Analyzing the structural disorder of nanocrystals

Research applies unprecedented technique in Brazil for the investigation of crystalline nanoparticles

The development of faster and more efficient electronic devices, better catalysts for the chemical industry, alternative energy sources, and so many other technologies depends increasingly on the in-depth understanding of the behavior of materials at the nanometer scale.
The properties of particles on this scale may be completely different from the properties of the same material in its macroscopic version. In addition, nanoparticles of different sizes and shapes can have completely different characteristics, even though they are formed by the same material.
The possibility of regulating the optical and electrical properties of nanoparticles by controlling their composition, shapes and sizes opens the door to an immense variety of applications. In this context, nanocrystals – nanometric particles that have a crystalline structure – have attracted great interest.
A crystal is a type of solid whose atoms or molecules are arranged in a well-defined three-dimensional pattern that repeats itself in space on a regular basis. The optical and electrical properties of crystalline materials depend not only on the atoms or molecules that constitute them but also on the way they are distributed. Therefore, defects or impurities present during crystal formation cause a disorder in the crystal structure. The consequent modification in the electronic structure of the crystal can lead to changes in its properties.

>Read more on the Brazilian Light Source Laboratory website
Image: PDF analysis obtained from electron diffraction data for nanocrystals before (ZrNC-Benz) and after ligand exchange (ZrNC-OLA).
Credit: Reprinted with permission from J. Phys. Chem. Lett. 2019, 10, 7, 1471-1476. Copyright 2019 American Chemical Society.

Control of light at the nanoscale

Research evaluates combination of graphene and hexagonal boron nitride for opto-electronic devices of the future

Photonics is the science that investigates phenomena related to light, such as its generation, transmission and detection. Its applications can be found in a wide range of technologies that directly impact our daily life: lasers used in surgery, fiber optics for data transmission, and screens of high definition TVs and smartphones. These advances are only possible by the in-depth knowledge of the interaction of light with supercompact electronic components.
The latest frontier of photonics is the production of nanoscale devices capable of transmitting information by means of light signals, called nanophotonic or optoelectronic devices. When compared to the already established electronic components, the new nanodevices will carry a greater volume of information at a faster pace.
Today, several research groups around the world are dedicated to building ultrathin photonic devices with outstanding performance. However, such development requires materials that have appropriate characteristics, besides being efficient and inexpensive.
One of the materials of interest is graphene, formed by a single layer of carbon atoms obtained from graphite. Graphene is a conductor with excellent properties that can be easily altered by applying electric fields or light. In addition, several other interesting structural, electronic and optical properties can be obtained by combining graphene with other materials. One of these combinations under study is the system formed by graphene in contact with a hexagonal boron nitride crystal (hBN), also a few molecules thick. This system allows the control of light transport on a nanometer scale.
Image: Schematics of the Graphene-hBN and the experimental analysis using infrared nanospectroscopy. Reprinted with permission from Nano Lett. 2019, 19, 2, 708-715.
Copyright 2019 American Chemical Society.

New materials for the reduction of vehicle pollution

Research develops nanostructured material with high oxygen storage and release capacity for the improvement of catalytic converters

Complete combustion of both fossil and biofuels generates carbon dioxide (CO2) and water as final products. However, incomplete combustion of these substances can occur in automobile engines, generating important pollutants such as carbon monoxide (CO), hydrocarbons, and nitrogen oxides (such as NO and NO2).
To reduce the emission of these toxic substances, an equipment called a catalytic converter is used in the exhaust of vehicles. Materials called catalysts promote and accelerate chemical reactions without being consumed during the process. They retain on their surface the reactant molecules, weakening the bonds between the atoms and causing the pollutants to be converted into less harmful gases.
The action of the catalytic converter happens in three stages. The first stage converts the nitrogen oxides into nitrogen (N2) and oxygen (O2) gases. The second stage breaks down bonds of unburnt hydrocarbons and carbon monoxide, turning them into CO2. Finally, the third stage has an oxygen sensor to regulate the intake of air and fuel to the engine, so that the amount of oxygen is always close to the most efficient for the different reactions.

