Figure 2.

Digital xz optical sections during lysoyzme-Cy5 uptake into SP Sepharose FF. The attenuation of the signal intensity with depth is caused by absorption and scattering of the incident laser and emitted fluorescent light caused by the base matrix, adsorbed protein molecules, and fluorescence labels. (A) Image using 40 × 1.2 numerical aperture water immersion objective for 6 mM ionic strength and 26 min of uptake of 2.1 mg/ml lysozyme solution at a superficial flow rate of 2,100 cm/h. The time for front penetration to the particle center was ≈40 min. (B) Image using 63 × 1.2 numerical aperture water objective for 100 mM ionic strength and 5 min of uptake of 2.2 mg/ml lysozyme solution at a superficial flow rate of 1,060 cm/h. The time for complete uptake (no significant increase in the image intensity) was ≈15 min. (C) Vertical intensity profiles for images in A and B obtained by drawing a box 10 pixels wide vertically through the center of the particle in Scion (Frederick, MD) image software and averaging the pixels in the horizontal direction to reduce noise in the profiles. (Magnifications: ×330.)