Tiny Electronic Tags Could Fit Inside Cells

Tiny Electronic Tags Could Fit Inside Cells

Electronics small enough to fit inside cells may one day help scientists track individual cells and monitor their behavior in real time, a new study finds. These new devices could help analyze diseases from their origins in single cells, researchers said.

The new electronics are microscopic radio-frequency identification tags, which are essentially bar codes that can be read from a distance.

An RFID tag usually consists of an antenna connected to a microchip. A nearby reader known as a transceiver can emit electromagnetic signals at the tags, and the tags can respond with what data it has stored, such as its identity, when and where it was made, how to best store and handle it, and so on. Many RFID tags do not have batteries — instead, they rely on the energy in the signals from the transceivers.

These tags are already being used in many applications today, including key cards, toll passes, library books and many other items, but the typical RFID tags are millimeters to centimeters in size. The new microscopic tags in comparison are only 22 microns wide each, or roughly one-fifth the average diameter of a human hair, making them the smallest known RFID tags, the researchers said. They detailed their findings online July 26 in the journal Physical Review Applied.

The microscopic tags are each made of two metal layers — one made of a 5-nanometer-thick titanium and 200-nanometer-thick gold film, the other of a 1,000-nanometer-wide aluminum sheet — sandwiching a 16-nanometer-thick electrically insulating layer of hafnium dioxide.

Each tag is octagonal in shape. This is the closest the scientists can get to a circular shape, which is ideal for interacting with the magnetic fields from transceivers, said study lead author Jasmine Xiaolin Hu at Stanford University in California. Finally, the devices are fully encapsulated in silicon dioxide, the same material found in sand, to make them safe for biological applications.

Conventional RFID readers used to communicate with the tags have just one antenna. Instead, the researchers used two antennas, each roughly twice the tag’s diameter. Doing so boosted the magnitude of the tag signals by more than tenfold, which can make the difference between detecting a moving tagged cell in a complex biological setting or losing track of the cell just a few microns away.

Although these new microscopic tags are still larger than many cells, they do “fit into a variety of cells of great interest,” Hu said. The researchers found that this includes mouse melanoma cells, human melanoma cells, human breast cancer cells, human colorectal cancer cells and healthy human connective tissue cells, she said.

The researchers soon plan to monitor tagged living cells flowing within microscopic silicone rubber channels from a range of a few microns. Future research can explore developing smaller tags and finding ways to keep track of them, Hu added.

“This is step one towards sending signals within the cell to the outside world without probing through or perturbing the cell membrane and risking damaging and destroying the cell in due process,” said Stephen Wong, a bioengineer and systems biologist at the Houston Methodist Research Institute, who did not take part in this research. “It opens up a whole new world of live-cell studies.”

Sensors and other devices could get coupled with these microscopic tags “to measure and perform a variety of things,” Hu said. “We will have a measure of control within a cell that has not been achieved before.”

The ability to embed electronics into cells could help researchers understand and manipulate cell activities to an unprecedented degree. “Most disease processes start at a single- to few-cell level, but currently we have no technology to monitor a few cells inside the living body of a person,” Hu said. “Tracking and monitoring single cells may enable the early detection of diseases and allow for the start of treatments as soon as possible so that treatments can be more successful.”

For example, a pH sensor within a cell could help measure its acidity, “which indicates the healthiness of a cell,” Wong said. “We can also measure glucose to measure a cell’s metabolism, as well as many other molecules in cells.”

Future research should also focus on extending the range at which the researchers can scan the tags, Wong said. “Currently, the wireless receiver has to be very close to the cells, which is not ideal,” Wong said. “Still, what they’ve shown is a good step forward.”

