Tag Archives: Spain

Mite silk as the basis for a new nanobiomaterial

For the record, this is spider mite silk (I have many posts about spider silk and its possible applications on this blog; just search ‘spider silk’)..

The international collaborative team includes a Canadian university in combination with a Spanish university and a Serbian university. The composition of the team is one I haven’t seen here before. From a December 17, 2020 news item on phys.org (Note: A link has been removed),

An international team of researchers has developed a new nanomaterial from the silk produced by the Tetranychus lintearius mite. This nanomaterial has the ability to penetrate human cells without damaging them and, therefore, has “promising biomedical properties”.

The Nature Scientific Reports journal has published an article by an international scientific team led by Miodrag Grbiç, a researcher from the universities of La Rioja (Spain), Western Ontario (Canada) and Belgrade (Serbia), in its latest issue entitled “The silk of gorse spider mite Tetranychus lintearius represents a novel natural source of nanoparticles and biomaterials.”

In it, researchers from the Murcian Institute for Agricultural and Food Research and Development (IMIDA), the Barcelona Institute of Photonic Sciences, the University of Western Ontario (Canada), the University of Belgrade (Serbia) and the University of La Rioja describe the discovery and characterisation of this mite silk. They also demonstrate its great potential as a source of nanoparticles and biomaterials for medical and technological uses.

A December 17, 2020 Universidad de La Rioja press release (also on EurekAlert), which originated the news item, further explains the research,

The interest of this new material, which is more resistant than steel, ultra flexible, nano-sized, biodegradable, biocompatible and has an excellent ability to penetrate human cells without damaging them, lies in its natural character and its size (a thousand times smaller than human hair), which facilitates cell penetration.

These characteristics are ideal for use in pharmacology and biomedicine since it is biocompatible with organic tissues (stimulates cell proliferation without producing toxicity) and, in principle, biodegradable due to its protein structure (it does not produce residues).

Researcher Miodrag Grbi?, who heads the international group that has researched this mite silk, highlights “its enormous potential for biomedical applications, as thanks to its size it is able to easily penetrate both healthy and cancerous human cells”, which makes it ideal for transporting drugs in cancer therapies, as well as for the development of biosensors to detect pathogens and viruses.

THE ‘RIOJANO BUG’

Tetranychus lintearius is an endemic mite from the European Atlantic coast that feeds exclusively on gorse (Ulex europaeus). It is around 0.3 mm in size, making it smaller than the comma on a keyboard, while the strength of its silk is twice as high as standard spider silk.

It is a very rare species that has only been found so far in the municipality of Valgañón (La Rioja, Spain), in Sierra de la Demanda. It was located thanks to the collaboration of Rosario García, a botanist and former dean of the Faculty of Science and Technology at the University of La Rioja, which is why researchers call it “the Rioja bug” (“El Bicho Riojano”).

The resistance of the silk produced by Tetranychus lintearius is twice that of spider silk, a standard material used for this type of research, and stronger than steel. It also has advantages over the fibres secreted by the silkworm due to its higher Young’s modulus, its electrical charge and its smaller size. These characteristics, along with its lightness, make it a promising natural nanomaterial for technological uses.

This finding is the result of work carried out by the international group of researchers led by Miodrag Grbi?, who sequenced the genome of the red spider Tetranychus urticae in 2011, publishing the results in Nature: https://www.nature.com/articles/nature10640.

Unlike the red spider (Tetranychus urticae), the gorse mite (Tetranychus lintearius) produces a large amount of silk. It has been reared in the laboratories of the Department of Agriculture and Food of the University of La Rioja, under the care of Professor Ignacio Pérez Moreno, allowing research to continue. Red spider silk is difficult to handle and has a lower production rate.

Here’s a link to and a citation for the 2020 paper,

The silk of gorse spider mite Tetranychus lintearius represents a novel natural source of nanoparticles and biomaterials by Antonio Abel Lozano-Pérez, Ana Pagán, Vladimir Zhurov, Stephen D. Hudson, Jeffrey L. Hutter, Valerio Pruneri, Ignacio Pérez-Moreno, Vojislava Grbic’, José Luis Cenis, Miodrag Grbic’ & Salvador Aznar-Cervantes. Scientific Reports volume 10, Article number: 18471 (2020) DOI: https://doi.org/10.1038/s41598-020-74766-7 Published: 28 October 2020

This paper is open access.

Natural nanodiamonds found in the ocean

An Oct. 16, 2020 news item on phys.org announces research that contradicts a common belief about how diamonds are formed ,

Natural diamonds can form through low pressure and temperature geological processes on Earth, as stated in an article published in the journal Geochemical Perspectives Letters. The newfound mechanism, far from the classic view on the formation of diamonds under ultra-high pressure, is confirmed in the study, which draws on the participation of experts from the Mineral Resources Research Group of the Faculty of Earth Sciences of the University of Barcelona (UB).

Other participants in the study are the experts from the Institute of Nanoscience and Nanotechnology of the UB (IN2UB), the University of Granada (UGR), the Andalusian Institute of Earth Sciences (IACT), the Institute of Ceramics and Glass (CSIC), and the National Autonomous University of Mexico (UNAM). The study has been carried out within the framework of the doctoral thesis carried out by researcher Núria Pujol-Solà (UB), first author of the article, under the supervision of researchers Joaquín A. Proenza (UB) and Antonio García-Casco (UGR).

