Chemistry: analytical and immunological testing – Involving an insoluble carrier for immobilizing immunochemicals
Reexamination Certificate
1995-07-28
2001-03-06
Chin, Christopher L. (Department: 1641)
Chemistry: analytical and immunological testing
Involving an insoluble carrier for immobilizing immunochemicals
C436S538000, C436S807000, C436S810000, C436S824000, C436S809000, C435S007100, C435S007930, C435S287900, C435S288100, C435S294100, C435S299200, C435S305300, C435S305400, C435S962000, C422S051000, C422S051000, C422S067000, C422S063000, C422S068100, C422S091000
Reexamination Certificate
active
06197597
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a solid-phase determination method and equipment as well as an adapter for use in these. The invention is especially suitable for use in automatic immunodetermination systems.
BACKGROUND OF THE INVENTION
Solid-phase immunodetermination is usually carried out in one vessel so that the analyte to be determined in the sample is first allowed to react with a separating reagent bound in a solid phase, whereupon the other determination steps are carried out in the same vessel. The troublesome thing here is that you must do much dosing and removing of fluids. When there are several different determinations, a large stock of different reagents is also required.
Specification EP-A-194789 also presents a system, wherein the determination is carried out by using several vessels. The solid phase is formed by a thin strip which is moved from one vessel to another. The vessels contain the reagents needed in the determination method.
DESCRIPTION OF THE INVENTION
A determination method as defined in claim
1
has now been invented. Advantageous applications of the invention are defined in the following claims.
As used herein, a separating reagent generally means such a substance which will react with the analyte to be determined and will bind it in the solid phase. In immunodeterminations the separating reagent is usually an antigen or antibody. As used herein, a medium generally means a solution to be used at some stage of the determination, such as a reaction liquid or a washing fluid.
The solid phase used in the method is the outer surface of a solid body separate from the reaction vessel, and the determination steps are performed in two or more vessels. The solid-phase body is kept in the vessel containing the sample and the separating reaction is allowed to take place. Then intermediate steps, if such are required, are carried out in the other vessels and the phase body is finally moved over into the measuring vessel. Mediums needed in the determination are dosed beforehand into the vessels.
The phase body is of a cross-section similar to the reaction vessel, usually a circular one. In this way the diffusion distances from the solution to the solid phase will be as short as possible. In addition, the body can be used for efficient agitating of the reaction mixture.
The surface of the phase body is preferably of such a shape that fluid will flow off the surface as completely as possible. The best shape is oval with a tip at the bottom. However, the solid body may have, for example, several pins which are directed downwards. To enlarge the surface area, there may be suitable grooves or nodules on the body's surface. The reaction vessel bottom is preferably given the same shape as the phase body so that as little medium as possible will be required.
The vessels are preferably made as one unit. However, it is possible in principle to perform a-part of the steps outside the vessel unit, especially the measurement of the formed reaction product, should this be desirable. Using are outside measuring vessel could be suitable especially if the complex is observed directly from the solid phase, for example, fluoro-metrically or radiometrically.
Correspondingly, several steps may be performed in the same vessel, for example, washes. Medium may also be dosed into some vessel or removed from it. Using separate dosings might be suitable in those steps where exact dosing is not needed and where, for example, the same medium is used in several different determinations. Washes, in particular, could be such steps. However, in normal cases it is most advantageous to use such vessel units where all different mediums are ready in different vessels.
Washes at least are usually performed in intermediate determination steps. In addition, in intermediate steps the formed reaction complex is usually joined to a tracer which is then detected in the measuring step. The tracer may be either directly detectable or of such a type which will release some detectable compound, especially from a substrate. Detection usually takes place fluorometrically luminometrically, absorptiometrically or radiometrically.
There is no risk of contamination in the method, because the sample is not drawn into the equipment from the plate vessels. Besides, the method can be implemented by using simple and very reliably-operating automatic equipment. In addition, the phase body works as an effective agitating piston in the reaction vessel.
The invention is suitable, for example, for immunological, DNA-hybridization or hormone determinations.
The solid body is preferably in one piece. However, it may also be assembled into a separate frame from several parts, for example, rings.
To speed up mass transport and thus the necessary reaction time, the medium should be agitated during the reaction. This is preferably done by moving the phase body. It is especially advantageous to move the remover vertically, whereby the medium must flow through the gap between the remover and the vessel, thus blending very efficiently. To make mixing more effective, the body is constructed so wide that a gap of a suitable narrowness is formed between the vessel and the remover. Mixing can also be promoted by suitable designing of the body and the vessel.
The vessel unit forms a plate for use in one determination. The phase body may be packed into some vessel in the plate. The vessels to be used in the different steps may also be of different sizes.
The vessels are preferably closed with a film, which is punctured for carrying out the method. The film may be punctured by using the phase body, but using a separate puncturing point is recommended. The point may have cutting blades forming strips which will tear in a controlled manner. In the equipment, the puncturing point may be attached to the same actuator as the phase body. The top edge of the vessel is preferably provided with an extension against which the strips of the punctured film can rest. Closed vessels may have an inert gas phase to improve durability. The plate surface is preferably provided with a small gap between the vessels. This will reveal possible leaks under the film leading from one vessel to another.
The equipment may also have a safeguarding system which checks that there is medium in the vessel before the step is started. The phase body may function conveniently as the detector in such a system based on electrical conductivity measurement.
If desired, some suitable substance may be attached into that reaction vessel, into which the sample is brought, whereby the substance is attached to the vessel wall or to a separate solid phase remaining in the vessel. This substance will bind any such substances from the sample or from the formed complex that may disturb later determination steps.
The plate vessels are preferably in a single straight row, whereby you need to move the phase body only along a straight path in a horizontal plane in relation to the plate. The vessels of different steps may be located in any order in relation to each other. The vessels are preferably permanently fixed to one another. The plate may be made of some suitable material, preferably of plastic.
The plate is preferably provided with detent pins and the equipment with their counterparts, so that the plate can not be placed in a wrong position by mistake.
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Chin Christopher L.
Fish & Richardson P.C.
Labsystems Oy
Nguyen Bao-Thuy L.
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