GB2254423A

GB2254423A - Analytical apparatus with agitation of samples

Info

Publication number: GB2254423A
Application number: GB9122053A
Authority: GB
Inventors: Aled Williams
Original assignee: ALPHA DYFFRYN CYFYNGEDIG
Current assignee: ALPHA DYFFRYN CYFYNGEDIG
Priority date: 1990-12-07
Filing date: 1991-10-17
Publication date: 1992-10-07
Also published as: AU9037291A; WO1992010754A1; GB9122053D0

Abstract

The apparatus comprises: a) a reagent package comprising at least one open topped receptacle; b) a support structure for the package comprising a platform having a plurality of magnetisable elements arranged around its edge; c) a plurality of electromagnets, each being spaced from and adjacent to a corresponding magnetisable element, and being arranged to produce controlled oscillatory movement of the support structure so as to induce circulation in a reaction mixture present in the or each receptacle; and d) a device such as a video camera for monitoring the extent of reaction (such as coagulation reaction) during induction of the circulation. The method comprises locating a reaction mixture within the or each receptacle, electromagnetically inducing circulation of the reaction mixture and monitoring the extent of the reaction during induction of the circulation.

Description

Analytical Apparatus and Method The present invention is concerned with an analytical method and apparatus, useful, inter alia, for inducing and monitoring coagulation and other reactions.

The apparatus according to the present invention is particularly applicable for studying the coagulation of human blood (although it can be used for any other reaction involving viscosity change or where thorough circulation and mixing is required in an opentopped receptacle). It is often necessary to detect the precise time at which coagulation occurs following the addition of certain substances to blood. The analysis generally comprises agitation of the sample whilst simultaneously monitoring its viscosity. It is known to shake reaction vessels (such as microplates) during an analytical procedure and subsequently monitor the extent of the reaction. However, with such apparatus it is difficult, or impossible, to carry out reproducible sample agitation.

There is now provided by the present invention an analytical method and apparatus capable of simultaneously agitating and monitoring one or more samples, such that the agitation is carried out in a controlled and reproducible manner. According to the present invention, therefore, there is provided analytical apparatus comprising: a) a reagent package comprising at least one open-topped receptacle arranged for the reaction therein of a sample and a reagent; b) support means for said package comprising a platform having, around a peripheral region thereof, a plurality of magnetisable elements; c) a plurality of electromagnets, each being spaced from and adjacent to a corresponding magnetisable element, and being arranged tc produce controlled oscillatory movement of said support means and thereby inducing circulation in a liquid present in the or each said receptacle about a respective vertical axis in the or each said receptacle; and d) means for monitoring the extent of raction between said sample and said reagent during induction of oaid circulation.

It is preferred that the magnetisable elements are located at substantially eui-distant positions around the peripheral region of the platform. Typically the magnetisable elements are of mild stee or other ferrvmagr.etic material.

In use of apparatus according to the invention each electromagnet is preferably switched sequentially (using known stepper motor technology) so as to cause attraction between a respective electromagnet and its corresponding adjacent magnetisable element. The frequency, arnpiitude and direction of this sequential "attraction process" can be varied and thus a vortex can be induced in the liquid in each receptacle, rotating around z vertical axis.

Typically, the monitoring eans can be arranged to follow separately the reaction withIn n 2 single receptacle or simultaneously the reactIons within a plurality of receptacles.

A floating object is often included in each receptacle and the monitoring means follows the movement characteristics of this object. This gives a measure of the sample viscosity and hence an indication of the extent of the reaction. Suitable monitoring means include any one of the following:a) a video camera arranged to view a plurality of receptacles simultaneously; b) an optical device such as a photodiode arranged to view each receptacle individually; c) a scanning device arranged to view receptacles in turn (e.g.

using optical fibres or a beam splitter); or d) electromagnetic means to detect a change in flux linkage with said object.

There is further provided a method comprising:a) locating within at least one open topped receptacle, disposed on a platform; a reaction mixture comprising a sample and reagent capable of undergoing a coagulation reaction with said sample; b) electromagnetically inducing circulation of said reaction mixture in the or each said receptacle about a respective vertical axis by controlled oscillatory movement of said platform; and c) monitoring the extent of reaction between said sample and said reagent during induction of said circulation.

The invention will now be further illustrated, by way of example only, with reference to the accompanying drawings wherein: Figure 1 is a plan view of apparatus according to the invention; Figure 2 is a vertical section along plane A-A of Figure 1; and Figure 3 is an enlarged plan view of a single receptacle used in the apparatus of Figure 1.

Referring to Figures 1 and 2 there is shown apparatus generally designated 1 comprising a base portion 2, a movable support 3 and an uppermost platform 4. Central axis 5-attaches the upper face of base portion 2 to support 3, whereas support legs 6 attach the upper face of support 3 to the lower face of platform 4. Fixed to platform 4, at substantially equi-distant positions, are four magnetisable elements 7. In the illustrated embodiment, these extend outwards beyond the outer circumference of support 3.

Support legs 6 and magnetisable elements 7 occupy alternating positions around the periphery of support 3. Remote from support 3 and adjacent to each element 7 are separate electromagnets 8.

Each electromagnet 8 sequentially attracts the corresponding adjacent magnetisable element 7 to produce oscillatory vibrational movement of platform 4. Microplate 9 lies on the surface of platform 4 and comprises an array (such as an 8 x 12 array) of open-topped microwells 10.

Referring to Figure 3 there is shown the circulation of the reagents within each microwell 10 as a result of the oscillatory movement of platform 4; this is anticlockwise in the illustrated embodiment, but it is of course possible to arrange for the circulation to be clockwise.

Claims

Claims:

1. Analytical analysis comprising: a) a reagent package comprising at least one open-topped receptacle arranged for the reaction therein of a sample and a reagent; b) support means for said package comprising a platform having, around a peripheral region thereof, a plurality of magnetisable elements; c) a plurality of electromagnets, each being spaced from and adjacent to a corresponding magnetisable element, and being arranged to produce controlled oscillatory movement of said support means and thereby inducting circulation in a liquid present in the or each said receptacle about a respective vertical axis in the or each said receptacle; and d) means for monitoring the extent of reaction between said sample and said reagent during induction of said circulation.

2. Apparatus according to claim 1, wherein said magnetisable elements are located at substantially equi-distant positions around the peripheral region of said platform.

3. Apparatus according to claim 1 or 2, wherein said magnetisable elements comprise mild steel.

4. Apparatus according to any of claims 1 to 3, wherein the monitoring means is arranged to follow separately the reaction within a single receptacle or simultaneously the reactions within a plurality of receptacles.

5. Apparatus according to any of claims 1 to 4, wherein said monitoring means comprises a video camera arranged to view a plurality of receptacles simultaneously; an optical device arranged to view each receptacle individually; a scanning device arranged to view receptacles in turn; or electromagnetic means arranged to detect a change in flux linkage with a floating object included in each receptacle.

6. An analytical method which comprises: a) locating within at least one open topped receptacle, disposed on a platform; a reaction mixture comprising a sample and a reagent capable of reacting with said sample; b) electromagnetically inducing circulation of said reaction mixture in the or each said receptacle about a respective vertical axis by controlled oscillatory movement of said platform; and c) monitoring the extent of reaction between said sample and said reagent during induction of said circulation.

7. A method according to claim 6, which is carried out in apparatus according to any of claims 1 to 5.