>Read more on the Brazilian Light Laboratory (LNLS) website

Unraveling plants resistance to drought

Research investigates the chemical nanostructure of water conducting vessels.

Plant cells are encased in a structure called the cell wall, composed mainly of cellulose and lignin. Among other functions, this wall gives structural stability to the cells and controls the entry of water, minerals and other substances. When they die, the cells leave behind their cell wall, forming different structures that support the plant giving rigidity to the stems and that facilitate the transport of substances from the roots to the leaves and vice versa. One such structure is the xylem: a continuous network of conduits about 100 micrometers in diameter that carries the water absorbed by the roots to the leaves.

When they lose water by transpiration, the leaves generate tension in the water column within the xylem. The pressure difference between the interior and exterior of the conduit causes the molecules to behave as links in a current: when a molecule of water evaporates, the rest of the “current” is pulled up.

>Read more on the Brazilian Synchrotron Light Laboratory at CNPEM website

Image: Schematic figure of the technique of infrared nanospectroscopy.

New possibilities against the HIV epidemic

Research identifies new antibodies with potent activity against virus and infected cells

The Human Immunodeficiency Virus type-1 (HIV-1) currently infects 37 million people worldwide, with an additional 2 million new infections each year. Following infection, the virus has a long period of latency, during which it multiplies without causing symptoms. HIV attacks the cells of the immune system, especially the cells called CD4+ T-lymphocytes, which are responsible for triggering the body’s response chain against infections. Thus, by suppressing the action of the immune system, the virus destroys the body’s ability to defend itself against other diseases, leading to the so-called Acquired Immunodeficiency Syndrome, or AIDS.
Even with the development of antiretroviral therapies that have improved quality of life and increased the life expectancy of patients with HIV/AIDS, it is widely accepted that the only way to effectively curb this devastating epidemic is through the development of an HIV-1 vaccine.

>Read more on the Brazilian Synchrotron Light Laboratory website

Image: Part of the structure of the CAP228-16H protein with the region of the V2 loop highlighted in yellow. (Full image here)

First electron beam loops around Sirius’ booster

New Brazilian synchrotron light source will allow unprecedented experiments benefitting many fields

In the early evening of March 8th, when the campus of the Brazilian Center for Research in Energy and Materials (CNPEM) was mostly silent, shouts of celebration echoed through the corridors of the Sirius building, the new Brazilian synchrotron light source.
Inside, the team responsible for the installation of the particle accelerators reached another milestone: the first loop around the second among its three accelerators: the booster. It is a finely tuned equipment, along which the electrons must travel with micrometric precision.
After the initial production and acceleration of the electrons in the Linac, the electrons gain more and more energy at each loop around the Booster. When they reach the appropriate energy levels, the electrons are deposited in the main accelerator, called storage ring, where they remain for long periods of time generating synchrotron light.

>Read more on the Brazilian Synchrotron Lights Laboratory (LNLS)

Image: Sirius in Campinas (Brazil).

Encapsulation of drugs for new cancer treatments

Research develops hydrogel from silk protein with potential application in photodynamic therapy

Cancer is a set of diseases characterized by uncontrolled multiplication of cells. One of the main methods for treating this disease is chemotherapy, which uses drugs to block the growth of those cells or to destroy them. In this way, most drugs used interfere with mitosis, the cellular mechanism by which new cells are produced. Therefore, both cancerous and healthy cells are affected, leading to several side effects.
Worldwide, considerable effort has been directed at developing new methods that act directly on the target of treatment. This is the case of so-called photodynamic therapy (PDT), a minimally invasive therapeutic procedure that selectively acts on malignant cells.
The procedure involves the administration of a light-sensitive substance, called a photosensitizing agent. When irradiated at specific wavelengths, the photosensitizer releases oxygen in reactive chemical forms that promote the death of malignant cells, infectious agents and the removal of burns.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website

Enzyme structure of bacteria that causes tuberculosis

Results on its interaction with antibiotics may lead to the development of new forms of treatment for this disease.

