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Category: chemistry

Encapsulated PbS quantum dots boost solar water splitting without sacrificial agents

A research team affiliated with UNIST has developed stable and efficient chalcogenide-based photoelectrodes, addressing a longstanding challenge of corrosion. This advancement paves the way for the commercial viability of solar-driven water splitting technology—producing hydrogen directly from sunlight without electrical input.

Jointly led by Professors Ji-Wook Jang and Sung-Yeon Jang from the School of Energy and Chemical Engineering, the team reported a highly durable, corrosion-resistant metal-encapsulated PbS quantum dot (PbS-QD) solar cell-based photoelectrode that delivers both high photocurrent and long-term operational stability for photoelectrochemical (PEC) water splitting without the need for sacrificial agents. The research is published in the journal Nature Communications.

PEC water splitting is a promising route for sustainable hydrogen production, where sunlight is used to drive the decomposition of water into hydrogen and oxygen within an electrolyte solution. The efficiency of this process depends heavily on the stability of the semiconductor material in the photoelectrode, which absorbs sunlight and facilitates the electrochemical reactions. Although chalcogenide-based sulfides, like PbS are highly valued for their excellent light absorption and charge transport properties, they are prone to oxidation and degradation when submerged in water, limiting their operational stability.

Enhanced Selenium Supplement Extends Lifespan and Delays Multi‐Organs Aging by Regulating the Sik1 Pathway Through Maintaining Calcium Homeostasis

In healthy aging strategies, nutritional supplements synergize with optimized dietary and lifestyle interventions by modulating aging-related molecular pathways.[ 8, 9 ] Notably, NMN exerts multi-organ anti-aging effects by elevating NAD+ levels to activate the SIRT1 pathway, thereby significantly enhancing mitochondrial function while reducing oxidative stress and DNA damage.[ 10 ] Similarly, curcumin delays aging and related diseases through pleiotropic mechanisms involving oxidative stress regulation, anti-inflammatory actions, telomere maintenance, and sirtuin protein modulation.[ 11 ] However, practical applications face significant challenges: bioactive compounds like resveratrol and curcumin suffer from limited bioavailability due to poor aqueous solubility and first-pass metabolism, while excessive supplementation of antioxidants such as vitamins C/E may disrupt reactive oxygen species (ROS) signaling homeostasis, potentially inducing cellular toxicity or even increasing hemorrhagic risk.[ 12-14 ] Future development of anti-aging supplements should focus on: 1) innovative formulation strategies to enhance bioavailability; 2) optimized dosing regimens to minimize toxicity; and 3) long-term clinical studies to validate efficacy.

Selenium, an essential trace element with diverse biological activities, plays a critical role in healthy aging.[ 15-17 ] ≈1 billion people worldwide are affected by selenium deficiency, which is closely linked to neurological disorders, cardiovascular abnormalities, malignancies, and immune dysfunction.[ 18-20 ] Substantial evidence supports the anti-aging effects of selenium through multiple mechanisms: 1) Selenomethionine (SeMet) effectively suppresses Fe2+/H2O2- or Aβ-induced free radical generation, demonstrating therapeutic potential for Alzheimer’s disease characterized by oxidative stress;[ 21 ] 2) Selenium supplementation elevates serum GPx3 levels, a selenoprotein predominantly localized in the basement membrane of renal proximal tubules, modulating mitochondrial quality control pathways to mitigate heavy metal-induced renal aging;[ 22 ] and 3) Our recent findings reveal that selenium supplementation significantly attenuates age-related muscle atrophy by preserving redox homeostasis and regulating muscle protein metabolism.[ 23 ] Recent clinical trials in patients with advanced non-small cell lung cancer (NSCLC) demonstrated that oral administration of selenium nanoparticles (SeNPs) as a dietary supplement (200 µg day−1) in combination with Bev+AP chemotherapy significantly enhanced therapeutic outcomes compared to chemotherapy alone. The SeNPs combination group showed remarkable tumor regression, with progression disease rates decreasing dramatically from 50% to 0% and partial response rates increasing to 83.3%, along with significantly improved objective response rate and disease control rate.[ 24 ] Importantly, this regimen maintained excellent safety profiles without triggering fluctuations in pro-inflammatory or immunosuppressive cytokines. These compelling findings not only establish SeNPs as a safe and effective adjuvant therapy for advanced NSCLC but also provide valuable clinical translation data for nano-selenium formulations in oncology. Despite selenium’s proven benefits in reducing oxidative damage, maintaining genomic stability, and delaying telomere shortening, its narrow therapeutic window, limited bioavailability, and specific mechanisms in multi-organ protection during natural aging require further investigation.

