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Am J Nucl Med Mol Imaging 2013;3(3):232-246
Review Article
Stem cell tracking with optically active nanoparticles
Yu Gao, Yan Cui, Jerry KY Chan, Chenjie Xu
Division of BioEngineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore; Division 
of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 
Singapore; Department of Reproductive Medicine, KK Women’s and Children’s Hospital, Singapore; Cancer and Stem Cell Biology 
Program, Duke-NUS Graduate Medical School, Singapore; Experimental Fetal Medicine Group, Department of Obstetrics and 
Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Received March 3, 2013; Accepted March 12, 2013; Epub April 9, 2013; Published April 15, 2013
Abstract: Stem-cell-based therapies hold promise and potential to address many unmet clinical needs. Cell tracking with modern 
imaging modalities offers insight into the underlying biological process of the stem-cell-based therapies, with the goal to reveal cell 
survival, migration, homing, engraftment, differentiation, and functions. Adaptability, sensitivity, resolution, and non-invasiveness have 
contributed to the longstanding use of optical imaging for stem cell tracking and analysis. To identify transplanted stem cells from the 
host tissue, optically active probes are usually used to label stem cells before the administration. In comparison to the traditional 
fluorescent probes like fluorescent proteins and dyes, nanoparticle-based probes are advantageous in terms of the photo-stabilities 
and minimal changes to the cell phenotype. The main focus here is to overview the recent development of optically active 
nanoparticles for stem cells tracking. The related optical imaging modalities include fluorescence imaging, photoacoustic imaging, 
Raman and surface enhanced Raman spectroscopy imaging. (ajnmmi1303001).
Keywords: Stem cell therapy, optical imaging, nanoparticles, fluorescence imaging, photoacoustic imaging, Raman and surface 
enhanced Raman spectroscopy imaging
Address correspondence to: Dr. Chenjie Xu, Division of BioEngineering, School of Chemical and Biomedical Engineering, Nanyang 
Technological University, Building N1.3, level B2, Room 06, 70 Nanyang Drive, Singapore 637457. Phone: 65-6513-8298; Fax: 65-
6791-1761; E-mail: cjxu@ntu.edu.sg