An Oct. 9, 2020 University of Barcelona (UB) press release (also on EurekAlert but published Oct. 16, 2020), which originated the news item, further explains the research,

A symbol of luxury and richness, the diamond (from the Greek αδ?μας, “invincible”) is the most valuable gem and the toughest mineral (value of 10 in Mohs scale). It formed by chemically pure carbon, and according to the traditional hypothesis, it crystalizes the cubic system under ultra-high-pressure conditions at great depths in the Earth’s mantle.

The study confirms for the first time the formation of the natural diamond under low pressures in oceanic rocks in the Moa-Baracoa Ophiolitic Massif, in Cuba. This great geological structure is in the north-eastern side of the island and is formed by ophiolites, representative rocks of the Oceanic lithosphere.

These oceanic rocks were placed on the continental edge of North America during the collision of the Caribbean oceanic island arch, between 70 and 40 million years ago. “During its formation in the abysmal marine seafloors, in the cretaceous period -about 120 million years ago-, these oceanic rocks underwent mineral alterations due to marine water infiltrations, a process that led to small fluid inclusions inside the olivine, the most common mineral in this kind of rock”, note Joaquín A. Proenza, member of the Department of Mineralogy, Petrology and Applied Geology at the UB and principal researcher of the project in which the article appears, and Antonio García-Casco, from the Department of Mineralogy and Petrology of the UGR.

“These fluid inclusions contain nanodiamonds -of about 200 and 300 nanometres-, apart from serpentine, magnetite, metallic silicon and pure methane. All these materials have formed under low pressure (<200 MPa) and temperature (<350 ºC), during the olivine alteration that contains fluid inclusions”, add the researchers.

“Therefore, this is the first description of ophiolitic diamond formed under low pressure and temperature, whose formation under natural processes does not bear any doubts”, they highlight.

Diamonds formed under low pressure and temperature

It is notable to bear in mind that the team published, in 2019, a first description of the formation of ophiolitic diamonds under low pressure conditions (Geology), a study carried out as part of the doctoral thesis by the UB researcher Júlia Farré de Pablo, supervised by Joaquín A. Proenza and the UGR professor José María González Jiménez. This study was highly debated on among the members of the international scientific community.

In the published article in Geochemical Perspectives Letters, a journal of the European Association of Geochemistry, the experts detected the nanodiamonds in small fluid inclusions under the surface of the samples. The finding was carried out by using the confocal Raman maps and using focused ion beams (FIB), combined with transmission electron microscopy (FIB-TEM). This is how they could confirm the presence of the diamond in the depth of the sample, and therefore, the formation of a natural diamond under low pressure in exhumed oceanic rocks. The Scientific and Technological Centres of the UB (CCiTUB) have taken part in this study, among other infrastructures supporting the country.

In this case, the study focuses its debate on the validity of some geodynamic models that, based on the presence of ophiolite diamonds, imply circulation in the mantle and large-scale lithosphere recycling. For instance, the ophiolitic diamond was thought to reflect the passing of ophiolitic rocks over the deep earth’s mantle up to the transition area (210-660 km deep) before settling into a normal ophiolite formed under low pressure (~10 km deep).

According to the experts, the low state of oxidation in this geological system would explain the formation of nano-çdiamonds instead of graphite -which would be expected under physical and chemical formation conditions of fluid inclusions.

The study counted on the support from the former Ministry for Economy and Competitiveness (MINECO), the Ramón y Cajal Program and the EU European Regional Development Fund (ERDF).

The researchers have an image showing inclusions which contain nanodiamonds,

Caption: The fluid inclusions inside the olivine contain nanodiamonds, apart from serpentine, magnetite, metallic silicon and pure methane.. Credit: UNIVERSITY OF BARCELONA

Here`s a link to and a citation for the paper,

Diamond forms during low pressure serpentinisation of oceanic lithosphere by
N. Pujol-Solà, A. Garcia-Casco, J.A. Proenza, J.M. González-Jiménez, A. del Campo, V. Colás, À. Canals, A. Sánchez-Navas, J. Roqué-Rosell. Geochemical Perspectives Letters v15 DOI: 10.7185/geochemlet.2029 Published 10 September 2020

This paper is open access.

Nanodevices show (from the inside) how cells change

Embryo cells + nanodevices from University of Bath on Vimeo.

Caption: Five mouse embryos, each containing a nanodevice that is 22-millionths of a metre long. The film begins when the embryos are 2-hours old and continues for 5 hours. Each embryo is about 100-millionths of a metre in diameter. Credit: Professor Tony Perry

Fascinating, yes? As I often watch before reading the caption, these were mysterious grey blobs moving around was my first impression. Given the headline for the May 26, 2020 news item on ScienceDaily, I was expecting the squarish-shaped devices inside,

For the first time, scientists have introduced minuscule tracking devices directly into the interior of mammalian cells, giving an unprecedented peek into the processes that govern the beginning of development.

This work on one-cell embryos is set to shift our understanding of the mechanisms that underpin cellular behaviour in general, and may ultimately provide insights into what goes wrong in ageing and disease.

The research, led by Professor Tony Perry from the Department of Biology and Biochemistry at the University of Bath [UK], involved injecting a silicon-based nanodevice together with sperm into the egg cell of a mouse. The result was a healthy, fertilised egg containing a tracking device.

