
The next generation of phones and wireless devices are going to need new antennae to access higher and higher frequency ranges. One way to make antennae that work at tens of gigahertz — the frequencies needed for 5G and higher devices — is to braid filaments about 1 micrometer in diameter. But today’s industrial fabrication techniques won’t work on fibers that small. | |
Now a team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed a simple machine that uses the surface tension of water to grab and manipulate microscopic objects, offering a potentially powerful tool for nanoscopic manufacturing. |
The research is published in Nature (“3D-printed machines that manipulate microscopic objects using capillary forces”). | |
“Our work offers a potentially inexpensive way to manufacture microstructured and possibly nanostructured materials,” said Vinothan Manoharan, the Wagner Family Professor of Chemical Engineering and Professor of Physics at SEAS and senior author of the paper. “Unlike other micromanipulation methods, like laser tweezers, our machines can be made easily. We use a tank of water and a 3D printer, like the ones found at many public libraries.” | |
The machine is a 3D-printed plastic rectangle, about the size of an old Nintendo cartridge. The interior of the device is carved with channels that intersect. Each channel has wide and narrow sections, like a river that expands in some parts and narrows in others. The channel walls are hydrophilic, meaning they attract water. | |
Through a series of simulations and experiments, the researchers found that when they submerged the device in water and placed a millimeter-sized plastic float in the channel, the surface tension of the water caused the wall to repel the float. If the float was in a narrow section of the channel, it moved to a wide section, where it could float as far away from the walls as possible. | |
Once in a wide section of the channel, the float would be trapped in the center, held in place by the repulsive forces between the walls and float. As the device is lifted out of the water, the repulsive forces change as the shape of the channel changes. If the float was in a wide channel to start, it may find itself in a narrow channel as the water level falls and need to move to the left or right to find a wider spot. |
“The eureka moment came when we found we could move the objects by changing the cross-section of our trapping channels,” said Maya Faaborg, an associate at SEAS and co-first author of the paper. | |
The researchers then attached microscopic fibers to the floats. As the water level changed and the floats moved to the left or right within the channels, the fibers twisted around each other. | |
“It was a shout-out-loud-in-joy moment when — on our first try — we crossed two fibers using only a piece of plastic, a water tank, and a stage that moves up and down,” said Faaborg. | |
The team then added a third float with a fiber and designed a series of channels to move the floats in a braiding pattern. They successfully braided micrometer-scale fibers of the synthetic material Kevlar. The braid was just like a traditional three-strand hair braid, except that each fiber was 10-times smaller than a single human hair. | |
The researchers then showed that the floats themselves could be microscopic. They made machines that could trap and move colloidal particles 10 micrometers in size — even though the machines were a thousand times bigger. | |
“We weren’t sure it would work, but our calculations showed that it was possible,” said Ahmed Sherif, a PhD student at SEAS and a co-author of the paper. “So we tried it, and it worked. The amazing thing about surface tension is that it produces forces that are gentle enough to grab tiny objects, even with a machine big enough to fit in your hand.” | |
Next, the team aims to design devices that can simultaneously manipulate many fibers, with the goal of making high-frequency conductors. They also plan to design other machines for micromanufacturing applications, such as building materials for optical devices from microspheres. |

News
Silver nanoparticles show promise in fighting antibiotic-resistant bacteria
In a new study, scientists with the University of Florida have found that a combination of silver nanoparticles and antibiotics is effective against antibiotic-resistant bacteria. The researchers hope to turn this discovery into viable [...]
Combating severe cancer with a new drug delivery system
Peritoneal cancer is difficult to treat and has a poor survival prognosis. But a new and effective nanomedicine delivery system is offering some hope. The company is called NaDeNo and is well underway with [...]
New Research Shows How Ketamine Acts As “Switch” in the Brain
According to a new study by researchers at Penn Medicine, ketamine, which is well-known as an anesthetic and is becoming increasingly popular as an antidepressant, dramatically reorganizes activity in the brain, almost as if [...]
Supercharged T Cells: A New Way To Kill Pancreatic Cancer With Minimal Side Effects
A new immunotherapy releases cancer-killing cytokines only within the tumor. Researchers at the University of California San Francisco (UCSF) have developed a new T cell-based immunotherapy that selectively targets cancer cells, producing a powerful anti-cancer cytokine [...]
AI has designed bacteria-killing proteins from scratch – and they work
An AI was tasked with creating proteins with anti-microbial properties. Researchers then created a subset of the proteins and found some did the job. An AI has designed anti-microbial proteins that were then tested [...]
Using nanoparticles, researchers can identify and deliver synergistic combinations of cancer drugs
Treating cancer with combinations of drugs can be more effective than using a single drug. However, figuring out the optimal combination of drugs, and making sure that all of the drugs reach the right [...]
Humanity May Reach Singularity Within Just 7 Years, Trend Shows
By one unique metric, we could approach technological singularity by the end of this decade, if not sooner. A translation company developed a metric, Time to Edit (TTE), to calculate the time it takes for professional [...]
HYPER (Highly Interactive Particle Relics) – A New Model for Dark Matter
Phase transition in early universe changes strength of interaction between dark and normal matter. Dark matter remains one of the greatest mysteries of modern physics. It is clear that it must exist, because without [...]
New Nanoparticles Deliver Therapy Brain-Wide and Edit Alzheimer’s Gene
Summary: Researchers have developed a new family of nano-scale capsules capable of carrying CRISPR gene editing tools to different organs of the body before harmlessly dissolving. The capsules were able to enter the brains of [...]
Cancer’s Secret Weapon? Enzyme That Protects Against Viruses May Fuel Tumor Evolution
An enzyme that defends human cells against viruses can help drive cancer evolution towards greater malignancy by causing myriad mutations in cancer cells, according to a study led by investigators at Weill Cornell Medicine. The [...]
Scientists Uncover Japanese Fruit Juice That May Help Prevent Lung Cancer
Using a mouse model, Japanese researchers unleash the likely mechanism of action of Actinidia arguta (sarunashi) juice on lung cancer development. Lung cancer is a leading cause of death in Japan and across the [...]
In-place manufacturing method improves gas sensor capabilities, production time
When used as wearable medical devices, stretchy, flexible gas sensors can identify health conditions or issues by detecting oxygen or carbon dioxide levels in the breath or sweat. They also are useful for monitoring [...]
In the core of the cell: New insights into the utilization of nanotechnology-based drugs
Novel drugs, such as vaccines against covid-19, among others, are based on drug transport using nanoparticles. Whether this drug transport is negatively influenced by an accumulation of blood proteins on the nanoparticle’s surface was [...]
The costly lesson from COVID: why elimination should be the default global strategy for future pandemics
Imagine it is 2030. Doctors in a regional hospital in country X note an expanding cluster of individuals with severe respiratory disease. Rapid whole-genome sequencing identifies the disease-causing agent as a novel coronavirus. Epidemiological [...]
How Artificial Intelligence Found the Words To Kill Cancer Cells
A predictive model has been developed that enables researchers to encode instructions for cells to execute. Scientists at the University of California, San Francisco (UCSF) and IBM Research have created a virtual library of thousands of “command sentences” [...]
Next-generation, light-activated nanotech for antibiotic-resistant superbugs
It's "lights out" for antibiotic-resistant superbugs as next-generation light-activated nanotech proves it can eradicate some of the most notorious and potentially deadly bacteria in the world. Developed by the University of South Australia and [...]