Targeted quantum rods probe blood-brain barrier

Jun 15 2008

One of the chief difficulties in treating brain tumors involves getting potential tumor-killing drugs across the blood-brain barrier and into the brain.

Now, researchers from a NCI Cancer Nanotechnology Platform Partnership at the University of Buffalo have used targeted quantum rods both to breach the blood-brain barrier and to study how such constructs move across this largely impermeable barrier. Paras Prasad, Ph.D., principal investigator of the SUNY-Buffalo Platform Partnership, led the research team that published results in the journal Bioconjugate Chemistry.  

The investigators began their work by preparing red- and orange-emitting quantum rods made of cadmium selenide, cadmium sulfide, and zinc sulfide. They then attached an iron-transporting protein known as transferrin to the surface of the quantum rods. Transferrin binds to a complex protein known as the transferrin receptor. The blood-brain barrier contains large numbers of this receptor, and research has shown that it can act to transport biomolecules across the blood-brain barrier.

Because of the intense fluorescence exhibited by quantum rods, the investigators were able to image these markers as they bound to and moved across a cell-based model of the blood-brain barrier. In contrast, quantum rods lacking surface transferrin did not cross the model blood-brain barrier. One interesting finding from these experiments is that there appears to be a critical period that starts after 26 hours at which time transport is most efficient across the blood-brain barrier. The investigators note that the data from these experiments should help them design new nanoscale agents for ferrying anticancer drugs into the brain.

This work, which was supported by the NCI's Alliance for Nanotechnology in Cancer, is detailed in the paper "Bioconjugated Quantum Rods as Targeted Probes for Efficient Transmigration Across an In Vitro Blood-Brain Barrier." Investigators from Buffalo General Hospital and ShenZhen University also participated in this study. An abstract of this paper is available at the journal's Web site. View abstract