This image looks to have been enhanced with colour,

Fluorescence of an embryo containing a nanodevice. Courtesy: University of Bath

A May 25, 2020 University of Bath press release (also on EurekAlert but published May 26, 2020)

The tiny devices are a little like spiders, complete with eight highly flexible ‘legs’. The legs measure the ‘pulling and pushing’ forces exerted in the cell interior to a very high level of precision, thereby revealing the cellular forces at play and showing how intracellular matter rearranged itself over time.

The nanodevices are incredibly thin – similar to some of the cell’s structural components, and measuring 22 nanometres, making them approximately 100,000 times thinner than a pound coin. This means they have the flexibility to register the movement of the cell’s cytoplasm as the one-cell embryo embarks on its voyage towards becoming a two-cell embryo.

“This is the first glimpse of the physics of any cell on this scale from within,” said Professor Perry. “It’s the first time anyone has seen from the inside how cell material moves around and organises itself.”

WHY PROBE A CELL’S MECHANICAL BEHAVIOUR?

The activity within a cell determines how that cell functions, explains Professor Perry. “The behaviour of intracellular matter is probably as influential to cell behaviour as gene expression,” he said. Until now, however, this complex dance of cellular material has remained largely unstudied. As a result, scientists have been able to identify the elements that make up a cell, but not how the cell interior behaves as a whole.

“From studies in biology and embryology, we know about certain molecules and cellular phenomena, and we have woven this information into a reductionist narrative of how things work, but now this narrative is changing,” said Professor Perry. The narrative was written largely by biologists, who brought with them the questions and tools of biology. What was missing was physics. Physics asks about the forces driving a cell’s behaviour, and provides a top-down approach to finding the answer.

“We can now look at the cell as a whole, not just the nuts and bolts that make it.”

Mouse embryos were chosen for the study because of their relatively large size (they measure 100 microns, or 100-millionths of a metre, in diameter, compared to a regular cell which is only 10 microns [10-millionths of a metre] in diameter). This meant that inside each embryo, there was space for a tracking device.

The researchers made their measurements by examining video recordings taken through a microscope as the embryo developed. “Sometimes the devices were pitched and twisted by forces that were even greater than those inside muscle cells,” said Professor Perry. “At other times, the devices moved very little, showing the cell interior had become calm. There was nothing random about these processes – from the moment you have a one-cell embryo, everything is done in a predictable way. The physics is programmed.”

The results add to an emerging picture of biology that suggests material inside a living cell is not static, but instead changes its properties in a pre-ordained way as the cell performs its function or responds to the environment. The work may one day have implications for our understanding of how cells age or stop working as they should, which is what happens in disease.

The study is published this week in Nature Materials and involved a trans-disciplinary partnership between biologists, materials scientists and physicists based in the UK, Spain and the USA.

Here’s a link to and a citation for the paper,

Tracking intracellular forces and mechanical property changes in mouse one-cell embryo development by Marta Duch, Núria Torras, Maki Asami, Toru Suzuki, María Isabel Arjona, Rodrigo Gómez-Martínez, Matthew D. VerMilyea, Robert Castilla, José Antonio Plaza & Anthony C. F. Perry. Nature Materials (2020) DOI: https://doi.org/10.1038/s41563-020-0685-9 Published 25 May 2020

This paper is behind a paywall.

They all fall down or not? Quantum dot-doped nanoparticles for preserving national monuments and buildings

The most recent post here but not the most recent research about preserving stone monuments and buildings is a December 23, 2019 piece titled: Good for your bones and good for art conservation: calcium. Spanish researchers (who seem particularly active in this research niche) are investigating a more refined approach to preserving stone monuments with calcium according to a May 8, 2020 news item on Nanowerk,

The fluorescence emitted by tiny zinc oxide quantum dots can be used to determine the penetration depth of certain substances used in the restoration of historical buildings. Researchers from Pablo de Olavide University (Spain) have tested this with samples collected from historical quarries in Cadiz, where the stone was used to build the city hall and cathedral of Seville.

One of the main problems in the preservation of historic buildings is the loss of cohesion of their building materials. Restorers use consolidating substances to make them more resistant, such as lime (calcium hydroxide), which has long been used because of its great durability and high compatibility with the carbonate stone substrate.

Now, researchers at Pablo de Olavide University, in Seville, have developed and patented calcium hydroxide nanoparticles doped with quantum dots that are more effective as consolidant and make it possible to distinguish the restored from the original material, as it is recommended for the conservation and restoration of historical heritage.

An April 28, 2020 Pablo de Olavide University press release (also on Alpha Gallileo but published May 5, 2020), which originated the news item, provides more details about the nature of the materials,

“The tiny quantum dots, which are smaller than 10 nanometres, are made of zinc oxide and are semiconductors, which gives them very interesting properties (different from those of larger particles due to quantum mechanics), such as fluorescence, which is the one we use,” explains Javier Becerra, one of the authors.

“Thanks to the fluorescence of these quantum dots, we can evaluate the suitability of the treatment for a monument,” he adds. “We only need to illuminate with ultraviolet light a cross-section of the treated material to determine how far the consolidating matter has penetrated.”

In addition, the product, which the authors have named Nanorepair UV, acts as a consolidant due to the presence of the lime nanoparticles. Consolidation is a procedure that increases the degree of cohesion of a material, reinforcing and hardening the parts that have suffered some deterioration, which is frequent in historical buildings.

