Tag Archives: microbubbles

Brain surgery with no scalpel or incisions

A December 3, 2021 news item on ScienceDaily announces some very exciting work from the University of Virginia UVA) and Stanford University,

University of Virginia School of Medicine researchers have developed a noninvasive way to remove faulty brain circuits that could allow doctors to treat debilitating neurological diseases without the need for conventional brain surgery.

The UVA team, together with colleagues at Stanford University, indicate that the approach, if successfully translated to the operating room, could revolutionize the treatment of some of the most challenging and complex neurological diseases, including epilepsy, movement disorders and more. The approach uses low-intensity focused ultrasound waves combined with microbubbles to briefly penetrate the brain’s natural defenses and allow the targeted delivery of a neurotoxin. This neurotoxin kills the culprit brain cells while sparing other healthy cells and preserving the surrounding brain architecture.

A November 22, 2021 University of Virginia news release (also on EurekAlert but published on December 3, 2021), which originated the news item, offers technical details (Note: Links have been removed),

“This novel surgical strategy has the potential to supplant existing neurosurgical procedures used for the treatment of neurological disorders that don’t respond to medication,” said researcher Kevin S. Lee of UVA’s Departments of Neuroscience and Neurosurgery and the Center for Brain Immunology and Glia, or BIG. “This unique approach eliminates the diseased brain cells, spares adjacent healthy cells and achieves these outcomes without even having to cut into the scalp.”

The Power of PING

The new approach, called “PING,” has already demonstrated exciting potential in laboratory studies. For instance, one of the promising applications for PING could be for the surgical treatment of epilepsies that do not respond to medication. Approximately a third of patients with epilepsy do not respond to anti-seizure drugs, and surgery can reduce or eliminate seizures for some of them. Lee and his team, along with their collaborators at Stanford, have shown that PING can reduce or eliminate seizures in two research models of epilepsy. The findings raise the possibility of treating epilepsy in a carefully targeted and noninvasive manner without the need for traditional brain surgery. 

Another important potential advantage of PING is that it could encourage the surgical treatment of appropriate patients with epilepsy who are reluctant to undergo conventional invasive or ablative surgery.

In a scientific paper newly published in the Journal of Neurosurgery, Lee and his collaborators detail the ability of PING to focally eliminate neurons in a brain region, while sparing non-target cells in the same area. In contrast, currently available surgical approaches damage all cells in a treated brain region. 

A key advantage of the approach is its incredible precision. PING harnesses the power of magnetic-resonance imaging to let scientists peer inside the skull so that they can precisely guide sound waves to open the body’s natural blood-brain barrier exactly where needed. This barrier is designed to keep harmful cells and molecules out of the brain, but it also prevents the delivery of potentially beneficial treatments.

The UVA group’s new paper concludes that PING allows the delivery of a highly targeted neurotoxin, cleanly wiping out problematic neurons, a type of brain cell, without causing collateral damage. 

Another key advantage of the precision of this approach is that it can be used on irregularly shaped targets in areas that would be extremely difficult or impossible to reach through regular brain surgery. “If this strategy translates to the clinic,” the researchers write in their new paper, “the noninvasive nature and specificity of the procedure could positively influence both physician referrals for, and patient confidence in, surgery for medically intractable neurological disorders.”

“Our hope is that the PING strategy will become a key element in the next generation of very precise, noninvasive, neurosurgical approaches to treat major neurological disorders,” said Lee, who is part of the UVA Brain Institute.

About the Research

Lee’s groundbreaking research has been supported by the National Institutes of Health, the Chester Fund and the Charlottesville-based Focused Ultrasound Foundation. The work is part of an expansive effort at UVA Health to explore the potential of scalpel-free focused ultrasound to treat complex diseases throughout the body.

UVA’s pioneering research has already paved the way for the federal Food and Drug Administration to approve focused ultrasound for the treatment of essential tremor, a common movement disorder, and Parkinson’s disease symptoms. Research is underway on its potential applications for many more conditions, including breast cancer and glioblastoma, a deadly form of brain tumor. Learn more about UVA’s focused ultrasound research.

The research team included Yi Wang, Matthew J. Anzivino, Yanrong Zhang, Edward H. Bertram, James Woznak, Alexander L. Klibanov, Erik Dumont and Max Wintermark. 

An application to patent the PING procedure has been submitted by members of the research group. 

The research was funded by the National Institutes of Health, grants R01 NS102194 and R01 CA217953-01; the Chester Fund; and the Focused Ultrasound Foundation.

To keep up with the latest medical research news from UVA, subscribe to the Making of Medicine blog at http://makingofmedicine.virginia.edu.

