Dual function

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.