Abstract: A neural modeling device comprising an electrolyte, a lipid or lipid-impregnated membrane which is situated in the electrolyte and in which an ion pump and an ion channel are buried, and an electrode for transmitting a potential of the lipid or lipid-impregnated membrane as an electrical signal. The ion pump actively transports selected ions in the electrolyte through the membrane from one side to the other side in response to an external stimulus such as light irradiation. When the difference in potential between the opposite sides of the membrane reaches a threshold, the ion channel opens to passively transport selected ions in a direction reverse to the ion transporting direction of the ion pump. When this device is exposed to light, the ion pump actively transports ions to generate a potential in the lipid or lipid-impregnated membrane.

Abstract: A passive process for selectively sensing analyte molecules in a fluid by reflection of acoustic waves from a sensing surface of a bulk accoustive wave quartz sensing device to which analyte molecules bind is provided. The sensing surface has a plurality of receptors for which analyte molecules have an affinity. The process has the following steps:i) contacting a fluid in which analyte molecules are suspected with the sensing surface so that acoustic waves are reflected from the sensing surface;ii) directing acoustic waves at the sensing surface; andiii) detecting a change in a characteristic of acoustic waves reflected from the sensing surface due to analyte molecules binding the receptors. The change in a reflected acoustic wave characteristic being measured by electrical means detecting values which are related to the amplitude and phase of the reflected acoustic waves.

Abstract: The present invention relates to contrast enhancing agents, conjugates thereof, pharmaceutical compositions thereof, and methods for diagnostic analysis, particularly NMR image analysis using these agents. The contrast enhancing agents are chelates of paramagnetic, ferromagnetic or diamagnetic metal ion(s) complexed with new lipophilic complexing acids related to polyaminopolycarboxylic acids.

Abstract: The invention relates to synthetic proteins that can be used in in vitro sensing devices to detect the presence of physiologically active substances. The synthetic proteins are mimetic to native ion channels in mammalian systems. The invention also relates to a biosensor comprising a support assembly, a synthetic lipid bilayer containing the active channel protein. Lastly, the invention relates to the use of the biosensor disclosed in the application for the in vitro detection of physiologically active substances including antiseptics, antibiotics, neurotransmittors, and others.

Abstract: Novel contrast media for use in magnetic resonance imaging are described. Such contrast media are comprised of biocompatible polymers either alone or in admixture with one or more contrast agents such as paramagnetic, superparamagnetic or proton density contrast agents. Additionally, the polymers or polymer and contrast agent admixtures may be mixed with one or more biocompatible gases to increase the relaxivity of the resultant preparation, and/or with other components. In a preferable embodiment, the contrast medium is hypoosmotic.

Abstract: In accordance with the present invention, compositions comprising fluorine-containing magnetic resonance imaging agent(s) contained within polymeric shells are provided. Invention compositions are useful, for example, as contrast agents for magnetic resonance imaging (MRI). Fluorinated compounds in general are hydrophobic and as such have limited water solubility; thus the invention method permits preparation of such compounds in a biocompatible form suitable for ready delivery. The shell diameter is typically approximately 2 microns in diameter. Consequently, these materials have organ specificity due to rapid scavenging by the reticuloendothial system (RES) or the mononuclear phagocyte (MNP) system upon intravenous injection. Furthermore, fluorocarbon filled polymeric shells of the invention can be used to measure and monitor local oxygen and temperature.

Abstract: A contrast medium useful for diagnostic imaging is provided. The contrast medium comprises gel particles, preferably of less than about 90.mu. in mean diameter, the gel particles comprising at least one polymer entrapping at least one contrast enhancing metal.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages or these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: An apparatus and a method for analyzing particles suspended in a liquid are described, which particles are of a type or are prepared so as to emit radiation characteristic of the particles when exposed to radiation. Particular fluorescence-photometrical flow cytometry is described in connection with biological cell populations.The apparatus comprises an elongated flow area in the shape of a channel provided in a cuvette comprising a first body member having a planar facial surface and a second body member having a planar facial surface. The first and the second body members are adapted to be moved relative to one another between a first position, in which the planar facial surfaces are in fluid-tight contact with one another, and a second position, in which the planar facial surfaces are spaced apart. At least one of the planar facial surfaces of one of the body members is provided with an elongated groove.