Tuberculosis is a chronic infection usually caused by a bacterium called Mycobacterium tuberculosis. This bacterium infects cells of the immune system called alveolar macrophages, which are responsible for removing pollutants and microorganisms from the surface of the alveoli, where the exchange of gases occurs during respiration.
It is estimated that approximately two billion people worldwide are infected with M. tuberculosis without symptoms. However, the clinical manifestations of the disease may appear at any time in life, especially when the immune system is weakened, such as due to malnutrition or diseases such as cancer and AIDS.
Tuberculosis is considered a curable disease when the patient is diagnosed and treated promptly with antibiotics. Nevertheless, the chronicity of this infection makes it difficult to eradicate bacteria altogether. Generally, patients must take the medication for several months, making it harder for them to persist in the treatment and favoring the emergence of antibiotic-resistant bacteria. In recent years, the emergence of new bacteria, resistant to routine treatments, has been a worldwide concern and it is imperative to seek new therapeutic strategies against this disease.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) 

Image: (extract, full image here) Elements of the secondary structure of L,D-transpeptidase-3 from Mycobacterium tuberculosis acylated by an acetyl fragment derived from faropenem. Beta sheets in red, α-helices in yellow and the loops are shown in green. The figure shows, at the amino terminus (N-ter), the bacterial domain similar to immunoglobulin (BIg) and in the carboxy terminus the catalytic domain (CD). B-loop is a unique structure of this enzyme when compared to the other M. tuberculosis L,D-transpeptidases. In blue is shown an acetyl fragment covalently attached to cysteine 246 at the active site of the enzyme. Figure taken with Pymol.

Identification of a new genetic mutation associated with intellectual disability

Study contributes to the understanding of mechanisms involved in neurodevelopmental disorders

Once a disease-related protein or enzyme is identified as a therapeutic target, the study of its three-dimensional structure – the positions of each of its atoms and their interactions – allows a deeper understanding of its mechanisms of action.

This is possible not only for these substances produced by microorganisms, such as viruses or bacteria, capable of attacking our body. It is also possible, for example, to understand molecules normally produced by the human body itself, but which had their structure and function altered due to some genetic mutation.

Thus, in an article recently published in Nature Chemical Biology, Juliana F. de Oliveira, of the Brazilian Biosciences National Laboratory (LNBio), and collaborators elucidates the mechanism of action of a new genetic mutation in the UBE2A gene identified in patients with intellectual disability.

The UBE2A gene is located on the X chromosome and encodes the protein of the same name that participates in the process of “labeling” defective proteins inside the cell. This labeling is done by adding and protein called ubiquitin to the defective proteins as if it were a label. Next, under normal conditions, the defective proteins are sent for degradation.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website

Image: Overlap of the patient’s UBE2A protein structure (blue) with the normal protein (gray) evidences similarity between them. On the right, it is shown in detail the only altered amino acid in the patient’s protein due to the genetic mutation.

Ceremony marks the first stage of the Sirius project

New Synchrotron Light Source is the largest and most complex research structure ever built in Brazil

The Brazilian President, Michel Temer, and the Minister of Science, Technology, Innovation and Communications, Gilberto Kassab, participated on Wednesday 14th November in the ceremony commemorating the first stage of the new Brazilian Synchrotron Light Source, Sirius, in the Brazilian Center for Research in Energy and Materials (CNPEM), in Campinas (SP). Started in 2012, Sirius is the largest project in Brazilian science, a state-of-the-art research infrastructure, strategic for cutting-edge scientific research and for finding solutions to global problems in areas such as health, agriculture, energy and the environment.

This first stage includes the conclusion of the construction works of the building that houses the entire research infrastructure, in addition to the assembly of the Linear and Booster Accelerators. The Storage Ring is currently being assembled.
The delivery of the next stage of the project, scheduled for the second half of 2019, includes the start of the Sirius operation and the opening of the first six beamlines for researchers. The complete project includes seven other beamlines, expected to be opened in 2021. However, the number of beamlines can be gradually expanded, reaching up to 40 experimental stations.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website

Nano-opto-electronics with Soapstone

Research shows potential of combining mineral with graphene for the design of new devices.

