Coating paramagnetic

I.H. Boyaci, Z.P. Aguilar, M. Hossain, H.B. Halsall, CJ. Seliskar, and W.R. Heineman, Amperometric determination of live Escherichia coli using antibody-coated paramagnetic beads. Anal. Bioanal. Chem. 382, 1234-1241 (2005). 

J. Richardson, P. Hawkins, and R. Luxton, The use of coated paramagnetic particles as a physical label in a magneto-immunoassay. Biosens. Bioelectron. 16, 989-993 (2001). 

The ability to coat paramagnetic beads with antibodies to surface antigens of bacteria has been exploited to separate and concentrate organisms from the sample. The bacteria can then be lysed, and the DNA released into the supernatant can be amplified by PCR. Such an approach has found a wide range of applications, among which is the detection of Helicobacter pylori in water and stool specimens (El). 

Fig. 37 Linear chain formation of DNA-coated paramagnetic polystyrene colloids with the different self-protection schemes displayed in Fig. 33. By using an external magnetic field, DNA-functionalized particles were brought together into linear chains, after which the temperature was lowered below the association temperature for beads, and the field turned off. (a) Representative microscopy picture of the resulting chain structures immediately after switching off the magnetic field, (b-d) Chains after 1 h at the specified temperature for particles functionalized with sticky end sequences able to form both loops and hairpins (b, c) or only loops (d). The degree of aggregation of chains in (d) is intermediate between the unprotected, branched chains in (b) and the perfectly linear, protected chains in (c). Adapted with permission from [157]...

Streptavidin-coated paramagnetic beads Biotinylated CF-B Probe... 

Tris(hydroxymethyl)methylamine (TRIS), sodium chloride, sodium citrate, ethylenediamine tetraacetic acid disodium salt (EDTA), lithium chloride, Tween 20, streptavidin 10 nm colloidal gold labelled, hydrochloric acid (37%), nitric acid, streptavidin-coated paramagnetic beads (MB) with a diameter of 2.8 pm, Dynabeads M-280 Streptavidin (Dynal Biotech, Oslo, Norway) biotinylated probe oligonucleotides which sequences are shown in Table 53.1. 

Fig. 9. Enzyme electrochemiluminescence (ECL) immunoassay protocol, (a) Trinitrotoluene (TNT) and dini-trophenyl of haptenylated dextran compete for antibody-binding sites, (b) Antibodies attached to dextran bound to streptavidin-coated paramagnetic beads, (c) ECL detection of enzyme-labelled antibodies magnetically concentrated on electrode. Reprinted from Wilson et al. [68], Copyright (2003), with permission...

TS-100 Thermo Shaker (Spain) for the binding of streptavi-din-coated paramagnetic beads (MB) with biotinylated probe (Immobilization DNA) and hybridization events. 

Streptavidin-coated paramagnetic beads of diameter 2.8 pm (concentration lOmg/mL) - Dynabeads M-280 Streptavi-... 

Fig. 3. Functionalization of monomaleimido-Nanogold 1.4nm diameter (A). Schematic representation (not in scale) of the analytical protocol (B) (I) Immobilization of the biotinylated CF-A probe onto streptavidin-coated paramagnetic beads (MB) (II) addition of the Target CF to the first hybridization event (III) addition of monomaleimido-nanogold (AuNPs) functionalized with signalling thiolated CF-B probe to the second hybridization event (IV) accumulation of final conjugate on the surface of the M-GECE and (V) magnetically trigged direct DPV electrochemical detection of AuNPs tags in the conjugate.

A TS-100 ThermoShaker (Spain) is used for all the incubations for the binding of streptavidin coated paramagnetic beads with biotinylated primary antibody. 

Preparation of template Typically for a reaction 15-/tl streptavidin-coated paramagnetic beads (Dynal) are washed twice with 2(X) /il each of the B/W buffer (Dynal), suspended in 15 tl B/W buffer and added to the PCR reaction mixture. After incubation for 30 minutes at room temperature, the supernatant was removed through magnetic separation and the beads incubated with 50 pA 100 mM aqueous NaOH for 5 minutes at room temperature to denature the non-biotinylated DNA... 

Boyaci IH, Aguilar ZP, Hossain M, Halsall HB, Sehskar CJ, Heineman WR (2005) Amperometric detennination of hve Escherichia coli using antibody-coated paramagnetic beads. Anal Bioanal Chem 382 1234-1241... 

To contribute to the elaboration of a p-TAS, Furdui et al. developed an immnnomagnetic cell separation technique on a microfluidic platform combined with magnetically trapped bead beds, to isolate specific cells from blood samples, in order to make the sample clean (Figure 14.7). Protein A-coated paramagnetic beads (1 to 2 pm of diameter), functionalized with antihuman CD3, are first introduced into the chips and captured in a field generated by an external magnet A blood sample is then introduced T cells are captured, rinsed, collected at the chip outlet and moved to a different module (off-chip in this case) for subsequent analysis. Several different formats for the fluidic design of a... 

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