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Category: nanotechnology

Fieldoscopy reveals femtosecond optical switching in 15 nm indium tin oxide nanocrystals

Just as an antenna interacts with radio waves, light interacts with metallic nanostructures. Therefore, understanding how a structure influences field oscillations provides valuable insights into the structure’s physical properties. An international research team, including scientists from the Max Planck Institute for the Science of Light (MPL), is investigating the changes in field oscillations that occur when light interacts with indium tin oxide (ITO) nanocrystals. This will deepen our understanding of how the interaction between light and these nanocrystals depends on time.

Precise and high-speed control of light is crucial to optical communication. It opens up the possibility to transmit data more quickly and efficiently in the future. Optical switches, which can activate or deactivate light pulses selectively, are a key component in achieving this.

To ensure optimal performance and prevent delays caused by switching times, the switches must respond very fast. Ideally, they also have the highest possible modulation depth. This refers to the difference in brightness between the light transmitted in the “on” and “off” states. Additionally, a suitable switch exhibits the same predictable behavior each time it is used.

Tiny LED design could power next-generation technology

From 3D movie screens to augmented-reality devices, many modern technologies rely on our ability to manipulate light. Doing so in a cost-effective and efficient way, however, is often a formidable task. In an article published in Optics Letters, researchers from the University of Osaka announced a new light-emitting diode (LED) design that may help shrink complex optical systems into much smaller devices. The LED produces circularly polarized light using a built-in nanostructured surface, eliminating the need for bulky external optical components.

Circularly polarized light, whose electric field rotates like a corkscrew as it travels, is essential for technologies such as 3D displays, advanced imaging systems, and quantum communication tools. Traditionally, generating this kind of light requires optical components such as polarizers and special plates that modify the light’s phase. However, these components make devices larger, more complex, and harder to integrate.

“Our goal is to simplify the way circularly polarized light is produced,” says corresponding author Shuhei Ichikawa. “By integrating polarization control directly into the LED with a specially designed metasurface, we remove the need for additional optical components.”

Silicon nanospheres boost WS₂ second-harmonic generation 40-fold while preserving polarization

A research team has demonstrated that silicon nanospheres can strongly enhance second-harmonic generation (SHG) from an atomically thin semiconductor while preserving the circular polarization information tied to its valley degree of freedom. The study, published in Nano Letters, provides design guidelines for efficient, polarization-preserving nonlinear light sources at the nanoscale.

SHG is a nonlinear optical process that converts light to twice its original frequency. Monolayer transition-metal dichalcogenides (TMDs) such as tungsten disulfide (WS2) possess valley-dependent optical selection rules that link circular polarization directly to the electronic valley index, making the SHG polarization state a direct readout of valley information.

To harness the valley degree of freedom as an information carrier in valleytronics, it is essential to enhance the SHG signal while preserving its circular polarization. However, the atomic-scale thickness of monolayer TMDs severely limits conversion efficiency, and previous approaches using nanostructures to boost the signal have disrupted the valley-polarization information—a dilemma of “enhance the signal, lose the polarization.”

DNA origami precisely positions single-photon emitters for quantum technologies

An international research team led by scientists from Skoltech has developed a method to position molecules on the surface of ultrathin materials with unprecedented precision using molecular DNA self-assembly, enabling the creation of quantum light sources. The results, published in the journal Light: Science & Applications, pave the way for the production of compact and efficient components for future quantum computers and secure communication networks.

Two-dimensional materials such as molybdenum disulfide are promising candidates for quantum light sources due to their ability to emit photons under laser excitation. However, until now, scientists have been unable to precisely control the location of emission centers—they emerged randomly upon ion beam irradiation or mechanical deformation of the material.

The authors of the study proposed a different approach. The research is based on the DNA origami method, which allows the construction of nanoscale objects of a specified shape from DNA molecules. Triangular structures measuring 127 nanometers were assembled, each carrying 18 thiol molecules. These structures were placed onto a silicon chip with a lithographic pattern. The positioning yield of each DNA origami structure at its designated location exceeded 90%, significantly surpassing the statistical limit of traditional single molecule deposition methods.

Electronics of the future: Ultra-efficient graphene switch developed at nanometer scale

A team of researchers from Tel Aviv University, in collaboration with colleagues from Japan, has taken an important step toward the next generation of electronics. The scientists achieved highly precise control of the internal structure of graphene—an exceptionally thin and strong material—using a minute, nearly negligible amount of energy.