Boosting the Sensitivity of Bio/Chemical Sensing with Nanogap Metasurfaces

Boosting the Sensitivity of Bio/Chemical Sensing with Nanogap Metasurfaces

In this regard, one of the most promising features of metallic nanostructures is their ability to confine optical fields and realize significant localized-field enhancement to produce plasmonic “hot spots”. This enables extremely high sensitivities for spectroscopic techniques such as surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared absorption spectroscopy (SEIRA). These two techniques are complementary, i.e., Raman scattering peaks in SERS correspond to absorption peaks of SEIRA. However, due to differing dependence on field enhancement, the signal enhancement factors for SEIRA are typically orders of magnitude less than those for SERS. One option for boosting SEIRA signals is to strengthen the plasmonic field enhancement by reducing the gap size between surface nanostructures, thereby confining light to volumes on the order of nanometers. However, due to the conventional diffraction limit, it is challenging to squeeze incident light into these extreme dimensions with high efficiency, particularly in the mid-infrared (IR) wavelengths that are of interest in SEIRA spectroscopy.

Researchers led by Qiaoqiang Gan’s team at University at Buffalo experimentally demonstrate a metamaterial superabsorber structure with sub-5-nanometer gaps that can trap mid-IR light within these extreme volumes with efficiencies up to 81%, significantly enhancing light–matter interaction on the nanoscale. By using these structures as a substrate for chemical/biological molecule analysis with SEIRA spectroscopy, they demonstrate an enhancement factor for molecular fingerprinting of chemical molecules of up to ca. 106–107, which approaches the enhancement factors of SERS. In addition, the methods used to produce these metasurfaces are amenable to large area fabrication such as optical interference patterning and nanoimprint lithography, making this a revolutionary material for biochemical infrared absorption spectroscopy.

How to ‘Film’ Firing Neurons

How to ‘Film’ Firing Neurons

Muybridge’s high-speed, stop-action photographs — of which the horse is just one famous example — captured detailed motions of humans and animals that the human eye alone could not observe. More than 130 years later, scientists are using a similar approach to reveal new insights about life at an even faster and much tinier scale: firing neurons.

Shigeki Watanabe, a cell biologist at the Johns Hopkins School of Medicine in Baltimore, and colleagues have developed a method to take flipbook-like images of brain cells in action.

The scientists start by cultivating modified mouse neurons that have been designed to fire in response to light. When the researchers hit the cells with a flash of light, it acts like a starter gun, sending electrical signals shooting down the neurons like runners in a race. In about one-thousandth of a second the “runners” reach the end of the cells, where they trigger the release of chemicals called neurotransmitters that pass the signal to other cells. After a set period — ranging from milliseconds to seconds — a high-pressure cooling system quickly douses the neurons with liquid nitrogen, literally freezing the moment in time.

The cold bath kills the cells, so the researchers can’t capture the continuous action of any individual neuron. But by looking with an electron microscope at thousands of cells frozen at various times, they can piece together key steps in the signaling process. They can see cell components that are hundreds of times smaller than a speck of dust and movements that happen faster than the blink of an eye.

A similar freezing experiment was performed with frog nerves in 1979 by lead scientists John Heuser and Thomas Reese. They dropped the tissue past an electrical switch that stimulated the nerve, then slammed it into an ultra-cold metal block to freeze it. The approach was both simple and effective, but Watanabe and his colleagues’ new method is far more flexible, said Graeme Davis, a neuroscientist at the University of California, San Francisco.

Comparing the experimental apparatuses, “Heuser and Reese had the Model-T, and Shigeki’s driving the Tesla,” he said.

Watanabe and his colleagues have been using their technique to study what happens at the synapse, or junction between neurons. The cells store neurotransmitters near the synapse in membrane-enclosed containers called vesicles. The vesicles merge with the outer membrane of the neuron to release their contents, but because there’s a limited number of vesicles at each synapse, the cell needs to regenerate the containers locally to communicate for longer than a few seconds.

The flipbook images have already illustrated one major discovery: a new, ultrafast way that neurons recycle the vesicles. Less than one-tenth of a second after the vesicles merge with the outer cell membrane, the membrane folds back in on itself, creating a large container that is later divided into multiple new vesicles. The process is similar to recycling beer bottles by melting the glass, Watanabe said. “[The neurons] are re-making the vesicles, but they are doing it in bulk, so that’s why it’s much faster,” he said.

