Plate and method for high throughput screening

Abstract

A multiple well plate and method for media exchange, including a body defining a plurality of cell wells each connected via a channel to one of a plurality of aspiration holes, is provided. The cell wells contain a porous, hydrophilic frit which is suspended on a ledge above a reservoir of fluid media and supports a tissue sample. The properties of the frit wick the fluid media upwards to supply the tissue sample with nutrients for growth and proliferation. Old media is aspirated from the wells by a liquid handling device which inserts a pipette tip into the aspiration holes. The pipette tip applies a suction pressure which draws the media out of the cell well, through the channel, into the aspiration hole and out through the pipette tip. New media is dispersed through the pipette tip and directly into the cell well.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a divisional of U.S. application Ser. No. 10 / 157,562, filed May 29, 2002, which claims the benefit of U.S. Provisional Application No. 60 / 294,430, filed May 30, 2001, both of which are hereby incorporated herein in their entirety by reference.FIELD OF THE INVENTION [0002] The present invention relates to devices and methods for promoting the growth of tissue in experimental and production settings, more particularly the use of specialized plates to house the tissue and the cycling of media to biologically sustain the tissue. BACKGROUND OF THE INVENTION [0003] High-throughput screening typically requires parallel processing of batches of samples, typically in multiple well plates (MWPs) of 24, 48, 96, and 384, or more, wells per plate. MWPs are standard sizes that can be used with existing high-throughput machinery, such as with robotic-controlled pipetters. Each pipetting station of a robotic controlled pipett...

AI Technical Summary

Benefits of technology

[0009] The present invention addresses the above needs and achieves other advantages by providing a multiple well plate (MWP) and method for media exchange that promotes the growth of plant tissue, and other types of tissue, by controlling the supply of media to the tissue and allowing for the regular exchange (removal and addition) of media without disturbing the tissue. The MWP includes an array of wells, with each well being coupled with an adjacent aspiration hole that allows media to be aspirated from the wells using a conventional, automated pipette head. The MWP and pipette head provide a virtually complete exchange of the spent media because of the novel dual-well architecture. A hydrophilic, porous frit housed within each well supports the tissue and holds the media in its interstices, allowing contact between the tissue and the media while avoiding an anaerobic condition. The media is wicked upwards in sufficient quantities to provide nutrients to the tissue and promote proliferation of the tissue.

[0016] The present invention has several advantages. For example, the tissue samples in the wells do not have to be moved or disturbed when the provided media is spent, cutting down on workload and ensuring sterile and optimal growth conditions. The plates may be used with conventional liquid handling pipette heads of the fixed tip or individually controllable tip versions because the aspiration holes are accessible from the upper surface of the body, i.e., a top-loading arrangement. The use of robotic liquid handlers with the plate promotes a well-to-well consistency in the treatment of the tissue, as well as the efficient removal and replacement of the media. The top-loading aspect allows the use of a standard lid for sterility control and removes the need for a separate vacuum manifold station for pulling out media. The lack of a manifold allows for the differential treatment of each well and provides flexibility in liquid handler design and selection, as well as experimental model and sample interrogation functions. The liquid head can be configured to remove the media as well as add new media with no change of tooling or pipette tips.

Problems solved by technology

Although used effectively for the screening of liquid samples, the current multiple well plates are generally ineffective for screening plant and other tissues, and the secretory products associated with these tissues, that require, or prefer, more complex environments such as solid support structures.

However, the plant tissue is deprived of oxygen when sitting in the liquid, effectively “drowning” the plant tissue in an anaerobic environment.

Although these types of supports avoid drowning the plants, they are difficult to exchange and replenish when the nutrients or media have been depleted.

However, empirical evidence has shown that paper bridges are difficult to manage in an automated system and are generally ineffective at promoting plant tissue growth.

Without being wed to any particular theory, this may be because the liquid media does not easily penetrate the paper bridge (i.e., the paper bridge is only mildly hydrophilic) and the tissue supported thereon lacks a continuous supply of media.

Movement of the plant tissue is a relatively slow and labor intensive process, as multiple plates must be replenished and otherwise prepared for each batch of plant tissue.

In addition there is a threat of loss or contamination of the tissue samples when they are removed from the wells.

Although the filter disks in the assay plate allow media to be drawn out of the plate, it is difficult for the filter disks to retain enough media to support tissue maintenance and growth for any length of time.

In addition, the wells of the assay plate cannot be individually sampled because the vacuum manifold harvests the media from all of the wells at once.

In addition, some of the cartilage cells proliferate within the collagen fibril matrix and cannot be moved independent of the matrix.

Moving the cells to a new plate with a fresh supply of media requires movement of the entire collagen matrix which is a relatively slow and inefficient process that exposes the tissue to contamination.

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