Abstract: Method for amperiometrically measuring the bacterial content of liquids in a bioelectrochemical cell wherein the mediator is initially oxidized in the cell, then brought into contact with a capturing system containing the bacteria of the sample, resulting in a first response at the electrodes, and finally brought into contact again with the capturing system after the bacteria present have been killed, producing a second response due to the interfering substances, which is subtracted from the first response. An apparatus is also provided for implementing this method.

Abstract: A method is described for measuring the amount of analyte present in a sample containing the analyte using a homogeneous amperometric immunoassay. The analyte is chemically bonded to a suitable carrier molecule, which is also chemically bonded to an electroactive molecule. The electroactive molecule, such as ferrocene carboxylic acid, contains a redox center which is capable of transferring a charge to an electrode. A preferred carrier molecule is bovine serum albumin (BSA), while suitable analytes include digoxin, theophylline and HCG. The immunoassay is conveniently performed by applying a voltage to a set of electrodes.

Abstract: A new class of magnetic resonance (MR) contrast agents are described whose in vivo biodistribution is based upon the ability of certain cells to recognize and internalize macromolecules, including the MR contrast agents of the present invention, via a process which substantially involves receptor mediated endocytosis. The RME-type MR contrast agents described herein comprised of biodegradable superparamagnetic metal oxides associated with a variety of macromolecular species, including but not limited to, serum proteins, hormones, asialoglycoproteins, galactose-terminal species, polysaccharides, arabinogalactan, or conjugates of these molecules with other polymeric substances such as a poly(organosilane) and dextran. One of the advantages of these MR contrast agents is that they may be selectively directed to those cells which bear receptors for a particular macromolecule or ligand and are capable of undergoing receptor mediated endocytosis.

Abstract: Starburst conjugates which are composed of at least one dendrimer in association with at least one unit of a carried agricultural, pharmaceutical, or other material have been prepared. These conjugates have particularly advantageous properties due to the unique characteristics of the dendrimer.

Abstract: Methods and diagnostic compositions are disclosed for enhancing magnetic resonance imaging which utilize a paramagnetic metal cluster. Magnetic resonance contrast media containing Z+[Mn.sub.12 X.sub.12 (OYR).sub.16 (L).sub.4 ], where OYR is an oxyacid such as benzoic acid, acetic acid, methyl sulphonic acid, methyl phosphonic acid; L is a neutral donor such as water, alcohol, pyridine, or other amines; X is a chalcogen, such as O or S; and Z is a pharmaceutically acceptable counterion are disclosed. Z may also be a paramagnetic counter ion, such as a high spin metal cluster. The paramagnetic cluster may optionally be complexed or conjugated to a carrier compound capable of altering the paramagnetic metal cluster's biodistribution, increasing its selectivity of tumor localization, and amplifying its proton relaxivity.

Abstract: A contrast enhancing agent for magnetic resonance images having a chelating agent, which can be bound to metals having at least one unpaired electron. Examples of such chelating agents include 3,6,9-tris(carboxymethyl)-1, 11-bis(dimethylamine)-3,6,9-triazaundecane; 3,6,9-tris(carboxymethyl)-1, 11-bis(diethanolamino) 3,6,9-triazaundecane; 3,6,9-tris(carboxymethyl)-1, 11-bis(tris(hydroymethyl) aminomethane)-3,6,9-triazaundecane; 3,6-bis(carboxymethyl-1,8-bis(N-carboxymethylglucosamino)-3,6-diazoctane; DTPA-bis(galactosamide), DTPA-Bis(glucosamide), DTPA-Bis(pyridoxamide), and poly-(DTPA-ethylenediamide).

Abstract: A composition containing magnetic metal oxide ultrafine particles, which comprises an aqueous sol of a complex of the magnetic metal oxide ultrafine particles with a polysaccharide, a polysaccharide derivative and/or a protein; and an organic monocarboxylic acid. The composition is free of side effects such as platelet aggregation, is safe for use with living bodies, and, in the case of intravascular administration, has no harmful effects on living bodies, and is useful in fields such as medicine and diagnostic drugs.