The study was conducted under the supervision of Prof. Moshe Ben-Shalom of the School of Physics and Astronomy, together with Prof. Michael Urbakh and Prof. Oded Hod of the School of Chemistry. The experiments and calculations were led by Dr. Nirmal Roy and Dr. Pengua Ying, supported by Simon Salleh Atri, Yoav Sharaby, Noam Raab, and Dr. Youngki Yao. The findings were published in the journal Nature Nanotechnology.

New lipid nanoparticle design improves precision of mRNA vaccine delivery

Penn Engineers have redesigned a key component of lipid nanoparticles (LNPs), the delivery vehicles behind mRNA vaccines, to steer the particles toward lymph nodes while reducing off-target delivery to the liver. The advance could make mRNA vaccines more efficient, potentially achieving strong immune protection at lower doses.

“The more particles that reach the lymph nodes, the fewer particles each dose needs,” says Michael J. Mitchell, Associate Professor in Bioengineering (BE) and senior author of a new study in Journal of the American Chemical Society that describes how the researchers modified the ionizable lipid, a key LNP ingredient that helps mRNA enter cells.

In animal models, the new “aroLNPs,” whose name refers to the addition of a chemical structure called an “aromatic ring” to the ionizable lipid, delivered at least 10-fold less mRNA to the liver compared to the LNP formulation in the Moderna COVID-19 vaccine, while maintaining similar levels of lymph-node delivery.

Ultrastructural preservation of a whole large mammal brain with a protocol compatible with human physician-assisted death

Ultrastructural Preservation of a Whole Large Mammal Brain (bioRxiv, 2026) ⚠️ Preprint – not yet peer-reviewed.

A 2026 preprint builds on over a decade of brain preservation research, demonstrating that whole mammalian brains (pigs) can be preserved with remarkable structural fidelity under near–real-world, end-of-life conditions.

The study refines aldehyde-stabilized cryopreservation (ASC)—a technique previously recognized by the Brain Preservation Foundation. This method combines chemical fixation (aldehydes), cryoprotectants, and controlled cooling to prevent ice damage and preserve neural structure at the nanoscale. — What the study shows.

Whole pig brains preserved with intact cellular and synaptic architecture.

Preservation remains viable even with delayed postmortem intervals (~10 minutes)

Tissue remains perfusable and structurally stable after fixation.

Protocol moves toward clinically realistic implementation, not just lab conditions.

Continue reading “Ultrastructural preservation of a whole large mammal brain with a protocol compatible with human physician-assisted death” | >

Researchers uncover gut-liver serotonin pathway that limits nanoparticle and viral delivery

A new study has for the first time elucidated the gut-liver immune regulatory axis jointly maintained by intestinal commensal bacteria and the intestinal endocrine system, and uncovered the fundamental mechanism underlying the body’s nonspecific clearance of drug delivery carriers. It provides a universal solution to the core problem plaguing the delivery field for decades, significantly improves the delivery efficiency and therapeutic effect of tumor-targeted therapy, mRNA therapy, gene editing and other treatments, and blazes a new trail for the clinical translation of biomedical delivery technologies.

The research team led by Professors Wang Yucai, Zhu Shu and Jiang Wei from the University of Science and Technology of China (USTC) published their research paper titled “Commensal-driven serotonin production modulates in vivo delivery of synthetic and viral vectors” in Science on March 19.

Impressionist sea slugs create their patterns by arranging colorful photonic crystals

Nudibranchs are often referred to as the butterflies of the sea. Nudibranchs live worldwide, primarily in warm, shallow marine regions, and stand out for their flamboyant colors and diverse shapes. A team from the Max Planck Institute of Colloids and Interfaces in Potsdam and the University of Cambridge has now discovered how they create their colorful patterns. According to their findings, published in the Proceedings of the National Academy of Sciences, the color is produced by nanostructures, each of which creates a specific color impression.

“We were surprised to find that nudibranchs use structural colors,” says Samuel Humphrey, who conducted the research at the Max Planck Institute of Colloids and Interfaces. “Biologists had previously assumed that the colors were produced by pigments.” Pigments are chemical compounds and differently colored pigments have different chemical compositions.

In contrast, in structural colors, color is not a chemical property of the material, but it depends on the length scale of nanostructures composing the material. Such nanostructures, also called photonic crystals, are responsible for the coloration of chameleons, as well as many birds and butterflies. In such structures, color is produced by the regular arrangement of materials with different refractive indices.

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