic shock.   
     
     
         25 . The method of  claim 24 , wherein the monitoring is intermittent. 
     
     
         26 . The method of  claim 24 , wherein the monitoring is continuous. 
     
     
         27 . A method of determining an appropriate dose of a therapeutic agent in a patient known to have or suspected to have sepsis or septic shock, the method comprising:
 (a) administering the therapeutic agent to the patient;   (b) following step (a), obtaining a sample comprising the therapeutic agent or metabolite thereof from the patient;   (c) placing the liquid sample in a device of  claim 1 , the device comprising (i) a permanent magnet defining a magnetic field, (ii) a support defining a well for holding a liquid sample comprising magnetic particles and the one or more analytes and having an RF coil disposed about the well, the RF coil configured to detect an echo response produced by exposing the liquid sample to a bias magnetic field created using the permanent magnet and an RF excitation, (iii) an electrical element in communication with the RF coil, the electrical element configured to amplify, rectify, transmit, and/or digitize the signal corresponding to the echo response, and (iv) a removable cartridge sized for convenient insertion into and removal from the device and having a compartment comprising one or more populations of magnetic particles having binding moieties on their surfaces, wherein the binding moieties are operative to alter an aggregation of the magnetic particles in the presence of the one or more analytes;   (d) contacting the sample with the magnetic particles in the presence of the bias magnetic field;   (e) exposing the sample to an RF excitation;   (f) following step (e), detecting an echo response produced by the sample; and   (g) on the basis of the result of step (f), determining the concentration of the therapeutic agent or metabolite thereof,   wherein, if the concentration of the therapeutic agent or metabolite thereof is above the appropriate therapeutic range, the dose of the therapeutic agent being administered to the patient is reduced, and if the concentration of the therapeutic agent or metabolite thereof is below the therapeutic range, the dose of the therapeutic agent being administered to the patient is increased.   
     
     
         28 . The method of  claim 27 , wherein the determining is intermittent. 
     
     
         29 . The method of  claim 27 , wherein the determining is continuous.