The results are an excellent example of how new technology often drives new discoveries, said Alberto Pereda, a neuroscientist at the Albert Einstein College of Medicine in New York who was not involved in the study.

Most recently, the team has identified key proteins that make the fast recycling possible, and whose absence may be linked to neurological diseases. Watanabe presented the technique and the new findings at a meeting of the American Crystallographic Association in late May in New Orleans, in a session devoted in part to cryo-electron microscopy, an increasingly popular approach to studying biological materials by freezing them and examining them with an electron microscope.

Traditionally, electron microscopy was best suited to seeing membranes in cells, but scientists are now figuring out ways to use the technique to see proteins — the cellular machines that “make things happen,” Davis said. Watanabe’s technique can add exquisite time resolution to the detailed static images that electron microscopy provides, he said.

Davis is so enthusiastic about Watanabe’s methods, in fact, that the two scientists recently started a collaboration to use the flash-and-freeze technique to study how neurons can work steadily for decades, even as all their component parts are replaced over time.

For anyone who’s interested in how life works inside of cells, “this is going to be one very powerful way to go forward,” he said.

Laboratory In A Needle Promises Rapid Diagnosis

Laboratory In A Needle Promises Rapid Diagnosis

Researchers in the U.S. and Singapore have designed a miniature chemistry laboratory inside a needle that could yield almost instantaneous results from routine laboratory tests, potentially accelerating the diagnosis and treatment of medical conditions.

The prototype device, created by miniaturizing existing “lab on a chip” technology, has shown its capability in studies of mice with liver toxicity, a common side effect of cancer chemotherapy in humans.

“It really integrates the whole laboratory process in one testing without any human in between,” said Stephen Wong of Houston Methodist Research Institute and Weill Cornell Medical Center, who created the idea for the new technology.

Diagnosis of medical conditions depends on the results of blood tests to identify toxicity and potential reactions to drugs. Obtaining the results of the tests can typically take a week. However, Wong said, “Using our approach, it takes less than an hour.”

The patented design combines individual components from a chemistry laboratory into a single small package attached to a conventional 32-gauge needle, a size used for several simple injections.

“This is a change in paradigm – a really disruptive technology,” Wong said. “You are no [longer] tied down to the lab” to carry out diagnostic procedures. “You can have a wireless device attached to your cell phone.”

Medical specialists could use the technology in healthcare offices, patients’ homes, or even remote locations to carry out diagnoses normally performed in hospitals.

“It’s a point-of-care mobile device,” Wong said. “But it can also be a device that you can use during the surgery to get instant results.” That would permit doctors and patients to discuss treatment options as early as possible.

“I found it very exciting,” said Shari Rubin, an internist at Houston Methodist Hospital. She was not involved in the research.

“Many of our patients travel really far to come to the medical center for blood work,” Rubin added. “If you can have them do things at home, that would be incredibly helpful. Anything that can keep patients away from the hospital is wonderful.”

She noted, however, that developers of the technology would need to persuade patients to use it at home and to convince insurers to cover it.

The technology stems from the “lab on a chip” approach.

“This is basically a device that includes one of several functions on a single chip, measuring square millimeters to a few square centimeters,” Wong said. The approach combines microfluidics, a technology that deals with miniscule volumes of liquids, and semiconductors, the gizmos at the heart of all modern computers and communications methods.

The lab on a needle is designed to carry out several steps in testing a patient’s tissue sample for any particular medical condition. It extracts the sample; prepares it; amplifies the material in it called messenger ribonucleic acid, or mRNA, a carrier of genetic material; and runs a process called the polymerase chain reaction, or PCR, to detect the existence and concentration of the gene or genes related to the sought-after disease.

The prototype needle uses two chips. The first carries out the initial three tasks while the second contains the chemicals that perform the PCR process.

“The prototype puts the two chips together and obtains a readout,” Wong said. “We’ve proved that the two can be put together in one package.”