Abstract: Accordingly, the present invention is directed to biological compounds derivatized so as to contain at least one perfluoro-t-butyl moiety for use in fluorine-19 NMR and/or MRI studies. The perfluoro-t-butyl (PFTB) moiety, ##STR1## is an excellent reported group for fluorine-19 NMR/MRI. It is a source of nine magnetically equivalent fluorine nuclei which generate a single intense resonance for each detection in spectroscopy or imaging. This signal is a sharp singlet, not split by neighboring nuclei or spread over a wide frequency range and eliminates any change of ghost images which might arise from multiple resonances. These spectral properties ensure a maximum signal-to-noise ratio (S/N) for readily detecting this moiety. The foregoing allows either reduction in the concentration of the derivatized compound, ability to use MRI instruments with lower field strengths, a reduction in imaging times, or a combination of the foregoing as a result of this moiety producing a single, sharp, intense resonance.

Abstract: Hybrid agents for enhancing in vivo diagnostic imaging of body organs and tissues, and methods of preparing and using the same.

Abstract: An amperometric biosensor and method for the detection of hydrogen peroxide, NADH, or NADPH with high sensitivity includes an electrode having on its testing surface a three-dimensional redox polymer network in which peroxidase is immobilized.

Abstract: An immunoassay method using magnetic particles comprising a core and a coating layer on the surface thereof, The core comprises an organic polymer and the coating layer comprises an iron oxide type ferrite coating layer. An antigen or an antibody is bound onto the surface of the coating layer and the particle has a particle size of 0.2 to 3 .mu.m.

Abstract: The present invention relates to a process for determining or detecting by immuno adherence a biological substance present in a sample, which consists in introducing the sample into a receptacle on whose walls there is a component which has a specific immunological affinity for the substance to be tested for, in adding magnetic particles on which there is a substance which has a specific immunological affinity for the substance to be tested for, in subjecting them to several successive magnetic actions in order to accelerate the deposition of the said particles onto the walls and to displace those which have not formed specific bonds with the substance to be tested for which adheres to the walls via the component with affinity which is fixed thereto, and in observing the particles deposited.

Abstract: The preparation and isolation of biodegradable superparamagnetic MR imaging contrast agents for the vascular compartment is described. These aggregates are comprised of individual biodegradable superparamagnetic metal oxide crystals which aggregates have an overall mean diameter less than about 4000 angstroms. The preferred vascular imaging contrast agent is comprised of aggregates of iron oxide crystals having an overall mean diameter less than about 500 angstroms. These contrast agents may be associated with a macromolecular species, which assist, among other things, in the preparation of these extremely small materials, and may be dispersed or dissolved in a physiologically acceptable medium. Preferred media also stabilize the materials against further aggregation even under harsh sterilization conditions.

Abstract: The invention relates to a modification of electron spin resonance enhanced magnetic resonance imaging (ESREMRI) in which two magnetically responsive materials (contrast agents) are introduced into the sample being investigated, one contrast agent serving as an ESREMRI free induction decay signal enhancing agent and the other as enhancement suppressing agent. In this way, image contrast may be enhanced further for regions in which the suppressing agent distributes poorly or not at all or which the suppressing agent reaches at a later time than the enhancing agent.

Abstract: The change in electrical resistance of an electroactive polymer such as polypyrrole, polyaniline or polythiophene when it reacts with an analyte is used to measure the analyte. The open circuit electrical potential of an electroactive polymer film is measured and an electrical potential is applied to the polymer film relative to a reference electrode to oxidize or reduce the polymer film to provide an initial reduced or oxidized state. Then the electrical resistance of the polymer film is measured in the absence of an analyte and the electrical resistance is again measured while the polymer film reacts with the analyte. The analyte concentration is determined from the rte and total amount of electrical resistance change.

Abstract: A method whereby the presence and/or amount of a chemical moiety containing terbium is determined by applying an electrical pulse to an electrode immersed in a solution and measuring the delayed light emission after some time from the end of the pulse, said chemical moiety being either bound to said electrode and/or present in said solution and said emitted light being taken as an indication of the amount of the chemical moiety present in the proximity of said electrode.

Abstract: An enzyme electrode is disclosed for use in voltammetric systems wherein a PQQ dehydrogenase enzyme is chemically bonded to a water soluble polyvinylpyridine osmium bipyridine polymer. The enzyme and polymer are adsorbed onto the surface of the electrode with the polymer providing direct electron transfer from enzyme to electrode and vice-versa without the aid of additional mediators or electron shuttles added to the system.