The development of electronic devices in the nanometric scale depends on the search for materials that have appropriate characteristics, and that are also efficient and inexpensive. This is the case of graphene, a material formed by a single layer of carbon atoms obtained from graphite. Graphene is a conductor with excellent optical and electrical properties that can be easily altered by the incidence of electric fields or light.

In addition, several other interesting structural, electronic and optical properties can be obtained by combining graphene with other materials. These new properties arise due to changes in the electronic structure in the interface of different materials when they are brought into contact. In this scenario, the search for new materials and ways of combining them becomes a natural trend.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website

Image: DOI: 10.1021/acsphotonics.7b01017

Nanotechnology in oil exploration

Research investigates use of nanoparticles for advanced oil recovery.

Brazil is a pioneering country in the exploration of oil in deep waters and a great quantity of this fossil fuel is stored in the porous space of carbonate rocks, especially in the pre-salt layer. These rocks are very heterogeneous and have complex pore systems, bringing great challenges to the extraction of oil and gas.
After drilling an oil or gas reservoir, the natural pressure inside it causes the contents to flow naturally to the surface where the fluid is collected and directed to a tanker. However, a few years after the opening of the well, the amount of oil extracted daily tends to decrease due to the drop in internal well pressure.

One of the ways to continue the exploration is by the injecting water or gas into the well, which helps in the transport of fluids and increases oil production, allowing it to be explored for several years. A more efficient way is, however, through the injection of surfactants, which facilitate the remobilization of oil, even in regions where water and gas have no further effect.
Recently, Tannaz Pak and collaborators from Brazil and the United Kingdom investigated [1] the use of nanoparticles to improve the advanced recovery of oil in carbonate rocks. By means of time-resolved X-ray microtomography, the research showed for the first time how oil droplets, retained in the pores of carbonate rocks, change shape when interacting with silica nanoparticles suspended in water, making it again available for extraction.

>Read more on the Brazilian Synchrotron Light Laboratory website

Image Credit: Geraldo Falcão / Banco de Imagens Petrobras

Inorganic nanoparticles activity as artificial pro-enzymes

Research opens perspective for treatment of several diseases tailored to the needs of each patient

From the biochemical point of view, we are a complex set of interconnected chemical reactions. The molecules that make up our bodies are in constant transformation, and this is what makes it possible for us to get energy from food, to regenerate damage to our tissues, and to synthesize the compounds necessary for life.
These modifications usually occur with the aid of other molecules called enzymes, which promote and accelerate chemical reactions without being consumed during the process.

For the proper functioning of this complex system, the enzymes must act only at the necessary place and time. Hence, nature has developed an ingenious strategy for this to happen: inactive forms of enzymes, known as proenzymes, are continuously produced, but are activated only by specific stimuli.
The occurrence of a problem in the production of these enzymes can result in highly debilitating diseases. However, the treatment of patients by means of enzymatic replacement from natural sources is not always an adequate solution.
Therefore, researchers have been investigating synthetic systems to mimic the action of natural enzymes for biomedical applications and one of the most promising alternatives is the use of nanoparticles.

>Read more on the Brazilian Synchrotron Light Laboratory website

Image: Schematic figure of the action of the ultrafine cerium(III) hydroxide and cerium oxide CeO (2-x) nanoparticles . Back cover image from the Journal of Materials Chemistry B [1].

Yves Petroff takes over as Director of the LNLS

French physicist was Director-General of the largest European synchrotron between 1993 and 2001 and LNLS’ Scientific Director from 2009 to 2013.

In ceremony held on the morning of August 29th, Yves Pierre Petroff became Director of the Brazilian Synchrotron Light Laboratory (LNLS). Yves Petroff was LNLS’ Scientific Director from November 2009 to March 2013. During the ceremony, Rogério Cesar de Cerqueira Leite, Chairman of the Board of Directors of CNPEM, and Antonio José Roque da Silva, CNPEM’s Director-General and former LNLS Director, highlighted Pretroff’s competence and his history within LNLS.

Yves Petroff is one of the world’s leading specialists in the use of synchrotron light. He received his doctorate in physics from the Ecole Normale Supèrieure of the University of Paris in 1970. Later, he went to the University of California, Berkeley, from 1971 to 1975. During this period, Yves Petroff worked on the investigation of optical properties of solids, having made important developments in the area of Resonant Raman Effect.

