Connect with us

Chemistry

Illuminating the Twist: Light-Controlled Supramolecular Chirality

In a striking demonstration of molecular control, a team of scientists has harnessed light to reverse the twist in self-assembling molecules. The study identifies how trace residual aggregates in photo-responsive azobenzene solutions can reverse helical chirality through secondary nucleation. By using precise control of ultraviolet and visible light, the researchers could switch between the rotation of helices, offering a breakthrough for novel materials with tunable properties.

Avatar photo

Published

on

The self-assembly of molecules into complex structures is a crucial phenomenon in material science. Researchers from Japan have made a significant breakthrough by elucidating a technique where a small amount of residual aggregates drastically alters the self-assembly process of photo-responsive molecules. This study, led by Professor Shiki Yagai and his team, was published online in Nature Nanotechnology on April 11, 2025.

In recent years, there has been an increasing focus on controlling the size and hierarchical structures of self-assembled aggregates to achieve materials with desired properties. However, self-assembly is a dynamic process that requires precise control. As Professor Yagai explains, “During the process of self-assembly, molecules repeatedly associate and dissociate,” making it challenging to predict the final structure of the formed aggregates.

The research team focused on the self-assembly of a chiral, photoresponsive azobenzene molecule that naturally forms left-handed helical aggregates. They discovered that the presence of a small amount of residual aggregates within the solution induces a drastic change in the assembly process and leads to the formation of right-handed helical aggregates instead.

The team found that when the scissor-shaped azobenzene molecule is dissolved in an organic solvent at room temperature, it forms a closed scissor-like folded structure that further extends into a helical assembly. This is due to the chirality of the molecule, which causes it to fold like left-handed scissors and twist to form a left-handed helical stacking of the assembly.

The molecules are photoresponsive, meaning they can change their structure in response to light. When exposed to weak ultraviolet (UV) light, the helical assembly disassembles back into individual molecules, and upon subsequent exposure to visible light, the molecules reassemble into helical structures again.

Interestingly, under certain conditions, the resulting helical aggregates were found to be right-handed instead of left-handed, and exposure to stronger UV light followed by visible light led to the regeneration of the original left-handed helical aggregates. The team attributed this phenomenon to “secondary nucleation,” which explains why meta-stable right-handed aggregates are preferably formed instead of left-handed aggregates.

The researchers also discovered that the intensity of visible light affects the timing of the assembly, with strong visible light promoting rapid assembly while minimizing the influence of residual aggregates. By optimizing the intensities of UV and visible light, the team successfully controlled the switching between left- and right-handed helical structures which were dependent on the influence of residual aggregates.

Furthermore, it was found that the stable left-handed aggregates and meta-stable right-handed aggregates also exhibit opposite electron spin polarization, signifying the tuning of electronic characteristics of the helices. This study aims to explore the critical role of residual aggregates and explained how light-enabled fine-tuning can result in the fabrication of novel functional materials, giving promising insights into the field of material science.

Chemistry

A Single Step Forward: Revolutionizing Drug Discovery with Carbon Insertion

A research team has pioneered a groundbreaking method that could accelerate drug discovery and reduce pharmaceutical development costs. Their work introduces a safe, sustainable way to insert a single carbon atom into drug molecules at room temperature.

Avatar photo

Published

on

The discovery of new medicines is an intricate process that requires patience, precision, and creativity. A research team from the University of Oklahoma has made a groundbreaking breakthrough that could accelerate this process, making it faster, safer, and more cost-effective. Their innovative method allows for the insertion of a single carbon atom into drug molecules at room temperature, opening up new possibilities for chemical diversity without compromising sensitive structures.

Nitrogen atoms and nitrogen-containing rings, known as heterocycles, play a crucial role in medicine development. A team led by OU Presidential Professor Indrajeet Sharma has found a way to modify these rings by adding just one carbon atom using a fast-reacting chemical called sulfenylcarbene. This process, called skeletal editing, transforms existing molecules into new drug candidates.

The significance of this discovery lies in its potential to change the molecule’s biological and pharmacological properties without altering its functionalities. This could unlock uncharted regions of chemical space in drug discovery, making it easier to find effective treatments for various diseases.

Unlike previous studies that relied on potentially explosive reagents and posed significant safety concerns, Sharma’s team has developed a bench-stable reagent that generates sulfenylcarbenes under metal-free conditions at room temperature. This achievement reduces environmental and health risks associated with metal-based carbenes.

The researchers are also exploring how this chemistry could revolutionize DNA-encoded library (DEL) technology, which allows for the rapid screening of billions of small molecules for their potential to bind to disease-relevant proteins. The metal-free, room-temperature conditions of the team’s new carbon insertion strategy make it a compelling candidate for use in DEL platforms.

By enabling precise skeletal editing in collaboration with the Damian Young group at the Baylor College of Medicine, Sharma’s approach could significantly enhance the chemical diversity and biological relevance of DEL libraries. This is particularly important as these are two key bottlenecks in drug discovery.

The cost of many drugs depends on the number of steps involved in making them. Adding a carbon atom in the late stages of development can make new drugs cheaper, akin to renovating a building rather than building it from scratch. By making these drugs easier to produce at large scale, we could reduce the cost of healthcare for populations around the world.