To test the prototype needle, the team hit on liver toxicity, which has the advantage of needing only two genetic markers to identify it.

Wong’s group induced liver toxicity in mice and used the needle to identify the markers for it, and the lack of the markers in untreated mice. They reported the results in the online publication Lab on a Chip.

The researchers emphasize that their lab in a needle is still in the development stage.

Wong’s team, along with collaborators in Singapore’s Nanyang Technological University and the Singapore Institute for Manufacturing Technology (SIMTech), are now engineering a practical version of the technology.

The teams also plan to develop the necessary procedures for testing the needle in humans. Those tests will seek the same genetic markers as the studies involving mice. But they will have to comply with much tighter government regulation.

The research team also aims to apply the technique to various medical conditions.

“We are planning to test other tissues or body fluids based on respective testing protocols for other human disease detection and diagnosis beyond liver toxicity,” said Zhiping Wang, director of research programs at SIMTech, in an e-mail message.

“The concept is working; the rest will be engineering,” Wong said.

If it passes the trials, the device could yield significant improvements in clinical practice.

“It’s less risky, faster, and cheaper than current methods,” Wong said. It also puts the lab on a chip concept at the service of medical personnel in addition to life scientists in the laboratory.

“In the long run if it’s successful it can deal with everything,” Wong said. “We try to bring the hospital to the patient, not the patient to the hospital.”

X-ray Science Gets New ‘Glasses’

X-ray Science Gets New ‘Glasses’

X-rays are short wavelengths of light with a long list of scientific accomplishments. Now researchers have made a simple quartz plate that could help take X-ray-powered science to new heights, such as uncovering how chemical reactions happen and making fundamental particles of mass from colliding beams of light.

X-rays can famously penetrate soft tissue, revealing broken bones. But their resume isn’t limited to the medical field. Cutting-edge scientific instruments like the Linac Coherent Light Source, located at the SLAC National Accelerator Laboratory in Menlo Park, California, generate ultra-short, intense X-ray pulses to probe matter at the scale of atoms and molecules.

Manufacturing the lenses and mirrors to steer the X-rays in such machines is a big technical challenge, and imperfections inevitably creep in that make it difficult to perfectly focus the beam. An international team of scientists has developed “glasses” that correct for the defects.

They demonstrated the technique for a stack of 20 X-ray lenses — the type of optics equipment that might be used for experiments requiring an intense beam of X-rays focused down to an extremely small area. The corrective plate helped focus most of the X-rays onto a spot just 250 nanometers across, tripling the intensity in that center area. The results were published in the journal Nature Communications.

The team plans to install corrective plates at the Linac Coherent Light Source and at the PETRA III X-ray source in Hamburg, Germany. The plates have the potential to push the capabilities of many X-ray instruments to new levels, the team said, which means X-rays may soon reveal even more scientific secrets.

Artificial Intelligence Predicts a Picture’s Future

Artificial Intelligence Predicts a Picture’s Future

Given a still image, a new artificial intelligence system can generate videos that simulate the future of that scene to predict what might happen next. Currently, these videos are less than two seconds long and can make people look like blobs. But researchers hope that in the future, more powerful versions of this system could help robots navigate homes and offices and also lead to safer self-driving cars.

Computers have grown steadily better at recognizing faces and other items within images. However, they still have major problems envisioning how the scenes they see might change, given the virtually limitless number of ways that items within images can interact.

To confront this challenge, computer scientist Carl Vondrick at the Massachusetts Institute of Technology’s Computer Science and Artificial Intelligence Lab in Cambridge and his colleagues explore machine learning, a branch of artificial intelligence devoted to developing computers that can improve with experience. Specifically, they research “deep learning,” where machine learning algorithms are run on advanced artificial neural networks designed to mimic the human brain.

In an artificial neural network, software or hardware components known as artificial neurons receive data, then cooperate to solve a problem such as reading handwriting or recognizing an image. The network can then alter the pattern of connections between those neurons to change the way they interact, after which the network attempts to solve the problem again. Over time, the network learns which patterns are best at computing solutions.

