Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Sample mechanical transport means in or for automated...
Reexamination Certificate
1999-05-18
2001-07-24
Warden, Jill (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Sample mechanical transport means in or for automated...
C422S063000, C422S131000, C422S136000, C422S134000, C435S006120, C435S911000, C435S091200, C436S043000, C436S047000, C436S174000, C436S177000
Reexamination Certificate
active
06264891
ABSTRACT:
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
This invention is directed to the fields of mechanical devices and methods of organic chemistry. More particularly, this invention provides a machine for preparing chemical libraries and methods of preparing those libraries.
Chemical libraries are collections of different chemical compounds, usually of the same class. Chemical libraries are useful in screening methods to determine whether any of the compounds have particular properties. Libraries of nucleic acids are particularly useful in hybridization analysis to detect the presence of target nucleic acids in a sample.
Methods in combinatorial chemistry are useful in the creation of chemical libraries. The methods usually involve adding different units sequentially to a base molecule, either randomly or by design. Apparatuses have been described that produce libraries of nucleic acids. These include, for example, U.K. Patent 2,194,176 (Nicholson), U.S. Pat. No. 5,288,468 (Church et al.), U.S. Pat. No. 5,445,934 (Fodor et al.) and U.S. Pat. No. 5,472,672 (Brennan). Improved apparatuses that increase the speed at which libraries of molecules can be made would be a useful addition to the art.
SUMMARY OF THE INVENTION
This invention provides an apparatus for preparing chemical libraries in which the members of the library are prepared in parallel, continuous reactions, rather than batch-wise. This arrangement allows more rapid synthesis of the libraries. The apparatus is especially adapted to the preparation of libraries of polymers, such as nucleic acids, polypeptides and peptide nucleic acids. The apparatus includes a rotatable carousel that contains a plurality of reaction mounts. Each reaction mount comprises at least one reaction well arranged on a radius with respect to the axis. The radii are spaced apart at equal angles so that the wells are arranged in at least one concentric circle around the axis. The apparatus also contains a rotator that rotates the carousel step-wise around the axis. Each incremental step docks each of the reaction mounts at a different reaction station where a physical step in the chemical protocol takes place. The reactions steps generally involve at least fluid delivery to a reaction well, drainage of fluid from a well, and incubation or wait (null) steps, in which fluid is neither added to nor removed from a well. Accordingly, the apparatus of this invention includes a fluid delivery system that delivers liquid to at least one reaction well in each of a plurality of docked reaction mounts and a drain system that drains liquid by differential pressure from at least one reaction well of each of a plurality of docked reaction mounts. The rotation of the carousel and the physical steps are controlled by a programmable digital computer.
The creation of chemical libraries involves the creation of chemical linkages in a parent molecule. Usually the process is iterative, generating multiple new linkages. Frequently, as is the case for polymers, the generation of a linkage involves coupling a component to the parent molecule. The creation of a chemical linkage, in turn, can be divided into a number of sequential chemical steps. For example, the creation of a phosphodiester bond in the synthesis of a nucleic acid generally involves deprotecting a sugar moiety of a parent molecule, coupling a reactive phosphoramidite to the sugar moiety, oxidizing the phosphoramidate bond into a phosphotriester bond, and capping unreacted molecules. Ultimate removal of a protecting group generates the phosphodiester. This procedure can, in turn, be broken down into the physical steps of adding liquid containing reagents or wash solutions to a reaction well containing the parent molecule, removing liquid from the well and incubating, or waiting. These physical steps are carried out at the stations designated by the apparatus. The stations are arranged in a circle around the carousel. Each station performs, in sequence, one of the physical steps of the reaction. Thus, as a reaction mount moves from station to station the set of sequential steps is performed on the wells of the reaction mount so that after one complete rotation, the entire series of steps has been performed on the reaction wells of the mount. In this way, the chemical linkage is established on the parent molecule in the well. The parent molecule is reversibly immobilized on an inserted solid support, such as glass or an inert polymer or plastic such as polystyrene, polyethylene or Teflon™ (available from, e.g., PE Biosystems). However, the reaction mounts also are arranged in a circle around the carousel. Therefore, at each incremental step, a different physical step in the process is carried out on the wells of one of the reaction mounts. Consequently, the creation of the linkages is carried out in parallel, with each reaction mount at a different stage of the reaction. Thus, the methods of this invention do not require all the reaction wells to pass through a single step in the reaction before any other reaction well can continue on the next step. This saves considerable time in the process.
The creation of a library is limited by the number of reaction wells that one can perform a physical step on at any one time. For example, if one wishes to prepare 192 different compounds, and one has the capacity to perform a physical step on eight reaction wells at a pass, it would require twenty-four passes before the next step can begin. In contrast, by performing the steps in parallel on eight wells at a time, twenty-four sets of wells are actively engaged in the chemical steps.
In one aspect this invention provides an apparatus comprising: a) a carousel that is rotatable around an axis, the carousel comprising a plurality of reaction mounts, each reaction mount comprising at least one reaction well arranged on a radius with respect to the axis, the radii spaced apart at equal angles, whereby the wells are arranged in at least one concentric circle around the axis; b) a rotator that rotates the carousel step-wise around the axis, each incremental step docking each of the reaction mounts at a separate station; c) a fluid delivery system that delivers liquid to at least one reaction well in each of a plurality of docked reaction mounts; d) a drain system that drains liquid by differential pressure from at least one reaction well of each of a plurality of docked reaction mounts; and e) a programmable digital computer that controls the rotator, the fluid delivery system and the drain system.
In one embodiment of the apparatus: (i) each reaction well comprises a drainage hole; (ii) the carousel comprises a plate which comprises a plurality of liquid conduits that connect with the drainage holes and are engagable with the drain system; and (iii) the drain system is a vacuum drain system comprising: (1) a plurality of vacuum lines that connect with vacuum source and (2) conduit engagement means that engage the vacuum lines with a plurality of the liquid conduits when the reaction mounts are docked at a station, whereby liquid in the reaction wells is drained through the vacuum lines.
In a further embodiment of the apparatus: (i) each liquid conduit comprises: (1) a depression in the plate below the reaction mount which forms a chamber with the reaction mount, wherein the chamber communicates with the drainage holes of the reaction mount; (2) an exit port exiting under the plate; and (3) a bore through the plate the connects the chamber with the exit port; and (ii) the conduit engagement means comprises: (1) a non-rotating connector plate positioned under the carousel; the connector plate having an engagement port that is engagable with the exit port positioned at each station, wherein each of a plurality of the engagement ports is connected to a vacuum line; and (2) an actuator that raises the connector plate to engage the plurality of engagement ports with the plurality of exit ports.
In a further embodiment of the apparatus the fluid
Ha Kim D.
Heyneker Herbert L.
Simonyi Victor
Steinmiller David K.
Bex Kathryn
EOS Biotechnology, Inc.
Townsend & Townsend & Crew LLP
Warden Jill
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