The research, led by Gisele Eva Bruch and Daniela M. Barros at the Federal University of Rio Grande, alongside collaborators at the Federal University of Minas Gerais and the Nuclear Technology Development Center, set out to answer two intertwined questions: where do intravenously delivered PEGylated single-walled carbon nanotubes (SWCNT-PEG) actually go in the body, and do they cause harm along the way? To answer the first question, the team turned to Raman spectroscopy, a technique exquisitely sensitive to the unique vibrational fingerprint of carbon nanotubes. To answer the second, they deployed a battery of biochemical, histological, hematological, and behavioral assays.

The choice of Raman spectroscopy was no accident. Single-walled carbon nanotubes possess a characteristic Raman spectrum dominated by the radial breathing mode near 180 wavenumbers and the tangential graphite-like phonon mode, or G band, near 1,600 wavenumbers. By exciting the samples with a 1,064-nanometer laser — an energy below the self-fluorescence range of biological tissue — the researchers could obtain background-free spectra from lyophilized tissue samples, allowing them to detect nanotube signatures with remarkable specificity. The excitation energy sat in resonance with the second optical transitions of semiconducting nanotubes, further amplifying the signal.

Twenty-four hours after injection, the Raman signatures of SWCNT-PEG appeared in the liver, bone, blood, cerebral cortex, lung, and spleen of the treated rats. Notably, the nanotubes were not detected in other brain structures examined, suggesting a region-specific pattern of accumulation that the authors describe as unprecedented. While a considerable portion of the administered material was sequestered by the liver and spleen — organs known for clearing particulate matter from circulation — a measurable fraction had evidently traversed the blood–brain barrier and embedded itself within the cortical parenchyma.

The toxicological picture was equally striking. Biochemical markers of liver and kidney function, including creatinine, alanine aminotransferase, and aspartate aminotransferase, all remained within normal limits across all treatment groups. Histological examination of the brain, lung, spleen, and kidney revealed no evidence of extensive cell injury, even in tissues where nanotubes were clearly present. Necropsy findings and overall health indicators such as body weight and activity levels showed no abnormalities.

Hematological analysis, however, told a more nuanced story. Rats receiving the highest dose of SWCNT-PEG — 1.25 milligrams per kilogram — exhibited a significant decrease in platelet count, dropping from approximately 703,000 per microliter in controls to roughly 373,000 per microliter. The same high-dose group also showed monocytosis and eosinophilia, elevations in monocytes and eosinophils that the researchers interpret as markers of an acute inflammatory response. The team suggests that these changes likely reflect platelet activation triggered by contact between blood cells and the nanotubes, possibly mediated by complement system activation — a known phenomenon even for PEG-coated nanomaterials. Uncoated patches on the nanotube surface, they propose, may have been rapidly enveloped by a protein corona composed of naturally circulating blood proteins, which in turn recruited the immune system’s first-line cellular defenders.

Perhaps the most intriguing result emerged from behavioral testing. Using the Morris water maze — a gold-standard assay for spatial learning and memory in rodents — the researchers trained rats for five days to locate a submerged platform, then injected them with SWCNT-PEG or saline after the final training session. When tested twenty-four hours later, the treated animals showed no impairment whatsoever in their ability to recall the platform’s location. In fact, rats receiving the two lowest doses spent significantly more time in the target quadrant during the test session, indicating enhanced memory evocation rather than any deficit. The authors caution that the mechanism underlying this improvement remains unknown, and that the lowest dose — 0.05 milligrams per kilogram — produced no detectable Raman signal in the cortex, possibly because the concentration fell below the detection limit of the technique.

The physical characterization of the nanotube dispersion offers important context for interpreting these results. Transmission electron microscopy revealed that the commercial SWCNT-PEG sample used in the study formed bundles of two to five tubes, occasionally connected by polymeric masses that gave rise to larger aggregates. Even prolonged bath sonication could not fully disperse them. Zeta potential measurements of approximately negative 60 millivolts indicated the presence of numerous unreacted carboxylic acid groups on the nanotube surface, evidence that the PEGylation was incomplete and unstable. The researchers attribute this to steric hindrance during the functionalization reaction and to the relatively short length of the PEG chains employed — molecular weight 600 daltons — which were insufficient to completely cloak the nanotube surface.

