Membrane-based immunoassay

Proteins bound to the surfaces of synthetic membranes retain their antigenicity and are accessible to antibody probes. The most common membrane-based immunoassay technique is called immunoblotting or, more popularly, Western blotting. In Western blotting, proteins are transferred from an electrophoresis gel to a... 

Syllabus of a 2-day Seminar on Solid Phase Membrane-Based Immunoassay, Paris, September 25-26, (1997), Millipore Corporation, Bedford, MA... 

Monji N, Cole C-A, Tam M, Goldstein L, Nowinski RC, Hoffman AS. Application of a thermally-reversible polymer-antibody conjugate in a novel membrane-based immunoassay. Biochem Biophys Res Commun 1990 172(2) 652-660. 

Dioxetanes, labeled with triggers sensitive to the alkaline-phosphatase enzyme, serve as highly sensitive chemiluminescent probes in numerous bioassays. Current applications include immunoassays, membrane-based detection of proteins and nucleic acids, and microplate-based and array-based nucleic-acid detection. ... 

A different renewable solid surface is this employed in membrane-based assays where the membrane allows the covalent immobilization of the reagents, giving rise to a more stable and reproducible assay. The membrane is brought into contact with a SPE so that the immunoassay can be directly transduced [30]. 

M.A. Penn, D.M. Drake, J.D. Driskell, Accelerated surface-enhanced Raman spectroscopy (SERS)-based immunoassay on a gold-plated membrane. Anal. Chem. 85, 8609 (2013)... 

The versatility of luminescence goes beyond intensity-, wavelength- and kinetic-based measurements. Fluorescence polarization (or anisotropy) is an additional parameter still largely unexplored for optical sensing yet widely used in Biochemistry to study the interaction of proteins, the microfluidity of cell membranes and in fluorescence immunoassays. Although only a few optosensors based on luminescence polarization measurements can be found in the literature, elegant devices have recently been reported to measure chemical parameters such as pFI or O2 even with the bare eye41. 

L. Wu, J. Chen, D. Du, and H. Ju, Electrochemical immunoassay for CA125 based on cellulose acetate stabilized antigen/colloidal gold nanoparticles membrane. Electrochim. Acta 51, 1208-1214 (2006). 

G.B. Sigal, D.G. Hafeman, J.W. Parce and H.M. Mcconnell, Electrical-properties of phospholipid-bilayer membranes measured with a light addressable potentiometric sensor, ACS Symp. Ser., 403 (1989) 46-64. J.D. Olson, P.R. Panfili, R. Armenta, M.B. Femmel, H. Merrick, J. Gumperz, M. Goltz and R.F. Zuk, A silicon sensor-based filtration immunoassay using biotin-mediated capture, J. Immunol. Methods, 134(1) (1990) 71-79. 

These PVC based ionophore carrying matrices are also membranes which can be adapted for immunoassay systems. Keating and Rechnitz (40) have described an antigen digoxin coupled to one of the potassium ionophores (eg cw-dibenzo-18 crown-6) and the resulting conjugate immobilised in the PVC membrane. 

When foreign cells enter the human body they are captured by antibodies, which attach themselves to the cell membrane surface. Complement binds to these antibodies in a specific order, after which the target cells are lysed. Because the liposome bilayer is structurally similar to the cell wall, complement can be used to completely lyse antibody-bound liposomes. Attention has to be paid to the fact that although complement is specific, some liposomes are susceptible to complement lysis, without being bound to an antibody. Most liposome immunoassays are homogeneous complement-based assays. 

Based on the principle of enzyme amplification for enzyme immunoassays adopted in the 1980s, Bobrow and associates developed a catalyzed reporter deposition technique (CARD) to achieve amplified signal for solid-phase immunoassay system and membrane immunoassays. Subsequently, this CARD technique was introduced to IHC in 1992. ... 

Immunoassay techniques rely upon synthetic antibodies that have been developed to form a complex with petroleum substances. The antibodies in the test kit are immobilised on the walls of a special cell or membrane. Water samples can be added directly, whereas soils are solvent extracted into a suitable water miscible solvent and added to the cell. A known amount of enzyme with an affinity for the antibody is added. After equilibrium is established, the cell is washed to remove any unreacted material. Colour development reagents which react with the enzyme are added. A solution that stops colour development is also added at a specific time, and the optical density is then measured. Samples showing high optical density (colour intensity) contain low concentrations of analytes. Concentration is inversely proportional to optical density. Kits are generally available for, among others, TPH, BTEX and PAH. A correction factor supplied by the manufacturer is used to calculate TPH and this is subject to variation depending on the product type. These tests do not provide information on product type and have limitations dependent upon soil type and homogeneity. Also, field extraction techniques are not as efficient as laboratory-based extraction techniques. 

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