Here’s a link to and a citation for the paper,

Noninvasive disconnection of targeted neuronal circuitry sparing axons of passage and nonneuronal cells by Yi Wang, Matthew J. Anzivino, Yanrong Zhang, Edward H. Bertram, James Woznak, Alexander L. Klibanov, Erik Dumont, Max Wintermark, and Kevin S. Lee. Journal of Neurosurgery DOI: https://doi.org/10.3171/2021.7.JNS21123 Online Publication Date: 19 Nov 2021

This paper is behind a paywall.

Microbubbles reform into nanoparticles after bursting

It seems researchers at the Toronto-based (Canada), Princess Margaret Cancer Centre, have developed a new theranostic tool made of microbubbles used for imaging that are then burst into nanoparticles delivering therapeutics. From a March 30, 2015 news item on phys.org,

Biomedical researchers led by Dr. Gang Zheng at Princess Margaret Cancer Centre have successfully converted microbubble technology already used in diagnostic imaging into nanoparticles that stay trapped in tumours to potentially deliver targeted, therapeutic payloads.

The discovery, published online today [March 30, 2015] in Nature Nanotechnology, details how Dr. Zheng and his research team created a new type of microbubble using a compound called porphyrin – a naturally occurring pigment in nature that harvests light.

A March 30, 2015 University Health Network news release on EurekAlert, which originated the news item, describes the laboratory research on mice,

In the lab in pre-clinical experiments, the team used low-frequency ultrasound to burst the porphyrin containing bubbles and observed that they fragmented into nanoparticles. Most importantly, the nanoparticles stayed within the tumour and could be tracked using imaging.

“Our work provides the first evidence that the microbubble reforms into nanoparticles after bursting and that it also retains its intrinsic imaging properties. We have identified a new mechanism for the delivery of nanoparticles to tumours, potentially overcoming one of the biggest translational challenges of cancer nanotechnology. In addition, we have demonstrated that imaging can be used to validate and track the delivery mechanism,” says Dr. Zheng, Senior Scientist at the Princess Margaret and also Professor of Medical Biophysics at the University of Toronto.

Conventional microbubbles, on the other hand, lose all intrinsic imaging and therapeutic properties once they burst, he says, in a blink-of-an-eye process that takes only a minute or so after bubbles are infused into the bloodstream.

“So for clinicians, harnessing microbubble to nanoparticle conversion may be a powerful new tool that enhances drug delivery to tumours, prolongs tumour visualization and enables them to treat cancerous tumours with greater precision.”

For the past decade, Dr. Zheng’s research focus has been on finding novel ways to use heat, light and sound to advance multi-modality imaging and create unique, organic nanoparticle delivery platforms capable of transporting cancer therapeutics directly to tumours.

Interesting development, although I suspect there are many challenges yet to be met such as ensuring the microbubbles consistently arrive at their intended destination in sufficient mass to be effective both for imaging purposes and, later, as nanoparticles for drug delivery purposes.

Here’s a link to and citation for the paper,

In situ conversion of porphyrin microbubbles to nanoparticles for multimodality imaging by Elizabeth Huynh, Ben Y. C. Leung, Brandon L. Helfield, Mojdeh Shakiba, Julie-Anne Gandier, Cheng S. Jin, Emma R. Master, Brian C. Wilson, David E. Goertz, & Gang Zheng. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.25 Published online 30 March 2015

This paper is behind a paywall but a free preview is available via ReadCube Access.

This is one of those times where I’m including the funding agencies and the ‘About’ portions of the news release,

The research published today was funded by the Canadian Institutes of Health Research (CIHR) Frederick Banting and Charles Best Canada Graduate Scholarship, the Emerging Team Grant on Regenerative Medicine and Nanomedicine co-funded by the CIHR and the Canadian Space Agency, the Natural Sciences and Engineering Research Council of Canada, the Ontario Institute for Cancer Research, the International Collaborative R&D Project of the Ministry of Knowledge Economy, South Korea, the Joey and Toby Tanenbaum/Brazilian Ball Chair in Prostate Cancer Research, the Canada Foundation for Innovation and The Princess Margaret Cancer Foundation.

About Princess Margaret Cancer Centre, University Health Network

The Princess Margaret Cancer Centre has achieved an international reputation as a global leader in the fight against cancer and delivering personalized cancer medicine. The Princess Margaret, one of the top five international cancer research centres, is a member of the University Health Network, which also includes Toronto General Hospital, Toronto Western Hospital and Toronto Rehabilitation Institute. All are research hospitals affiliated with the University of Toronto. For more information, go to http://www.theprincessmargaret.ca or http://www.uhn.ca .

I was not expecting to see South Korea or Brazil mentioned in the funding. Generally, when multiple countries are funding research, their own research institutions are also involved. As for the Princess Margaret Cancer Centre being one of the top five such centres internationally, I wonder how these rankings are determined.