3.5. Cell proliferation of bioprinted LOC and drug response
The growth of hepatocytes on the LOC was determined using the CCK-8
proliferation assay kit over a period of 10 days. The graphical data of
hepatocyte proliferation as percentage O.D. increase are shown in Fig.
7A. An increased hepatocyte proliferation rate was observed during the
initial 7 days; the number of cells increased approximately tenfold.
Post day 7, the proliferative capability reduced, and the growth of
hepatocytes saturated. The considerable increase in the initial cell
numbers was due to the abundant availability of medium and diffused
gases throughout the in-vitro model as well as sufficient space for
cellular growth and proliferation. This rapid increase in cell numbers
during the first week reduced the per-cell-volume availability of medium
components and diffused gases, inhibiting the cell growth cycle and
resulting in increased cell necrosis. Furthermore, due to the
overcrowding of cells, cell–cell contact inhibition occurred, which
restricted cellular proliferation.