Research article

Quantum dot imaging for embryonic stem cells

Shuan Lin^{* 1} , Xiaoyan Xie^{* 1} , Manishkumar R Patel¹ , Yao-Hung Yang¹ , Zongjin Li¹ , Feng Cao¹ , Oliver Gheysens¹ , Yan Zhang¹ , Sanjiv S Gambhir^1,2 , Jiang Hong Rao¹ and Joseph C Wu^1,3

¹Molecular Imaging Program at Stanford (MIPS) and Bio-X Program, Department of Radiology, Stanford University, Stanford, CA 94305, USA

²Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, CA 94305, USA

³Department of Bioengineering, Stanford University, Stanford, CA 94305, USA

author email corresponding author email* Contributed equally

BMC Biotechnology 2007, 7:67doi:10.1186/1472-6750-7-67

Published:	9 October 2007

Abstract

Background

Semiconductor quantum dots (QDs) hold increasing potential for cellular imaging both in vitro and in vivo. In this report, we aimed to evaluate in vivo multiplex imaging of mouse embryonic stem (ES) cells labeled with Qtracker delivered quantum dots (QDs).

Results

Murine embryonic stem (ES) cells were labeled with six different QDs using Qtracker. ES cell viability, proliferation, and differentiation were not adversely affected by QDs compared with non-labeled control cells (P = NS). Afterward, labeled ES cells were injected subcutaneously onto the backs of athymic nude mice. These labeled ES cells could be imaged with good contrast with one single excitation wavelength. With the same excitation wavelength, the signal intensity, defined as (total signal-background)/exposure time in millisecond was 11 ± 2 for cells labeled with QD 525, 12 ± 9 for QD 565, 176 ± 81 for QD 605, 176 ± 136 for QD 655, 167 ± 104 for QD 705, and 1,713 ± 482 for QD 800. Finally, we have shown that QD 800 offers greater fluorescent intensity than the other QDs tested.

Conclusion

In summary, this is the first demonstration of in vivo multiplex imaging of mouse ES cells labeled QDs. Upon further improvements, QDs will have a greater potential for tracking stem cells within deep tissues. These results provide a promising tool for imaging stem cell therapy non-invasively in vivo.