Nanodelivery carriers have emerged as a next-generation platform for gene and drug delivery, offering tunable physicochemical properties such as size, composition, and surface modifications.[ 25 ] Our team has developed organically-bridged mesoporous silica nanoparticles (MSNs) by incorporating functional diselenide bonds into the silica framework at the molecular level, addressing the critical challenge of poor biodegradability in conventional silica materials.[ 26 ] This nanocarrier exhibits unique dual redox-responsive properties, allowing for more precise maintenance of redox homeostasis compared to traditional antioxidants, aligning with the core goal of preserving organismal homeostasis in anti-aging research. Building on this breakthrough, a comprehensive research framework was established: first, this study constructed a natural aging mouse model with MSNs, disulfide-bridged MSNs (SMSNs), commercially available SeMet as controls and then compared the effects of diselenide-bridged MSNs (SeMSNs) on lifespan extension, frailty delay, and multi-organ anti-aging. Next, key pathways and targets were identified through multi-organ transcriptome sequencing, followed by in-depth mechanistic studies. Finally, clinical translation was integrated by analyzing the correlation between serum selenium levels and aging biomarkers in the elderly, and validating the clinical effects of SeMSNs using primary adipose precursor cells (APCs) models. This systematic approach provides a solid theoretical foundation and clinical evidence for the application of nano-selenium in anti-aging research.

Quantum defects in carbon nanotubes as single-photon sources

This Review surveys progress in the development of carbon nanotubes as single-photon sources for emerging quantum technologies, with a focus on chemical synthesis and quantum defect engineering, computational studies of structure-property relationships, and experimental investigations of quantum optical properties.

The surprising way the brain’s dopamine-rich reward center adapts as a romance matures

A new study published in the journal Social Cognitive and Affective Neuroscience provides evidence that the human brain processes romantic partners differently than close friends, specifically within the reward system. The research suggests that while the brain creates a unique neural signature for a partner early in a relationship, this distinction tends to fade as the bond matures. These findings offer insight into how the biological drivers of romantic love may evolve from passion to companionship over time.

Relationships involve complex psychological states that differentiate a committed partner from a platonic friend. Scientists have sought to map these differences in the brain to understand the biological foundations of human bonding. Much of this research focuses on the nucleus accumbens. This small region deep within the brain, which relies heavily on the neurotransmitter dopamine, plays a central role in processing rewards and motivation.

Evidence from animal studies indicates that the nucleus accumbens is essential for forming pair bonds. Research on monogamous prairie voles shows that neurochemical signaling in this area drives the preference for a specific partner. The brain appears to undergo plastic changes that reinforce the bond.

JWST uncovers rich organic chemistry in a nearby ultra-luminous infrared galaxy

A study led by the Center for Astrobiology (CAB), CSIC-INTA, using modeling techniques developed at the University of Oxford, has uncovered an unprecedented richness of small organic molecules in the deeply obscured nucleus of a nearby galaxy, thanks to observations made with the James Webb Space Telescope (JWST).

The work, published in Nature Astronomy, provides new insights into how complex organic molecules and carbon are processed in some of the most extreme environments in the universe.

The study focuses on IRAS 07251–0248, an ultra-luminous infrared galaxy whose nucleus is hidden behind vast amounts of gas and dust. This material absorbs most of the radiation emitted by the central supermassive black hole, making it extremely difficult to study with conventional telescopes.

Self-regulating living implant could end daily insulin injections

A pioneering study marks a major step toward eliminating the need for daily insulin injections for people with diabetes. The study was led by Assistant Professor Shady Farah of the Faculty of Chemical Engineering at the Technion—Israel Institute of Technology, in co-correspondence with MIT, and in collaboration with Harvard University, Johns Hopkins University, and the University of Massachusetts. The findings are published in the journal Science Translational Medicine.

The research introduces a living, cell-based implant that can function as an autonomous artificial pancreas, essentially a living drug that is long-term, thanks to a novel crystalline shield-protecting technology. Once implanted, the system operates entirely on its own: it continuously senses blood-glucose levels, produces insulin within the implant itself, and releases the exact amount needed—precisely when it is needed. In effect, the implant becomes a self-regulating, drug-manufacturing organ inside the body, requiring no external pumps, injections, or patient intervention.

