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Quantum Rod System May Safely 'Sneak' Drugs, Diagnostics into Brain
System also can serve as "test kit" for evaluating new transporter molecules
Release Date: July 16, 2008
BUFFALO, N.Y. -- A unique nanoparticle system developed by University at
Buffalo scientists takes advantage of the versatility of bioconjugated quantum
rods to ferry novel diagnostic and therapeutic agents across the blood-brain
barrier, according to recent in vitro findings.
Described in a paper published in Bioconjugate Chemistry, the system uses
the rod-shaped semiconductor nanoparticles that are bioconjugated, or
coupled, with biomolecules capable of crossing the blood-brain barrier.
The blood-brain barrier acts as a physiological "checkpoint" that selectively
allows certain molecules in blood circulation to enter the brain. While it
naturally evolved in order to protect the brain from invasion of various
circulating toxins and other harmful molecules, the blood-brain barrier also
serves as a major impediment to the brain-specific delivery of various
diagnostic/therapeutic molecules needed for combating various neuronal
disorders.
The quantum rod system the UB researchers developed has the potential to
simultaneously and non-invasively deliver diagnostic and therapeutic agents
targeted to a wide variety of neurological diseases as well as obesity and drug
addiction, according to Paras N. Prasad, Ph.D., executive director of the UB
Institute for Lasers, Photonics and Biophotonics and SUNY Distinguished
Professor in the Department of Chemistry, who led the UB team.
"These brain-specific nanoparticle systems represent a significant
improvement over commonly used, highly-invasive methods of delivering
active molecules into the brain, most of which rely on direct injection," he
said.
The UB team, together with colleagues from Buffalo General Hospital, has
developed a simple method for linking quantum rods to the iron-transporting
protein, transferrin and other biomolecules, which routinely pass through the
blood-brain barrier.
"Our findings unfold a new dimension in blood-brain barrier transport using
inorganic nanoparticles, which are structurally robust and demonstrate the
potential to transport multiple agents across this physiological barrier," said
Indrajit Roy, Ph.D., deputy director for biophotonics at the UB institute.
"This system allows the nanoparticles and the multiple therapeutic and
imaging agents they carry to 'sneak' safely across the barrier and into the
brain. It's a Trojan horse approach."
The functionalized quantum rods proved to have very low toxicity, according
to Ken-Tye Yong, Ph.D., postdoctoral research associate in the UB institute,
providing additional evidence that when linked to drug molecules, they could
make very suitable treatment probes for diseases of the brain.
The new nanoparticle platform could provide scientists with a kind of
window on the blood-brain barrier, enhancing what they know about it and
allowing them to view non-invasively in real-time how imaging and
therapeutic agents affect the brain.
The quantum rod system also serves as the basis of a blood-brain barrier-
crossing test kit the UB researchers are developing.
The test kit would enable scientists to competitively evaluate which
molecules would most efficiently transport diagnostic and therapeutic agents
across the blood-brain barrier by exploiting the ability of quantum rods to
emit light in different colors, depending on their size.
The research is closely aligned with the strategic strength in integrated
nanostructured systems identified in the UB 2020 strategic planning process.
In addition to Prasad, Roy and Yong, co-authors included Gaixia Xu, Ph.D.,
former postdoctoral associate, and Hong Ding, Ph.D., postdoctoral associate,
both of the UB Institute for Lasers, Photonics and Biophotonics; Supriya D.
Mahajan, Ph.D., research assistant professor in the Department of Medicine
in the UB School of Medicine and Biomedical Sciences and at Buffalo
General Hospital, and Stanley A. Schwartz, M.D., Ph.D., UB professor of
Medicine, Pediatrics and Microbiology and director of the Division of
Allergy, Immunology and Rheumatology in the Department of Medicine at
Buffalo General Hospital.
This research was supported by the John R. Oishei Foundation and by UB's
New York State Center of Excellence in Bioinformatics and Life Sciences.