Engineers create nanoparticles that deliver gene-editing tools to specific tissues and organs


Credit: CC0 Public Domain

One of the most remarkable recent advances in biomedical research has been the development of highly targeted gene-editing methods such as CRISPR that can add, remove, or change a gene within a cell with great precision. The method is already being tested or used for the treatment of patients with sickle cell anemia and cancers such as multiple myeloma and liposarcoma, and today, its creators Emmanuelle Charpentier and Jennifer Doudna received the Nobel Prize in chemistry.

While gene editing is remarkably precise in finding and altering genes, there is still no way to target treatment to specific locations in the body. The treatments tested so far involve removing blood stem cells or immune system T cells from the body to modify them, and then infusing them back into a patient to repopulate the bloodstream or reconstitute an immune response—an expensive and time-consuming process.

Building on the accomplishments of Charpentier and Doudna, Tufts researchers have for the first time devised a way to directly deliver gene-editing packages efficiently across the blood brain barrier and into specific regions of the brain, into immune system cells, or to specific tissues and organs in mouse models. These applications could open up an entirely new line of strategy in the treatment of neurological conditions, as well as cancer, infectious disease, and autoimmune diseases.

A team of Tufts biomedical engineers, led by associate professor Qiaobing Xu, sought to find a way to package the gene editing “kit” so it could be injected to do its work inside the body on targeted cells, rather than in a lab.

They used lipid nanoparticles (LNPs)—tiny “bubbles” of lipid molecules that can envelop the editing enzymes and carry them to specific cells, tissues, or organs. Lipids are molecules that include a long carbon tail, which helps give them an “oily” consistency, and a hydrophilic head, which is attracted to a watery environment.

There is also typically a nitrogen, sulfur, or oxygen-based link between the head and tail. The lipids arrange themselves around the bubble nanoparticles with the heads facing outside and the tails facing inward toward the center.

Xu’s team was able to modify the surface of these LNPs so they can eventually “stick” to certain cell types, fuse with their membranes, and release the gene-editing enzymes into the cells to do their work.

Making a targeted LNP takes some chemical crafting.

By creating a mix of different heads, tails, and linkers, the researchers can screen— first in the lab—a wide variety of candidates for their ability to form LNPs that target specific cells. The best candidates can then be tested in mouse models, and further modified chemically to optimize targeting and delivery of the gene-editing enzymes to the same cells in the mouse.

“We created a method around tailoring the delivery package for a wide range of potential therapeutics, including gene editing,” said Xu. “The methods draw upon combinatorial chemistry used by the pharmaceutical industry for designing the drugs themselves, but instead we are applying the approach to designing the components of the delivery vehicle.”

In an ingenious bit of chemical modeling, Xu and his team used a neurotransmitter at the head of some lipids to assist the particles in crossing the blood-brain barrier, which would otherwise be impermeable to molecule assemblies as large as an LNP.

The ability to safely and efficiently deliver drugs across the barrier and into the brain has been a long-standing challenge in medicine. In a first, Xu’s lab delivered an entire complex of messenger RNAs and enzymes making up the CRISPR kit into targeted areas of the brain in a living animal.

Some slight modifications to the lipid linkers and tails helped create LNPs that could deliver into the brain the small molecule antifungal drug amphotericin B (for treatment of meningitis) and a DNA fragment that binds to and shuts down the gene producing the tau protein linked to Alzheimer’s disease.

More recently, Xu and his team have created LNPs to deliver gene-editing packages into T cells in mice. T cells can help in the production of antibodies, destroy infected cells before viruses can replicate and spread, and regulate and suppress other cells of the immune system.

The LNPs they created fuse with T cells in the spleen or liver—where they typically reside—to deliver the gene-editing contents, which can then alter the molecular make-up and behavior of the T cell. It’s a first step in the process of not just training the immune system, as one might do with a vaccine, but actually engineering it to fight disease better.

Xu’s approach to editing T cell genomes is much more targeted, efficient, and likely to be safer than methods tried so far using viruses to modify their genome.

“By targeting T cells, we can tap into a branch of the immune system that has tremendous versatility in fighting off infections, protecting against cancer, and modulating inflammation and autoimmunity,” said Xu.

Xu and his team explored further the mechanism by which LNPs might find their way to their targets in the body. In experiments aimed at cells in the lungs, they found that the nanoparticles picked up specific proteins in the bloodstream after injection.

