Sorbent assays

Doi, H., Shibata, H., Shoji, M., Sakai, S., and Akiyama, H. (2008). A reliable enzyme linked immuno-sorbent assay for the determination of walnut proteins in processed foods. /. Agric. Food Chem. 56, 7625-7630. 

ELISA enzyme linked immuno sorbent assay... 

Figure 15.6 Comparison of the values measured by an enzyme-multiplied immunoassay technique (EMIT) assay and a molecularly imprinted sorbent assay (MIA) for determination of theophylhne in 32 patient semm samples. The correlation coefficient was 0.98. Reprinted from Vlatakis et al. (2003). Copyright 1993 Macmillan Ltd.

Use of a surrogate end point that is quick and easy to obtain Permeation experiments using a radiolabeled, fluorescent, HPLC-detectable, or radio immuno assay/enzyme linked immuno sorbent assay-detectable marker necessitate the need of extensive sample handling and sample analysis. This accentuates the cost of sample analysis and overall time spent in characterizing the efficacy of formulations. Furthermore, current state of the art fluidics systems put a fundamental limit on the number of samples handled in a given time. 

It is necessary to give some background information to understand the principle underlying immunochemical tests such as ELISA (Enzyme Linked Immuno Sorbent Assay). Such information is not always available to chemists, since chemistry and immunology have traditionally been separate disciplines. 

Atrazine herbicide in solution MAA MIP-based competitive inhibition assay (molecularly imprinted sorbent assay) 1 ug/ml Muldoon and Stanker, 1995... 

MIP-based sensors and molecularly imprinted sorbent assays... 

LAI E P C, FARFARA A, VANDERNOOT V A, KONO M and POLSKY B (1998), Surface plasmon resonance sensors using molecularly imprinted polymers for sorbent assay theophylline, caffeine and xanthan , Can J Chem, 76, 265. 

SURUGIU I, YE L, YILMAZ E, DZGOEV A, DANIELSSON B, MOSBACH K and HAUPT K (1999), An enzyme-linked molecularly imprinted sorbent assay , Analyst, 125, 13-16. 

Fig. 1. Comparison of enzyme-linked immuno sorbent assay (ELISA, left) and immuno-polymerase chain reaction (IPCR, right). During ELISA, an antibody-enzyme conjugate is bound to the target antigen. The enzyme converts a substrate in solution to a detectable product. In IPCR, the antibody-enzyme conjugate is replaced by an antibody-DNA conjugate. The subsequent addition of a DNA polymerase enzyme (e.g., Taq), nucleotides and a specific primer pair uses the antibody-linked DNA marker sequence as a template for amplification of the DNA. The PCR product is finally detected as an indicator of the initial amount of antigen.

Hepatitis B surface-antigen (HBsAg) 1995 C Factor 100 (IPCR 0.5 pg RIA 50 pg) Maia et al. [30], sandwich IPCR with subsequent PCR-enzyme linked oligonucleotide sorbent assay (see also Fig. 6 and Section 2.2.2)... 

Fig. 3. Comparison of different enzyme-linked immuno sorbent assay (ELISA) methods adapted for immuno-polymerase chain reaction (IPCR). Dependent on the purification grade of the sample to be analyzed and the availability of specific and functionalized antibodies, several typical ELISA protocols were adapted to IPCR. In the direct approach (A), the pure antigen is immobilized to the microplate surface and subsequently detected by a labeled specific antibody. If no labeled antibody is available (e.g., because of unpurified ascites fluid containing the antibody or loss in activity following labeling), a standardized labeled secondary species-specific antibody is used for detection of the primary antigen-specific antibody (B). For the detection of the antigen from matrices such as serum, plasma, tissue homogenate, and so on, a capture antibody immobilized to the microplate surface was used either in a direct (C) or indirect (D) sandwich approach, with the latter one additionally including a secondary species-specific detection antibody. For different methods of coupling antibody and DNA, abbreviated by in this figure, compare Fig. 2. Note that protein A chimeras (Fig. 2A) are not compatible with capture antibodies (Fig. 3C, D).

In the multiplex-IPCR assays carried out by Joerger and Hendrickson, DNA of different lengths was used for separation of the PCR amplificates (see Fig. 4). Results of their experiments are discussed below in Section 3.5. The ability to discriminate between different DNA markers by length is nevertheless limited by the separation capabilities of the gel. For a large number of different DNA probes, a sequence-specific detection carried out, for example, by PCR-enzyme-linked oligonucleotide sorbent assay (ELOSA Section 2.2.2) should be preferable. 

Muldoon, M.T. and L.H. Stanker (1995). Polymer synthesis and characterization of a molecularly imprinted sorbent assay for atrazine. J. Agric. Food Chem., 43 1424-1427. 

Schlaeppi, J-M., W. Fory, and K. Ramsteiner (1989). Hydroxyatrazine and atrazine determination in soil and water by enzyme-linked immuno-sorbent assay using specific monoclonal antibodies. J. Agric. Food Chem., 37 1532-1538. 

ADA BEVS BHK CHO ELISA mAb MDCK MMR SCID tPA VLP adenosine deaminase deficiency baculovirus expression vector system baby hamster kidney cell line Chinese hamster ovary cell line enzyme linked immuno sorbent assay monoclonal antibodies Madin-Darby canine kidney epithelial cells measles, mumps, rubella severe combined immunodeficiency plasminogen activator virus-like particle... 

ELOSA Enzyme Link Oligo-Sorbent Assay... 

Molecularly imprinted polymers have come to be recognised as antibody mimics since Mosbach and co-workers demonstrated the use of imprinted polymers for the sorbent assay of drugs [1], Not only in applications, but also in preparation principle, imprinted polymers can be regarded as antibody mimics the synthesis proceeds in a tailor-made fashion and the resultant polymers show specific binding for a given guest molecule. Also, imprinted polymers have many characteristic features as synthetic antibody mimics that contrast with natural antibodies. 

Batch use of imprinted polymers has been applied in the evaluation of polymers by saturation binding tests and in the applications of molecularly imprinted sorbent assays [1,23,24]. In a common procedure, imprinted polymers obtained as blocks were crushed, ground and sieved to prepare sized polymer particles. The resultant particles were then distributed into each vial and recovered by filtration after use. Recently, a new batch-type in situ procedure has been reported. It utilises a polymer coating prepared on an inner surface at the bottom of a vial and allows direct assessment of the polymers. In this section, this type of in situ preparation of imprinted polymers and an application to combinatorial chemistry are described. 

SD = selective desorption SA = selective adsorption CZE = capillary zone electrophoresis ELISA = enzyme linked sorbent assay. 

Wellenberg GJ, Banks JN. Enzyme linked sorbent assay to quantify d-biotin in blood. J Sci Fd Agric 1993 63 1-5. 

The basic tool for detecting antibodies binding to a specific antigen is the ELISA, or Enzyme Linked Immuno-Sorbent Assay [3]. In this assay, antigen-specific antibodies are detected by antigen-mediated attachment to a solid support and secondary detection with an Fc-specific enzyme-labeled secondary antibody (Fig. 2). For hapten immunization, ELISA is performed using a carrier protein, typically BSA (bovine serum albumin), different from the carrier protein used for immunization. In this manner only antibodies with binding specificity to the hapten are revealed by the assay. 

---