Features | Partner Sites | Information | LinkXpress
Sign In
Demo Company

Acoustic Pressure Helps Deliver Drugs to the Brain

By BiotechDaily International staff writers
Posted on 26 Aug 2014
Image: Fluorescence images of the murine hippocampus after diffusion of Dextran through the FUS opened BBB (Left), compared to contralateral that shows no uptake (Right) (Photo courtesy of Dr. Elisa Konofagou/ Columbia University).
Image: Fluorescence images of the murine hippocampus after diffusion of Dextran through the FUS opened BBB (Left), compared to contralateral that shows no uptake (Right) (Photo courtesy of Dr. Elisa Konofagou/ Columbia University).
A new technique uses a focused ultrasound (FUS) beam to control the size of molecules penetrating the blood-brain barrier (BBB).

Researchers at Columbia University (New York, NY, USA) conducted a study that applied FUS onto a mouse hippocampus in the presence of systemically administered microbubbles (MBs) containing fluorescently labeled dextrans with molecular weights of 3-2,000 kDa (2.3–54.4 nm in diameter), to examine the possibility of trans-BBB dextran delivery. Outcomes were evaluated using ex vivo fluorescence imaging, and cavitation detection was employed to concomitantly monitor the MB activity associated with the delivery of the dextrans.

The results showed that FUS-induced BBB opening size—defined by the size of the largest molecule that can permeate through the BBB—can be controlled by acoustic pressure. BBB opening size was smaller than 3 kDa (2.3 nm) at 0.31 MPa, reached 70 kDa (10.2 nm) at 0.51 MPa, and was as large as 2,000 kDa (54.4 nm) at 0.84 MPa. Relatively smaller opening size (up to 70 kDa) was achieved with stable cavitation only; however, inertial cavitation was associated with relatively larger BBB opening size (above 500 kDa). The study was published in the July 2014 issue of the Journal of Cerebral Blood Flow & Metabolism.

“Most small and all large molecule drugs do not currently penetrate the blood-brain barrier that sits between the vascular bed and the brain tissue,” said study coauthor professor of biomedical engineering and radiology Elisa Konofagou, PhD, of Columbia Engineering. “This is an important breakthrough in getting drugs delivered to specific parts of the brain precisely, noninvasively, and safely, and may help in the treatment of central nervous system diseases like Parkinson's and Alzheimer's.”

FUS in conjunction with MBs—gas-filled bubbles coated by protein or lipid shells—is so far the only technique can permeate the BBB safely and noninvasively. When MBs are hit by an FUS beam, they start oscillating due to cavitation, the formation of vapor cavities in the liquid phase; depending on the magnitude of the pressure, they continue oscillating or collapse. The study showed that the pressure of the FUS can be adjusted depending on the size of the drug that needs to be delivered to the brain - small molecules at lower pressures and larger molecules at higher pressures.

Related Links:

Columbia University



view channel
Image: A new catalyst that improved the sensitivity of the standard PSA ELISA test by about 110-fold was made of palladium nanocubes coated with iridium (Photo courtesy of Dr. Xiaohu Xia, Michigan Technological University).

Peroxidase Mimic Outperforms Natural Horseradish Peroxidase in ELISA Test

A test-of-concept study demonstrated that a synthetic catalyst that mimics the action of horseradish peroxidase (HRP) could increase the sensitivity of a colorimetric enzyme-linked immunosorbent assay... Read more

Drug Discovery

view channel
Image: Endoscopic image of a bowel section known as the sigmoid colon afflicted with ulcerative colitis. The internal surface of the colon is blotchy and broken in places (Photo courtesy of Wikimedia Commons).

Orally Delivered Curcumin-Loaded Microparticles Effectively Treat Mouse Model of Ulcerative Colitis

Microparticles (MPs) loaded with the efficient anti-inflammatory agent curcumin were found to effectively treat a mouse model of ulcerative colitis. Ulcerative colitis is a chronic relapsing disease... Read more


view channel

Biopharmaceutical Partners Seek Alternatives to Glucocorticoid Steroid Drugs

Collaboration between American and Japanese biopharmaceutical companies is expected to lead to the development of a new class of small molecule drugs for treatment of hematological and inflammatory diseases. Gencia LLC (Charlottesville, VA, USA) and Takeda Pharmaceutical Company Ltd. (Osaka, Japan) announced the formation... Read more


17 Oct 2015 - 21 Oct 2015
25 Oct 2015 - 29 Oct 2015
16 Nov 2015 - 19 Nov 2015
Copyright © 2000-2015 Globetech Media. All rights reserved.