Quantifying Cytosolic Cytochrome c Concentration Using Carbon Quantum Dots as a Powerful Method for Apoptosis Detection
Cristian Silviu Moldovan,
Anca Onaciu,
Valentin Toma,
Radu Marginean,
Alin Moldovan,
Adrian Bogdan Tigu,
Gabriela Fabiola Stiufiuc,
Constantin Mihai Lucaciu,
Rares Ionut Stiufiuc
Affiliations
Cristian Silviu Moldovan
Department of Pharmaceutical Physics & Biophysics, Faculty of Pharmacy, “Iuliu Hatieganu” University of Medicine and Pharmacy, Louis Pasteur Street No. 4-6, 400349 Cluj-Napoca, Romania
Anca Onaciu
Department of Pharmaceutical Physics & Biophysics, Faculty of Pharmacy, “Iuliu Hatieganu” University of Medicine and Pharmacy, Louis Pasteur Street No. 4-6, 400349 Cluj-Napoca, Romania
Valentin Toma
Medfuture-Research Center for Advanced Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Marinescu 23/Louis Pasteur Street No. 4-6, 400337 Cluj-Napoca, Romania
Radu Marginean
Medfuture-Research Center for Advanced Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Marinescu 23/Louis Pasteur Street No. 4-6, 400337 Cluj-Napoca, Romania
Alin Moldovan
Medfuture-Research Center for Advanced Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Marinescu 23/Louis Pasteur Street No. 4-6, 400337 Cluj-Napoca, Romania
Adrian Bogdan Tigu
Medfuture-Research Center for Advanced Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, Marinescu 23/Louis Pasteur Street No. 4-6, 400337 Cluj-Napoca, Romania
Gabriela Fabiola Stiufiuc
Faculty of Physics, “Babes Bolyai” University, Mihail Kogalniceanu Street No. 1, 400084 Cluj-Napoca, Romania
Constantin Mihai Lucaciu
Department of Pharmaceutical Physics & Biophysics, Faculty of Pharmacy, “Iuliu Hatieganu” University of Medicine and Pharmacy, Louis Pasteur Street No. 4-6, 400349 Cluj-Napoca, Romania
Rares Ionut Stiufiuc
Department of Pharmaceutical Physics & Biophysics, Faculty of Pharmacy, “Iuliu Hatieganu” University of Medicine and Pharmacy, Louis Pasteur Street No. 4-6, 400349 Cluj-Napoca, Romania
Background: Cytochrome c (Cyt c) is a key biomarker for early apoptosis, and many methods were designed to detect its release from mitochondria. For a proper evaluation of these programed cell death mechanisms, fluorescent nanoparticles are excellent candidates due to their valuable optical properties. Among all classes of nanoparticles developed thus far, carbon-based quantum dots bring qualitative and efficient imaging strategies for biomedical applications as a consequence of their biocompatibility and low cytotoxicity. Methods: In this study, we synthesized carbon quantum dots smaller than 5 nm from sodium citrate and polyethylene imine. These nanoparticles were rigorously characterized, and their quenching capacity in apoptotic events was assessed in A549 cells treated with staurosporine and etoposide. For the evaluation of Cyt c release, a phenomenon directly correlated with apoptotic events, we ran a semiquantitative analysis using confocal laser scanning microscopy. Results: Carbon quantum dots were synthesized and were successfully employed for Cyt c detection by means of fluorescence microscopy. Significant drops in fluorescence intensity were observed in the case of cells treated with apoptosis-inducing therapeutic compounds compared to untreated cells, confirming Cyt c release from mitochondria to cytosol. Conclusion: Considering these results, we strongly believe this method can contribute to an indirect in vitro evaluation of apoptosis.