Agar-gelatin hybrid sponge-induced three-dimensional in vitro 'liver-like' HepG2 spheroids for the evaluation of drug cytotoxicity.

Agar-gelatin hybrid sponges were used as scaffolds to induce the formation of three-dimensional (3D) spheroids of HepG2 cells. Agar and gelatin in 2:1 ratio were used to make films and sponges. The cell adhesive properties of the films were evaluated by the attachment kinetics. The growth kinetics of HepG2 cells was studied using MTT assay and morphology of the 3D spheroids was observed through inverted optical microscopy. The liver cell-specific functions of the 3D spheroids were evaluated in terms of albumin secretion and urea synthesis. Paracetamol was used as a model drug to investigate the use of these 3D spheroids in the preliminary cytotoxicity evaluation of drugs. The results showed that the agar-gelatin hybrid sponges induced the formation of 3D HepG2 spheroids with significant liver-specific functions. These spheroids exhibited higher amounts of albumin and urea synthesis than the control monolayer culture. These 3D spheroids were found to be more sensitive to the drug (TCIC(50) value of 4.6 mM) than the control monolayer (TCIC(50) value of 6.2 mM). The study shows that agar-gelatin-induced HepG2 3D spheroids can be used for the preliminary evaluation of the toxicity of drugs and chemicals.