Studying the interaction of alpha-gal carbohydrate antigen and proteins by quartz-crystal microbalance

Abstract

The interaction of alpha-galacosyl antigen and its binding protein (anti-Gal antibody) has been studied by quartz crystal microbalance through a SAM immobilization technique which overcomes the nonspecific interactions and molecule trapping for current piezoelectric biosensors.

Figure 1

Thiol-tailored trisaccharide α-Gal immobilized on Au surface.

Figure 2

(a–c) Frequency change vs time curve when (a) 50 µL of 1 × 10⁻⁵ M ConA; (b) 30 µL of 1 × 10⁻⁶ M polycolonal anti-Gal antibody; (c) 20 µL, 40 µL, and 50 µL of 7.6 × 10⁻⁶ M lectin GS-1-B₄ and 40 µL of PBS (pH 7.2) buffer were added to trisaccharide α-Gal modified unpolished Au electrode in 3 mL of PBS buffer, respectively. (d) Reciprocal plot of [anti-Gal]₀/Δf vs [anti-Gal]₀, apparent K_d value was (2.8 ± 0.3) × 10⁻⁸ M. The average value of four measurements was (3.5 ± 1.2) × 10⁻⁸ M (Table 1).