Immunosensing Platforms Using Spontaneously Adsorbed Antibody Fragments on Gold

Abstract

This paper describes the construction and characterization of miniaturized antigenic immunosurfaces composed of spontaneously adsorbed Fab′-SH fragments on gold. Rabbit Fab′-SH fragments contain a free sulfhydryl group that forms a thiolate bond with a gold substrate as detailed by X-ray photoelectron spectroscopy. This approach creates surfaces of higher epitope density, a factor critical to the early detection of disease, than surfaces composed of adsorbed whole molecule IgG on gold. The viability and specificity of antigenic Fab′-SH immunosurfaces is demonstrated using atomic force microscopy and confocal fluorescence microscopy, and possible explanations for the larger epitope density are discussed.

Nanogold particle-enhanced oriented adsorption of antibody fragments for immunosensing platforms

“…The protein A-based immobilization procedure which can specifically bind antibodies in an oriented way might, however, have the problems associated with the low loading amount and unfavorable stability of antibodies bound (Nakanishi et al, 1996). In recent years, there has emerged another oriented immobilization methodology for antibodies through their native thiol ( SH) groups liberated after the splitting of the intact immunoglobulin (IgG) into two antibody fragments (Karyakin et al, 2000;O'Brien et al, 2000;Ihalainen and Peltonen, 2002;Lu et al, 1995). Karyakin et al (2000) reported that antibodies in the form of half-IgG fragments could be oriented, immobilized onto gold supports with high antigen binding capability and operational stability, the affinity constant might be 30 times higher than that measured for similar intact antibodies.…”

Electrical biochip technology?a tool for microarrays and continuous monitoring

“…These self-assembled monolayers could be chemically activated to bind DNA [15]. Thiolated DNA capture probes or protein fragments have been linked directly onto gold successfully [16,21]. The electrical array chip technology adapted this approach.…”

Self-Assembled DNA-Conjugated Polymer for Novel DNA Chip

“…A selfassembly technique can be applied to the immobilization of biomaterials, such as protein, antibody and oligonucleotide, as well as synthetic polymers, [1][2][3] to develop novel biosensor configurations. [4][5][6][7][8][9][10][11][12][13][14][15][16] In our previous work, we fabricated a reusable enzyme electrode based on the formation of a stable self-assembly technique and polyion complex. 13 Most conventional DNA chips have used the direct immobilization of probe DNA on a substrate.…”