Abstract: A method is disclosed for detecting the occurrence of a binding or complex-forming reaction between specific substances by utilizing the binding reaction to modify an electrical circuit, and then measuring a change in the electrical state of the circuit. A diagnostic element useful in such a method includes a layer of a biogenic substance, such as an antigen, coated onto a non-conductive base between a pair of electrical conductors superposed on the base. Antibodies which react with the antigen are treated so that they become bound to particles. The particles having antibody bound thereto are then added to is the antigen lay e base and allowed to react therewith. The particles are thereby bound to the base due to the binding reaction between the antigen and antibody to thereby form aggregates of electrically conductive particles which modify the circuit. The particles are then selectively coated with a conductive substance.

Abstract: A device and process for detecting the presence of organic molecular analytes in a fluid comprising a first binding component having a predetermined first affinity for specifically reversibly binding an analyte, a molecular conjugate of the analyte with a signal generating molecule that generates a detectable signal, and a second binding component having a predetermined second affinity for reversibly binding the signal generating molecule. In the presence of analyte, a fluid conducting system allows competitive binding of the analyte with the molecular conjugate and causes displacement of the conjugate and conducts the displaced conjugate to the second binding component. The signal generating molecule generates a detectable signal distinguishing binding thereof at the first or second binding components thereby indicating the presence of the analyte in the fluid.

Abstract: Methods are disclosed for detecting the effects of cell affecting agents on living cells. The method steps include providing living cells that are retained in a micro flow chamber. The micro flow chamber is adapted for either continuous or intermittent flow of solutions or suspensions in intimate contact with the cells. The solutions or suspensions, which contain a cell affecting agent, are then flowed in intimate contact with the cells and at least one effect of the cell affecting agent on the cells is measured by an appropriate detecting means, which is operatively associated with the micro flow chamber.

Abstract: Compositions comprising a covalently bounded adduct of deferoxamine, ferric iron and polymer for image enhancement in magnetic resonance (MR) imaging are provided. A pharmaceutical composition comprising the adduct and method of using the composition in magnetic resonance imaging are also disclosed.

Abstract: Enzyme electrodes having a surface coated with a film. The film is formed from materials in which a redox enzyme is covalently bonded to a three dimensional molecular structure. The molecular structure is of the class having multiple redox centers, for example, a crosslinked redox polymer.

Abstract: Improved compositions and methods for selective access to tumor regions (or other regions of abnormal endothelial properties). This capability provides powerful contrast-enhancement agents for nuclear magnetic resonance imaging. A polyatomic complex which includes intramolecular ferromagnetic coupling between metal atoms is associated with a polymer or microsphere carrier matrix which will bind to endothelial determinants. A solution containing this carrier complex is injected into a human (or other) body to be imaged. The carrier complex will preferentially extravasate at locations where the blood vessel walls have increased porosity or microvascular surface changes, and especially at tumor sites. Thus, the changes in relaxation time induced by the presence of the carrier complex will provide a high-gain marker for magnetic resonance imaging.

Abstract: The present invention involves a novel tripyrrole dimethine-derived "expanded porphyrin" (texaphyrin), the synthesis of such compounds, their analogs or derivatives and their uses. These expanded porphyrin-like macrocycles are efficient chelators of divalent and trivalent metal ions. Metal complexes of these compounds are active as photosensitizers for the generation of singlet oxygen and thus potentially for inactivation or destruction of human immunodeficiency virus (HIV-1), mononuclear or other cells infected with such virus and tumor cells as well. A variety of texaphyrin derivatives have been produced and many more are readily obtainable. Various metal (e.g., transition, main group, and lanthanide) complexes with the texaphyrin and texaphyrin derivatives of the present invention have unusual water solubility and stability which render them particularly useful. These metallotexaphyrin complexes have optical properties making them unique as compared to existing porphyrin-like or other macrocycles.

Abstract: A new ligand binding assay is based upon measurements of relaxation rates of the solvent, which are obtained with a magnetic resonance (MR) spectrometer. It is termed a solvent mediated relaxation assay system (SMRAS). SMRAS is based on the observation that the enhancement of proton relaxation rates produced by a magnetic material can be modulated by the binding of various analytes to a magnetic material. Hence the relaxation rate of the solvent can be interpreted to give information on the concentration of an analyte.

Abstract: An Fc receptor protein conjugated with Ferritin binds to an exposed Fc region of an antibody to form a cell/Ferritin complex. Magnetic particles are added to the medium and bind to the complex. The magnetic particles when bound to the complex significantly enhance the magnetic field gradient of the complex such that it may be separated magnetically from the medium.

