Experimental Set-Up

Three different types of experiments were performed for the microcarrier screening of ten different commercial microcarriers, shown in Table 1. The three experiments are briefly described hereafter and in more detail in the following sections. A scheme of all three experiments is represented in Figure 1.

General scheme of the experiments, starting with a static microcarrier screening of 8 microcarriers and followed by a dynamic microcarrier screening of 5 microcarriers. The final experiment evaluated the hPDCs, which were dynamically expanded on the chosen microcarrier Star-Plus, in vitro as well as in vivo.

The first experiment consisted of a broad static screening in well plates using eight microcarriers (Plastic, Plastic-Plus, Star-Plus, FactIII, HillexII, Collagen; Cytodex-1, and Corning untreated). A cell pool was seeded for each of the microcarriers in six individual wells of a 24-well plate for the evaluation of seeding efficiency and proliferation rate. 24 h after seeding, three wells were sacrificed for measuring the DNA content of the cells attached to the beads and the DNA of the cells in the supernatant. After 6 days of cell culture, the three other wells of each type of microcarrier were sacrificed to measure the total content of DNA on the cells attached to the microcarriers.

The second experiment selected three microcarriers (Plastic-Plus, Star-Plus, Cytodex-1) from the static screening and added Cultispher-S and Synthemax II dissolvable to perform a dynamic microcarrier screening experiment. The same cell pool as previous screening experiment was used in combination with the five microcarriers in a dynamic expansion. Each microcarrier type was cultured in duplicates in spinner flaks of 100 mL for 8 days. The DNA and metabolites were sampled daily at the same time, before medium replacement.

The third and final experiment evaluated the dynamic expansion of cells from two different donors using one specific microcarrier, Star-Plus. The cells of these two donors were cultured in triplicate spinner flasks resulting in a total of six spinner flasks for the duration of 8 days. After the dynamic culture, the quality of the cells was extensively evaluated.