Self-assembled monolayer antibody immobilization

Figure 8. Immobilization of antibodies via self-assembled monolayers of alkylthiols terminated with functional group (left) and self-assembled monolayers of alkylthiols terminated with biotin and subsequent capture of streptavidin (right).

The Protein Profiling Biochip is composed of six chips assembled in a flow cell cassette device. Each chip provides 200 data points (200 pillars per chip) for a total of 1200 data points per cassette. Pillars are 50 p in diameter. The mesa on each pillar is covered with a self-assembled monolayer (20 to 25 A thickness) of biotin-derivatized PLL-g-PEG groups. A constant grafting ratio of 3.5 parts Lys to 1 part PEG is maintained with variable biotin-PEG content. sAV antibody is immobilized at 0.5 to 2 pmole/cm and Fab fragments at 4 pmole/cm. ... 

Antibodies are commonly used for the capture of target molecules on the waveguides and they are immobilized by either physical adsorption or through a self-assembly monolayer (SAM). In the former situation. 

Kwon, Y. Han, Z. Karatan, E. Mrksich, M. Kay, B. K., Antibody arrays prepared by cutinase-mediated immobilization on self-assembled monolayers, Anal. Chem. 2004, 76, 5713-5720... 

Following this first published study on SPR detection of E. coli 0157 Ft7, other direct detection studies have been performed. In 2002, Oh et al. used a Multiskop SPR biosensor to detect E. coli 0157 FI7 at concentrations as low as 10" cells/mL [19]. This was done using a monoclonal antibody (Mab) immobilized on a protein G surface, similar to the study by Fratamico [18]. In 2003, Oh et al. used the same sensing system as in their previous study, but altered their sensing surface to be an optimized mixed self-assembled monolayer (SAM). This lowered the detection hmit of E. coli 0157 H7 to... 

Direct detection of a cytokine protein, recombinant human interferon-y, using an IBIS SPR sensor is presented in [60]. Several types of sensor chip coatings, including self-assembled monolayers and hydrogel-derivatized SAMs, were characterized in terms of their ability to resist non-specific adsorption from plasma. The best results with respect to plasma adsorption and surface regenerability were obtained with antibodies immobilized on the dextran-modified 11-mercaptoimdecanoic acid SAM. The detection limit for detection of human interferon-y in 1 100 diluted plasma was established at 250ngmL . ... 

Delarache, E., Sundarababu, G. Biebuyck, H., Michel, B., Gerber, C., Sigrist, H., Wolf, H., Ringsdorf, H., Xanthopoulos, N., Mathieu, H. J. (1996). Immobilization of antibodies on a photoactive self-assembled monolayer on gold, Langmuir, 12 1997. 

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