Figure legends
Figure 1. Microplate Bioreactor Design. A . MXR is an array of Redbud Posts (50 µm length, 4 µm diameter) molded from a single film. The film is mounted on an acrylic backing for rigidity and topped with a laser cut double sided adhesive to define the chamber mask. The assembled “chip” can be integrated into No Bottom Microplates by peeling off the adhesive liner covering the mask and mounting under the microplate. B. RedBud Stage modified to accept multiwell microplate bioreactor. The stage provides control over the actuation rate of posts and is compatible with incubator for environmental control.
Figure 2. Oxygen Mass Transfer Coefficient Evaluation in Microplate Bioreactor. A . Comparison of Dissolved Oxygen Profile demonstrating an increased rate of oxygen recovery following deoxygenation when mixed via Redbud Labs microposts than via diffusion alone (no mixing). B. Linear (by logarithmic scale) Prediction of kLa between Unmixed and Mixed (7400 rpm) microplate reactors at a culture volume of 150 µL corresponding to kLa values of 42.48 h-1 (Mixed) and 21.24 h-1 for diffusion alone. C . kLa as a function of magnet rotational speed in the microbioreactor for three culture volumes (150 µL, 200 µL, 300 µL). At 150 µL, kLa values ranged from 12.37 h-1 (Unmixed), 14.64 h -1 (3500 rpm) 34.2 h -1 (6500 rpm) to 88.2 h -1(9000 rpm). At 200 µL, kLa values ranged from 9.60 h-1 (Unmixed), 8.88 h -1 (3500 rpm), 33.6 h -1 (6500 rpm) to 89.28 h -1(9000 rpm). At 300 µL, kLa values ranged from 3.72 h-1 (Unmixed), 9.12 h-1 (3500 rpm), 19.44 h -1 (6500 rpm) to 37.2 h -1(9000 rpm).
Figure 3. Planar (XY) Mixing Analysis. A . Comparison of planar mixing rates in wells driven by RBL posts (active mixing) versus diffusion alone (static RBL posts). Homogeneity was achieved in agitated wells in 2 minutes, verse 120 minutes in the wells mixed via diffusion alone. B . Average Relative Mixing Index (Outlined by Hashmi, 2014 [14]) of the active mixing wells (3000, 6000, 9000 rpm) over time. Wells are considered fully mixed when they achieve a RMI of 0.85. At 3000 rpm, complete mixing was achieved after 180 s, whereas at 6000 rpm complete mixing was achieved after 215 s and at 9000 rpm complete mixing was achieved after 90 s.
Figure 4. Vertical Transport Mixing Analysis. A . Video Evaluation of Vertical Transport. Images displayed are selected frames from real-time video at timepoints t=0,2.5, 5, 7.5, and 10 min. One well (shown left) includes active RBL posts, whereas the well on the right has static RBL posts to establish diffusion baseline. The RBL drive magnet was placed below the wells, operating at 9000 rpm. B . Vertical distance traveled comparison between active agitation (3000, 6000, 9000 rpm) and diffusion alone. After 10 minutes, at 9000 rpm dye traveled 4.23 mm compared to 2.93 mm (6000 rpm), 1.88 mm (3000 rpm) and 1.23 mm (diffusion alone).
Figure 5. Evaluation of Mammalian Cell Growth in Microbioreactor. A. Comparison of Chinese Hamster Ovary (CHO) growth results following 72 hr expansion in three culture vessels. When expanded in the presence of active Redbud posts, increased CHO cell growth was observed (566,000 cells/mL) compared to both standard 96-well plate (432,071 cells/mL) and the unmixed Redbud posts (499,214 cells/mL). B. Comparison of CD4+ Cell growth results in active (mixed) Redbud posts or static (unmixed) Redbud posts at two cytokine levels (110, 000). Highest cell yield was observed on day 5 where 110 condition had higher cell yields (117,500 cells/mL mixed, 72,500 cells/mL unmixed) compared to 000 condition (45,000 cell/mL mixed, 45,000 cells/mL unmixed).