Cirrhosis is the consequence of chronic liver disease, which is common in people of Asian countries. In this experimental approach, HepG2 cells are treated as experimental model (appropriate biological sample), extracted from the hepatocellular site of tissue. The author tried to demonstrate the comparison of biological damaging effects of zinc oxide nonmaterial's (ZnO NMs) and carbon tetrachloride CCl4 labeled with HepG2 cells and normal liver tissue as experimental model. Laser scanning microscopy (confocal microscopy) as well as neutral red assay (NRA) has been applied for the assessment of cell toxicity which acts as milestone in the field of photodynamic therapy (PDT). In addition, photodynamic damage in HepG2 cell line was examined using a continuous wave (CW) He-Ne laser. Malignant cell lines are a good source for the optimization of different PDT parameters. We used HepG2 (liver carcinoma) as biological sample in first and last step of our conducted experiment. At the end, two different experiments were performed to analyze the photodynamic damage. For the first one, 1 ml of ALA (300 µg /ml) was added to cell suspension and incubated for 0–24 hours then irradiated with He-Ne lasers at wavelength 630 nm at different light doses 5, 10, 15, 20 mW (0–15 minutes suggested as optimal time of irradiation for each cell line) and obtained photodynamic damage of cell line was recorded by cell count. In the second experiment, 1 ml of ALA with different concentration 0–1000 µg/ml was added to cell suspension and incubated for 48 hours then irradiated with He-Ne Laser 630 nm at light dose 20 mw (15 minutes act as time of optimization for each cellular model) and complied photodynamic damage of relevant cell line was assessed by cell count. Loss in cell viability in labeled (HepG2 cells) is significantly higher for 630 nm He-Ne (CW).