The researchers have successfully applied their technique to samples collected in the historic quarries of El Puerto de Santa María and Espera (Cadiz), from where the stone used to build such iconic monuments as Seville Cathedral, a World Heritage Site since 1987, or the town’s city hall, was extracted.

“In the laboratory, we thus obtain an approximation of how the treatment will behave when it is actually applied to the monuments,” says Becerra, who together with the rest of the team, is currently also testing mortars from the Italica and Medina Azahara archaeological sites.

Oddly, this work is not all that recently published. In any event, here’s a link to and a citation for the paper,

Nanolimes doped with quantum dots for stone consolidation assessment by Javier Becerra, Pilar Ortiz, José María Martín, Ana Paula Zaderenko. Construction and Building Materials Volume 199, 28 February 2019, Pages 581-593 DOI: https://doi.org/10.1016/j.conbuildmat.2018.12.077 Available online 19 December 2018

This paper is behind a paywall.

Entangling 15 trillion atoms is a hot and messy business

A May 15, 2020 news item on Nanowerk provides context for an announcement of a research breakthrough on quantum entanglement,

Quantum entanglement is a process by which microscopic objects like electrons or atoms lose their individuality to become better coordinated with each other. Entanglement is at the heart of quantum technologies that promise large advances in computing, communications and sensing, for example detecting gravitational waves.

Entangled states are famously fragile: in most cases even a tiny disturbance will undo the entanglement. For this reason, current quantum technologies take great pains to isolate the microscopic systems they work with, and typically operate at temperatures close to absolute zero.

The ICFO [Institute of Photonic Sciences; Spain] team, in contrast, heated a collection of atoms to 450 Kelvin, millions of times hotter than most atoms used for quantum technology. Moreover, the individual atoms were anything but isolated; they collided with each other every few microseconds, and each collision set their electrons spinning in random directions.

Caption: Artistic illustration of a cloud of atoms with pairs of particles entangled between each other, represented by the yellow-blue lines. Image credit: © ICFO

A May 15, 2020 (?) ICFO press release (also on EurekAlert), which originated the news item, delves further into details abut the research,

The researchers used a laser to monitor the magnetization of this hot, chaotic gas. The magnetization is caused by the spinning electrons in the atoms, and provides a way to study the effect of the collisions and to detect entanglement. What the researchers observed was an enormous number of entangled atoms – about 100 times more than ever before observed. They also saw that the entanglement is non-local – it involves atoms that are not close to each other. Between any two entangled atoms there are thousands of other atoms, many of which are entangled with still other atoms, in a giant, hot and messy entangled state.

What they also saw, as Jia Kong, first author of the study, recalls, “is that if we stop the measurement, the entanglement remains for about 1 millisecond, which means that 1000 times per second a new batch of 15 trillion atoms is being entangled. And you must think that 1 ms is a very long time for the atoms, long enough for about fifty random collisions to occur. This clearly shows that the entanglement is not destroyed by these random events. This is maybe the most surprising result of the work”.

The observation of this hot and messy entangled state paves the way for ultra-sensitive magnetic field detection. For example, in magnetoencephalography (magnetic brain imaging), a new generation of sensors uses these same hot, high-density atomic gases to detect the magnetic fields produced by brain activity. The new results show that entanglement can improve the sensitivity of this technique, which has applications in fundamental brain science and neurosurgery.

As ICREA [Catalan Institution for Research and Advanced Studies] Prof. at ICFO Morgan Mitchell states, “this result is surprising, a real departure from what everyone expects of entanglement.” He adds “we hope that this kind of giant entangled state will lead to better sensor performance in applications ranging from brain imaging to self-driving cars to searches for dark matter

A Spin Singlet and QND

A spin singlet is one form of entanglement where the multiple particles’ spins–their intrinsic angular momentum–add up to 0, meaning the system has zero total angular momentum. In this study, the researchers applied quantum non-demolition (QND) measurement to extract the information of the spin of trillions of atoms. The technique passes laser photons with a specific energy through the gas of atoms. These photons with this precise energy do not excite the atoms but they themselves are affected by the encounter. The atoms’ spins act as magnets to rotate the polarization of the light. By measuring how much the photons’ polarization has changed after passing through the cloud, the researchers are able to determine the total spin of the gas of atoms.

The SERF regime

Current magnetometers operate in a regime that is called SERF, far away from the near absolute zero temperatures that researchers typically employ to study entangled atoms. In this regime, any atom experiences many random collisions with other neighbouring atoms, making collisions the most important effect on the state of the atom. In addition, because they are in a hot medium rather than an ultracold one, the collisions rapidly randomize the spin of the electrons in any given atom. The experiment shows, surprisingly, that this kind of disturbance does not break the entangled states, it merely passes the entanglement from one atom to another.

Here’s a link to and a citation for the paper,

Measurement-induced, spatially-extended entanglement in a hot, strongly-interacting atomic system by Jia Kong, Ricardo Jiménez-Martínez, Charikleia Troullinou, Vito Giovanni Lucivero, Géza Tóth & Morgan W. Mitchell. Nature Communications volume 11, Article number: 2415 (2020) DOI: https://doi.org/10.1038/s41467-020-15899-1 Published1 5 May 2020

This paper is open access.

Get better protection from a sunscreen with a ‘flamenco dancing’ molecule?