The scientists first trained their system on how to generate videos by having it analyze more than 2 million videos downloaded from the image and video hosting website Flickr. Next, they took images from beaches, train stations, hospitals and golf courses and had their system generate videos predicting what the next few seconds of that scene might look like. For instance, beach scenes had crashing waves, while golf scenes had people walking on grass.

Vondrick and his colleagues used a deep-learning technique called “adversarial learning” that involves two competing neural networks. One network generates videos, while the other attempts to discriminate between real videos and the fakes its rival creates. Over time, the generator learns to fool the discriminator. A key trick for generating more realistic videos involved simulating moving foregrounds and stationary backgrounds.

Flexible Graphene Energy Storage Membrane

Flexible Graphene Energy Storage Membrane

“Free of conductive additives, binders, commercial separators, and current collectors.” This claim, from researchers at Tsinghua University, China, reads like the health claims on my box of afternoon cereal. More seriously, it reads like the recipe for a highly simplified, low cost energy storage device, which they have produced using a TiO2-assisted UV reduction of sandwiched graphene components.

The sandwich structure consists of two active layers of reduced graphene oxide hybridised with TiO2, with a graphene oxide separator (rGO-TiO2/rGO/rGO-TiO2). In the completed device, the separator layer also acts as a reservoir for the electrolyte, which affects ion diffusion—a known problem for layered membrane devices—and affects both the capacity and rate performance.

A step-by-step vacuum filtration process is used to form the membrane structure, and the amount of graphene oxide used in the filtration solutions can be adjusted to precisely tune t he thickness of each layer. Irradiation of the dried membrane with UV light then reduces the graphene oxide to rGO with assistance from the TiO2.

The electrochemical performance of the hybrid active layer was clearly affected by the reduction time, with anything less than 40 minutes being too short to completely reduce the graphene oxide, leading to lower electrical conductivity and, therefore, reduced capacitance of the membrane. Going beyond 40 minutes of UV irradiation, suggest the researchers, strips the functional groups from the rGO surface, leading to a lower pseudocapacitance.

The membrane supercapacitor also demonstrated good mechanical stability, with an essentially unchanged electrochemical performance when tested at bending angles of 90 and 180 degrees.

The method used by these researchers to generate compact, thin-film, energy storage structures offers good control over the synthetic parameters while being very easy and user-friendly, and is not limited to the production of supercapacitors.

Researchers Are Developing Shape-Shifting Fluid Robots

Researchers Are Developing Shape-Shifting Fluid Robots

By using fluids similar to Silly Putty that can behave as both liquids and solids, researchers say they have created fluid robots that might one day perform tasks that conventional machines cannot.

Conventional robots are made of rigid parts that are vulnerable to bumps, scrapes, twists and falls. In contrast, researchers worldwide are increasingly developing robots made from soft, elastic plastic and rubber that are inspired by worms, starfish and octopuses. These soft robots can resist many of the kinds of damage, and can squirm past many of the obstacles, that can impede hard robots.

However, even soft robots and the living organisms they are inspired by are limited by their solidity — for example, they remain vulnerable to cutting. Instead, researcher Ido Bachelet of Bar-Ilan University in Israel and his colleagues have now created what they call fluid robots that they say could operate better than solid robots in chaotic, hostile environments. They detailed their findings online Jan. 22 in the journal Artificial Life.

The researchers experimented with so-called non-Newtonian fluids. Water acts mostly like a Newtonian fluid, meaning the degree to which it resists flowing — its viscosity — generally stays constant regardless of the mechanical force applied against it. In contrast, the viscosity of a non-Newtonian fluid can vary depending on the rate that mechanical force is applied against it. For instance, the non-Newtonian fluid Silly Putty can flow like a viscous liquid but also snap or bounce like an elastic solid.

Suspensions — that is, liquids with particles mixed into them — are often non-Newtonian fluids. For example, when water is filled with starch particles, it becomes a doughy substance known as oobleck that acts solid if you run across it but liquid if you stand still on it.

