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.