Microplate carrier having magnets

• US 8,658,042 B2
• Filed: 08/26/2008
• Issued: 02/25/2014
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Tecan Trading AG (Tecan Group AG)
• Original Assignee: Tecan Trading AG (Tecan Group AG)
• Inventors: Hruschka, Teresa, Niggl, Lutz, Niklaus, Patrick, Fasching, Gerhard
• Primary Examiner(s): Mellon, David C
• Application Number:
  US12/198,210
• Publication Number:
  US 20090064800A1
• Time in Patent Office: 2,009 Days
• Field of Search: 210/222, 210/223, 210/695, 422/102, 422/104, 422/407, 422/551, 422/552, 422/553, 422/569, 422/534, 436177-178
• US Class Current: 210/695
• CPC Class Codes: B01L 2300/0829 Multi-well plates; Microtitration plates
• CPC Class Codes: B01L 3/5085 for multiple samples, e.g. microtitration plates
• CPC Class Codes: B01L 9/523 for multisample carriers, e.g. used for microtitration plates
• CPC Class Codes: B03C 1/0332 using permanent magnets
• CPC Class Codes: B03C 1/288 disposed at the outer circumference of a recipient
• CPC Class Codes: B03C 2201/18 Magnetic separation whereby the particles are suspended in a liquid
• CPC Class Codes: G01N 35/0098 involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation magnetic particles used in immunoassays G01N33/54326; magnetic separation in general B03C

Abstract

Relates to a microplate carrier (1) for a microplate (2), in whose wells (3) magnetic particles (5), which are suspended in a liquid (4), with or without samples adhering thereto are located, the microplate carrier (1) comprising permanent magnets (6) generating magnetic fields which are implemented to collect and retain the magnetic particles (5) on the floor (14) and/or on the walls (7) of the wells (3) of this microplate (2). The microplate carrier (1) according to the invention is characterized in that it comprises two permanent magnets (6) situated diametrically opposite in relation to the well (3) for each well (3) of the microplate (2), which have the same polarity directed toward the well (3) and whose magnetic axis (25) is at least essentially perpendicular to the footprint of the microplate (2) to be placed. A corresponding method based on the use of the microplate carrier (1) is also disclosed.

Claims

1. A microplate washing device with a microplate carrier for carrying a microplate, the microplate having an array of wells and a footprint according to the SBS standard, as published by the American National Standards Institute, the wells comprising a center, a floor, and walls, the wells further comprising magnetic particles, the magnetic particles being suspended in a liquid with or without samples adhering thereto;

wherein the microplate carrier comprises 108 permanent magnets generating magnetic fields to collect and retain the magnetic particles on the floor and/or on the walls of the wells of the microplate;

wherein all of the permanent magnets of the microplate carrier have an identically oriented polarity and an upper face and a magnetic axis, which magnetic axis of each permanent magnet is at least essentially perpendicular to the footprint of the microplate;

wherein the permanent magnets of the microplate carrier are situated so that for the microplate that is placed on the microplate carrier in a processing position, two of the permanent magnets are situated diametrically opposite in relation to each well of said microplate each well of the microplate being situated above the upper faces of the two permanent magnets of the microplate carrier assigned to said well; and

wherein all the permanent magnets of the microplate carrier have an identically-oriented polarity;

wherein the permanent magnets are oriented with their magnetic axes along column axes 1 to 12 of a 96 well standard microplate placed on the microplate carrier, so that for each well of said microplate the well center is located in the middle between two adjacent permanent magnets arranged in the respective column axis and assigned to said well and that said two adjacent permanent magnets generate an at least essentially particle-free space in the well assigned thereto, the at least essentially particle-free space extending over essentially the entire diameter of the well transversely to a column axis connecting said two adjacent permanent magnets.

2. The microplate washing device according to claim 1, wherein the permanent magnets are essentially cylindrical, the north pole or the south pole being located on the upper circular face of the cylinder.

3. The microplate washing device according to claim 1, wherein the essentially particle-free space is implemented to allow a cannula of the microplate washing device to be lowered into a well and the liquid to be aspirated from this well, without a significant quantity of the magnetic particles being suctioned off by the cannula.

4. The microplate washing device according to claim 1, wherein the floor of the wells is selected from a group which comprises flat floors, round floors, and V floors.