Caption: illustrative image for the University of Warwick research on ‘Flamenco dancing’ molecule could lead to better-protecting sunscreen created by Dr. Michael Horbury. Credit:: created by Dr Michael Horbury

There are high hopes (more about why later) for a plant-based ‘flamenco dancing molecule’ and its inclusion in sunscreens as described in an October 18, 2019 University of Warwick press release (also on EurekAlert),

A molecule that protects plants from overexposure to harmful sunlight thanks to its flamenco-style twist could form the basis for a new longer-lasting sunscreen, chemists at the University of Warwick have found, in collaboration with colleagues in France and Spain. Research on the green molecule by the scientists has revealed that it absorbs ultraviolet light and then disperses it in a ‘flamenco-style’ dance, making it ideal for use as a UV filter in sunscreens.

The team of scientists report today, Friday 18th October 2019, in the journal Nature Communications that, as well as being plant-inspired, this molecule is also among a small number of suitable substances that are effective in absorbing light in the Ultraviolet A (UVA) region of wavelengths. It opens up the possibility of developing a naturally-derived and eco-friendly sunscreen that protects against the full range of harmful wavelengths of light from the sun.

The UV filters in a sunscreen are the ingredients that predominantly provide the protection from the sun’s rays. In addition to UV filters, sunscreens will typically also include:

Emollients, used for moisturising and lubricating the skin
Thickening agents
Emulsifiers to bind all the ingredients
Water
Other components that improve aesthetics, water resistance, etc.

The researchers tested a molecule called diethyl sinapate, a close mimic to a molecule that is commonly found in the leaves of plants, which is responsible for protecting them from overexposure to UV light while they absorb visible light for photosynthesis.

They first exposed the molecule to a number of different solvents to determine whether that had any impact on its (principally) light absorbing behaviour. They then deposited a sample of the molecule on an industry standard human skin mimic (VITRO-CORNEUM®) where it was irradiated with different wavelengths of UV light. They used the state-of-the-art laser facilities within the Warwick Centre for Ultrafast Spectroscopy to take images of the molecule at extremely high speeds, to observe what happens to the light’s energy when it’s absorbed in the molecule in the very early stages (millionths of millionths of a second). Other techniques were also used to establish longer term (many hours) properties of diethyl sinapate, such as endocrine disruption activity and antioxidant potential.

Professor Vasilios Stavros from the University of Warwick, Department of Chemistry, who was part of the research team, explains: “A really good sunscreen absorbs light and converts it to harmless heat. A bad sunscreen is one that absorbs light and then, for example, breaks down potentially inducing other chemistry that you don’t want. Diethyl sinapate generates lots of heat, and that’s really crucial.”

When irradiated the molecule absorbs light and goes into an excited state but that energy then has to be disposed of somehow. The team of researchers observed that it does a kind of molecular ‘dance’ a mere 10 picoseconds (ten millionths of a millionth of a second) long: a twist in a similar fashion to the filigranas and floreos hand movements of flamenco dancers. That causes it to come back to its original ground state and convert that energy into vibrational energy, or heat.

It is this ‘flamenco dance’ that gives the molecule its long-lasting qualities. When the scientists bombarded the molecule with UVA light they found that it degraded only 3% over two hours, compared to the industry requirement of 30%.

Dr Michael Horbury, who was a Postgraduate Research Fellow at The University Warwick when he undertook this research (and now at the University of Leeds) adds: “We have shown that by studying the molecular dance on such a short time-scale, the information that you gain can have tremendous repercussions on how you design future sunscreens.
Emily Holt, a PhD student in the Department of Chemistry at the University of Warwick who was part of the research team, said: “The next step would be to test it on human skin, then to mix it with other ingredients that you find in a sunscreen to see how those affect its characteristics.”

Professor Florent Allais and Dr Louis Mouterde, URD Agro-Biotechnologies Industrielles at AgroParisTech (Pomacle, France) commented: “What we have developed together is a molecule based upon a UV photoprotective molecule found in the surface of leaves on a plant and refunctionalised it using greener synthetic procedures. Indeed, this molecule has excellent long-term properties while exhibiting low endocrine disruption and valuable antioxidant properties.”

Professor Laurent Blasco, Global Technical Manager (Skin Essentials) at Lubrizol and Honorary Professor at the University of Warwick commented: “In sunscreen formulations at the moment there is a lack of broad-spectrum protection from a single UV filter. Our collaboration has gone some way towards developing a next generation broad-spectrum UV filter inspired by nature. Our collaboration has also highlighted the importance of academia and industry working together towards a common goal.”

Professor Vasilios Stavros added, “Amidst escalating concerns about their impact on human toxicity (e.g. endocrine disruption) and ecotoxicity (e.g. coral bleaching), developing new UV filters is essential. We have demonstrated that a highly attractive avenue is ‘nature-inspired’ UV filters, which provide a front-line defence against skin cancer and premature skin aging.”

Here’s a link to and a citation for the paper,

Towards symmetry driven and nature inspired UV filter design by Michael D. Horbury, Emily L. Holt, Louis M. M. Mouterde, Patrick Balaguer, Juan Cebrián, Laurent Blasco, Florent Allais & Vasilios G. Stavros. Nature Communications volume 10, Article number: 4748 (2019) DOI: https://doi.org/10.1038/s41467-019-12719-z

This paper is open access.

Why the high hopes?

