Microscopically tiny nanomachines which move like submarines with their own propulsion—for example in the human body, where they transport active agents and release them at a target: What sounds like science fiction has, over the past 20 years, become an ever more rapidly growing field of research. However, most of the particles developed so far only function in the laboratory. Propulsion, for example, is a hurdle. Some particles have to be supplied with energy in the form of light, others use chemical propulsions which release toxic substances. Neither of these can be considered for any application in the body. A solution to the problem could be acoustically propelled particles. Johannes Voß and Prof. Raphael Wittkowski from the Institute of Theoretical Physics and the Center for Soft Nanoscience at the University of Münster (Germany) have now found answers to central questions which had previously stood in the way of applying acoustic propulsion. The results have been published in the journal ACS Nano.
Ultrasound is used in acoustically propelled nanomachines as it is quite safe for applications in the body. Lead author Johannes Voß sums up the research carried out so far as follows: “There are many publications describing experiments. However, the particles in these experiments were almost always exposed to a standing ultrasound wave. This does admittedly make the experiments considerably simpler, but at the same time it makes the results less meaningful as regards possible applications—because in that case traveling ultrasound waves would be used.” This is due to the fact that standing waves are produced when waves traveling in opposite directions overlap one another.
What researchers also did not previously take into account is that in applications the particles can move in any direction. Thus, they left aside the question of whether propulsion depends on the orientation of the particles. Instead, they only looked at particles aligned perpendicular to the ultrasound wave. Now, for the first time, the team of researchers in Münster studied the effects of orientation using elaborate computer simulations.
They came to the conclusion that the propulsion of the nanoparticles depends on their orientation. At the same time, the acoustic propulsion mechanism in traveling ultrasound waves functions so well for all orientations of the particles—i.e. not only exactly perpendicular to the ultrasound wave—that these particles really can be used for biomedical applications. Another aspect the Münster physicists examined was the propulsion the particles exhibited when they were exposed to ultrasound coming from all directions (i.e. “isotropic ultrasound”).
A basis for the step towards application
“Our results showed how the particles will behave in applications and that the propulsion has the right properties for the particles to actually be used in these applications,” Johannes Voß concludes. As Raphael Wittkowski adds, “We have revealed important properties of acoustically propelled nanoparticles which had not previously been studied, but which need to be understood to enable the step to be made from basic research to the planned applications involving the particles.”
The two Münster researchers examined conical particles, as they can move fast even at a low intensity of ultrasound—i.e. they have efficient propulsion—and also they can easily be produced in large numbers. The particles are almost one micrometer in size—almost a thousand nanometres. In comparison, a red blood cell has a diameter of around 7.7 micrometers. This means that the nanoparticles could move through the bloodstream without blocking up the finest blood vessels. “The particle size can be selected in line with what is needed in the particular application intended, and the propulsion mechanism also functions in the case of smaller and larger particles,” Johannes Voß explains. “We simulated the particles in water, but the propulsion is also suitable for other fluids and for tissue.”
By means of computer simulations, the team investigated systems and their properties which could not be studied in the many preceding experiments. Looking into the future, Raphael Wittkowski says, “An important step would be for experiment-based research to move on to looking at these systems.”
News
Why Most Animal Viruses Never Become Human Pandemics
From receptor mismatch to risky human-animal interfaces, this article explains why spillover is common but true pandemic emergence remains rare. Introduction Humans are constantly exposed to animal viruses through farming, wildlife contact, and the [...]
Stem cell organoids repair heart microvessels in coronary artery disease models
A Stanford University team has shown that vascular organoids derived from human stem cells can repair the heart’s microvessel network in pigs with ischaemic heart disease – a proof-of-concept advancement that could open new therapeutic [...]
Goodbye GP waiting rooms, hello prevention at home
Prevention is suddenly everywhere in NHS reform. The recent £340m community pharmacy deal is moving more services onto the high street. Community Diagnostic Centres are being expanded, and the Neighbourhood Health Framework sets out [...]
Ebola control is weakened by mistrust and cultural insensitivity
Effective response depends on cooperation with communities and frontline workers, writes Zaeem ul Haq The current Bundibugyo Ebola outbreak in the Democratic Republic of the Congo (DRC) and Uganda is exposing dangerous gaps in [...]
Building the Brain Requires Millions of Dangerous DNA Breaks
Scientists discovered that building a healthy brain involves an unexpected step: young neurons routinely break and rapidly repair their own DNA. As the brain develops, newly formed nerve cells must travel through tightly packed tissue [...]
One Tiny Change May Explain How Viruses Jump From Bats to Humans
Scientists found that one tiny genetic change may determine whether a bat virus stays in bats or becomes a human threat. Most infectious disease outbreaks begin when a virus or other pathogen crosses from animals into [...]
Scientists Discover 250+ Genes That Could Lead to New Ways To Prevent Melanoma
The world’s largest study of mole genetics identified hundreds of genes tied to melanoma risk, uncovering potential new drug targets and paving the way for more accurate melanoma screening and prevention. Researchers at QIMR [...]
Breakthrough Diabetes Treatment Reprograms the Immune System
An engineered stem cell therapy reversed new-onset Type 1 diabetes in mice by shifting the immune system away from attacking insulin-producing cells. For more than a century, people with Type 1 diabetes have relied [...]
Taking the world’s temperature: WHO chief spotlights global health emergencies
Taking the world’s temperature on pressing health matters, WHO Director-General Tedros Adhanom Ghebreyesus provided the latest on current global challenges - and successes when it comes to international cooperation. “The outbreaks of hantavirus, Ebola and Marburg all show [...]
Scientists Create Tiny “Mini Livers” That Could One Day Replace Liver Transplants
Engineered tissue grafts could help perform key liver functions and benefit thousands of people living with liver failure. The liver is one of the body’s hardest-working organs, carrying out hundreds of vital jobs, from [...]
NanoMedical Brain/Cloud Interface – Explorations and Implications. A new book from Frank Boehm
New book from Frank Boehm, NanoappsMedical Inc Founder: This book explores the future hypothetical possibility that the cerebral cortex of the human brain might be seamlessly, safely, and securely connected with the Cloud via [...]
Scientists Discover Surprising Way To Help the Brain Recover After Stroke
A new study suggests that strengthening the body’s natural circadian rhythms may help the brain recover after stroke, even when treatment begins days after the injury. Every year, millions of people survive a stroke, [...]
Our books now available worldwide!
Online Sellers other than Amazon, Routledge, and IOPP Indigo Global Health Care Equivalency in the Age of Nanotechnology, Nanomedicine and Artifcial Intelligence Global Health Care Equivalency In The Age Of Nanotechnology, Nanomedicine And Artificial [...]
Younger Generations Are Aging Faster – and It May Be Fueling a Surge in Cancer
Younger generations may be aging biologically faster than those before them, and that shift could help explain rising rates of cancer at younger ages. For decades, cancer was viewed largely as a disease of [...]
Using Cannabis Could Raise Your Stroke Risk by 37%, Massive Study Reveals
Large-scale evidence suggests cannabis, cocaine, and amphetamines may directly raise stroke risk, including in younger adults. As recreational drug use becomes increasingly common, researchers are uncovering evidence that its health consequences may extend far beyond [...]
Could Vitamin C Be the Secret to Keeping Your Brain Younger?
Lower vitamin C levels were linked to reduced brain volume and weaker neural connectivity in older adults, suggesting a potential connection between nutrition and brain health. Could a common vitamin help preserve the brain [...]
