3.3.1 Agarose Particles
By microscopy observation, both ABT and CSS were activated by the Mix&GoTM solution with significant colour change on the particle surface. Seen from Figure 3-1 and 3-2, a dark green layer was formed outside the particle after treating with Mix&GoTM. By visual observation, the agarose particles turned from colourless to green, which supported the microscopy observation. The activated particles were also sent for zeta potential measurement and the results were around +40mV for ABT hydroxyl particle and +20mV for CSS carboxyl particle. Although the Zetasizer settings for agarose particle was not validated, the results, however, suggested successful activation of both types of agarose particles by Mix&GoTM, and the hydroxyl surfaced sample showed better compatibility compared with carboxyl surfaced one.
After activation, the …show more content…
Bare Agarose Particles: ABT Hydroxyl (left) and CSS Carboxyl (right) Figure 3-2. Mix&GoTM Activated Agarose Particles: ABT Hydroxyl (left) and CSS Carboxyl (right) Figure 3-3. Mouse IgG Coupled Agarose Particles: ABT Hydroxyl (left) and CSS Carboxyl (right) By the A280 method, the mouse IgG titration curves of agarose particle samples were determined. As showed in Figure 3-4, ABT hydroxyl agarose particle showed better compatibility in mouse IgG coupling compared with CSS carboxyl agarose particle, as more mouse IgG could be coupled to the particles at same antibody loading concentration. The highest A280 signal change appeared after 2 mg/ml mouse IgG coupling concentration for CSS particles and appeared around 3-5 mg/ml for ABT particles, suggesting the antibody concentration required for full coupling was higher in ABT particles than CSS. However, we cannot claim 2 and 3-5 mg/ml were the concentrations required for full coupling due to the existence of passive absorption. An investigational experiment about passive absorption was then performed on these