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Effects of chemical agents on human cell cultures (Bachelor thesis)

Nikolidaki, Olga/ Νικολιδάκη, Όλγα

Post-combustion carbon capture via chemical absorption represents a cornerstone strategy for reducing greenhouse gas emissions in industrial and maritime sectors. However, the operational use, thermal regeneration, and inadvertent release of conventional amine-based solvents raise significant occupational and biosafety concerns. In this bachelor’s thesis, the cytotoxicity of traditional amine-based solvents, specifically monoethanolamine (MEA), diethanolamine (DEA), piperazine (PZ), and 2-amino-2-methyl-1-propanol (AMP), was comparatively evaluated against the amino-acid salt potassium glycinate (GlyK). Toxicological analyses were performed across three distinct human in vitro cellular models: immortalized embryonic kidney cells (HEK293T), alveolar adenocarcinoma cells (A549), and primary dental-derived mesenchymal stem cells (hDMSCs). Furthermore, the biological impact of key operational lifecycle stages was investigated by examining unsaturated solutions, acid gas-saturated solutions (CO2 και NOx), and regenerated solutions obtained following the thermal stripping of the chemical solvents from the acid gases mentioned above. Cell viability and culture recovery dynamics were assessed via MTT assays following acute (24 h, 48 h) and prolonged (6 days) exposure, while underlying toxicological mechanisms were examined by measuring intracellular reactive oxygen species (ROS/H2O2) production and the enzymatic activity of executioner caspases-3/7, which induce apoptosis upon upstream activation by caspases-8/9. The results revealed a clear cytotoxicity hierarchy among unsaturated solvents, with PZ and AMP inducing the highest acute toxicity, MEA and DEA displaying intermediate concentration-dependent cytotoxicity, and GlyK exhibiting outstanding biocompatibility even at high concentrations (50 mM). Primary hDMSCs displayed significantly higher vulnerability than immortalized lines, serving as a highly sensitive physiologically relative model for biosafety assessment. While CO2 and NOx saturation temporarily mitigated alkaline stress due to pH buffering, high-temperature thermal regeneration increased the toxicity of DEA as a result of degradation product accumulation and hazardous nitrosative derivatives. Moreover, conventional amines caused excessive ROS production and strong activation of caspases-3/7 at lethal concentrations. In contrast, GlyK maintained ROS levels close to basal control values, did not trigger apoptotic activation, and allowed cellular proliferation across all tested forms. Overall, these findings highlight potassium glycinate as a biologically safe, non-volatile, and environmentally sustainable alternative to conventional alkanolamines for carbon capture applications in maritime and industrial sectors.