Patent ID: 7052650

Claim:
An apparatus for manipulating and testing molecules comprising: (A) a surface to which a molecule is anchored at one or more points proximate to a first extremity of the molecule; (B) a paramagnetic bead on which the molecule is anchored at one or more points proximate to a second extremity of the molecule, the surface being an internal surface of a capillary tube in which solutions are injected; (C) a magnetic means for providing a magnetic field to thereby apply a force to the bead, said magnetic means being arranged such that the bead is maintained by the force at a distance from the surface; (D) an optical magnification means having an optical axis and a camera for capturing images of the bead; and (E) a computer means to which the images from the camera are transmitted, said computer means being configured to compute the position of the bead in three spatial directions (x,y,z) and the fluctuation (δx,δy,δz) of the position of the bead in the three spatial directions, the computer means also being configured to analyze the diffraction pattern of the bead to determine a position of the bead along the z direction of the optical axis of the magnification means.