Nov 12, 2009
QD-modified microbubbles operate as bifunctional imaging agents
The Nanobiotechnology Group from Harbin Institute of Technology in collaboration with researchers at the Peking University Third Hospital, Thomas Jefferson University and National Center of Nanoscience and Technology of China, has successfully developed and tested a novel bimodal ultrasonic/fluorescent imaging agent based on quantum dot (QD)-modified microbubbles (MBs).
QD-modified MBs were constructed by combining the self-assembly of gas-filled MBs with layer-by-layer deposition of QD nanoparticles onto the resulting MBs. The agent provides excellent contrast enhancement for ultrasound imaging and delivers fluorescent material for tissue and cell studies.
In a clinical setting, QD-modified MBs could be intravenously injected into patients with lesions (for example, tumors). First, contrast-enhanced ultrasonography would be applied to detect the lesions. During the procedure, MBs would be destroyed by high-intensity ultrasound beams, releasing QDs in the region around and within the lesion.
The dissociated QDs could easily cross the endothelial layer of blood vessels to enter the abnormal tissues as the vascular permeability would be enhanced by insonated MBs. In addition, the forced entry of QDs into the cytoplasm through the transient "sonopore" could also occur.
Full results can be found in the journal Nanotechnology and detailed studies are now underway.
About the author
This research is funded by NSFC and 863 program of China. Hengte Ke and Zhanwen Xing are currently pursuing their PhD degrees in the Nanobiotechnology Group at Harbin Institute of Technology under the supervision of Prof. Zhifei Dai. They focus on the design and fabrication of nano- and microbubbles that are capable of delivering active drugs and nanoparticles to target specific sites. Prof. Jinrui Wang and Prof. Jibin Liu are involved in the evaluation of contrast ultrasound imaging.