The proteins, now incorporated into the surface of the LNPs, became the main component that helped the LNPs to latch on to their target. This information could help improve the design of future delivery particles.

While these results have been demonstrated in mice, Xu cautioned that more studies and clinical trials will be needed to determine the efficacy and safety of the delivery method in humans.


Explore furtherNovel drug delivery particles use neurotransmitters as a ‘passport’ into the brain


More information: Xuewei Zhao et al. Imidazole‐Based Synthetic Lipidoids for In Vivo mRNA Delivery into Primary T Lymphocytes, Angewandte Chemie International Edition (2020). DOI: 10.1002/anie.202008082Journal information:Angewandte Chemie International EditionProvided by Tufts University

Graphene microbubbles make perfect lenses – And Much More … Drug Delivery .. Water Treatment


gRAPHENE NANO BUBBLES graphenemicr
In situ optical microscopic images showing the process of the microbubble generation and elimination. Credit: H. Lin et al

Tiny bubbles can solve large problems. Microbubbles—around 1-50 micrometers in diameter—have widespread applications. They’re used for drug delivery, membrane cleaning, biofilm control, and water treatment. They’ve been applied as actuators in lab-on-a-chip devices for microfluidic mixing, ink-jet printing, and logic circuitry, and in photonics lithography and optical resonators. And they’ve contributed remarkably to biomedical imaging and applications like DNA trapping and manipulation.

Given the broad range of applications for microbubbles, many methods for generating them have been developed, including air stream compression to dissolve air into liquid, ultrasound to induce bubbles in water, and laser pulses to expose substrates immersed in liquids. However, these bubbles tend to be randomly dispersed in liquid and rather unstable.

According to Baohua Jia, professor and founding director of the Centre for Translational Atomaterials at Swinburne University of Technology, “For applications requiring precise bubble position and size, as well as high stability—for example, in photonic applications like imaging and trapping—creation of bubbles at accurate positions with controllable volume, curvature, and stability is essential.” Jia explains that, for integration into biological or photonic platforms, it is highly desirable to have well controlled and stable microbubbles fabricated using a technique compatible with current processing technologies.

Balloons in graphene

Jia and fellow researchers from Swinburne University of Technology recently teamed up with researchers from National University of Singapore, Rutgers University, University of Melbourne, and Monash University, to develop a method to generate precisely controlled graphene microbubbles on a glass surface using laser pulses. Their report is published in the peer-reviewed, open-access journal, Advanced Photonics.

Graphene microbubbles make perfect lenses
Photonic jet focused by a graphene oxide microbubble lens. Credit: H. Lin et al., doi 10.1117/1.AP.2.5.055001

The group used graphene oxide materials, which consist of graphene film decorated with oxygen functional groups. Gases cannot penetrate through graphene oxide materials, so the researchers used laser to locally irradiate the graphene oxide film to generate gases to be encapsulated inside the film to form microbubbles—like balloons. Han Lin, Senior Research Fellow at Swinburne University and first author on the paper, explains, “In this way, the positions of the microbubbles can be well controlled by the laser, and the microbubbles can be created and eliminated at will. In the meantime, the amount of gases can be controlled by the irradiating area and irradiating power. Therefore, high precision can be achieved.”

Such a high-quality bubble can be used for advanced optoelectronic and micromechanical devices with high precision requirements.

The researchers found that the high uniformity of the graphene oxide films creates microbubbles with a perfect spherical curvature that can be used as concave reflective lenses. As a showcase, they used the concave reflective lenses to focus light. The team reports that the lens presents a high-quality focal spot in a very good shape and can be used as light source for microscopic imaging.

Lin explains that the reflective lenses are also able to focus light at different wavelengths at the same focal point without chromatic aberration. The team demonstrates the focusing of a ultrabroadband white light, covering visible to near-infrared range, with the same high performance, which is particularly useful in compact microscopy and spectroscopy.

Jia remarks that the research provides “a pathway for generating highly controlled microbubbles at will and integration of  microbubbles as dynamic and high precision nanophotonic components for miniaturized lab-on-a-chip devices, along with broad potential applications in high resolution spectroscopy and medical imaging.”


Explore further

Monolayer transition metal dichalcogenide lens for high resolution imaging


More information: Han Lin et al, Near-perfect microlenses based on graphene microbubbles, Advanced Photonics (2020). DOI: 10.1117/1.AP.2.5.055001
Provided by SPIE

Mainstream EV Adoption: 5 Speedbumps to Overcome


** Article from the Visual Capitalist **

Many would agree that a global shift to electric vehicles (EV) is an important step in achieving a carbon-free future. However, for various reasons, EVs have so far struggled to break into the mainstream, accounting for just 2.5% of global auto sales in 2019. 

To understand why, this infographic from Castrol identifies the five critical challenges that EVs will need to overcome. All findings are based on a 2020 survey of 10,000 consumers, fleet managers, and industry specialists across eight significant EV markets. 

The Five Challenges to EV Adoption

Cars have relied on the internal combustion engine (ICE) since the early 1900s, and as a result, the ownership experience of an EV can be much more nuanced. This results in the five critical challenges we examine below. 

Challenge #1: Price

The top challenge is price, with 63% of consumers believing that EVs are beyond their current budget. Though many cheaper EV models are being introduced, ICE vehicles still have the upper hand in terms of initialaffordability. Note the emphasis on “initial”, because over the long term, EVs may actually be cheaper to maintain. 

Taking into account all of the running and maintenance costs of [an EV], we have already reached relative cost parity in terms of ownership.

—President, EV consultancy, U.S.

For starters, an EV drivetrain has significantly fewer moving parts than an ICE equivalent, which could result in lower repair costs. Government subsidies and the cost of electricity are other aspects to consider. 

So what is the tipping price that would convince most consumers to buy an EV? According to Castrol, it differs around the world. 

Country EV Adoption Tipping Price ($)
🇯🇵 Japan $42,864
🇨🇳 China  $41,910
🇩🇪 Germany $38,023
🇳🇴 Norway $36,737
🇺🇸 U.S. $35,765
🇫🇷 France $31,820
🇮🇳 India $30,572
🇬🇧 UK $29,883
Global Average $35,947

Many budget-conscious buyers also rely on the used market, in which EVs have little presence. The rapid speed of innovation is another concern, with 57% of survey respondents citing possible depreciation as a factor that prevented them from buying an EV. 

Challenge #2: Charge Time

Most ICE vehicles can be refueled in a matter of minutes, but there is much more uncertainty when it comes to charging an EV. 

Using a standard home charger, it takes 10-20 hours to charge a typical EV to 80%. Even with an upgraded fast charger (3-22kW power), this could still take up to 4 hours. The good news? Next-gen charging systems capable of fully charging an EV in 20 minutes are slowly becoming available around the world. 

Similar to the EV adoption tipping price, Castrol has also identified a charge time tipping point—the charge time required for mainstream EV adoption. 

Country Charge Time Tipping Point (minutes)
🇮🇳 India 35
🇨🇳 China 34
🇺🇸 U.S. 30
🇬🇧 UK 30
🇳🇴 Norway 29
🇩🇪Germany 29
🇯🇵 Japan 29
🇫🇷 France 27
Global Average 31

If the industry can achieve an average 31 minute charge time, EVs could reach $224 billion in annual revenues across these eight markets alone. 

Challenge #3: Range

Over 70% of consumers rank the total range of an EV as being important to them. However, today’s affordable EV models (below the average tipping price of $35,947) all have ranges that fall under 200 miles. 

Traditional gas-powered vehicles, on the other hand, typically have a range between 310-620 miles. While Tesla offers several models boasting a 300+ mile range, their purchase prices are well above the average tipping price. 

For the majority of consumers to consider an EV, the following range requirements will need to be met by vehicle manufacturers.

Country Range Tipping Point (miles)
🇺🇸 U.S. 321
🇳🇴 Norway 315
🇨🇳 China 300
🇩🇪 Germany 293
🇫🇷 France 289
🇯🇵 Japan 283
🇬🇧 UK 283
🇮🇳 India 249
Global Average 291

Fleet managers, those who oversee vehicles for services such as deliveries, reported a higher average EV tipping range of 341 miles. 

Challenge #4: Charging Infrastructure

Charging infrastructure is the fourth most critical challenge, with 64% of consumers saying they would consider an EV if charging was convenient.

Similar to charge times, there is much uncertainty surrounding infrastructure. For example, 65% of consumers living in urban areas have a charging point within 5 miles of their home, compared to just 26% for those in rural areas. 

Significant investment in public charging infrastructure will be necessary to avoid bottlenecks as more people adopt EVs. China is a leader in this regard, with billions spent on EV infrastructure projects. The result is a network of over one million charging stations, providing 82% of Chinese consumers with convenient access. 

Challenge #5: Vehicle Choice

The least important challenge is increasing the variety of EV models available. This issue is unlikely to persist for long, as industry experts believe 488 unique models will exist by 2025. 

Despite variety being less influential than charge times or range, designing models that appeal to various consumer niches will likely help to accelerate EV adoption. Market research will be required, however, because attitudes towards EVs vary by country.

Country Consumers Who Believe EVs Are More Fashionable Than ICE Vehicles (%)
🇮🇳 India 70%
🇨🇳 China 68%
🇫🇷France 46%
🇩🇪Germany 40%
🇺🇸 UK 40%
🇯🇵 Japan 39%
🇺🇸 U.S. 33%
🇳🇴Norway  31%
Global Average 48%

A majority of Chinese and Indian consumers view EVs more favorably than traditional ICE vehicles. This could be the result of a lower familiarity with cars in general—in 2000, for example, China had just four million cars spread across its population of over one billion. 

EVs are the least alluring in the U.S. and Norway, which coincidentally have the highest GDP per capita among the eight countries surveyed. These consumers may be accustomed to a higher standard of quality as a result of their greater relative wealth. 

So When Do EVs Become Mainstream?

As prices fall and capabilities improve, Castrol predicts a majority of consumers will consider buying an EV by 2024. Global mainstream adoption could take slightly longer, arriving in 2030. 

Caution should be exhibited, as these estimates rely on the five critical challenges being solved in the short-term future. This hinges on a number of factors, including technological change, infrastructure investment, and a shift in consumer attitudes. 

New challenges could also arise further down the road. EVs require a significant amount of minerals such as copper and lithium, and a global increase in production could put strain on the planet’s limited supply.

Spinal carbon nanotube implants restore motor functions


A new study conducted by SISSA and the University of Trieste shows the efficacy of carbon nanotube implants to restore motor functions and paves the way for a new therapeutic approach for spinal cord injuries.
Re-establishing motor skills and neuronal connectivity thanks to the implantation of carbon nanotubes in the injury site. This is the result of a new study conducted by SISSA – Scuola Internazionale Superiore di Studi Avanzati and the University of Trieste that rewards a ten years interdisciplinary collaboration. For the first time, the researchers have used nanomaterial implants in animals with spinal injury, observing the regrowth of nerve fibres and the restoration of motor functions.
The research, published in PNAS (“Functional rewiring across spinal injuries via biomimetic nanofiber scaffolds”), shows the potential of therapeutic approaches that use the mechanical and electric properties of regenerative scaffolds to treat the injured area.
“We have been studying the interaction between neurons and carbon nanotubes for 15 years. Finally, we have been able to challenge their function in vivo”, say Laura Ballerini, neurophysiologist at SISSA, and Maurizio Prato, chemist at the University of Trieste, who have been investigating nerve cell growth when interfaced to smart materials, such as carbon nanotubes in the last decade, using increasingly complex systems. “In recent years, we passed from single neurons to brain tissue explants and from single nanotubes to two-dimensional structures and, now, three dimensional ones.”
“We studied the effect of the carbon nanotube implant in small mammals with a disease model of incomplete spinal cord injury,” explains Sadaf Usmani, PhD in neurobiology and lead author of the study. “We observed their motor recovery during the next six months through standard protocols for locomotor evaluation which revealed a greater recovery of motor skills when compared to non-implanted animals”.
This phenomenon is associated with nerve fibre regrowth through the injury site, as shown by the magnetic resonance experiments carried out in collaboration with the Center for Cooperative Research in Biomaterials (CIC biomaGUNE). A regrowth that is certainly favoured by nanotube implantation, explain Ballerini and Prato.
“Nerve fibre regeneration is promoted by the physical characteristics of nanomaterials. These implants are able to guarantee mechanical support and, at the same time, interact electrically with neurons.”
“The functionality of the regenerated tissue was not taken for granted, just as the biocompatibility of the implants” continue the researchers “And yet, not only there have been no cases of rejection, but electron microscope observations and the use of specific markers have confirmed that there is no real boundary between the tissue surrounding the injury, the regenerated tissue and the nanomaterials.”
These results not only confirm the possible applications of the nanomaterials in the biomedical sector but also pave the way to new therapeutic approaches which use the physical, mechanical and electrical properties in particular, of the injured zone to favour functional recovery.
Source: SISSA

Is This Tesla’s ‘Nano Tech’ Battery of the Future?


With recent announcements and developments, it would seem that Tesla is poised to take the next step in Battery Evolution.

Watch the video below for latest from Tesla and Amprius.

Read More About ‘Silicon Nanowire’ Battery Technology

Silicon Nanowire Technology – The World Needs Better Batteries

Pathways and Challenges for Biomimetic Desalination Membranes with Sub-Nanometer Channels – The Future of Desalination?


The authors acknowledge the support received from the National Science Foundation through the Engineering Research Center for Nanotechnology-Enabled Water Treatment (EEC1449500) and via Grant CBET 1437630. The authors also acknowledge funding from the National Science Foundation Graduate Research Fellowship Program under grant no. DGE-1752134, awarded to C.J.P. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

ABSTRACT

Transmembrane protein channels, including ion channels and aquaporins that are responsible for fast and selective transport of water, have inspired membrane scientists to exploit and mimic their performance in membrane technologies. These biomimetic membranes comprise discrete nanochannels aligned within amphiphilic matrices on a robust support. While biological components have been used directly, extensive work has also been conducted to produce stable synthetic mimics of protein channels and lipid bilayers.

However, the experimental performance of biomimetic membranes remains far below that of biological membranes. In this review, we critically assess the status and potential of biomimetic desalination membranes. We first review channel chemistries and their transport behavior, identifying key characteristics to optimize water permeability and salt rejection.

We compare various channel types within an industrial context, considering transport performance, processability, and stability. Through a re-examination of previous vesicular stopped-flow studies, we demonstrate that incorrect permeability equations result in an overestimation of the water permeability of nanochannels. We find in particular that the most optimized aquaporin-bearing bilayer had a pure water permeability of 2.1 L m–2 h–1 bar–1, which is comparable to that of current state-of-the-art polymeric desalination membranes.

Through a quantitative assessment of biomimetic membrane formats, we analytically show that formats incorporating intact vesicles offer minimal benefit, whereas planar biomimetic selective layers could allow for dramatically improved salt rejections. We then show that the persistence of nanoscale defects explains observed subpar performance. We conclude with a discussion on optimal strategies for minimizing these defects, which could enable breakthrough performance.

Biomimetic Desalination Membranes

As stressors like population growth, industrialization, and climate change threaten to deplete and contaminate our freshwater resources, larger bodies of saline water could provide a vast supply of water for drinking, agricultural, and industrial use.(1) However, desalination of these waters requires more energy and financial resources than traditional freshwater purification methods.(2) Currently, the state-of-the-art technology for desalination is reverse osmosis (RO) using thin-film-composite (TFC) polyamide membranes.(3,4) Fully aromatic TFC-RO membranes are readily produced at industrial scale through interfacial polymerization, whereby a rapid reaction occurs at the interface of immiscible organic and aqueous phases to form a highly cross-linked polyamide selective layer on a porous support(5) (Figure 1). With the advent of the TFC-RO membrane and energy recovery devices, seawater desalination energy requirements for the RO stage have drastically reduced from ∼15 kWh m–3 using the original cellulose acetate membranes of the 1970s down to only ∼2 kWh m–3, only ∼25% above the practical minimum energy.(2)

Figure 1. Transition in desalination research from focusing on dense polymers that reject salt by a solution-diffusion mechanism to considering sub-nanometer channels capable of molecularly sieving ions. In the solution-diffusion panel (left), common reactants for TFC-RO membranes are represented, which rapidly react at an organic–aqueous interface during interfacial polymerization to form a cross-linked, fully aromatic polyamide selective layer with characteristic ridge-valley morphology. Salt rejection determined by a solution-diffusion mechanism results from the higher partitioning and/or diffusion rates of water over ions. In the ion sieving panel (right), common molecular sieves that have been considered for desalination are shown, with ideal water pathways illustrated. In pores similar in size to water, single-file water transport is induced. Nanotubes and nanochannels can be synthetic (e.g., carbon nanotubes) or biological (e.g., aquaporins). To produce nanoporous sheets, sub-nanometer pores where only a few atoms are vacant have been etched in single-layer graphene using chemical oxidation, electron beam irradiation, doping, and ion bombardment.(12) For 2D laminates, the water pathway is through interlayer spaces between sheets. Studies so far have primarily considered graphene oxide nanosheets for 2D laminates.(13,14) The molecular sieving mechanism for ion rejection is by size exclusion, where highly uniform pores exclude larger solutes and ideally transport only molecules similar in size to water.

Reduced Operational Costs, Improved Reliability and Efficiency and Enhanced Product Water Quality

Despite the substantial reduction in energy consumption and overall cost, seawater RO still has room for improvement. While current water permeabilities enable near-optimal performance, increased water-solute selectivity would allow for reduced operational costs, improved reliability and efficiency, and enhanced product water quality.(4) For example, TFC-RO membranes inadequately retain chloride and some small neutral solutes, such as boron in seawater desalination and trace organic contaminants in wastewater reuse, necessitating extra purification steps which increase the cost of desalination.(4)Transport through the polyamide layer is well described by the solution-diffusion model, in which permeants (i.e., water and solutes) partition into the dense polyamide layer and diffuse through it (Figure 1).(6) 

The resultant permselectivity of the membrane is attributed to differences in abilities and rates of species to dissolve into and diffuse through the polyamide membrane material.(7) Although intrinsic water permeability can far exceed salt permeability during solution diffusion, as it does for polyamide, historical data suggest that it will be difficult to significantly advance performance with polymeric systems. Commercial desalination and water purification membranes typically exhibit a permeability–selectivity trade-off, similar to the Robeson plot for polymeric gas separations.(8−11) 

Furthermore, despite many decades of extensive research, no polymeric material has yet surpassed the desalination performance (i.e., water permeability, water-salt selectivity, and cost-effectiveness) of fully aromatic polyamide.

To overcome the limitations of the solution-diffusion-based polyamide membranes, research focus has shifted toward the development of desalination membranes that remove solutes via molecular sieving. In this mechanism of ion rejection, highly uniform, rigid pores that are smaller than the diameter of hydrated salt ions transport water and nearly completely reject ions by size exclusion (Figure 1). Recent formats of molecular sieves considered for desalination include nanotubes and nanochannels, two-dimensional (2D) laminates, and nanoporous sheets (Figure 1).(14) 

However, these top-down efforts have failed so far to achieve adequate salt rejection due to the persistence of defects coupled with the daunting challenges of tuning interlayer spacing or pore size.(12,13,15) 

Biomimetic membranes, or composites comprising an amphiphilic matrix with discrete, aligned nanochannels on a robust support, may provide a platform for industrial-scale molecular sieves that overcome the limitations of solution-diffusion-based polyamide membranes.

After over 3.5 billion years of evolution,(16,17) the cell membranes of modern organisms can perform an array of highly complicated functions, which rely on a system of complex transmembrane proteins aligned within the amphiphilic lipid bilayer. In this system, water and only select ions pass through channel pores and pumps, depending on the energy and nutrient needs of the cell.(18,19) In pioneering work, Preston et al. determined that an integral membrane protein formed a biological channel that selectively transports water in and out of many types of cells. This protein was the CHannel-forming Integral Protein of 28 kDa (CHIP28),(20,21) later called the aquaporin. For these discoveries, Peter Agre and Roderick MacKinnon shared the 2003 Nobel Prize in Chemistry. Through additional biophysical studies, ion channels also showed impressive selectivity, inspiring the design of synthetic ion channels.(22−25) 

Eventually, researchers realized the potential implications of these channels for industrial-scale water purification, especially aquaporin in the use of desalination, and attempted to produce biomimetic membranes, or materials that mimic the structure and performance of biological membranes.(26−35) 

While much of the work has focused on water-solute separations, the biomimetic membrane format also presents opportunities to develop membranes with tunable selectivity based on a chosen channel type.However, translating biological mechanisms into industrial-scale technology necessitates scale-up by orders of magnitude—from the microscopic size of a cell membrane to tens of square meters.(36) For industrial relevance, the synthesis of a biomimetic membrane would need to be cost-effective and simple. Simultaneously, such a membrane would need to be mechanically stable under RO pressures exceeding 70 bar and chemically stable during repeated membrane cleaning and usage.(37) Notably, even at the lab scale, sufficiently high-salt rejection has not yet been achieved for biomimetic desalination membranes after over a decade of research.(37,38) 

