Hexbyte Glen Cove Tiny bubbles making large impact on medical ultrasound imaging thumbnail

Hexbyte Glen Cove Tiny bubbles making large impact on medical ultrasound imaging

Hexbyte Glen Cove

Schematic of bubble membrane showing the influence of membrane stiffener and membrane softener in the phospholipid packing. Credit: Amin Jafari Sojahrood and Al C. de Leon

If you were given “ultrasound” in a word association game, “sound wave” might easily come to mind. But in recent years, a new term has surfaced: bubbles. Those ephemeral, globular shapes are proving useful in improving medical imaging, disease detection and targeted drug delivery. There’s just one glitch: bubbles fizzle out soon after injection into the bloodstream.

Now, after 10 years’ work, a multidisciplinary research team has built a better bubble. Their new formulations have resulted in bubbles with customizable outer shells—so small and durable that they can travel to and penetrate some of the most inaccessible areas in the human body.

The work is a collaboration between Al C. de Leon and co-authors, under the supervision of Agata A. Exner of the Department of Radiology at the Case Western Reserve University School of Medicine in Cleveland and Amin Jafari Sojahrood under the supervision of Michael Kolios of the Department of Physics at Ryerson University and the Institute for Biomedical Engineering, Science and Technology (iBEST) in Toronto. Their results were recently published in ACS Nano, in a paper entitled “Towards Precisely Controllable Acoustic Response of Shell-Stabilized Nanobubbles: High-Yield and Narrow-Dispersity”.

“The advancement can eventually lead to clearer ultrasound images,” says Kolios. “But more broadly, our joint theoretical and experimental findings provide a fundamental framework that will help establish nanobubbles for applications in biomedical imaging—and potentially into other fields, from material science to surface cleaning and mixing.”

Bubbles in Ultrasound: Shrinking Down to Nanoscale

Ultrasound is the second most used medical imaging modality in the world. As with other modalities, a patient may swallow or be injected with an agent to create image contrast, thereby making bodily structures or fluids easier to see.

With ultrasound, bubbles serve as the contrast agent. These gas-filled globes are enclosed by a phospholipid shell. Contrast is generated when ultrasound waves interact with the bubbles, causing them to oscillate and reflect soundwaves that differ significantly from waves reflected by body tissues. Bubbles are used routinely in patients to improve image quality and enhance the detection of diseases. But due to their size (about the same as red blood cells), microbubbles are confined to circulating in blood vessels, and cannot reach diseased tissue outside.

“Our research team at CWRU now engineered stable, long-circulating bubbles at the nanoscale—measuring 100-500 nm in diameter,” says Exner. “They’re so that they can even squeeze through leaky vasculature of cancerous tumours.”

With such capabilities, nanobubbles are well-suited for finer applications such as molecular imaging and targeted drug delivery. Working together with the Ryerson team, the researchers have developed a clearer understanding of the theory of how nanobubbles are visualized with ultrasound, and what imaging techniques are needed to best visualize the bubbles in the body.

Controlling Nanobubble Behaviour

Size issues aside, bubbles are also complex oscillators, exhibiting behaviours that are difficult to control. In the current work, the research team also devised a way to precisely control and predict how bubbles interact with and respond acoustically to ultrasound.

“By introducing membrane additives to our bubble formulations, we demonstrated the ability to control how stiff (or how flexible) the bubble shells become,” says de Leon. “Bubble formulations can then be customized to match the particular needs of different applications.”

For example, stiffer, stable bubble designs may last long enough to reach body tissues that are difficult to access. Softer bubbles may produce clearer ultrasound images of certain types of body tissue. Bubble oscillation could even be tweaked to increase cell permeability, potentially increasing drug delivery to diseased cells, which may in turn decrease the dosage required.

Patients, the Ultimate Beneficiaries

Having successfully demonstrated the ability to customize bubble shell properties and their interaction with sound waves, the current work has exciting implications for nanobubble potency—in both diagnostic and therapeutic applications.

Sojahrood sees many potential benefits, for biomedicine and for patients in clinic. “Compared to other imaging or treatment options, such as surgery with scalpels, bulky MRI machinery, or the risk of radioactive iodine in CT scans, ultrasound could be a lot faster, cheaper, more effective and less invasive,” he says. “By advancing through nanobubbles, we could eventually make diagnosis and treatment more available and more effective, even in more remote areas of the world, ultimately improving patient outcomes and saving more lives.”

More information:
Amin Jafari Sojahrood et al, Toward Precisely Controllable Acoustic Response of Shell-Stabilized Nanobubbles: High Yield and Narrow Dispersity, ACS Nano (2021). DOI: 10.1021/acsnano.0c09701

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Hexbyte Glen Cove Making the best decision: Math shows diverse thinkers equal better results thumbnail

Hexbyte Glen Cove Making the best decision: Math shows diverse thinkers equal better results

Hexbyte Glen Cove

Sketch of the collective decision-making process described by Karamched et al. In a population of undecided agents (blue), an early adopter (red) makes a poor decision. Seeing this decision, a set of early adopters follow suit, but a slightly larger set of early adopters (green) picks the most beneficial solution. After observing the decision-making dynamics of the early adopters, laggards make their decision, leading a large fraction of the population to correct the initial, poor decision. Credit: APS/Alan Stonebraker

Whether it is ants forming a trail or individuals crossing the street, the exchange of information is key in making everyday decisions. But new Florida State University research shows that the group decision-making process may work best when members process information a bit differently.

Bhargav Karamched, assistant professor of mathematics, and a team of researchers published a new study today that tackles how groups make decisions and the dynamics that make for fast and accurate decision making. He found that networks that consisted of both impulsive and deliberate individuals made, on average, quicker and better decisions than a group with homogenous thinkers.

“In groups with impulsive and deliberate individuals, the first decision is made quickly by an impulsive individual who needs little evidence to make a choice,” Karamched said. “But, even when wrong, this fast decision can reveal the correct options to everyone else. This is not the case in homogenous groups.”

The paper is published in Physical Review Letters.

Researchers noted in the paper that the exchange of is crucial in a variety of biological and social functions. But Karamched said although information sharing in networks has been studied quite a bit, very little work has been done on how individuals in a network should integrate information from their peers with their own private evidence accumulation. Most of the studies, both theoretical and experimental, have focused on how isolated individuals optimally gather evidence to make a choice.

“This work was motivated by that,” Karamched said. “How should individuals optimally accumulate evidence they see for themselves with evidence they obtain from their peers to make the best possible decisions?”

Krešimir Josić, Moores Professor of Mathematics, Biology and Biochemistry at the University of Houston and senior author of the study, noted that the process works best when individuals in a group make the most of their varied backgrounds to collect the necessary materials and knowledge to make a final decision.

“Collective social decision making is valuable if all individuals have access to different types of information,” Josić said.

Karamched used mathematical modeling to reach his conclusion but said there is plenty of room for follow-up research.

Karamched said that his model assumes that evidence accrued by one individual is independent of evidence collected by another member of the group. If a group of individuals is trying to make a decision based on information that is available to everyone, additional modeling would need to account for how correlations in the information affects collective -making.

“For example, to choose between voting Republican or Democrat in an election, the information available to everyone is common and not specifically made for one individual,” he said. “Including correlations will require developing novel techniques to analyze models we develop.”

More information:
Bhargav Karamched et al. Heterogeneity Improves Speed and Accuracy in Social Networks, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.218302

Making the best decision: Math shows diverse thinkers equal better results (2020, November 16)
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