This incomplete coverage has consequences. Hydrophobic regions and free carboxyl groups on the nanotube surface can interact promiscuously with biological molecules, forming protein coronas that alter biodistribution and immune recognition. Prior work by Liu and colleagues demonstrated that longer PEG chains and more complete surface coverage extend blood circulation time and reduce uptake by the liver and spleen. The Brazilian team’s findings are consistent with this framework: the substantial hepatic and splenic accumulation they observed likely reflects opsonization and scavenging by the mononuclear phagocyte system, the body’s standard disposal route for foreign particulates.

Despite these caveats, the study’s central finding — that systemically administered PEGylated carbon nanotubes can reach the brain cortex without acute toxicity — represents a meaningful step forward for the field of nanoneuroscience. The blood–brain barrier remains the single greatest obstacle to treating Alzheimer’s disease, Parkinson’s disease, brain tumors, and stroke, conditions in which even the most potent pharmacological agents fail to reach their targets in therapeutically meaningful concentrations. If carbon nanotubes can be engineered to cross this barrier reliably and safely, they could serve as versatile platforms for drug delivery, biosensing, and even direct neural interfacing. The Brazilian team emphasizes that their results are preliminary, based on a single twenty-four-hour time point and a limited dose range. Long-term studies examining chronic exposure, biodegradation, clearance kinetics, and behavioral outcomes across extended timeframes will be essential before any clinical translation. Nevertheless, the demonstration that these cylindrical carbon lattices — each one tens of thousands of times thinner than a human hair — can navigate the bloodstream, slip past one of biology’s most selective barriers, and settle into the brain’s outermost layer without leaving a trace of damage opens a tantalizing window onto the future of neurological medicine.

Subject of Research: Biodistribution and safety of PEGylated single-walled carbon nanotubes crossing the blood–brain barrier in rats

Article Title: Biodistribution of intravenously delivered PEGylated carbon nanotubes to the rat brain cortex

Article References: Bruch, G. E., Dal Bosco, L., Cordeiro, A. P., Cordeiro, M. F., Sahoo, S. K., Peixoto, C., Klosterhoff, M. C., Romano, L. A., Fantini, C., Santos, A. P., & Barros, D. M. (2025). Biodistribution of intravenously delivered PEGylated carbon nanotubes to the rat brain cortex. Frontiers in Carbon, 3, Article 1363919. https://doi.org/10.3389/frcrb.2024.1363919

Image Credits: AI Generated

DOI: 10.3389/frcrb.2024.1363919

Keywords: carbon nanotubes, PEGylation, blood-brain barrier, Raman spectroscopy, biodistribution, nanomedicine, neuroscience, Morris water maze, drug delivery, nanotoxicology, cerebral cortex, single-walled carbon nanotubes

Carbon nanotubes have long fascinated scientists and engineers as extraordinary materials with immense potential applications, ranging from electronics to energy storage and environmental remediation. Among their many touted capabilities is their capacity to adsorb and capture gases, including CO₂. However, the practical application of SWCNTs in carbon capture has been historically limited by their inherently closed end structures. These “caps” act like sealed tubes, restricting access to their inner hollow channels where surface area—and thus adsorption potential—could be maximized.

The team at Skoltech tackled this challenge head-on by devising an elegant one-step thermal treatment. Essentially, they subjected the SWCNTs to controlled heating at 400 degrees Celsius in ambient air for a duration of four hours. This straightforward “baking” process has profound consequences: it oxidizes residual catalyst particles found on the nanotubes and simultaneously combusts the carbonaceous end caps, effectively opening access to the nanotubes’ inner surfaces.

This method not only doubles the available specific surface area of the SWCNTs—from an initial 448 square meters per gram to an impressive 858 square meters per gram—but also preserves the structural integrity and dispersibility of the nanotubes. Unlike many chemical purification methods prone to causing nanotube bundling and loss of accessible surface sites, this thermal approach maintains an expansive and reactive surface that is directly exposed to CO₂ molecules.

The increased accessibility leads to remarkable enhancements in CO₂ capture performance. Dynamic breakthrough adsorption experiments performed by the researchers reveal an uptake capacity of 5.0 millimoles per gram of thermally treated SWCNTs. This represents an 85% improvement compared to untreated samples, a quantum leap that could make these materials viable candidates in real-world carbon capture applications.

Crucially, the study doesn’t just stop at experimental results. Through an insightful blend of Monte-Carlo simulations and geometric modeling, the team elucidates the precise nature of the interactions between CO₂ molecules and the nanotube surfaces. Their findings confirm that the “opened” nanotube channels provide energetically favorable adsorption sites, dramatically increasing the effective trapping of CO₂ at the nanoscale. This combined theoretical and experimental approach strengthens the robustness of their conclusions and opens pathways for further optimization.

