Tag: nanoparticles

New strategy combines techniques to study intracellular transport of nanoparticles

New strategy combines techniques to study intracellular transport of nanoparticles

Research led by CNPEM scientists reveals intracellular movement of nanoparticles coated with a protein corona. The technique employed in the study will be available at the Sibipiruna beamline, which is dedicated to research on BSL-4 pathogens.

Researchers from the Brazilian Center for Research in Energy and Materials (CNPEM), in collaboration with institutions in Brazil, the United Kingdom and the United States, have demonstrated a new strategy to monitor the intracellular trajectory of nanoparticles. The study was one of the cover features for the journal Small in June 2025, and combined different high-resolution microscopy techniques to observe how these particles move around in the cellular environment over time.

The research used advanced microscopy resources from the Nanotechnology National Laboratory (LNNano) and Sirius facilities, and included a technique not yet available at the center, X-ray cryotomography. Measurements were obtained using a beamline with characteristics similar to the future Sibipiruna line, which will be part of Project Orion. The resulting data verified the use of this technique in cryogenic conditions, as well as its ability to reveal cellular structures smaller than the viruses that will be studied in the future laboratory complex. 

The approach made it possible to identify the migration of nanoparticles to the perinuclear region of cells and fusion of the vesicles that transport them, without the use of contrast agents. The results overcome common limitations in studies of this type, and offer a promising tool for understanding how nanomaterials behave in complex biological systems.  

Nanoparticles and the challenge of cell internalization

Nanoparticles have been widely studied for their potential in biomedical applications such as controlled release of medications, diagnostic imaging and targeted therapy. But these applications still face major obstacles, especially with regard to detailed understanding of the mechanisms through which these particles are internalized and move within cells. 

The formation of the protein corona, a layer of biomolecules that adsorbs onto the surface of nanoparticles when they come into contact with biological fluids, is a good example of the complexity involved in investigating the mechanisms of internalization and intracellular transit. This layer significantly alters the physical and chemical properties of the particles, influencing their stability and interaction with different cell types. Understanding the behavior of these nanoparticles in the intracellular environment consequently requires approaches that take into account both cell dynamics and the variability introduced by the corona’s composition. 

Despite advances in characterization techniques, most studies offer only specific or static views of the internalization process; it is generally not possible to distinguish between particles absorbed at different times, or to follow their precise location within the cell over time. This study conducted by CNPEM researchers proposes an alternative approach intended to overcome these obstacles through an experimental strategy that employs different imaging methods, providing a broader analysis that extracts the best from each technique. 

A new approach to studying cell dynamics

The researchers proposed a protocol based on a short period of cell exposure, followed by complete removal of the unabsorbed nanoparticles and cryopreservation of the cells after different time intervals (0, 2, and 24 hours). Nanoparticle internalization by the cells was then evaluated using wide-field fluorescence microscopy, and showed progressive migration to the perinuclear region. 

“Previous studies investigating the internalization process of nanoparticles also used cells that were fixed after different time intervals but incubated continuously. As a result of this method, nanoparticles internalized at the beginning of the incubation period cannot be distinguished from those internalized at the end. The alternative method we are proposing avoids this problem and facilitates analysis of the sequence of events and changes associated with the cell internalization process,” explains Mateus Cardoso, an author of the article and researcher at the Synchrotron Light National Laboratory (LNLS), which is part of CNPEM. 

Read more on CNPEM website

Image: FFibroblasts after incubation with silica nanoparticles in the presence of bovine serum albumin (BSA). Wide-field fluorescence microscopy image. (Image adapted from Galdino et al., Small, 2024, https://doi.org/10.1002/smll.202409065)

Exploring how tiny particles affect our lungs

Exploring how tiny particles affect our lungs

Very small particles — either naturally occurring in the air or engineered for industrial purposes — can penetrate deep into our lungs because they are smaller than 100 nanometers (about 1,000 times thinner than a human hair). These particles can cause serious long-term health problems, such as inflammation, and tissue damage, which can lead to fibrosis or even cancer.

To assess the health risks of these nanoparticles and predict how they might affect us, it is essential to understand exactly how they interact with lung cells at the molecular level — from the moment they come into contact with lung tissue. Such a detailed investigation requires sophisticated imaging techniques that can reveal both the structure and function of these tiny interactions. One powerful method is Correlated Light and Electron Microscopy (CLEM), which combines different types of microscopes to provide a more complete picture. Thanks to recent advances in resolution and sensitivity, CLEM has become an important tool in biological research.