Abstract: There is provided a contrast medium comprising a physiologically tolerable paramagnetic metal species containing substance together with a water soluble iodinated X-ray contrast agent. The contrast medium can be used for both X-ray and magnetic resonance imaging of the gastro-intestinal tract but overcomes or greatly reduces the side effects experienced by mannitol-containing prior art contrast media.

Abstract: A chemical moiety is disclosed which comprises a chemical, biochemical, or biological substance attached to one or more electrochemiluminescent organometallic compounds. In a preferred embodiment of the invention the substance is attached to one or more ruthenium-containing or osmium-containing luminescent organometallic compounds. Methods are disclosed for detecting very small amounts of the chemical moiety using chemiluminescent, electrochemiluminescent, and photoluminescent means. Compounds are disclosed which are useful for labelling substances of interest with ruthenium-containing and osmium-containing labels or other electrochemiluminescent labels. These labelled substances are useful in methods provided for detecting and quantifying analytes of interest in binding assays and competitive binding assays. The labelled substances are of particular use in homogeneous binding assays.

Abstract: A laser magnetic immunoassay (LMIA) method which enables detection of less than picograms of target analyte in milliliter of analyte solution. The method involves the steps of: affixing an antibody or antigen on the surface of non-magnetic carrier particles; immunoreacting the affixed antibody or antigen to capture a target analyte contained in a specimen; preparing magnetic labeled microparticles treated so as to bind with the target analyte; reacting the labeled complex to sandwich the target analyte between the magnetic particles and the non-magnetic carrier particles; separating the free species from the bound species by centrifugation; dispersing the precipitated solid to make an analyte solution; applying a spot magnetic field gradient on the analyte solution and irradiating a selected spot with a laser beam; and analyzing the resulting interference patterns to quantitatively determine the quantity of target analyte.

Abstract: A laser magnetic immunoassay (LMIA) technique is presented which combines the high detection sensitivity of the radioimmunoassay (RIA) technique with the simplicity of particle agglutination (PA) technique. The LMIA technique dispenses with the separation step of bound and free species (B/F separation), yet provides detectivity of the order of picogram of viral species per milliliter of analyte solution. The procedure includes of the steps of: preparing a superparamagnetic-labeled body of antigen or antibody; subjecting a specimen sample and the magnetic-labeled body to a specific immunoreaction to produce a reacted body; subjecting the reacted body containing both bound and free species to a spot magnetic field gradient; irradiating the spot with a laser beam; measuring the intensity of the outgoing light from the spot; and making a quantitative determination of the virus according to the time difference in the outgoing light signals generated by bound and free species.

Abstract: .sup.19 F labelled compounds are disclosed which are useful in methods of NMR imaging and spectroscopy. The compounds comprise a .sup.19 F-containing sensor moiety, and a transport polymer or substrate, and can optionally also comprise a spacer moiety to separate the sensor moiety and the transport polymer.

Abstract: An in-situ laser magnetic immunoassay ("LMIA") method which eliminates the step of B/F separation generally required in the labeling method of immunoassays. The laser magnetic immunoassay permits a quantitative determination of a target immunological substance, for example, an antigen, an antibody, lymphocytes, viruses, tumorous cells and infections cells, in an analyte solution containing both bound and free species. A transitory increase in the magnetophoretic scattering of laser beam is observed when the analyte solution contains magnetic-labeled, bound target analyte, while no such increase is observed in a control test solution, containing only the relevant reagents. A magnetophoretic LMIA apparatus is provided which includes a magnetic gradient generating device which forms an integral part of the in-situ LMIA.

Abstract: An enzyme sensor, which comprises an enzyme-modified electrode and a counter electrode, wherein the enzyme-modified electrode comprises, as electrode components, an enzyme and/or an enzyme-containing substance and mediator. The enzyme sensor is useful in analysis, such as the analysis of compounds in foods or components in the living body, the diagnosis of diseases and the control of reaction processes. The preparation of the enzyme-modified electrode is also described.

Abstract: Polyphosphonate ligands containing three or more phosphonate groups, combined with paramagnetic metal cations and administered in the form of pharmacologically acceptable salts, are useful as MRI contrast enhancement agents, which tend to localize in bone tissue without being conjugated to bone-specific biomolecules. Triazacyclononanes and tetraazacyclododecanes, with dihydroxyphosphorylmethyl or dihydroxyphosphorylethyl groups, optionally substituted at the methyl or ethyl bridges with alkyl, aryl, hydroxyl or amino groups, are particularly preferred.

