Method and apparatus for quantitative determination of accumulations of magnetic particles
AssigneeQuantum Design, Inc.
InventorsRonald E. Sager, Michael B. Simmonds, Jost H. Diederichs, Kurt G. Jensen, Randall C. Black
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Abstract
Apparatus for detection and measurement of agglutinations of magnetic particles employing Hall sensors. A low frequency AC signal is employed to excite or bias the Hall sensors which reside in a DC magnetic field. The particles are moved into operative relationship with the Hall sensors in order to generate a signal representing the number of particles on the substrate. The method for such detection and measurement is also part of the invention.
Claims53
Apparatus for making quantitative measurements of agglutinations of magnetic particles comprising complexes of non-magnetized, magnetizable particles and target molecules, said apparatus comprising:
- a substrate configured to receive samples of the agglutinations including unknown quantities of said magnetic particles in defined patterns thereon, the magnetizable particles in the samples being of known size and magnetic characteristics bound to the target molecules;
- a magnet for providing a DC magnetic field, the magnetic field producing magnetization in the magnetizable particles when they are in the magnetic field;
- at least one magnetic field sensing element in the magnetic field, said sensing element having an output signal conductor and producing an output signal when the samples are in operative relationship with said at least one sensing element;
- and,
- a signal processor for converting said output signals from said at least one sensing element to provide a signal indicative of the quantity of the target molecules in a sample pattern.
Apparatus for making quantitative measurements of agglutinations of magnetic particles comprising complexes of non-magnetized, magnetizable particles and target molecules, said apparatus comprising:
- a substrate configured to receive samples of the agglutinations including unknown quantities of said magnetic particles in defined patterns thereon, the magnetizable particles in the samples being of known size and magnetic characteristics bound to the target molecules;
- means for providing a DC magnetic field, the magnetic field producing magnetization in the magnetizable particles when they are in the magnetic field;
- magnetic field sensing means in the magnetic field, said sensing means having output signal means and producing an output signal when the samples are in operative relationship with said sensing means;
- and,
- means for converting said output signals from said sensing means to provide a signal indicative of the quantity of the target molecules in a sample pattern.
A method for quantitatively determining target molecules in a sample pattern, said method comprising:
- applying at least one sample pattern having unknown quantities of target molecules in a predetermined configuration on a substrate, the sample pattern being comprised of non-magnetized, magnetizable particles of known size and magnetic characteristics coupled to the target molecules to form magnetic bound complex samples;
- providing a DC magnetic field;
- causing relative motion between the substrate and the magnetic field to place the sample pattern within the magnetic field;
- exciting the magnetizable particles in the pattern by means of the DC magnetic field to make them magnetic and thereby cause the magnetic particles to perturb the magnetic field;
- sensing the magnetic field changes caused by the presence of the magnetized particles in the magnetic field;
- and
- creating a signal representative of the quantity of target molecules in the field.
Dependencies are inferred from the claim text.