FULL ARTICLE Nanodiamond for biolabelling and toxicity evaluation in the zebrafish embryo in vivo Y.-C. Lin 1 , K.-T. Wu 1 , Z.-R. Lin 1 , E. Perevedentseva 1, 2 , A. Karmenyan 1 , M.-D. Lin 3 , and C.-L. Cheng* ,1 1 Department of Physics, National Dong Hwa University, 1, Sec. 2 Da Hsueh Rd., Shoufeng, 97403 Hualien, Taiwan 2 P. N. Lebedev Physics Institute, Russian Academy of Science, Moscow, Russia 3 Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan Received 24 November 2015, revised 27 February 2016, accepted 1 March 2016 Published online 20 April 2016 Key words: nanodiamond, bioimaging, embryonic developmental toxicity, zebrafish embryo 1. Introduction With the nanotechnology advancement in material development, biomedical applications have also en- tered the nanoworld [1, 2]. Among all recently de- veloped nanomaterials, nanodiamond (ND) has emerged as a new class of nanomaterial in the car- bon families with superb physical and chemical prop- erties for these purposes [3]. Its low cytotoxicity in cellular models and high surface engineering possibi- * Corresponding author: e-mail: clcheng@mail.ndhu.edu.tw Nanodiamond (ND) has been proposed for various bio- medical applications, including bioimaging, biosensing and drug delivery, owing to its physical-chemical proper- ties and biocompatibility. Particularly, ND has been de- monstrated as fluorescence- and Raman-detectable labels in many cellular models. Different surface functionaliza- tion methods have been developed, varying the ND’s sur- face properties and rendering the possibility to attach bio- molecules to provide interaction with biological targets. For this, toxicity is of major concern in animal models. Aside from cellular models, a cost-effective animal test will greatly facilitate the development of applications. In this study, we use the rapid, sensitive and reproducible zebrafish embryo model for in vivo nanotoxicity test. We optimize the conditions for using this animal model and analyze the zebrafish embryonic development in the pre- sence of ND. ND is observed in the embryo in vivo using laser confocal fluorescence microscopy and fluorescence lifetime imaging. Using the zebrafish model for a safety evaluation of ND-based nanolabel is discussed. J. Biophotonics 1–10 (2016) / DOI 10.1002/jbio.201500304 © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim