Biocompatible Near-Infrared Quantum Dots as Ultrasensitive Probes for Long-Term in vivo Imaging Applications

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2009-09, Vol.5 (17), p.1997-2004
• Main Authors: Yong, Ken-Tye, Roy, Indrajit, Ding, Hong, Bergey, Earl J., Prasad, Paras N.
• Format: Article
• Language: English
• Subjects: Animals; Biocompatibility; Biocompatible Materials - chemistry; biodistribution; bioimaging; Biomedical materials; Cell Survival; Female; HeLa Cells; Humans; Imaging; Imaging, Three-Dimensional - methods; In vivo testing; In vivo tests; Luminescent Measurements; Mice; Mice, Inbred BALB C; Microscopy, Electron, Transmission; Molecular Probes - chemistry; nanotoxicity; Particle Size; Quantum Dots; Spectrometry, Fluorescence; Spectroscopy, Near-Infrared; Spleen; Surgical implants; targeted delivery; Time Factors
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.200900547

A facile synthesis method to produce monodisperse, biocompatible, lysine crosslinked mercaptoundecanoic acid (MUA) CdSe0.25Te0.75/CdS near‐infrared (NIR) quantum dots and use them as probes to study their long term in vivo distribution, clearance, and toxicity is presented. Large signal enhancements are demonstrated by these quantum dots, which enables their use as efficient and sensitive probes for live‐animal imaging. An important finding is that mice intravenously injected with ≈10.5 mg kg−1 of NIR QDs survive for more than three months without any apparent adverse effect to their health. Furthermore, it is determined that there is a significant reduction in the number of the QDs in the liver and spleen three months post injection. In addition, histological analysis of heart, kidney, liver, spleen, and lung tissue indicates that there are no acute toxic effects from these lysine cross‐linked MUA NIR QDs. This study suggests that these NIR QDs can be potentially used for long‐term targeted imaging and therapy studies in vivo. A solution‐phase synthesis method is developed to produce monodisperse, biocompatible, lysine crosslinked mercaptoundecanoic acid near‐infrared quantum dots (QDs) for in vivo bioimaging applications (see image). The functionalized QDs are used as probes for long‐term in vivo distribution, clearance, and nanotoxicity studies. No ill observational or histological effects are observed in the mice receiveing QDs at concentrations as high as 10.5 mg kg−1.