After testing a variety of non-Newtonian fluids, Bachelet and his colleagues developed prototype fluid robots made of blobs of starch grains suspended in a sugary solution. Sound waves from audio speakers underneath the surface where the blobs rested helped control their mechanical properties, and depending on the volumes and frequencies of the sounds, the researchers could make the blobs move.

The scientists could make the fluid robots drag metal items more than five times their weight. The blobs could also change shape, split into smaller blobs that could be controlled individually, merge to form larger blobs, and drip through gratings. These qualities suggest that fluid robots might find use in search and rescue missions, dripping into otherwise unreachable places and merging at their destinations to carry weights and perform work, the researchers noted.

“It’s really novel — it’s a robot that basically doesn’t have any parts,” said mechanical engineer David Hu at the Georgia Institute of Technology, who did not take part in this research.

The blobs could even be made to “count” up to three, Bachelet and his colleagues said. When they absorbed aluminum oxide, they became more rigid, and after they engulfed three dough packets laced with aluminum oxide, they became too stiff to move.

The scientists suggest that fluid robots carrying chemical payloads could interact and perform chemical reactions. Potential applications might include multiple fluid robots working together in an assembly line to synthesize compounds or break down waste, they said.

The fact that these blobs need to rest on sound-generating platforms to move is an obvious limitation, Bachelet and his colleagues admitted. However, the researchers said that future research could likely extend the concept to new control methods. For instance, sound beams could steer these blobs from a distance, they said. Moreover, using magnetic or electrically charged fluids could lead to fluid robots that could also be steered with magnetic or electric fields. Combining multiple techniques of control might lead to very elaborate and capable designs, they added.

Bachelet and his colleagues suggested that fluid robots could be given coatings much like those protecting cells, which could prevent incidental mixing and reduce water loss from evaporation. “In this regard, fluid robots could show unexpected similarities to primitive life forms,” they wrote in their paper.

The researchers developed their fluid robot designs through trial and error, since the physics underlying non-Newtonian fluids is still not well understood. They suggested further research into fluid robots could in turn help scientists better understand non-Newtonian fluid behavior.

“Overall, I think the concept of fluid robots is exciting,” said roboticist Michael Tolley at the University of California, San Diego, who did not participate in this work. However, he noted that in order to classify a machine as a robot, most researchers would require it to have the ability to make decisions by itself. “We are a long way off from addressing the tough challenge of designing a fluid that is able to think and act autonomously,” Tolley said.

The New Age in Clinical Digital Pathology

The New Age in Clinical Digital Pathology

The compound microscopes were invented in the 1590s.  XVII and XVIII centuries were productive for medical science thanks to the prolific careers of Antonie van Leeuwenhoek, Giovanni Battista Morgagni, and Marcello Malpighi – the “fathers” of microbiology, modern anatomical pathology, and microscopic anatomy, respectively. Microscopes have been reliable companions of clinical pathologists ever since. With the emergence of high-resolution scanners, cameras and computer software, the field is now opening up to a new endeavor – Digital Pathology.

The computer-aided image analysis of clinical pathology samples can either be fully automated on the whole slide image or the pathologist can select the regions of interest as he scans the field:

  • The first option provides an immediate and preset automated processing following the scan. However, it requires full automation adjusting e.g. to different staining intensities and setting the processing parameters automatically.
  • The interactive option allows input of critical parameters and direct monitoring and tuning of the data analysis by the pathologist in real time. However, this approach must produce fast results to expedite the diagnosis.

This Special Issue includes the Editorial by Guest Editors and 7 articles that report the latest advances in both approaches used to identify cancerous and/or metastatic tissues based on their morphology, cell proliferation frequency, and cancer-specific surface receptors that can be used as biomarkers in ER-positive breast cancer, follicular lymphoma, and several other types of cancer.

