Effect of TNF-α on the viability of human HCT116 cells cultured in hydrogel particles and petri dish. The change of percentage of living cells, (N/N0 × 100%), with time at different concentrations of TNF-α when cells are cultured in hydrogel particles (a) and petri dish (b). N0 is the number of living cells at t = 0 h, and N is number of living cells at t = n hours (n = 24, 48, 72, 96, 120, 144, and 168). Error bar is presented as standard deviations of the mean that is calculated based on three sets of independent experiments.