In our study, we developed a new, expanded CLEM approach that combines several advanced imaging techniques to better understand how lung cells respond to a specific type of nanoparticle: titanium dioxide nanotubes (TiO₂ NTs), which are known to cause inflammation and are considered potentially carcinogenic. Our approach integrates a wide range of complementary tools, providing a morpho-functional assessment of the studied interface (Fig. 1):

  • Confocal Laser-Scanning Microscopy (CLSM), together with Fluorescence Lifetime Imaging Microscopy (FLIM) and Hyperspectral Fluorescence Imaging (fHSI) to study live cells at the organelle and nanoscopic scales.
  • Scanning Electron Microscopy (SEM) and Helium Ion Microscopy (HIM) for extremely detailed surface imaging.
  • Synchrotron-based X-ray Fluorescence (SR μXRF) combined with Scanning Trasnmission X-ray Microscopy (STXM) for analyzing the chemical elements in and around the cells at submicrometric length scales.

Among these, SR μXRF has crucial importance, as it provides chemical sensitivity. Together, these methods allowed us to study interactions across many scales — from whole cells down to individual molecules.

Scanning transmission X-ray Microscopy (STXM) combined with low energy micro-X-ray Fluorescence (LE-μXRF) were carried out at the TwinMic beamline of Elettra. These measurements were complemented by Correlative light,electron and ion microscopy, namely fluorescence lifetime imaging microscopy (FLIM), hyperspectral fluorescence imaging (fHSI), scanning electron microscopy (SEM) and ultra-high resolution helium ion microscopy (HIM).

Read more on Elettra website

A powerful tool for nanoparticles analysis in complex biological media

A powerful tool for nanoparticles analysis in complex biological media

An article published by CNPEM researchers was featured on the Nano Letters scientific journal’s cover and explores how the X-ray Photon Correlation Spectroscopy (XPCS) technique can distinguish protein corona formation from nanoparticle aggregation in complex biological media.

The innovative work, carried out at Sirius, expands analysis capacity in nanomedicine and highlights the XPCS potential to characterize nanoparticle interactions in biological environments in real time, providing a valuable resource for nanobiotechnology research and new biomedical materials development. 

The innovative nanoparticles applications in biomedicine

Nanoparticles are tiny structures, with dimensions generally between 1 and 100 nanometers. Due to its size, they can interact with cells, proteins and molecules in a highly precise way, which allows driven delivery of medicines and therapeutic agents. This allows, for example, for cancer treatments to be more effective, by releasing drugs directly into tumor cells, minimizing side effects on healthy tissues.

Furthermore, nanoparticles can be designed for responding to specific stimuli, such as pH, temperature or biological signs, allowing a controlled release of medicines only when necessary.

In the diagnosis area, nanoparticles offer new ways ​​to prematurely detect diseases. They can be linked to specific biomarkers that bind to molecular targets, making it easier to identify cancerous cells or the presence of viruses and bacteria, for example. 

The interaction between nanoparticles and proteins in biological systems

These applications, however, are conditioned to a predictable behavior of these nanoparticles in complex biological systems. In some cases, by coming into contact with biological fluids, such as blood, a protein coating can be formed around nanoparticles, a phenomenon known in biomedicine by the English term “protein corona”. 

This happens because nanoparticles attract proteins present in the biological environment, forming a “corona” or “crown” around its surface. The formation of this protein corona strongly influences how do nanoparticles interact with cells and tissues in the organism, which can affect its efficacy and safety in medical applications, such as drug therapies, diagnostics, and vaccine development. 

For these reasons, studying the protein corona formation and characteristics is crucial for the development of nanoparticles that are safe and effective for biomedical use. 

Read more on LNLS website

Image: Schematic representation of a functionalized SiO2 nanoparticle

BESSY II: Surface analysis of catalyst particles in aqueous solutions

BESSY II: Surface analysis of catalyst particles in aqueous solutions

In a special issue on the liquid jet method, a team reports on reactions of water molecules on the surfaces of metal oxide particles. The results are relevant for the development of efficient photoelectrodes for the production of green hydrogen.