Briefly (the long story stretches over 10 years), the most recommended sunscreens today (2020) are ‘mineral-based’. This is painfully amusing because civil society groups (activists) such as Friends of the Earth (in particular the Australia chapter under Georgia Miller’s leadership) and Canada’s own ETC Group had campaigned against these same sunscreen when they were billed as being based on metal oxide nanoparticles such zinc oxide and/or titanium oxide. The ETC Group under Pat Roy Mooney’s leadership didn’t press the campaign after an initial push. As for Australia and Friend of the Earth, their anti-metallic oxide nanoparticle sunscreen campaign didn’t work out well as I noted in a February 9, 2012 posting and with a follow-up in an October 31, 2012 posting.

The only civil society group to give approval (very reluctantly) was the Environmental Working Group (EWG) as I noted in a July 9, 2009 posting. They had concerns about the fact that these ingredients are metallic but after a thorough of then available research, EWG gave the sunscreens a passing grade and noted, in their report, that they had more concerns about the use of oxybenzone in sunscreens. That latter concern has since been flagged by others (e.g., the state of Hawai’i) as noted in my July 6, 2018 posting.

So, rebranding metallic oxides as minerals has allowed the various civil society groups to support the very same sunscreens many of them were advocating against.

In the meantime, scientists continue work on developing plant-based sunscreens as an improvement to the ‘mineral-based’ sunscreens used now.

Neuronal regenerative-interfaces made of cross-linked carbon nanotube films

If I understand this research rightly, they are creating a film made of carbon nanotubes that can stimulate the growth of nerve cells (neurons) thus creating a ‘living/nonliving’ hybrid or as they call it in the press release a ‘biosynthetic hybrid’.

An August 2, 2019 news item on Nanowerk introduces the research (Note 1: There seem to be some translation issues; Note 2: Links have been removed),

Carbon nanotubes able to take on the desired shapes thanks to a special chemical treatment, called crosslinking and, at the same time, able to function as substrata for the growth of nerve cells, finely tuning their growth and activity.

The research published in ACS Nano (“Chemically Cross-Linked Carbon Nanotube Films Engineered to Control Neuronal Signaling”), is a new and important step towards the construction of neuronal regenerative-interfaces to repair spinal injuries.

The study is the new achievement of a long-term and, in terms of results, successful collaboration between the scientists Laura Ballerini of SISSA (Scuola Internazionale Superiore di Studi Avanzati), Trieste, and Maurizio Prato of the University of Trieste. The work team has also been assisted by CIC biomaGUNE of San Sebastián, Spain.

Caption: Carbon nanotubes able to take on the desired shapes thanks to a special chemical treatment, called crosslinking and, at the same time, able to function as substrata for the growth of nerve cells, finely tuning their growth and activity. Credit: Rossana Rauti

An August 2, 2019 SISSA press release (also on EurekAlert), which originated the news item, adds detail,

The carbon nanotubes used in the research have been modified by appropriate chemical treatments: “For many years, in our laboratories we have been working on the chemical reactivity of carbon nanotubes, a fascinating but very difficult material to work. Thanks to our experience, we have crosslinked them or, to say it more clearly, we have treated the nanotubes so they could link themselves to one another thanks to specific chemical reactions. We have discovered that this procedure gives the material very interesting characteristics. For example, the material organises itself in a stable manner according to a precise shape, we choose: a tissue where nerve cells need to be planted, for example. Or around some electrodes” explains Professor Prato. “We know from previous research that nerve cells grow well on carbon nanotubes so they could be used as a surface to build hybrid devices to regenerate nerve tissues. It was necessary to ensure that this chemical modification did not compromise this process and study whether the interaction with neurons was altered”.

Towards biosynthetic hybrids

Professor Ballerini continues: “We have discovered that the chemical process has important effects because through this treatment we can modulate the activity of neurons, in terms of growth, adhesion and survival. These materials can also regulate the communication between neurons. We can say that the carpet of crosslinked carbon nanotubes interacts intensely and constructively with the nerve cells”. This interaction depends on how much the different carbon nanotubes are linked to each other, or rather crosslinked. The lower the link number among the nanotubes the higher the activity of neurons that grow on their surface. Through the chemical control of their properties, and of the links between them, it is possible to regulate the response of the neurons. Ballerini and Prato explain: “This is an intriguing result that emerges from the important and fruitful collaboration between our research groups involving advanced research in chemistry, nanoscience and neurobiology . This study provides a further step in the design of future biosynthetic hybrids to recover injured nerve tissues functions”.

Here’s a link to and a citation for the paper,

Chemically Cross-Linked Carbon Nanotube Films Engineered to Control Neuronal Signaling by Myriam Barrejón, Rossana Rauti, Laura Ballerini, Maurizio Prato. ACS Nano2019 XXXXXXXXXX-XXX Publication Date:July 22, 2019 DOI: https://doi.org/10.1021/acsnano.9b02429 Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Good for your bones and good for art conservation: calcium

The statues on Easter Island, the Great Wall of China, Egyptian pyramids, MesoAmerican pyramids, castles in Europe and other structures made of stone are deteriorating and now comes another approach to halting the destruction. (I have covered other approaches to the problem in two previous postings, a December 5, 2017 posting, Europe’s cathedrals get a ‘lift’ with nanoparticles, and an October 21, 2014 posting, Heart of stone.)

An August 7, 2019 news item on ScienceDaily announces the latest in conserving stone monuments and structures,

When it comes to cultural heritage sites, there are few things historians wouldn’t do to preserve them for future generations. In particular, stone buildings and sculptures made of plaster and marble are increasingly at risk of damage from air pollution, acid rain and other factors. Researchers now report a new, calcium-based conservation treatment inspired by nature that overcomes many drawbacks of currently used methods.

