Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Calorimeter
Patent
1990-12-13
1993-03-09
Johnston, Jill A.
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Calorimeter
356246, 385 12, 422 8211, G01N 2101
Patent
active
051925028
DESCRIPTION:
BRIEF SUMMARY
This invention relates to devices for use in chemical, biochemical or clinical test procedures, to processes for their manufacture, and to methods of using the devices.
More particularly, the invention relates to devices suitable for use in specific binding assays, among which an important group is constituted by immunoassays.
Various analytical devices for handling and metering small volumes of test samples have been described in the prior art. In particular, EP-A-171148 describes capillary fill cell devices which can be conveniently manufactured and which are suitable for specific binding assays using very small liquid samples. These devices possess a cavity or cavities each having a dimension small enough to enable sample liquid to be drawn into the cavity by capillary action, wherein a surface of the cavity carries an immobilised reagent appropriate to the test to be carried out in the device, and wherein said surface is a surface of a transparent solid plate adapted to act as a light-transmissive waveguide and forming a wall of the cavity, said plate having an edge which is substantially optically smooth ("the optical edge") and transverse, e.g. at some transverse angle, but most preferably perpendicular, to the plane of the plate. Such devices enable convenient sample collection and optical analysis in situ of the products of reaction of the sample with the said immobilised reagent. The waveguide plate should be transparent to radiation of the wavelength intended to be employed, e.g. infrared, visible and/or ultraviolet light, and one method of using a device as described in EP-A-171148 is to arrange for a fluorescent material to become bound to the immobilised reagent to an extent which will vary depending on the assay and the sample material being assayed and then to carry out optical measurement of the resulting bound fluorescent material.
EP-A-171148 discloses the possibility that for some forms of assay it may be appropriate for the wall of the capillary cavity opposite to the reagent-bearing waveguide surface to be made of a light-absorbing, opaque or reflective material, i.e. for the device to have the structure depicted in FIG. 1, described in more detail later.
The difference in angular distributions of fluorescence arising from fluorophores in the analyte solution and fluorophores bound to the waveguide surface is well known in the art. Under ideal conditions, angular discrimination of fluorescence emerging from the edge of the waveguide would be sufficient to separate the different emission signals. In practice, however, various imperfections in the device can cause fluorescence from the fluorophores in solution to be scattered and to emerge from the optical edge at angles which are normally associated with evanescently coupled fluorescence, i.e. from surface-bound fluorophores.
We have now surprisingly found that this problem can be overcome, with a significantly improved performance over structures described in EP-A-171148 including the structure depicted in FIG. 1, if the wall of the capillary cell opposite to the reagent-bearing waveguide surface is formed of a material transparent to radiation of the wavelengths involved in the assay, but a layer of opaque or light-absorbing material is applied to one or more external surfaces of the said transparent material, preferably at least to the external surface parallel to the waveguide. The term "opaque layer" will be used hereinafter to mean such a layer of opaque or light-absorbing material.
Thus, according to one aspect of the invention we provide a specifically-reactive sample-collecting and testing device possessing a cavity or cavities each having a dimension small enough to enable sample liquid to be drawn into the cavity by capillary action, one surface of the or each cavity carrying an immobilized reagent appropriate to the test to be carried out in the device, said surface being a surface of a first transparent solid plate adapted to act as a light-transmissive waveguide, said plate having an edge which is substantially optically s
REFERENCES:
patent: 4824789 (1989-04-01), Yafuso et al.
patent: 4978503 (1990-12-01), Shanks et al.
Attridge John W.
Smith Alan M.
Ares-Serono Research & Development Limited Partnership
Johnston Jill A.
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