In the early 1970s, the first generation of synchrotron accelerators began to be built, focused primarily on particle physics. In 1975, Yves Petroff returned to France to work in the ACO, one of the first synchrotrons in the world, located in Orsay. Pioneering work was performed by Petroff’s team on the use of synchrotron light to understand the properties of solids. His group was also the first in the world to build a Free Electron Laser in the region of visible light.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) website.

>Read also an article published on the ESRF website.

 

Unprecedented 3D images of neurons in healthy and epileptic brains

Results open new perspectives for the study of neurodevelopment and neurodegenerative diseases.

A comprehensive understanding of the brain, its development, and eventual degeneration, depends on the assessment of neuronal number, spatial organization, and connectivity. However, the study of the brain architecture at the level of individual cells is still a major challenge in neuroscience.
In this context, Matheus de Castro Fonseca, from the Brazilian Biosciences National Laboratory (LNBio), and collaborators [1] used the facilities of the Brazilian Synchrotron Light Laboratory (LNLS) to obtain, for the first time, three-dimensional images in high resolution of part of the neuronal circuit, observed directly in the brain and with single cell resolution.

The researchers used the IMX X-Ray Microtomography beamline, in combination with the Golgi-Cox mercury-based impregnation protocol, which proved to be an efficient non-destructive tool for the study of the nervous system. The combination made it possible to observe the points of connectivity and the detailed morphology of a region of the brain, without the need for tissue slicing or clearing.
The mapping of neurons in healthy and unhealthy tissues should improve the research in neurodegenerative and neurodevelopmental diseases. As an example of this possibility, the work presents, for the first time in 3D, the neuronal death in an animal model of epilepsy.

The researchers are now working to extend the technique to animal models of Parkinson’s disease. The intention is to better understand the cellular mechanisms involved in the onset and progression of the disease. In the future, with the inauguration of the new Brazilian synchrotron light source, Sirius, the researchers believe that it will be possible to obtain images at the subcellular level, that is, images of the interior of the neurons.

>Read more on the Brazilian Synchrotron Light Laboratory website

Image: X-ray microtomography of the cerebral cortex showing the segmentation of individual neurons. Each color represents a single neuron or a group of neurons.

Synchrotron infrared beamline optics optimized…

…for nano-scale vibrational spectroscopy. First experimental report of a special optical layout dedicated to correct typical aberrations derived from large extraction ports in IR beamlines.

Infrared nanospectroscopy represents a major breakthrough in chemical analysis since it allows the identification of nanomaterials via their natural (label free) vibrational signatures. Classically powered by laser sources, the experiment called scattering Scanning Near-field Optical Microscopy (s-SNOM) has become a standard tool for investigations of chemical and optical properties of materials beyond the diffraction limit of light.

Lately, s-SNOM is achieving unprecedent sensitivity range by exploring the outstanding spectral irradiance of synchrotron light sources in the full range of infrared (IR) radiation. In the last few years, the combination of s-SNOM and ultra-broadband IR synchrotron (SINS or nano-FTIR) has helped studies in relevant scientific fronts involving atomic layered materials, fundamental optics, nanostructured bio-materials and, very recently, it was demonstrated to be feasible to work in the far-IR.

IR ports in synchrotron storage rings can be up to a thousand times more brilliant than classical IR black body sources. This advantage allowed IR beamlines to be the only places capable of performing IR micro-spectroscopy for many years. However, in comparison to X-ray ports, IR beamlines require large apertures for allowing long wavelengths to be extracted. Consequently, IR beamlines typically present optical aberrations such as extended source depth and coma.

>Read more on the Brazilian Synchrotron Light Laboratory website

Images (extracts): Figure 1 – Proposed optical layout, IR extraction chamber indicating the source depth, conical mirror illustration, aberration-corrected focal spot at the sample stage and nano-FTIR experimental scheme in operation in the IR endstation of the LNLS. Figure adapted from R. Freitas et al., Optics Express 26, 11238 (2018).