Multiwell membrane filtration apparatus

• US 4,734,192 A
• Filed: 06/21/1985
• Issued: 03/29/1988
• Est. Priority Date: 07/01/1982
• Status: Expired due to Fees

• Current Assignee: Millipore Investment Holdings, Ltd. (Merck & Co., Inc.)
• Original Assignee: Millipore Corporation (Merck & Co., Inc.)
• Inventors: Pierog, Joseph J., Champion, Helena M., Peters, Joseph E.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/747,687
• Time in Patent Office: 1,012 Days
• Field of Search: 210/321, 210/335, 210/436, 210/472, 210/489-492, 210/927, 210/433.2, 422/101, 55/159, 555/421
• US Class Current: 210/335
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01L 3/5025 for parallel transport of multiple samples
• CPC Class Codes: B01L 3/50255 Multi-well filtration
• CPC Class Codes: G01N 33/48 Biological material, e.g. blood, urine G01N33/02, G01N33/26, G01N33/44, G01N33/46 take precedence; Haemocytometers counting blood corpuscules distributed over a surface by scanning the surface G06M11/02

Abstract

A multiwell filtration apparatus for the assay of microliter quantities is provided which prevents fluid loss by capillary action and gravity flow through a microporous membrane or ultrafilter. The filtration apparatus is particularly advantageous in assays requiring maintenance of fluid within the reaction wells for substantial time periods and in small sample volume assays in the range of 100 microliter volumes.

Claims

1. A filtration apparatus able to retain liquid for extended periods of time comprising:

a plate having a thickness and a plurality of apertures extending through the thickness of the plate;

filtration means comprising a member selected from the group consisting of a microporous membrane and an ultrafiltration membrane disposed over one end of each of said apertures such that a plurality of wells each having a discrete filtering area are formed;

a hydrophobic fabric attached to said filtration means adjacent to said filtering areas and spaced apart from said filtering areas, said filtering areas and hydrophobic fabric defining spaces where liquid can be retained, said hydrophobic fabric positioned to prevent liquid placed in said wells from passing through said filtration means and said hydrophobic fabric by capillary action and gravity flow;

operably connected means for applying a differential pressure across said filtering areas and said hydrophobic fabric for effecting passage of said liquid sequentially through a said filtering area, said filtration means, a said space and said hydrophobic fabric;

a second plate defining a plurality of chambers, only one chamber being associated with each of said apertures, and operably connected means for providing that only one said chamber receives all liquid passing through the associated aperture.

2. A filtration apparatus able to retain liquid for extended periods of time comprising:

a plate having a thickness and a plurality of apertures extending through the thickness of the plate;

filtration means comprising a membrane selected from the group consisting of a microporous membrane and an ultrafiltration membrane disposed over one end of each of said apertures such that a plurality of wells each having a discrete filtering area are formed;

a hydrophobic fabric attached to said filtration means adjacent to said filtering areas and spaced apart from said filtering areas, said filtering areas and hydrophobic fabric defining spaces where liquid can be retained, said hydrophobic fabric positioned to prevent liquid placed in said wells from passing through said filtration means and said hydrophobic fabric by capillary action and gravity flow;

a second plate defining a plurality of chambers, only one chamber being associated with each of said apertures;

operably connected means for applying a differential pressure across said filtering areas and said hydrophobic fabric for effecting passage of said liquid sequentially through a said filtering area, said filtration means, a said space and said hydrophobic fabric and into a chamber; and

operably connected means for providing that only one said chamber receives all liquid passing through the associated aperture including

a plurality of projections each aligned with an aperture and positioned beneath said filtration means to direct liquid passing through said filtration means and said hydrophobic fabric to only one of said chambers.

3. The filtration apparatus as recited in claim 1 or 2 wherein said filtration means includes a microporous membrane.

4. The filtration apparatus as recited in claim 1 or 2 wherein said filtration means includes a microporous membrane having a pore size of at least 25 nanometers.

5. The filtration apparatus as recited in claims 1 or 2 wherein said filtration means is an ultrafiltration membrane havine a pore size which effects retention of molecules ranging in molecular weight from one hundred to two million daltons.

6. The filtration apparatus as recited in claim 1 or 2 wherein said hydrophobic fabric is selected from the group consisting of woven or nonwoven polymers.

7. The filtration apparatus as recited in claim 1 or 2 wherein said hydrophobic fabric is selected from the group consisting of polyesters, polyolefins and polytetrafluoroethylene.

8. The filtration apparatus as recited in claim 1 or 2 wherein said hydrophobic fabric is heat bondable.

9. The filtration apparatus as recited in claim 1 or 2 wherein said hydrophobic fabric is attached with adhesive.