Chemistry: analytical and immunological testing – Involving an insoluble carrier for immobilizing immunochemicals
Reexamination Certificate
2000-05-26
2001-10-09
Chin, Christopher L. (Department: 1641)
Chemistry: analytical and immunological testing
Involving an insoluble carrier for immobilizing immunochemicals
C210S321610, C210S321620, C210S321630, C210S321640, C210S321650, C210S321660, C210S321670, C210S650000, C210S651000, C210S782000, C385S012000, C385S015000, C385S033000, C385S129000, C356S426000, C356S427000, C422S044000, C422S063000, C422S064000, C422S068100, C422S082050, C422S082110, C422S105000, C422S105000, C366S208000, C435S007100, C435S007920, C435S287100, C435S287300, C435S287600, C435S287700, C435S288300, C435S288400, C435S288500, C435S288700, C435S297100, C435S962000, C435S967000, C436S043000, C436S
Reexamination Certificate
active
06300142
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus, instrument and device for conducting an assay. More particularly, it relates to a device suitable for use in assaying analytes, for example glycated proteins in biological samples such as, for example, blood.
BACKGROUND OF THE INVENTION
The percentage of total haemoglobin (Hb) that is glycated is widely regarded as an important tool in diabetes management, because it provides an indirect measure of the mean blood glucose concentration over the previous 2-3 months. One of the three main methods available for assaying glycated Hb relies on boronate affinity. In this method glycohaemoglobin can be separated from non-glycohaemoglobin through condensation of solid-phase dihydroxyboronate with the cis-diols present on the sugar moieties of glycohaemoglobin. This method is specific for all glycohaemoglobins which is an advantage over other methods, which rely on separation based on differences in net charge.
However, although the boronate method has certain advantages, it remains an assay which requires laboratory facilities and quite complicated equipment. In particular, the need to determine the percentage of glycated Hb present means that two assay results need to obtained and a comparison made. It is the case that rapid diagnostic assays have been developed, and continue to be developed, which make use of “simple” easy to use diagnostic devices, which can be used either by a subject in their own home, or by a subject's own doctor in the surgery. One example of such a test device is that marketed by Cortecs Diagnostics as HELISAL®ONE-STEP, which is for the detection of H. pylori infection. The principle of this device is, however, generally applicable to a range of assays. The device consists of two parts, a sample collector and a second part containing an assay strip. The collector is used to collect a sample (of blood in the case of HELISAL®ONE-STEP) and the collector is then inserted into the second part, with which is interconnects, to release the sample to an assay strip. The sample travels along the strip through various “zones” which contain various reagents, including a coloured label (blue latex particles). If antibodies to H. pylori are present then the label concentrates in a detection zone. The specifics of this particular assay are not important, however. The essential features which are common to this type of assay and which allow its use in their home or doctor's surgery are the ease of sample collection and handling as well as the simplicity in initiating the reaction and the speed with which the result is obtained. Such one-step devices can be utilised in the measurement of glycated Hb but only if the assay method can incorporate the necessary sample treatment to allow comparison of total protein with glycated protein.
SUMMARY OF THE INVENTION
To that end, therefore, we have in a first aspect of the invention devised an apparatus which allows rapid, easy sample treatment combined with compatibility with a one-step device such as that exemplified by HELISAL®ONE-STEP.
According to a first aspect the present invention there is provided an apparatus, for use in an assay in which a sample is presented to an instrument, comprising a first inlet, a second inlet, and an inlet port, said inlet port being moveable relative to each of said first and second inlets such that the port can be brought into liquid communication with each inlet in turn as required, wherein said inlet port accommodates a filter means or a binder retaining means.
In one embodiment the apparatus is adapted to be used in an assay system where some form of particulate is added to a sample which may contain a detectable analyte, where the particulate is capable of binding the analyte. Thus when the sample plus particulate is added to the inlet port, the particulate, with bound analyte, is retained by the filter. The filter can of course be constructed of any suitable material. Suitably, it will be made of material which is inert in terms of the analyte etc. Also the “mesh” of the filter must be such that it is capable of retaining particulates as used in the separation step. The inlet port can then be moved into alignment with the second inlet means and one or more reagents capable of interfering with the binding of the analyte to the particulate can be added to the inlet port. The analyte (if present) will then pass through the filter in solution, leaving the particulates behind.
Thus, taking the example of glycated Hb, a sample of blood is treated to lyse the blood cells and is then admixed with particulates, eg agarose or cellulose, to which is bound phenyl boronate. The treated sample is then introduced into the apparatus via the inlet port, which will have been moved into liquid communication with the first inlet. The liquid part of the sample, which contains non-glycated Hb, will pass through into the body of the apparatus, while the particulates, to which will be bound any glycated Hb, will be retained by the filter means associated with the inlet port. The inlet port can then be moved into liquid communication with the second inlet and the particulates can be washed with one or more suitable reagents to cause release of the bound glycated Hb from the particulates.
In an alternative approach, the inlet port can incorporate means capable of binding the analyte. For example, it could incorporate particulates such as those described above. Thus, in one embodiment the invention provides apparatus for use in a diagnostic assay, comprising a first inlet, a second inlet and an inlet port, said inlet port being moveable relative to each of said first and second inlets such that the port can be brought into liquid communication with each inlet in turn as required, wherein said inlet port incorporates binding means, capable of binding an analyte which may be present in a biological sample. Such an apparatus would of course also incorporate some means of retaining the binding means in the inlet port.
In preferred embodiments of both the above-described aspects of the invention, the apparatus will also incorporate a third inlet, and the inlet port will be capable of being moved between the three inlets as required. The third inlet will ideally be placed in an intermediate position between the first and second inlets. The provision of this third inlet will allow for an intermediate washing step to be carried out prior to treating the binding means to release the analyte. In one embodiment the apparatus will be generally circular and the inlet port will form part of a rotatable top portion of the apparatus.
In another embodiment the inlet port will be stationary and the first and second inlets will rotate into communication with the inlet port
As described above the apparatus of the present invention allows a relatively unskilled operative to treat samples, eg blood samples, for assaying in systems such as that used for measuring glycated haemoglobin.
In a preferred embodiment of the above described aspects of the invention the apparatus is designed to be used in conjunction with one-step assay devices such as those described in WO 97/18036. Thus, the apparatus of the present invention can be adapted to allow insertion of one or more sample collectors as described in WO 97/18036. In practice the one or more sample collectors will be inserted such that they are in liquid communication with the first and/or second inlets. Thus, in use, a first sample collector can be inserted such that it is in liquid communication with the first inlet. In the case of the first aspect described above, the inlet port will also initially be in liquid communication with the first inlet and the sample plus particulate is added to the inlet port which will retain the particulate, and any bound analyte, allowing the rest of the sample to pass through for collection by the first sample collector.
This sample collector can then be removed and inserted into a test instrument as described in WO 97/18036. The inlet port can then be moved to the intermediate inl
Andrewes David
Attridge John Worthington
Curtis John
Fernando Felix
Gresswell Mark
Chin Christopher L.
Hogan & Hartson LLP
Padmanabhan Kartic
Provalis Diagnostics LTD
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