Moths’ Eyes Inspire New Tech

Moths’ Eyes Inspire New Tech

Moths’ eyes sport nanoscale structures on their surfaces that minimize light reflection. This feature helps the insects to see better in the dark by reducing glare, and also makes it more difficult for predators to spot them by looking for the twinkle in their eyes.

Inspired by moths, engineers and materials scientists have been developing anti-reflection films to increase efficiencies for solar panels, to lower battery consumption for smartphone displays, or even just to improve the appearance of highway billboards. Moth lovers, don’t be alarmed — we are not harvesting the insects for their eyeballs. Instead, the researchers are experimenting with materials and fabrication techniques to recreate this nanoscale structure in the lab.

Just this week, a research group at the University of Central Florida in Orlando published a paper in the journal Optica that introduces a new anti-reflection film. They claim to have optimized their product specifically for smartphone screens, and they also provide a model that other researchers can use to optimize their own films in the future.

How it’s made

The scientists, part of the optics and photonics research group led by Shin-Tson Wu, use a technique similar to stamping to create the special new film. They first deposit a solution with nanoscale silicon oxide spheres onto a surface. The nanospheres are only about 100 nanometers across, or almost one-thousandth the width of a human hair. Then, they spin the surface to spread out the nanospheres — the faster the spin, the farther apart the particles. The surface is then dried with the now embedded tiny spheres, and used as a stamp to imprint tiny dimples onto the final product, creating the nanoscale structure that mimics what moths have on the surface of their eyes.

The technique still has some issues to iron out. According to Wu, some of the silicon oxide nanoparticles would come loose during the imprinting process and get stuck to the film, which makes the stamp nonreusable. In the future the researchers hope to develop a reusable stamp using a mold instead of nanoparticles.

“Whenever you talk about applications where you have to fabricate things with large areas, imprinting is usually a good choice,” said Dietmar Knipp, a materials scientist from Stanford University in California who was not involved in the study. “But the way that they are doing it, the stamp with the nanostructure is destroyed in the end, so that if you want to do it again, you’d have to start the process all over again.”

The road from lab to market is often lined with such obstacles. In the case of anti-reflection films, manufacturing cost is a big one. The consumer electronics company Sharp has been talking about making a TV with the technology since at least 2012, and Philips has actually made one, but with a $3,000 price tag.

“There are already some commercial products that use this kind of anti-reflection surface, but there are still some issues,” said Guanjun Tan, a graduate student in Wu’s research group at the University of Central Florida.

For instance, the anti-reflection film used in the Philips TV is known to stain easily. If it coated smartphone screens, the constant touching from people’s fingertips would damage it. Tan said that after experimenting with several materials, they have found a film that is considerably more resistant to scratches and staining from water and oil. They also considered flexibility to be an important feature, since scientists and engineers are working to develop foldable displays for the near future.

“For this paper, we optimized the material to have more flexibility, but then we lose some surface hardness, and less anti-scratching,” said Tan. Such tradeoffs, it seems, are common in the world of engineering. Nevertheless, the researchers claim their film can provide a four-fold improvement in color contrast for a smartphone screen viewed under sunlight.

More to learn from nature

Another part of the study may help researchers develop different applications for the anti-glare technology.

“We have also developed a simulation model that other people can use to optimize the nanoparticle’s shape, depth [and] diameter, for the optimal anti-reflection,” said Wu.

For example, an anti-reflection film for solar cells or highway billboards might not require the same resolution as a smartphone screen, so researchers can choose to sacrifice certain attributes for other ones.

For now, the researchers’ model is based on their approach of imprinting films with tiny spherical dimples — but there might be better nanostructures out there. Other researchers have tried nanoscale pillars and even cones, but according to a 2011 paper by Knipp, the ideal nanostructure for anti-reflection may be tiny, parabolically curved domes.

“Ultimately, that is probably the closest to optimum — after all, that’s what’s found in nature, in moth eyes,” said Knipp.

However, compared to pillars, cones and dimples, a surface with tiny parabolic domes is even trickier to make. So, when it comes to perfecting anti-reflection, we are still chasing after the moths.