Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving antigen-antibody binding – specific binding protein...
Patent
1991-07-03
1995-08-22
Spiegel, Carol A.
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving antigen-antibody binding, specific binding protein...
4353171, 436501, 436512, 436518, G01N 33567
Patent
active
054439558
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a membrane bilayer in which each layer has incorporated therein ionophores and in which the conductance of the membrane is dependent on the presence or absence of an analyte. The present invention further relates to membranes including receptors directed against the Fc region of antibodies. In addition, the present invention also relates to devices adapted for implantation in a mammalian body, the surface of the device being coated with a membrane which includes receptors.
It is known that amphiphilic molecules may be caused to aggregate in solution to form two dimensional membrane arrays in a variety of morphologies such as monolayers, black lipid membranes, vesicles and liposomes. It is also known that such amphiphilic molecules may be formed with cross linkable moieties. Under appropriate stimulus, such as UV radiation or ionising radiation, the cross-linkable moieties can be caused to polymerise after the amphiphilic molecules have been caused to assume a suitable ordered two dimensional array. It is also known that suitable receptor molecules may be included in ordered arrays of amphiphilic molecules.
The selectivity and flux of ions through membranes can depend on the number, size and detailed chemistry of the pores or channels they possess. It is through these pores or channels that the permeating solubilised molecules pass across the membrane. It is also known that membranes may incorporate a class of molecules, called ionophores which facilitate the transport of ions across these membranes.
In co-pending application No. WO 89/01159 it is disclosed that suitably modified receptor molecules may be caused to co-disperse with amphiphilic molecules and produce membranes with altered surface binding properties, which are useful in the production of biosensor receptor surfaces of high binding ability and high binding specificity. It is also disclosed in this co-pending application that ion channels such as polypeptide ionophores may be co-dispersed with amphiphilic molecules, thereby forming membranes with altered properties in relation to the permeability of ions. This application also discloses various methods of gating these ion channels such that in response to the binding of an analyte the conductivity of the membrane is altered. The disclosure of application No. WO 89/01159 is incorporated herein by way of reference.
When membranes formed from these various components are maintained at a temperature above a critical temperature, Tc, variously known as the transition temperature, chain melting temperature or phase transition temperature, the ion channels, and receptor molecules present in the membrane are able to diffuse laterally within the two dimensional plane of the membrane.
Immunoglobins possess characteristics such as high specificity, high affinity, variety and stability, which make them ideal for use as analytical reagents. Antigen-antibody interactions form the basis of sensitive diagnostic techniques such as radioimmunoassay (RIA) and enzyme-linked immunosorbant assay (ELISA). Although these techniques are sensitive and widely used, commercial antibody-based diagnostic kits which include disposable single-use devices are semi-quantitative, time-consuming and cannot be calibrated which limits their analytical potential. The optimum immuno-based assay system should be fast, reliable, specific, sensitive and quantitative.
ELISA's and RIA's commonly immobilize the antibody via non-covalent association of antibodies with glass or plastic surfaces. This typically blocks many antibody binding sites, reducing activity and preventing precise quantitation of the number and affinity of the remaining sites. More recently, orientation of antibody binding sites has been achieved by specific attachment of the antibody or antibody fragments, F(ab).sub.2 and Fab, to a surface via groups remote from the antigen binding region. The binding between the antibody and antigen can be detected by a variety of methods some of which use electrical measurements. However, this procedu
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Baxter Claire R.
Braach-Maksvytis Vijoleta L. B.
Cornell Bruce A.
Hall Ruth M.
King Lionel G.
Australian Membrane and Biotechnology Research Institute
Spiegel Carol A.
Wortman Donna C.
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