Abstract: The present invention provides a biosensor comprising at least one lipid membrane, each membrane including at least one gated ion channel. The membranes comprise a closely packed array of self-assembly amphophilic molecules and the gated ion channel has a conductance which is dependent upon an electric field applied across the membrane. The biosensor of the present invention may comprise a plurality of discrete membranes each including at least one gated ion channel. The conductance of each of the membranes is measurable independently of the conductance of the other membranes.

Abstract: Improved methods of selectively localizing, imaging and/or treating tumors, which have a net negative charge, employ novel compositions containing non-immunogenic complexes having a net positive charge in a sterile solution. The complexes contain polylysine, a linking agent bound to less than all of the lysyl groups of the polylysine, and an imaging agent or a chemotherapeutic agent which is also bound to the linking agent.

Abstract: A chemical moiety is disclosed which comprises a chemical biochemical, or biological substance attached to one or more electrochemiluminescent organometallic compounds. In a preferred embodiment of the invention the substance is attached to one or more ruthenium-containing or osmiumcontaining luminescent organometallic compounds. Methods are disclosed for detecting very small amounts of the chemical moiety using chemiluminescent, electrochemiluminescent, and photoluminescent means. Compounds are disclosed which are useful for labelling substances of interest with ruthenium-containing and osmium-containing labels or other electrochemiluminescent labels. These labelled substances are useful in methods provided for detecting and quantifying analytes of interest in binding assays and competitive binding assays. The labelled substances are of particular use in homogeneous binding assays.

Abstract: Magnetic resonance imaging contrast media used to affect the relaxation times of atoms in body tissues undergoing NMR diagnosis are disclosed. Such media comprise (1) a paramagnetic, physiologically compatible complex of (a) a chelant consisting of a N-carboxy methylated tetraazacyclododecane, and (b) a paramagnetic ion of a lanthanide element of atomic numbers 59-70, or of a transition metal of atomic numbers 21-29, 42 or 44, or a physiologically compatible salt of such a complex, and (2) a toxicity-reducing amount of labile calcium ions. The labile calcium ions can be derived from a source other than a salt of said chelant, e.g. an inorganic or organic calcium salt. NMR image-enhancing compositions comprising NMR image-enhancing effective amounts of said contrast media and pharmaceutically acceptable diluents are also disclosed.

Abstract: Improved compositions and methods for selective access to tumor regions (or other regions of abnormal endothelial properties). This capability provides powerful contrast-enhancement agents for nuclear magnetic resonance imaging. A polyatomic complex which includes intramolecular ferromagnetic coupling between metal atoms is associated with a polymer or microsphere carrier matrix which will bind to endothelial determinants. A solution containing this carrier complex is injected into a human (or other) body to be imaged. The carrier complex will preferentially extravasate at locations where the blood vessel walls have increased porosity or microvascular surface changes, and especially at tumor sites. Thus, the changes in relaxation time induced by the presence of the carrier complex will provide a high-gain marker for magnetic resonance imaging.

Abstract: A method is described for measuring the amount of analyte present in a sample containing the analyte using a homogeneous amperometric immunoassay. The analyte is covalently bonded to a suitable carrier molecule, which is also covalently bonded to an electroactive molecule. The electroactive molecule, such as ferrocene carboxylic acid, contains a redox center which is capable of transferring a charge to an electrode. A preferred carrier molecule is bovine serum albumin (BSA), while suitable analytes include digoxin, theophylline and HCG. The immunoassay is conveniently performed by applying a voltage to a set of electrodes.

Abstract: The present invention relates to a method of using a polyazamacrocyclic compound or a salt thereof to measure intracellular metal ions formula ##STR1## where x is 2, 3 or a combination of p 2(s) and q 3(s) where p +q=y;y is 3 or 4;R is (CH.sub.2).sub.z P(=O)R.sup.1 R.sup.2;R.sup.1 is R.sup.3 or OR.sup.3 where R.sup.3 is alkyl, cycloalkyl or aryl;R.sup.2 is H, alkyl or ##STR2## where R.sup.4 is alkyl, cycloalkyl or aryl; and z is 1 to 3.