An August 7, 2019 American Chemical Society (ACS) news release, which originated the news item, provides a bit more technical detail,

Historically, conservation scientists have turned to alkoxysilanes, silicon-based molecules used to consolidate stone and other artworks, in their preservation efforts. However, alkoxysilane treatments do not bond properly with non-silicate surfaces, are prone to cracking and are limited in their ability to repel water. Adding other compounds to this treatment have helped overcome these effects, but only to a point. Instead Encarnación Ruiz Agudo and colleagues looked to nature for inspiration, and found that calcium could be the answer. As a major element of strong, natural structures like bone and kidney stones, the researchers theorized that nanoparticles made from calcium could bolster alkoxysilanes and provide the desired protective effects to conserve historical artifacts.

The researchers made calcium carbonate and calcium oxalate nanoparticles and included polydimethylsiloxane (PDMS) as a stabilizer. PDMS also likely helps the nanoparticles bond to surfaces. The team added the nanoparticles to traditional alkoxysilane treatments, then applied them to samples of three different building materials: white marble, calcarenite limestone and gypsum plaster, and put the samples through a battery of tests. Overall, the results showed enhanced hydrophobicity, less cracking and improved surface adhesion compared to alkoxysilane treatments alone, with calcium oxalate providing a marked improvement in acid resistance. A minimal color effect was observed, but the researchers say this change was within acceptable values for conservation efforts.

The authors acknowledge funding from the European Regional Development Fund, the Regional Government of Andalusia, the Spanish Ministry of Economy and Finance and the University of Granada.

Here’s a link to and a citation for the paper,

Bioinspired Alkoxysilane Conservation Treatments for Building Materials Based on Amorphous Calcium Carbonate and Oxalate Nanoparticles by A. Burgos-Cara, C. Rodríguez-Navarro, M. Ortega-Huertas, E. Ruiz-Agudo. ACS Appl. Nano Mater.2019XXXXXXXXXX-XXX DOI: https://doi.org/10.1021/acsanm.9b00905 Publication Date:July 18, 2019 Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Membrane stretching as a new transport mechanism for nanomaterials

This work comes from Catalonia, Spain by way of a collaboration between Chinese, German, and, of course, Spanish scientists. From a December 12, 2018 Universitat Rovira i Virgili press release (also on EurekAlert),

Increasing awareness of bioeffects and toxicity of nanomaterials interacting with cells puts in focus the mechanisms by which nanomaterials can cross lipid membranes. Apart from well-discussed energy-dependent endocytosis for large objects and passive diffusion through membranes by solute molecules, there can exist other transport mechanisms based on physical principles. Based on this hypothesis, the team of theoretical physics at Universitat Rovira i Virgili in Tarragona, led by Dr. Vladimir Baulin, designed a research project to investigate the interaction between nanotube and lipid membranes. In computer simulations, the researchers studied what they call a “model bilayer”, composed only by one type of lipids. Based on their calculations, the team of Dr. Baulin observed that ultra -short nanotube (10nm length) can insert perpendicularly to the lipid bilayer core.

They observed that these nanotubes stay trapped in the cell membrane, as commonly accepted by the scientific community. But a surprise appears when they stretched their model cell membrane, then inserted nanotubes which were trapped in the bilayer, suddenly started to escape from the bilayer on both sides. This means that it is possible to control the transport of nanomaterial across a cell membrane by tuning the membrane tension.

This is where Dr. Baulin contacted Dr. Jean-Baptiste Fleury at the Saarland University (Germany) to confirm this mechanism and to study experimentally this tension-mediated transport phenomena. Dr. Fleury and his team, designed a microfluidic experiment with a well-controlled phospholipid bilayer, an experimental model for cell membranes and added ultra-small carbon nanotubes (10nm in length) in solution. The nanotubes had an adsorbed lipid monolayer that guarantees their stable dispersion and prevent their clustering. Using a combination of optical fluorescent microscopy and electrophysiological measurements, the team of Dr. Fleury could follow individual nanotube crossing a bilayer and unravel their pathway on a molecular level. And as predicted by the simulations, they observed that nanotubes inserted into the bilayer by dissolving their lipid coating into the artificial membrane. When a tension of 4mN/m was applied to the bilayer, nanotubes spontaneously escaped the bilayer just in few milliseconds, while at lower tensions nanotubes remain trapped inside the membrane.

This discovery of translocation of tiny nanotubes through barriers protecting cells, i.e. lipid bilayer, may raise concerns about safety of nanomaterials for public health and suggest new mechanical mechanisms to control the drug delivery.

Caption: Nanotubes trapped inside the membrane. Credit: © URV

Here’s a link to and a citation for the paper,

Tension-Induced Translocation of an Ultrashort Carbon Nanotube through a Phospholipid Bilayer by Yachong Guo, Marco Werner, Ralf Seemann, Vladimir A. Baulin, and Jean-Baptiste Fleury. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b04657 Publication Date (Web): November 19, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Real-time tracking of UV (ultraviolet light) exposure for all skin types (light to dark)

It’s nice to find this research after my August 21, 2018 posting where I highlighted (scroll down to ‘Final comments’) the issues around databases and skin cancer data which is usually derived from fair-skinned people while people with darker hues tend not to be included. This is partly due to the fact that fair-skinned people have a higher risk and also partly due to myths about how more melanin in your skin somehow protects you from skin cancer.

