The present invention provides multi-well plates and column arrays in which samples (e.g., cell lysates containing nucleic acids of interest, such as RNA) can be analyzed and/or processed. In one embodiment, the microfiltration arrangement is a multilayer structure, including (i) a column plate having an array of minicolumns into which samples can be placed, (ii) a discrete filter element disposed in each minicolumn, (iii) a drip-director plate having a corresponding array of drip directors through which filtrate may egress, and (iv) a receiving-well plate having a corresponding array of receiving wells into which filtrate can flow. The invention provides multi-well microfiltration arrangements that are relatively simple to manufacture and that overcome many of the problems associated with the prior arrangements relating to (i) cross-contamination due to wicking across a common filter sheet or (ii) individual filter elements entrapping sample constituents within substantial dead volumes. Further, the invention provides multi-well microfiltration arrangements that adequately support discrete filter elements disposed in the wells without creating substantial preferential flow. Additionally, the invention provides multi-well microfiltration arrangements that avoid cross-contamination due to aerosol formation, pendent drops and/or splattering. Other disclosed features of the invention provide for the automated covering or heat-sealing of filtrate samples separately collected in an array of wells.
A multi-well microfiltration apparatus and method are provided and feature a manual touch-off system for transferring pendent drops hanging from discharge-conduits of a discharge-conduit array to respective receiving wells or receiving holes of a corresponding receiving array, with minimum or no cross-contamination between the discharge conduits, or the receiving wells or receiving holes. The manual touch-off is achieved by manually shifting a carriage that supports one of the arrays, into a position whereat pendent drops of fluid hanging from the distal ends of the discharge conduits contact the inner sidewalls of the corresponding receiving wells or receiving holes of the receiving array.