The significance of this work extends far beyond academic curiosity. Developing cost-effective, scalable, and efficient carbon capture materials is a critical cornerstone of global strategies to mitigate climate change. By simplifying the modification process for SWCNTs—arguably one of the most promising nanomaterials in environmental technology—Skoltech’s research offers an accessible manufacturing blueprint that can be integrated into industrial workflows. This is especially relevant for industries looking to reduce their carbon footprint without incurring exorbitant costs associated with complex chemical processing or energy-intensive purification.

Furthermore, this innovation contributes to closing the gap between nanoscale material science breakthroughs and practical technologies. Achieving high-performance carbon capture often involves trade-offs between surface area, accessibility, and material stability. The Skoltech thermal treatment uniquely reconciles these factors by enabling high surface area realization without sacrificing the structural and functional advantages of SWCNTs.

Given the urgency of climate change mitigation, the ability to “turn up the heat” and unlock the latent potential within raw nanocarbon materials represents a crucial advancement. The research heralds a versatile, streamlined approach that could be adapted and scaled for a variety of carbon capture systems, including those integrated into power plants, industrial exhaust streams, and possibly even portable filtration devices.

It’s also a leap forward in sustainable material design philosophy. Opting for an ambient air thermal treatment avoids the environmental and safety issues tied to harsh chemical reagents. This eco-friendly methodology aligns with global green chemistry principles and reinforces the value of simplicity in high-tech solutions.

The Skoltech team’s interdisciplinary expertise in nanomaterial synthesis, surface chemistry, and computational modeling underpins this achievement. Corresponding authors Dmitry V. Krasnikov and Albert G. Nasibulin guide a research consortium that exemplifies effective collaboration between experimental and theoretical domains. Their work is sending ripples through the materials science and environmental engineering communities alike.

Skoltech has cemented its role as a crucible for cutting-edge nanomaterial innovation with tangible environmental benefits. This study is a compelling example of how fundamental research in physical sciences can lead directly to transformative technologies addressing one of humanity’s biggest challenges: climate change.

In summary, this advancement embodies how scientific elegance—using nothing more than a carefully controlled heat treatment—can unlock the tremendous potential hidden within advanced nanomaterials. As the world races to develop practical carbon capture solutions, these findings shine a spotlight on SWCNTs as viable, powerful agents for capturing CO₂ with high efficiency and scalability. The message is clear: sometimes, the key to transforming the future lies in mastering the simplest of techniques.

Subject of Research: Not applicable

Article Title: Single-step thermal treatment of single-walled carbon nanotubes for enhanced CO2 adsorption capacity

News Publication Date: 8-Jan-2026

Web References:

• Journal Carbon Research: https://link.springer.com/journal/44246
• DOI Link: http://dx.doi.org/10.1007/s44246-025-00246-0

References:
Pal, A.K., Krasnikov, D.V., Varlamova, L.A. et al. Single-step thermal treatment of single-walled carbon nanotubes for enhanced CO₂ adsorption capacity. Carbon Res. 5, 2 (2026).

Image Credits: Amit Kumar Pal, Dmitry V. Krasnikov, Liubov A. Varlamova, Konstantin K. Zamansky, Kseniya A. Litvintseva, Sergei V. Porokhin, Nikita E. Gordeev, Anastasia E. Goldt, Eugene E. Nazarov, Stanislav S. Fedotov, Pavel B. Sorokin & Albert G. Nasibulin

Keywords: Nanomaterials, Nanotechnology, Surface chemistry, Carbon nanotubes

Wearable electronics have seamlessly integrated into various aspects of our lives, appearing in forms like smartwatches, fitness trackers, augmented reality glasses, and advanced hearing aids. One of the challenges in producing these devices has been to create components that are not only effective but also lightweight and energy-efficient. Traditional materials such as copper can be heavy and limit the usability of such devices. Thus, the need for conductive materials that can deliver performance without compromising weight is crucial.

Carbon nanotubes, known for their extraordinary strength—about 100 times stronger than steel—and excellent electrical conductivity comparable to that of copper, emerge as ideal candidates for this purpose. The unique structural arrangement of carbon atoms in CNTs, arranged in hexagonal patterns, contributes to their commendable properties. This intrinsic structure not only enhances conductivity but also imparts exceptional flexibility, making CNTs a valuable resource in the development of advanced wearable technologies.

