Abstract: Microtiter-like plates containing virtual wells formed by an arrangement of relatively hydrophilic domains within relatively hydrophobic fields are provided. Assay mixtures are confined to the hydrophilic domains of the virtual wells by the edges of the hydrophobic fields. The use of virtual wells allows one to perform homogeneous and capture and wash high throughput screening assays with assay mixtures having volumes on the order of about 100 nl to 10 &mgr;. Virtual wells also provide a means of easily moving fluids, which is particularly useful for simultaneous additions needed for kinetic studies and flash detection and washing. Methods for controlling evaporation during the dispensing of reagents as well as during incubation of high throughput screening utilizing microtiter-like plates containing virtual wells are also provided.

Abstract: Method and apparatus for enabling resuspension wash and magnetic localization of sample components bound to particles with magnetic properties in reaction vessels during separation and wash for enhanced chemiluminescent signal generation in biomedical assays. The assays involve moving reaction vessels past magnetic arrays that partially localized the particles prior to passing a gap where washing occurs, with or without resuspension, after separating out the unbound components and liquid. The band of particles is further localized by a focusing magnet at the end of the array prior to dosing the vessel with acid for chemiluminescent purposes. A block of soft magnetic material is employed in place of a magnet in the gap to minimize magnetic strength at the gap. Trimmed magnets adjacent the gap cause left, then right, particle shifting that localizes the magnetizable particles. The gap enables improved resuspension by wash, whereas the localized particles enable more efficient resuspension by reagent.

Abstract: A lyophilization bag is provided in which a fluid, such as blood, may be introduced, lyophilized without collapsing the bag, stored, reconstituted and distributed from the bag without intermediate transfer of the useful contents from the bag.