| 摘要 |
<p>Washing/aspiration systems and associated methods for assays employing paramagnetic solid phase binding particles (422) remove fluid and unbound components from the test well (18) without losing the paramagnetic particles (422) in the process. In one arrangement, the surface tension of the fluid in the well (18) is altered in a preselected manner to redistribute larger volumes of fluid away from the center region of the well (18) and toward the side region of the well (18). Fluid is aspirated from the side region, freeing the center region of the well (18) for the collection and concentration of the paramagnetic particles (422) away from the aspiration flow. In another arrangement, the distribution of the paramagnetic particles (422) in the well (18) is altered by subjecting the particles to a dynamic magnetic field (602; 608) that varies the direction and intensity of the magnetic gradient as a function of time. The dynamic magnetic field (602; 608) collects and concentrates the particles (422) within a region of the test well (18) away from the aspiration probe.</p> |
