Biological detector and method

Abstract

A biological detector includes a conduit for receiving a fluid containing one or more magnetic nanoparticle-labeled, biological objects to be detected and one or more permanent magnets or electromagnet for establishing a low magnetic field in which the conduit is disposed. A microcoil is disposed proximate the conduit for energization at a frequency that permits detection by NMR spectroscopy of whether the one or more magnetically-labeled biological objects is / are present in the fluid.

Description

[0001]This application claims benefits and priority of U.S. provisional application Ser. No. 60 / 839,006 filed Aug. 21, 2006, the disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The invention relates to a NMR-based biological detector and detection method that involve NMR detection of magnetic nanoparticle-labeled biological objects using a microcoil.BACKGROUND OF THE INVENTION[0003]Nuclear magnetic resonance (NMR) spectroscopy is widely used for the real-time identification of chemical compounds in solids, liquids, and gases because it can easily detect and characterize all components of mixtures without requiring separations. Unfortunately, standard high-resolution NMR spectroscopy is not useful for directly detecting dilute biological objects, such as tumor cells, bacteria, bacterial toxins, or viruses, in fluid samples. The weak signals from the analytes in the dilute species are lost against the much stronger background water signal. Even if t...

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Benefits of technology

[0008]In an illustrative embodiment of the present invention, the microcoil has an inner diameter of about 50 to about 550 microns, preferably about 75 to about 125 microns, and even more preferably about 100 microns. The microcoil can comprise a solenoid-shaped or a flat, planar shaped microcoil. The solenoid-shaped microcoil preferably comprises a metallic wire microcoil wound on a tubular microconduit to reduce cost of the detector. The fluid in the tubular conduit is disposed in a magnetic field of about 0.5 to about 1.5 T established by one or more permanent magnets or electromagnets. The microcoil on the conduit can be mounted on a ceramic chip substrate to provide a compact assembly. A microfluidic chip also can be used to this end.

[0010]The present invention is advantageous in a preferred embodiment in providing a microcoil together with one or more compact permanent magnets with benefits of reduced cost, maintenance, and space requirements of the NMR-based detector as well as portability thereof.

Problems solved by technology

Unfortunately, standard high-resolution NMR spectroscopy is not useful for directly detecting dilute biological objects, such as tumor cells, bacteria, bacterial toxins, or viruses, in fluid samples.

Even if the dynamic range challenge is met by suppressing the bulk water signal or concentrating the dilute species, the rapid transverse relaxation characteristics of macromolecular, viral, or cellular samples renders their direct detection by NMR difficult.

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