One of the study’s most significant breakthroughs addresses the longstanding challenge of immune rejection, which has limited the success of cell-based therapies for decades. The researchers developed engineered therapeutic crystals—called “crystalline shield”—that shield the implant from the immune system, preventing it from being recognized as a foreign object. This protective strategy enables the implant to function reliably and continuously for several years.

Engineered enzymes enable greener one-pot amide synthesis for drug manufacturing

A single type of chemical structure that shows up again and again in modern medicine is the amide bond that links a carbonyl group (C=O) to a nitrogen atom. They’re so ubiquitous that 117 of the top 200 small-molecule drugs by retail sales in 2023 feature at least one amide bond. And now, researchers have discovered a clever new way to reengineer natural enzymes to build amides from simple chemicals like aldehydes and amines.

The team chose a naturally abundant enzyme family called aldehyde dehydrogenases (ALDHs), specifically p-hydroxybenzaldehyde dehydrogenase (PHBDD), which can efficiently convert aldehydes into acids. The team turned it into a new catalyst, known as an oxidative amidase (OxiAm), by modifying its internal pocket of the enzyme in two major ways: making it hydrophobic to prevent the formation of unwanted acids and making it bigger to allow larger, diverse chemical parts to fit inside so they could be bonded together.

According to the results published in Science, the team was able to obtain amides directly from commercially available alcohols via a two-step enzymatic cascade reaction carried out in a single container. This approach could enable new, greener methods for producing five major drug molecules, including a key component of imatinib, an essential drug used to treat chronic myeloid leukemia and gastrointestinal stromal tumors.

Three-way quantum correlations fade exponentially with distance at any temperature, study shows

The properties of a quantum material are driven by links between its electrons known as quantum correlations. A RIKEN researcher has shown mathematically that, at non-zero temperatures, these connections can only exist over very short distances when more than two particles are involved. This finding, now published in Physical Review X, sets a fundamental limit on just how “exotic” a quantum material can be under realistic, finite-temperature conditions.

A fascinating aspect of quantum physics is the concept that two particles that are spatially separated can communicate with each other. This so-called “spooky action at a distance,” as Einstein referred to it, is crucial for understanding the origin of the exotic properties that arise in some materials, particularly at low temperatures.

These unusual material properties are determined by the exact nature of the quantum correlation, and the material is said to be in a specific quantum phase. This is analogous to the traditional phases of matter—solid, liquid, and gas—being defined by the chemical interactions between the atoms.

Stabilized iron catalyst could replace platinum in hydrogen fuel cells

Japan and California have embraced hydrogen fuel-cell technologies, a form of renewable energy that can be used in vehicles and for supplying clean energy to manufacturing sectors. But the technology remains expensive due to its reliance on precious metals such as platinum. Engineers at Washington University in St. Louis are working on this challenge, finding ways to stabilize ubiquitous iron components for use in fuel cells to replace the expensive platinum metals, which would make hydrogen fuel-cell vehicles more affordable.

Cost challenges for fuel-cell vehicles

“The hydrogen fuel cell has been successfully commercialized in Japan and California in the U.S.,” said Gang Wu, a professor of energy, environmental and chemical engineering at the McKelvey School of Engineering. “But these vehicles struggle to compete with the battery vehicle and combustion engine vehicle, with cost being the main issue.”

When silicon fills the role of carbon: Debut of all-silicon cyclopentadienides

Carbon’s unique chemical properties allow it to be an essential building block for life on Earth and many other molecules we rely on for day-to-day life—but what about carbon’s neighbor? Silicon is located one row below carbon in the periodic table of elements, and similarly has many possible uses, and is a key component of semiconductors, silicon carbide fibers, and silicones. However, silicon has some key weaknesses compared to carbon.

For example, carbon forms very stable π-electron compounds (compounds linked by pi bonds, or π-bonds, which affect a molecule’s reactivity) called benzene and fullerene. In comparison, silicon cannot readily form these compounds, as the π-bonds forming π-electron compounds are not strong in this element. Synthesizing such silicon-based π-electron compounds consequently becomes increasingly difficult as the number of silicon atoms increases. However, researchers at Tohoku University found a way to overcome these limitations.

A research group led by Professor Takeaki Iwamoto, Graduate Student Tomoki Ishikawa, and Associate Professor Shintaro Ishida at the Graduate School of Science, Tohoku University, has successfully synthesized π-electron compounds with a pentagonal silicon framework, “pentasilacyclopentadienide,” and elucidated their molecular structures. The study is published in the journal Science.

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