Green hydrogen can be produced directly in a photoelectrochemical cell, splitting water with solar energy. However, this requires the development of super-efficient photoelectrodes that need to combine many talents at the same time: They must be excellent at converting sunlight into electricity, remain stable in acidic or basic water, act as catalysts to promote the splitting of water into hydrogen and oxygen, and be cheap, abundant and non-toxic. The large material class of metal oxides comes into question. However, it is difficult to find out what really happens at the interfaces between the solid metal oxide electrodes and the aqueous electrolyte. This is because standard X-ray analysis does not work to investigate processes on samples in liquid environments. One of the few suitable methods are experiments with a liquid jet: an extremely fine jet of liquid in which nanoparticles of metal oxide are suspended. This jet shoots through the X-ray light of BESSY II, and the interference of the evaporated molecules with the measurement data is negligible (more in the foreword to the special issue).

Dr. Robert Seidel is an expert on this liquid jet method, which is the subject of a special issue of Accounts of Chemical Research. He was invited to be the guest-editor of the issue and to report also on new experiments at BESSY II that he conducted with Dr. Hebatallah Ali and Dr. Bernd Winter from the Fritz Haber Institute.

They investigated two important model systems for photoelectrodes: Nanoparticles of iron oxide (hematite, α-Fe2O3, and anatase (titanium oxide or TiO2) in aqueous electrolytes with different pH values. Hematite and anatase in suspension are photocatalytic model systems. They are ideal for studying the solid/electrolyte interface at the molecular level and for exploring the chemical reactions at electrode-electrolyte interfaces.

“We used resonant photoelectron spectroscopy (PES) to identify the characteristic fingerprints of different reactions. This allowed us to reconstruct which reaction products are formed under different conditions, particularly as a function of pH.” The key question: How do the water molecules react with or on the nanoparticle surfaces?

In fact, how acidic or how basic an electrolyte is makes a big difference, Seidel noted. “At low pH, the water molecules on the surface of hematite tend to split. This is not the case with anatase, where water molecules are adsorbed on the surface of the TiO2 nanoparticles,” says Seidel. A basic pH value is required for water molecules to break down on the anatase nanoparticles. “Such insights into surface interactions with water molecules are only possible with this liquid-jet method,” says Seidel.

The spectra also revealed ultra-fast electron transitions between the metal oxide and the (split) water molecules on the surface. The results provide insights into the first steps of water dissociation and help to clarify the mechanisms of light-induced water splitting on metal oxide surfaces.

Read more on this story here

Image: The microjet is a fast-flowing stream of liquid so narrow that it produces only an extremely dilute vapour cloud. Photons and particles can reach and leave the surface of the jet without colliding with the vapour molecules.

Quantitative analysis of cell organelles with artificial intelligence

Quantitative analysis of cell organelles with artificial intelligence

The analysis of cryo-X-Ray-microscopy data still requires a lot of time. Scientists developed a convolutional neural network, which identifies structures at high accuracy within a few minutes.

BESSY II’s high-brilliance X-rays can be used to produce microscopic images with spatial resolution down to a few tens of nanometres. Whole cell volumes can be examined without the need for complex sample preparation as in electron microscopy. Under the X-ray microscope, the tiny cell organelles with their fine structures and boundary membranes appear clear and detailed, even in three dimensions. This makes cryo x-ray tomography ideal for studying changes in cell structures caused, for example, by external triggers. Until now, however, the evaluation of 3D tomograms has required largely manual and labour-intensive data analysis. To overcome this problem, teams led by computer scientist Prof. Dr. Frank Noé and cell biologist Prof. Dr. Helge Ewers (both from Freie Universität Berlin) have now collaborated with the X-ray microscopy department at HZB. The computer science team has developed a novel, self-learning algorithm. This AI-based analysis method is based on the automated detection of subcellular structures and accelerates the quantitative analysis of 3D X-ray data sets. The 3D images of the interior of biological samples were acquired at the U41 beamline at BESSY II.

“In this study, we have now shown how well the AI-based analysis of cell volumes works, using mammalian cells from cell cultures that have so-called filopodia,” says Dr Stephan Werner, an expert in X-ray microscopy at HZB. Mammalian cells have a complex structure with many different cell organelles, each of which has to fulfil different cellular functions. Filopodia are protrusions of the cell membrane and serve in particular for cell migration. “For cryo X-ray microscopy, the cell samples are first shock-frozen, so quickly that no ice crystals form inside the cell. This leaves the cells in an almost natural state and allows us to study the structural influence of external factors inside the cell,” Werner explains.

“Our work has already aroused considerable interest among experts,” says first author Michael Dyhr from Freie Universität Berlin. The neural network correctly recognises about 70% of the existing cell features within a very short time, thus enabling a very fast evaluation of the data set. “In the future, we could use this new analysis method to investigate how cells react to environmental influences such as nanoparticles, viruses or carcinogens much faster and more reliably than before,” says Dyhr.