However, despite the potential of CNTs, their application in electronics has been hampered by the tendency of these nanotubes to clump together, making it challenging to disperse them uniformly within a medium. The research team at KERI addressed this critical issue by manipulating the surface of the CNTs. They introduced small amounts of strong acids and compatible additives to the CNT powder, thereby functionalizing the surface with oxygen groups that help achieve uniform dispersion in organic solvents. This innovative approach draws parallels with traditional food preparation techniques, likening the process of mixing and kneading to making dough for bread or noodles.

To further enhance the performance of the CNTs, the team incorporated graphene oxide, a material known for its unique properties at the nanoscale. By controlling the size of graphene oxide to around 100 nanometers, the researchers improved the dispersion of CNTs in their dope. This deliberate co-processing played a pivotal role in preventing clogging during the spinning process, allowing the material to be shaped into fine wires. As the mixture underwent the spinning process, these wires were bonded together through hydrogen bonding, forming highly functional strands of material.

The development of these CNT functional wires has extended beyond mere electronics; they were successfully transformed into textile supercapacitors in collaboration with Dr. Kim Taehoon’s team at the Korea Institute of Materials Science (KIMS). Through rigorous performance evaluations, these textile supercapacitors showcased promising energy storage capabilities, underscoring the versatility of the material in energy applications. This capability opens up new possibilities for the creation of smart clothing, particularly in specialized fields such as firefighting where monitoring environmental conditions is paramount.

Moreover, the application of these CNT wires has been recognized for its gas-sensing abilities, particularly in detecting harmful gases. When subjected to scientific scrutiny by Professor Lee Wi Hyeong’s research team at Konkuk University, it was determined that the functionalized CNT wires exhibit impressive sensitivity in detecting hazardous gases. This feature further enhances the functionality of smart textiles designed for safety, particularly in emergency response scenarios.

The significance of this research transcends its immediate applications. Recognized for its excellence, the findings have been published in ACS Nano, a leading journal in nanoscience. This recognition reflects the rigorous peer review process and the high regard the scientific community has for the work presented. The journal’s influence is notable too, boasting an impact factor of 15.8, indicating that the research not only engages but also informs and shapes ongoing conversations in the field.

Dr. Han Joong Tark has expressed optimism regarding the future implications of this research, stating, “This is the world’s first achievement of dispersing functionalized CNTs in organic solvents for solution spinning. It will drive the development of lightweight and long-lasting wearable electronic devices.” This statement encapsulates the potential high-tech future that lies ahead as these innovations can transition quickly into consumer markets, especially in the burgeoning fields of mobility and energy efficiency.

In addition to their contributions to wearable technology, these advancements may pave the way for replacing heavy copper wiring in various fields, including electric vehicles and drones. The lightweight and efficient nature of CNTs not only improves design possibilities but also enhances energy conservation, a critical aspect in the race for sustainability in technological advancements.

KERI itself is positioned as a frontrunner in research, bolstered by its governmental backing as part of the National Research Council of Science & Technology (NST). This support plays a vital role in nurturing innovative projects, with this particular endeavor underlining the institute’s commitment to pioneering research that addresses contemporary challenges in materials science. The collaborative effort among multiple research teams highlights the synergy of interdisciplinary approaches in addressing technological hurdles.

As the global demand for innovative and reliable wearable electronics continues to rise, the implications of this research stretch far beyond the laboratory. It touches on the convenience in daily lives, influencing everything from fitness to personal safety. Each advancement in this field propels us closer to a future where wearable devices become even more integrated and essential to human life. With innovations such as these, we stand on the brink of a technological evolution that promises to enhance our interaction with the world around us in ways previously imagined only in science fiction.

The path from initial concept to actual application is paved with challenges; however, the strides made by KERI and its collaborators promise a future ripe with possibilities. As the research progresses, it will be fascinating to witness how the genius of carbon nanotubes transforms wearable electronics from a novelty to an integral part of human experience.

Subject of Research: The development of functional wires using single-walled carbon nanotubes for wearable electronic devices.

Article Title: Hydrogen Bond-Driven Hierarchical Assembly of Single-Walled Carbon Nanotubes for Ultrahigh Textile Capacity.

News Publication Date: 23-Jan-2025.

Web References: ACS Nano DOI.

References: ACS Nano Journal.

Image Credits: Korea Electrotechnology Research Institute.

Keywords

CNTS, Wearable Technology, Nanotechnology, Energy Efficiency, Functional Materials, Supercapacitors, Gas Sensors, Carbon Nanotubes, Textile Electronics.