Richard B Colton, 73826 Pembroke Ct, Vero Beach, FL 32963

5481189, Jan 2, 1996

Feb 7, 1994

8/193690

Daniel DiLella - Lorton VA
Richard J. Colton - Springfield VA

The United States of America as represented by the Secretary of the Navy - Washington DC

G01R 3302

324259

The magnetic sensor of this invention is characterized by a magnet suspen on a torsion bar or wire and by a tunneling tip separated from one end of the magnet, a gap between the tip and the magnet that is small enough to support a tunneling current, an electrical source for imposing a constant biasing voltage across the gap, an electrical force to maintain the magnet and the tip sufficiently close so that a constant tunneling current is maintained therebetween, a feedback circuit to monitor current changes in the gap that result from rotation of the magnet due to changes in the surrounding magnetic field, and at least one recorder to record changes in the magnetic field. The method for detecting rotation of a magnet by a sensor caused by a change in the surrounding magnetic field includes the steps of biasing tunneling tip and a magnet with respect to each other, positioning the tip and/or magnet so there is a tunneling current therebetween, adjusting width of the tunneling gap to establish a constant tunneling current therebetween, exposing the magnet to a magnetic field that causes the magnet to rotate and to change the width of the gap, adjusting the width of the gap to re-establish a constant tunneling current in the gap, and recording the change in the feedback control voltage which is proportional to the change in the magnetic field.

5372930, Dec 13, 1994

Sep 16, 1992

7/945057

Richard J. Colton - Springfield VA
David A. Kidwell - Alexandria VA

The United States of America as represented by the Secretary of the Navy - Washington DC

G01N 33543

435 6

A sensor for ultra-low concentration chemical recognition comprises a force transducer, a tip coupled to this force transducer, and a substrate positioned for force interaction with the force transducer tip, where the substrate and tip are chemically modified with antigens, antibodies, nucleic acids, or chelating agents so that there is a specific force interaction between the tip and the substrate in the presence of the target species, and a measurably different force interaction in the absence of the target species.

5807758, Sep 15, 1998

Jul 21, 1995

8/505547

Gil U. Lee - Alexandria VA
David A. Kidwell - Alexandria VA
Richard J. Colton - Springfield VA

C12Q 170
C12Q 168
C01N 33573
G01N 33573
G01N 2700

436526

The present invention is a method and apparatus for detecting a target species. The target molecule may be in liquid phase (in solution) or (for some embodiments of the invention) in vapor phase. A sensor according to the present invention monitors whether a target species has selectively bound to groups on the cantilever surface by monitoring the displacement of the cantilever, and hence the force acting on the cantilever. This force acting on the cantilever arises from the force acting on a structure that moves in electric or magnetic field, and that may be selectively bound to the cantilever. In the case of target species having a sufficiently large net electric charge or dipole moment, the target species itself may serve as the structure that moves in an electric field. More typically however, separate modified structures, such as modified magnetic beads or modified beads having a net charge or a dipole moment, will, when selectively bound to the cantilever, exert a force on the cantilever that relates to the presence of the target species.

5193383, Mar 16, 1993

Jul 11, 1990

7/560391

Nancy A. Burnham - Alexandria VA
Richard J. Colton - Springfield VA

The United States of America as represented by the Secretary of the Navy - Washington DC

G01B 2130
G01B 734
G01N 1300
G01N 340

73105

A method and apparatus to use an Atomic Force Microscope to take measurements of surface forces, indentation, adhesion and mechanical properties such as hardness and elasticity. The force between a probe mounted cantilever and a sample is measured as a function cantilever deflection measured by a electron tunneling microscope. The sample and the tip of the tunneling microscope are each mounted on piezoelectric manipulators which provide for position control. Position of the sample and probe are measured from the voltages applied to the piezoelectric manipulators. Penetration is determined by the relative motion between the probe and sample. Presently, this invention has a force resolution of 1 nN and a depth resolution of 0. 02 nm.