This October 4, 2018 news item on ScienceDaily announces research into a way to track UV exposure for all skin types,

Researchers from the University of Granada [Spain] and RMIT University in Melbourne [Australia] have developed personalised and low-cost wearable ultraviolet (UV) sensors that warn users when their exposure to the sun has become dangerous.

The paper-based sensor, which can be worn as a wristband, features happy and sad emoticon faces — drawn in an invisible UV-sensitive ink — that successively light up as you reach 25%, 50%, 75% and finally 100% of your daily recommended UV exposure.

The research team have also created six versions of the colour-changing wristbands, each of which is personalised for a specific skin tone  [emphasis mine]– an important characteristic given that darker people need more sun exposure to produce vitamin D, which is essential for healthy bones, teeth and muscles.

An October 2, 2018 University of Granada press release (also on EurekAlert) delves further,

Four of the wristbands, each of which indicates a different stage of exposure to UV radiation (25%, 50%, 75% and 100%)

The emoticon faces on the wristband successively “light up” as exposure to UV radiation increases

Skin cancer, one of the most common types of cancer throughout the world, is primarily caused by overexposure to ultraviolet radiation (UVR). In Spain, over 74,000 people are diagnosed with non-melanoma skin cancer every year, while a further 4,000 are diagnosed with melanoma skin cancer. In regions such as Australia, where the ozone layer has been substantially depleted, it is estimated that approximately 2 in 3 people will be diagnosed with skin cancer by the time they reach the age of 70.

“UVB and UVC radiation is retained by the ozone layer. This sensor is especially important in the current context, given that the hole in the ozone layer is exposing us to such dangerous radiation”, explains José Manuel Domínguez Vera, a researcher at the University of Granada’s Department of Inorganic Chemistry and the main author of the paper.

Domínguez Vera also highlights that other sensors currently available on the market only measure overall UV radiation, without distinguishing between UVA, UVB and UVC, each of which has a significantly different impact on human health.  In contrast, the new paper-based sensor can differentiate between UVA, UVB and UVC radiation. Prolonged exposure to UVA radiation is associated with skin ageing and wrinkling, while excessive exposure to UVB causes sunburn and increases the likelihood of skin cancer and eye damage.

Drawbacks of the traditional UV index

Ultraviolet radiation is determined by aspects such as location, time of day, pollution levels, astronomical factors, weather conditions such as clouds, and can be heightened by reflective surfaces like bodies of water, sand and snow. But UV rays are not visible to the human eye (even if it is cloudy UV radiation can be high) and until now the only way of monitoring UV intensity has been to use the UV index, which is standardly given in weather reports and indicates 5 degrees of radiation;  low, moderate, high, very high or extreme.

Despite its usefulness, the UV index is a relatively limited tool. For instance, it does not clearly indicate what time of the day or for how long you should be outside to get your essential vitamin D dose, or when to cover up to avoid sunburn and a heightened risk of skin cancer.

Moreover, the UV index is normally based on calculations for fair skin, making it unsuitable for ethnically diverse populations.  While individuals with fairer skin are more susceptible to UV damage, those with darker skin require much longer periods in the sun in order to absorb healthy amounts of vitamin D. In this regard, the UV index is not an accurate tool for gauging and monitoring an individual’s recommended daily exposure.

UV-sensitive ink

The research team set out to tackle the drawbacks of the traditional UV index by developing an inexpensive, disposable and personalised sensor that allows the wearer to track their UV exposure in real-time. The sensor paper they created features a special ink, containing phosphomolybdic acid (PMA), which turns from colourless to blue when exposed to UV radiation. They can use the initially-invisible ink to draw faces—or any other design—on paper and other surfaces. Depending on the type and intensity of the UV radiation to which the ink is exposed, the paper begins to turn blue; the greater the exposure to UV radiation, the faster the paper turns blue.

Additionally, by tweaking the ink composition and the sensor design, the team were able to make the ink change colour faster or slower, allowing them to produce different sensors that are tailored to the six different types of skin colour. [emphasis mine]

Applications beyond health

This low-cost, paper-based sensor technology will not only help people of all colours to strike an optimum balance between absorbing enough vitamin D and avoiding sun damage — it also has significant applications for the agricultural and industrial sectors. UV rays affect the growth of crops and the shelf life of a range of consumer products. As the UV sensors can detect even the slightest doses of UV radiation, as well as the most extreme, this new technology could have vast potential for industries and companies seeking to evaluate the prolonged impact of UV exposure on products that are cultivated or kept outdoors.

The research project is the result of fruitful collaborations between two members of the UGR BIONanoMet (FQM368) research group; Ana González and José Manuel Domínguez-Vera, and the research group led by Dr. Vipul Bansal at RMIT University in Melbourne (Australia).

Here’s a link to and a citation for the paper,

Skin color-specific and spectrally-selective naked-eye dosimetry of UVA, B and C radiations by Wenyue Zou, Ana González, Deshetti Jampaiah, Rajesh Ramanathan, Mohammad Taha, Sumeet Walia, Sharath Sriram, Madhu Bhaskaran, José M. Dominguez-Vera, & Vipul Bansal. Nature Communicationsvolume 9, Article number: 3743 (2018) DOI: https://doi.org/10.1038/s41467-018-06273-3 Published 25 September 2018

This paper is open access.