One of the unique and appealing properties of GrowDex is the possibility to remove the matrix by enzymatic degradation. GrowDaseTM, cellulase enzyme is a purified and optimized mixture of enzymes that specifically degrades cellulose to soluble glucose without affecting the cells. The use of GrowDaseTM enables easy degradation of the matrix whilst retaining the 3D spheroid structure. The grown 3D structures, such as cell spheroids, can be sub-cultured or collected for further analysis.
As the cellular structure remains intact, detailed downstream analysis of the formed spheroids or cellular structure is possible. In addition to brightfield and confocal imaging, immunohistochemistry and scanning electron microscopy (SEM) are also possible following GrowDaseTM treatment. SEM images show that after enzyme treatment microvilli structures typical for hepatocytes are retained (Fig 1).
GrowDaseTM is delivered in 10mg/ml concentration. The amount of GrowDaseTM used in the degradation of GrowDex is dependent on the amount of cellulose in GrowDex. The recommended working concentration of GrowDaseTM is 300µg/mg (300 µg enzyme/one mg cellulose). The GrowDaseTM can be simply mixed with cell culture medium and incubated with cell-hydrogel complex at 37°C until the hydrogel has completely degraded.
Figure 1. Scanning electron microscopy (SEM) images of HepG2 spheroids after GrowDaseTM treatment and silica bioreplication reveals the microvilli structure typical for hepatocytes. Images from Liisa Kanninen (Ph.D.) and Yan-Ru Lou (Ph.D.), University of Helsinki, Finland.