In-vitro-Untersuchung der Zytotoxizität der synthetischen Nanomaterialien Kohlenstoffnanohörner und CdSe/CdS Nanostäbchen
by Nora Hoberg
Date of Examination:2024-10-08
Date of issue:2024-10-04
Advisor:Prof. Dr. Astrid Heutelbeck
Referee:Prof. Dr. Astrid Heutelbeck
Referee:PD Dr. Anke Zieseniß
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Abstract
English
As the variety and quantity of synthetic nanoparticles produced increases, so does the potential for inhalation uptake, including as free and airborne pollutants. This work investigated effects of synthetic nanomaterials (CNH A, CNH B and CdSe/CdS NaSt) on the human lung tumor cell lines NCI H322 as bronchial epithelial cells and A 549 as alveolar epithelial cells with the intention to provide further contributions to the complex risk profile of these substances. Cytotoxicity was assessed using the neutral red test, which examines the integrity of the lysosomal membrane and the cell membrane, and the WST 1 test, which examines an enzymatically intact mitochondrial respiratory chain. A key result of this work is that all synthetic nanomaterials tested here cause a concentration-dependent inhibition of the mitochondrial activity of both cell lines. The alveolar epithelial cells reacted particularly sensitively to exposure to the nanoparticles. A small size does not appear to be the only decisive factor for an increase in inhibition. For example, the larger CNH B fraction had a stronger cytotoxic effect on mitochondrial activity than the smaller CNH A fraction. Effective concentrations were determined in the cell lines for both CNH size fractions; bronchial epithelial cells: EC50(CNH-A) = 995.65 µg/mL, EC50(CNH-B) = 932.50 µg/mL and alveolar epithelial cells: EC50(CNH-A) = 671.06 µg/mL, EC50(CNH-B) = 501.65 µg/mL. The CdSe/CdS-NaSt, the smallest synthetic nanomaterial investigated in this work, had the strongest cytotoxic effect. The cytotoxicity tests showed concentration-dependent inhibition of CdSe/CdS NaSt greater than 100 µg/mL on cell viability in alveolar epithelial cells and mitochondrial activity in both cell lines. The lowest effective concentration of this work of 341.33 µg/mL, which causes a 50% inhibition and thus the strongest degree of inhibition, could be determined by CdSe/CdS NaSt in the cytotoxicity test for mitochondrial activity in alveolar epithelial cells. Overall, alveolar epithelial cells show stronger inhibition compared to bronchial epithelial cells due to exposure to the CdSe/CdS NaSt than due to exposure to the two CNH fractions, with differences in size within the same CNH substance class. Based on the results of both cytotoxicity tests, bronchial epithelial cells are more robust than alveolar epithelial cells. This is particularly evident in the cytotoxicity test for mitochondrial activity. In summary, it was found that both cell lines showed less inhibition in their cell viability determined by the neutral red test as a result of exposure to the synthetic nanomaterials than the mitochondrial activity determined in the WST-1 test. Mitochondrial activity provides a more sensitive marker for detecting concentration-dependent cytotoxicity.
Keywords: cytotoxicity; nanomaterial