In conclusion, Sharma’s team has pioneered a groundbreaking method that accelerates drug discovery and reduces pharmaceutical development costs. Their innovative approach has far-reaching implications for the field of medicine, making it faster, safer, and more cost-effective.

Continue Reading

Chemistry

“Nature’s Filter: Plant-Based Extracts Show Promise in Removing Microplastics from Water”

The substances behind the slimy strings from okra and the gel from fenugreek seeds could trap microplastics better than a commonly used synthetic polymer. Previously, researchers proposed using these sticky natural polymers to clean up water. Now, they report that okra and/or fenugreek extracts attracted and removed up to 90% of microplastics in ocean water, freshwater and groundwater.

Avatar photo

Published

on

The fight against microplastic pollution has taken a promising turn. Researchers have discovered that extracts from plants like okra and fenugreek can trap and remove up to 90% of these tiny plastic particles from various types of water – ocean, freshwater, and groundwater. This breakthrough, published in ACS Omega, offers a biodegradable and non-toxic alternative to synthetic polymers currently used for wastewater treatment.

Researchers led by Rajani Srinivasan have been exploring plant-based approaches to clean contaminated water. In lab experiments, they found that extracts from okra, fenugreek, and tamarind formed sticky natural polymers that clump together with microplastics, making it easy to separate them from the water. The team demonstrated successful removals in freshwater and ocean water at a meeting of the American Chemical Society.

To extract these sticky plant polymers, researchers soaked sliced okra pods and blended fenugreek seeds in water overnight. They then removed the dissolved extracts, dried them into powders, and analyzed their composition. Initial tests showed that the powdered extracts contained polysaccharides, natural polymers capable of attracting microplastics.

The researchers then tested these plant extracts on real-world samples from waterbodies around Texas. The results varied depending on the original water source: okra worked best in ocean water (80%), fenugreek in groundwater (80-90%), and a combination of both in freshwater (77%). The team hypothesizes that this difference is due to the varying types, sizes, and shapes of microplastics present in each water sample.

Currently, polyacrylamide is used for contaminant removal during wastewater treatment. However, the researchers propose using okra and fenugreek extracts as biodegradable and non-toxic alternatives.

“Utilizing these plant-based extracts in water treatment will remove microplastics and other pollutants without introducing additional toxic substances to the treated water,” says Srinivasan. “This can significantly reduce long-term health risks to the population.”

The researchers acknowledge funding from various institutions, including the U.S. Department of Energy, Tarleton State University, and the National Science Foundation Research Experiences for Undergraduates program.

Continue Reading

Air Pollution

Breaking Down Plastic Pollution: A Revolutionary New Tool for Detecting Nanoplastics and Microplastics

A team of researchers has developed a cost-effective, high-throughput technology for detecting nanoplastics and microplastics in the environment. These particles are pervasive, posing health and environmental risks, yet detecting them at the nanoscale has been difficult. The 3D-printed HoLDI-MS test platform overcomes the limitations of traditional mass spectrometry by enabling direct analysis of samples without requiring complex sample preparation. The researchers say it also will work for detection of waterborne plastic particles. HoLDI-MS stands for hollow-laser desorption/ionization mass spectrometry.

Avatar photo

Published

on

By

The world is facing an unprecedented crisis due to the proliferation of nanoplastics and microplastics in our environment. These tiny particles, often overlooked, pose significant health and environmental risks. However, detecting them at the nanoscale has been a daunting challenge. That’s why a team of researchers from McGill University has developed a groundbreaking technology that makes it possible to detect these plastic particles efficiently and accurately.

The HoLDI-MS (Hollow-Laser Desorption/Ionization Mass Spectrometry) test platform is a 3D-printed device that overcomes the limitations of traditional mass spectrometry. This innovative tool allows for direct analysis of samples without requiring complex sample preparation, making it a cost-effective and high-throughput solution.

“We’re excited to provide a method that is effective, quantitative, highly accurate, and affordable,” said Professor Parisa Ariya, who led the study published in Nature’s Communications Chemistry. “It requires little energy, is recyclable, and costs only a few dollars per sample.”

The HoLDI-MS platform has significant implications for international cooperation in combating plastic pollution. As part of their study, the researchers identified polyethylene and polydimethylsiloxanes in indoor air, as well as polycyclic aromatic hydrocarbons in outdoor air.

“This technology allows us to pinpoint the major sources of nano and microplastics in the environment,” said Professor Ariya. “More importantly, it enables data comparison and validation across laboratories worldwide, a crucial step toward harmonizing global research on plastic pollution.”

The development of HoLDI-MS is a testament to the power of interdisciplinary collaboration and innovation. Funded by organizations such as the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), and National Research Council Canada (NRC), this technology has the potential to revolutionize the way we detect and address plastic pollution.

As the world continues to grapple with the consequences of plastic waste, the HoLDI-MS platform offers a beacon of hope. By providing a cost-effective and efficient solution for detecting nanoplastics and microplastics, this technology can help us take a significant step toward mitigating the impact of plastic pollution on our environment.

Continue Reading

Trending