Read more in the Proceedings of the National Academy of Sciences journal article

Image: The images show part of a frozen mammalian cell. On the left is a section from the 3D X-ray tomogram (scale: 2 μm). The right figure shows the reconstructed cell volume after applying the new AI-supported algorithm

Credit: HZB

Understanding how nanoparticles interact is key to improve metal nanocatalysts

Understanding how nanoparticles interact is key to improve metal nanocatalysts

Nanocatalysts are key for the future of sustainable chemistry, yet, they typically suffer from rapid deactivation caused by a process called sintering. In a recent study led by the ALBA Synchrotron and Ghent University, researchers have developed an integrated approach where they complement the use of several characterization techniques to study platinum nanoparticle sintering at the micro-, meso- and macroscale. The demonstrated approach shows that mesoscale heterogeneities in the nanoparticle population drive sintering. This work will help broaden the fundamental understanding of nanoparticle sintering and thus design better strategies for catalyst fabrication.

Metal nanoparticle catalysts are the workhorses in a broad range of industrially important chemical processes such as producing clean fuels, chemicals and pharmaceuticals or cleaning exhaust from automobiles. These nanocatalysts are key for the future of sustainable chemistry, yet they typically suffer from rapid deactivation caused by a process called sintering. Due to sintering, the average nanoparticle size increases since this is energetically more efficient for the nanoparticles. However, this decreases their catalytic power.

To date, sintering phenomena are analyzed either at the macroscale, to examine averaged nanoparticle properties, or at the microscale, studying individual nanoparticles. However there is a knowledge gap on the nanocatalysts behavior at the mesoscale, the intermediate length scale between the macro and the micro worlds. At the mesoscale, large ensembles with thousands of nanoparticles can be studied as a “population” in which nanoparticles “communicate” – interact – with each other. In this context, nanoparticle sintering can be considered as a dynamic population of interacting nanoparticles, each of them trading and exchanging atoms to gain stability within the nanoparticle hierarchy.

In a recent study led by the ALBA Synchrotron and Ghent University, researchers have developed an integrated approach where they complement the use of several characterization techniques to study platinum nanoparticle sintering at the micro-, meso- and macroscale. More specifically, they used different analytical techniques and X-ray scattering characterization at the NCD-SWEET beamline in ALBA to show that mesoscale heterogeneities in the nanoparticle population drive sintering. Thus, deleting these heterogeneities would help to avoid sintering.

Read more on the ALBA website

Image: Researchers inside the experimental hutch of the NCD-SWEET beamline at the ALBA Synchrotron. From left to right: Zhiwei Zhang (Ghent University), Matthias Minjauw (Ghent University), Matthias Filez (Ghent University – KU Leuven) and Juan Santo Domingo Peñaranda (Ghent University).

Nanoparticles made from marine polymers for cutaneous drug delivery applications

Nanoparticles made from marine polymers for cutaneous drug delivery applications

A research led by the University of Porto in collaboration with the ALBA Synchrotron has studied for the first time the interaction of nanoparticles with the skin, using synchrotron light at the MIRAS beamline. The findings unveil the role of the different skin components and the mechanism of the permeation enhancement conferred with nanoparticles, made from marine polymers. A nano delivery system application in the skin will reduce the dosage needed due to controlled drug delivery and allow newer and better-targeting therapeutic strategies towards cutaneous administration.

Cutaneous drug delivery allows the administration of therapeutic and cosmetic agents through the skin. Advantages of this administration route include high patient compliance, avoidance of high concentration levels of the drug when reaching systemic circulation, and far fewer side effects compared to other administration routes.

Still, the peculiar skin structure assures protection to the human organism and hampers drug delivery. To overcome this issue, skin permeation enhancers, such as nanoparticles, can be used. They are pharmacologically inactive molecules that can increase skin permeability by interacting with the stratum corneum, the first layer of the epidermis, which is the outermost layer of the skin. However, the mechanisms of nanoparticles’ interaction with the skin structure are still unknown.

A research project led by the University of Porto (Portugal) in collaboration with the ALBA Synchrotron has studied for the first time the interaction of polymeric nanoparticles with the skin, using synchrotron light.

Read more on the ALBA website

Image: Nanoparticles made visible on human skin – 3D Rendering

Credit: Adobe Stock