Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences 1 article published in JoVE Bioengineering Synthesis of Near-Infrared Emitting Gold Nanoclusters for Biological Applications Goutam Pramanik1, Alena Keprova1, Jan Valenta2, Vaclav Bocan3, Klaudia Kvaková1,4, Lenka Libusova3, Petr Cigler1 1Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 2Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, 3Department of Cell Biology, Faculty of Science, Charles University, 4First Faculty of Medicine, Charles University A reliable and easily reproducible method for preparation of functionalizable, near-infrared emitting photoluminescent gold nanoclusters and their direct detection inside HeLa cells by flow cytometry and confocal laser scanning microscopy is described.