High surface area multiwell test plate

The present invention comprises a microtiter plate formed of a substantially rigid, polymeric plate having a substantially flat upper surface and a regular array of similar wells, typically either cylindrical or frusto-conical, each well being defined by a fluid-impervious peripheral wall extending a predetermined distance along an axis substantially perpendicularly to that upper surface between an opening in the upper surface and a well bottom. Disposed within the well adjacent the bottom is a porous structure providing a surface area at least five times greater than the surface area of the interior well bottom. The well bottom may be either fluid impervious or pervious. Where the well bottom is fluid pervious, it may be formed from a fluid impervious sheet apertured to accept and be bonded to the peripheries of the ends of a plurality of fluid pervious ultrafiltration fibers that may have hollow cores. In embodiments with fluid pervious well bottoms, a vacuum plenum is provided below the wells for drawing fluid from the wells through the pervious material. In embodiments in which the well bottom is fluid impervious, the porous structure within the well and coupled to the inner surface of the well bottom can be formed from either continuous or closed cells, a plurality of loops of fibers having both ends coupled to the bottom, a plurality of fibers having one end coupled to the bottom, a coil of fiber, and other configurations.