5. A method for processing a microplate in the microplate washing device of claim 1, wherein the method comprising the steps of:

placing a microplate having an array of wells and a footprint according to the SBS standard, as published by the American National Standards Institute, in whose wells magnetic particles, which are suspended in a liquid, with or without samples adhering thereto are located in a processing position on the microplate carrier of the microplate washing device;

generating an essentially particle-free space in each well of the microplate by the two adjacent permanent magnets assigned to each well, the at least essentially particle-free space extending over essentially the entire diameter of the well transversely to a column or row axis connecting said two adjacent permanent magnets;

lowering at least one cannula of the microplate washing device into the essentially particle-free space in each well; and

aspirating a majority of the liquid from each well, without a significant quantity of the magnetic particles retained on the floor and/or on the walls of the wells of the microplate being suctioned off by this cannula.

6. The method according to claim 5,

wherein a re-suspension liquid is dispensed into each well of the microplate using at least one cannula of the microplate washing device, the magnetic particles retained on the floor and/or on the walls of the wells of this microplate being re-suspended by the turbulence of the inflowing liquid.

7. The method according to claim 6, wherein the re-suspension is supported using a shaking device, onto which the microplate is transferred.

8. The method according to claim 5, wherein, to elute the samples adhering to the magnetic particles, at least one suctioning cannula of the microplate washing device is lowered into the essentially particle-free space in each well, and a majority of the liquid is aspirated, without a significant quantity of the magnetic particles retained on the floor and/or on the walls of the wells of the microplate being suctioned off using the suctioning cannula.

9. The method according to claim 8, wherein an eluent is dispensed into each well of the microplate using at least one dispensing cannula of the microplate washing device, the magnetic particles retained on the floor and/or on the walls of the wells of this microplate being re-suspended by the turbulence of the inflowing eluent and the samples being detached from the magnetic particles.

10. The method according to claim 5, wherein the at least one cannula is lowered into the center of the well when the microplate comprises a round floor or V floor well, or onto the periphery of the well when the microplate comprises a flat floor well, to suction off the liquid.

11. The method according to claim 5,

wherein the magnetic particles are collected and retained at identical locations on the floor and/or on the walls in each case in all wells of the microplate;

and

wherein the microplate washing device comprises a washing head with a cannula array of suctioning cannulas, all suctioning cannulas of the washing head encountering exactly identical situation and geometry of the magnetic particle configuration for suctioning the liquid from the wells.

12. A microplate washing device with a microplate carrier for carrying a microplate, the microplate having an array of wells and a footprint according to the SBS standard, as published by the American National Standards Institute, the wells comprising a floor and walls, the wells further comprising magnetic particles, the magnetic particles being suspended in a liquid with or without samples adhering thereto;

wherein the microplate carrier comprises 104 permanent magnets generating magnetic fields, the permanent magnets, each having a magnetic axis and an upper face, being configured to collect and retain the magnetic particles on the floor and/or on the walls of the wells of the microplate;

wherein all of the permanent magnets of the microplate carrier have an identically oriented polarity and the magnetic axis of each permanent magnet is at least essentially perpendicular to the footprint of the microplate;

wherein the permanent magnets of the microplate carrier are situated so that for the microplate that is placed on the microplate carrier in a processing position, two of the permanent magnets are situated diametrically opposite in relation to each well of said microplate, each well of the microplate being situated above the upper faces of the two permanent magnets of the microplate carrier assigned to said well; and

wherein the permanent magnets are oriented with their magnetic axes along row axes A to H of a 96 well standard microplate placed on the microplate carrier, so that for each wells of said microplate the well center is located in the middle between two adjacent permanent magnets arranged in the respective row axis and assigned to said well and that said two adjacent permanent magnets generate an at least essentially particle-free space in the well assigned thereto, the at least essentially particle-free space extending over essentially the entire diameter of the well transversely to a row axis connecting said two adjacent permanent magnets.

13. The microplate washing device according to claim 12, wherein the permanent magnets are essentially cylindrical, the north pole or the south pole being located on the upper circular face of the cylinder.

14. The microplate washing device according to claim 12,

wherein the essentially particle-free space is implemented to allow a cannula of a the microplate washing device to be lowered into a well and the liquid to be aspirated from this well, without a significant quantity of the magnetic particles being suctioned off by the cannula.

15. The microplate washing device according to claim 12,

wherein the floor of the wells is selected from a group which comprises flat floors, round floors, and V floors.