Figure 5. 3D cell culture glucose test. Cells consumed glucose in the
cell culture medium through the decrease in the current of the w/ cell
over time. (A: Day 1, B: Day 2)
Furthermore, to assess the applicability of the fabricated biosensor for
the LOC platform 3D-bioprinted with hydrogels, we performed the glucose
readout test by using HepG2 cells in 3D hydrogels. First, the
hydrogel-containing cells were printed, and HepG2 cells were cultured
with DMEM to conduct a current test. DMEM, the medium of the cell,
contained 4.5 g/L of glucose and approximately 17.5–25 mM of glucose;
the blank value was obtained similarly (Figure 3). However, as cells
metabolized and consumed glucose contained in the medium, the
concentration of glucose in the medium decreased. The current
measurement of the medium in the hydrogel revealed that the current
decreased more reliably on Day 2 than on Day 1 (Fig. 5), indicating that
an electrode coated with Nafion/MWCNT/GOx can be used to measure the
concentration of glucose remaining in the medium as the cells consume
glucose, avoiding electrochemical interference with the interference
material contained in the cells and the medium.