Cytotoxicity of Lipoic Acid and a Novel Form of the Lipoic Acid-Based Anticancer Drug Encapsulated in Phospholipid Nanoparticles

Drug cytotoxicity study using an electrochemical analysis method without the need for labels, additional reagents, or external electrolytes offers a viable alternative to existing in vitro assays. In this study, we performed a quantitative electrochemical analysis of alpha-lipoic acid (ALA) and a novel form of ALA (ALA encapsulated in phospholipid nanoparticles, ALA-NPhs) in a concentration range of 0.25–2.5 mM. The human breast adenocarcinoma cell line MCF-7 (used as a model) was registered electrochemically at the potential of +(0.594 ± 0.009) V. A linear relationship between the electro-oxidation peak current intensity and the number of MCF-7 cells on the electrode (ranging from 10,000 to 200,000 cells; limit of detection: 7800 cells) was obtained. Cell proliferation was assessed by comparing the peak electro-oxidation current intensities of MCF-7 cells cultured for 72 h with that corresponding to the initial number of seeded cells (which correlates with the number of cells on the electrode); the resulting proliferation level was determined to be 176%. Cellular electrochemical activity was used to assess the cytotoxic effects of ALA or ALA-NPhs. The electrochemical results regarding the cytotoxic effects of the drugs at a concentration of 2.5 mM on MCF-7 cells align with those obtained via the MTT assay, showing values of (80 ± 6) % for ALA and (37 ± 9) % for ALA-NPhs.