Automated chemical synthesis device

Abstract

The disclosed synthesis system is based on the idea of designing a synthesis and treatment procedure, substrates and anchor groups which enable biomolecules to be simultaneously produced in an entirely automatic manner. By using a pipetting robot to dispense the reagents, the reaction column can be arranged in a format suitable for subsequent treatment. For a pipetting robot to carry out even water-sensitive or air-sensitive synthesis protocols, certain structural measures must be taken. The operation principle of the automaton and the synthesis sequence are described below as an example of a possible solution. The automaton can work with conventional substrates and reagents. Handling, however, is simplified by new, specially adapted substrates and anchor groups. A special, simultaneous purification and aliquot portioning process improves product quality and makes the device easier to use.

1 . Apparatus for automated simultaneous chemical synthesis and optional purification of a large number of products on solid phase, which apparatus has a large number, especially from 10 to 100, preferably 48 or a multiple thereof, and preferably 400, of separate reaction vessels/reactors, which are open at the top and at the bottom, in the form of channels/reaction channels or columns/reaction columns, especially small columns, which are arranged in parallel in a block/reactor block (FIG. 6) and which are removable either together or separately; wherein support material for the synthesis, that is to say a solid phase, is placed in the channels/columns, either being arranged between two inert porous frit plates or being itself in the form of chemically modified frit or filter plates, so that liquid media added from above can be held in the reactor/reaction vessels solely as a result of surface tension and wetting of the support material; and optionally an inert gas supply is provided, and the block/reactor block is mounted on a trough connected to a vacuum pump by means of a switchable valve so that liquid media can be aspirated simultaneously from the reaction vessels/reactors and the support materials contained therein, characterised in that the upper inlets to the columns/reaction columns in the reactor block are covered by a perforated screen mounted above them or a baffle plate mounted above them, so that the reaction columns can be flooded with an inert gas, especially nitrogen or argon, and the flow of inert gas can optionally be increased considerably during the aspirating procedure; or the space above the reaction columns/reaction channels can be selectively closed off by means of a displaceable perforated screen so that the reagents can be blown out of the reaction columns or reaction channels by pressurised inert gas.  
     
     
         2 . Apparatus according to  claim 1 , characterised in that the apparatus is provided with an xyz-pipetting robot, having electronically controllable dispensing syringes/dilutors having one or more dispensing needles and optionally, in addition, having one or more dispensing manifolds, so that chemical building blocks, reagents and solvents can be distributed to the reaction vessels and each reactor can be addressed individually.  
     
     
         3 . Apparatus according to  claim 2 , characterised in that each dispensing needle is equipped with a plurality of, at least two, internal channels, which are connected to separate dispensing syringes and which consequently can be filled separately, the ends of which channels meet only shortly before the outlet (FIG. 8), so that, when a plurality of reagents are being dispensed simultaneously, mixing occurs only shortly before delivery in the tip of the dispensing needle; a channel optionally being connected to the inert gas supply also, so that a pulse of inert gas can expel the mixed volume.  
     
     
         4 . Apparatus according to  claim 2  or  3 , characterised in that the dispensing needles are mounted so as to be resilient along the longitudinal axis, so that they can be set down on the support material or top frits in the reactor channels, and so even extremely small volumes down to 1 nanolitre can be reliably deposited.  
     
     
         5 . Apparatus according to any one of the preceding claims, characterised by vessels which are sealed by means of septa and provided in a reagent block separate from the reaction block for a large number, especially from 2 to 100 and preferably 24, of chemical building blocks and reagents.  
     
     
         6 . Apparatus according to  claim 5 , characterised in that the necks of the vessels in the reactor block are sealed by means of septa and covered by a perforated screen, especially a baffle plate, mounted above them, so that they can be flooded with inert gas, preferably nitrogen or argon.  
     
     
         7 . Apparatus according to  claim 2  or  3 , characterised by transfer ports, which are connected to storage vessels/storage bottles either directly or by means of switchable valves (FIG. 6), those storage vessels optionally being arranged to be slightly pressurised, so that reagents can also be withdrawn from transfer ports by means of dispensing needles.  
     
     
         8 . Apparatus according to any one of the preceding claims, especially according to  claim 2 , characterised by solvent bottles, dispensing syringes and one or more dispensing manifolds, so that solvents and/or reagents can be distributed from solvent bottles by means of dispensing syringes or by pressurised inert gas and also by way of one or more dispensing manifolds simultaneously to a plurality of reactors row by row.  
     
     
         9 . Apparatus according to any one of the preceding claims, especially according to  claim 1 , characterised in that the support material forms a layer in the reactor channel, through which an even flow of applied reagents and/or solvents can pass solely under the action of gravity.  
     
     
         10 . Apparatus according to any one of the preceding claims, characterised by a control computer, by means of which it is possible, using a list of ASCII words of software wherein the chemical building blocks/monomers used for building up the products are coded as ASCII characters and the products are therefore described as a sequence of build-up reactions/monomer incorporation reactions by means of ASCII words, for the totality of all products for a synthesis program to be converted into valve-switching operations, dispensing-syringe movement operations and robot arm movement operations, it being possible for each monomer incorporation to consist of a succession of several reaction steps and switching operations.  
     
     
         11 . Reactor according to any one of the preceding claims, characterised by an arrangement of affinity columns (FIG. 9) which is complementary to the reactor/reactor arrangement and/or an arrangement of collection vessels which is complementary to the reactor arrangement.  
     
     
         12 . Method especially using an apparatus according to any one of the preceding claims, characterised in that, linking building blocks/linkers suitable for covalently linking the products to support material are provided, which allow final removal of the products to take place selectively under mild conditions, there being provided, especially, for the synthesis of oligomeric compounds, especially oligonucleotides or peptides, a universal linker, to which there can also be linked the building blocks of the first build-up reaction of the same chemical reaction type as that used for the further build-up reactions, as a result of which only one type of building block is needed for the entire synthesis of a class of compounds, especially only one nucleoside-3′-phosphoramidite for the synthesis of 3′-OH-oligonucleotides.  
     
     
         13 . Method according to  claim 12 , characterised in that, in the final removal reactions, the linker is, in a manner known per se, firstly converted into a labile, but still intact, form, that is to say a safety-catch linker, which is then cleaved by means of mild chemical treatment, preferably a pH change, and, especially, the covalently bonded products are purified of chemical reagents in a simple manner by means of automatic washing operations on the support material and only at the very end are eluted from the reactors into an arrangement of collection vessels which is complementary to the reactor arrangement (FIG. 9).  
     
     
         14 . Method according to claims  12  or  13 , characterised in that the target products of the syntheses are provided with a group that can be used as an affinity label, by means of which the target products can be bound to a corresponding affinity phase, and, especially, the products eluted from the reactors are transferred to an arrangement of affinity columns which is complementary to the reactor arrangement (FIG. 9) and are purified of by-products by means of automated washing operations, whereafter the target products are eluted, by means of automated washing or removal operations, from the affinity columns into an arrangement of collection vessels which is complementary to the reactor arrangement.  
     
     
         15 . Method according to  claim 12 ,  13  or  14 , wherein there are used affinity columns having binding capacities that are limited in such a manner that, even when synthesis yields differ, an identical minimum amount of target product is bound and eluted per reactor, so that all the products of a multiple synthesis can be obtained in equimolar amounts.