Toxicological evaluation of fluorescent 11-mercaptoundecanoic gold nanoclusters as promising label-free bioimaging probes in different cancer cell lines

• Published in: Toxicology in vitro Vol. 73; p. 105140
• Main Authors: Kvakova, Monika, Stroffekova, Katarina, Stofilova, Jana, Girman, Vladimir, Bomba, Alojz, Antalik, Marian
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2021; Elsevier Science Ltd
• Subjects: Annexin V; Apoptosis; Biocompatibility; Biomedical materials; Cancer; Cell viability; Cytoplasm; Cytotoxicity; Drug delivery; Drug delivery systems; Evaluation; Fluorescence; Fluorescent gold nanoclusters; Fluorescent indicators; Gold; In vitro toxicity; Iodides; Label-free; Labeling; Mammalian cells; Mammals; Medical imaging; Nanoclusters; Nanomaterials; Nanotechnology; Probes; Propidium iodide; Purification; Toxicity testing; Tumor cell lines; Fluorescent gold nanoclusters; Purification; In vitro toxicity; Label-free
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2021.105140

Due to advancement in nanomaterials and increasing use of functionalized gold nanoclusters (AuNCs) in different biomedical applications, better understanding of their potential cytotoxicity is necessary. Interactions of ultra-small fluorescent AuNCs with mammalian cells remains up to this day poorly understood, therefore, cytotoxic evaluation of thoroughly characterized ca. 2.5 nm spherical water-soluble 11-mercaptoundecanoic acid coated AuNCs (AuNC@M) with diverse fluorescent properties in variety of mammalian cancer cell lines was performed. Cell viability was assessed by traditional MTT assay and xCELLigence real time cell analyzer. Cell apoptosis was evaluated via an Annexin V-FITC/propidium iodide (PI) assay. Confocal fluorescence imaging confirmed that tested AuNC@M entered live cells and were homogeneously distributed in their cytoplasm. The results suggested that the cytotoxicity of tested nanoclusters was very low, or near the control level at concentrations 0.1 and 0.5 mg/mL in the cell lines after 24 h exposition. The purity of tested AuNC@M had no relevant effect on cell viability and no differences were observed after 24 h in our study. The low toxicity toward cancer cells further strengthens our view that AuNC@M are promising label-free fluorescent probes for bio-labelling and bio-imaging, or they can even serve as platforms for antitumor drug delivery systems. [Display omitted] •Upgraded bottom-up synthesis of AuNC@M.•Reaction time and success of synthesis are dependent on complete solubilization of MUA.•Fluorescent AuNC@M enable cellular imaging without necessity to use any organic dye.•AuNC@M induced dose, cell type and time dependent cytotoxicity and necrosis could be the main cell death pathway.•Purification process before any biomedical use of AuNCs is recommended.