Therefore, channels, selective layer formats, synthesis strategies, and support layer types must be carefully considered to attain the capabilities of this technology. While certain aspects of biomimetic desalination membranes have been reviewed recently,(37−42) a critical analysis of their performance and their potential application in water-treatment processes remains necessary.In this critical review, we examine efforts toward biomimetic desalination membranes for water purification in order to identify the best strategies to realize their full potential for both desalination and solute–solute selectivity. We first examine molecular transport, contrasting solution-diffusion with molecular sieving and assessing transport through the mixed matrix of biomimetic selective layers. We next identify the key characteristics of the aquaporin that explain its ultraselectivity and fast water transport, comparing this biological channel to several synthetic channels and placing each in industrial context. Using corrected analysis of reported permeability measurements, we then show that the water permeabilities of many channels have been overestimated. Subsequently, we predict best-case-scenario outcomes for common biomimetic formats, including membranes with intact vesicles and membranes with planar biomimetic layers. For the more promising planar format, the biggest challenge is the presence of nanoscale defects. Through mathematical models, we estimate the defect density for several reported biomimetic membranes. We then discuss synthesis pathways that could limit both the presence of defects and the effect of defects on transport performance.

We conclude with a discussion on the practicality of biomimetic desalination membranes and how to best exploit the strengths of discrete nanochannels as molecular sieves in other applications beyond desalination.

Figure 2. Channel types for biomimetic membranes, including biological as well as bioinspired and bioderived. (a) Single channel water permeability versus pore interior diameter. The pore interior diameter here is defined as the inner diameter of the most constricted region. For PAH[4], the pore diameter shown refers to the average width of dynamic voids that formed in channel clusters.

Channel permeabilities from stopped-flow data and simulations were adjusted to 25 °C and corrected for any previous errors in permeability calculation (see SI, Section S1 for details). (b) (left) Overhead view of AqpZ tetramer and (right) side view of single AqpZ channel with characteristic hourglass shape. (c) GramA dimer as it exists in biological and vesicular environments. In organic solvents, the monomers can intertwine to form a parallel or antiparallel helix. AqpZ and GramA diagrams were drawn using PyMOL(69) with protein sequences from the Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB-PDB, https://www.rcsb.org/), PDB-ID codes 1RC2(70) and 1NRM.(71) (d) Dependence of water diffusivity through pores on the number of interior hydrogen-bond points.

Data extracted from ref (56). (e) Cyclic peptide nanotubes. (left) Hydrogen-bonding pattern of pore-forming, stacked cyclic peptides. A polyglycine structure is shown for simplicity; side residues would typically be present. (right) Modified cyclic peptide with interior peptide-mimicking functional groups. The analogous unmodified cyclic peptide is radially symmetrical with a fourth primary amine side chain (cyclo[(d-Ala-Lys)4]).(72) (f) Single-walled carbon nanotube porins (wide and narrow) with armchair pattern. Number of carbons approximate those of wCNTP and nCNTP. (g) (left) PAP[5] and (right) PAH[4] nanochannels with peptide appendages that form interarm hydrogen bonds. (h) (left) Aquafoldamer subunits with “sticky” ends. Differences in end groups that comprise Aqf1 and Aqf2 subunits are illustrated. (right) Weak hydrogen-bonding pattern of pore-forming, stacked aquafoldamers. Six subunits are needed to cross a DOPC membrane. (i) Pure water permeability versus total channel areal coverage in a DOPC bilayer. Single channel permeabilities from (a) were divided by channel cross-sectional area and converted into channel water permeability (A) coefficients using eq 3. Overall biomimetic layer A coefficients were calculated for various densities of channels within a DOPC bilayer using eq 7. DOPC bilayer hydraulic permeability was taken as 0.15 L m–2 h–1 bar–1.(73) The shaded region indicates the water permeability of current commercial TFC-RO membranes, an adequate range for desalination performance. Permeabilities are listed in Table S1.

** Read the Complete Paper and Conclusions from AZ Nano by Following the Link Below

https://pubs.acs.org/doi/10.1021/acsnano.0c05753#

Authors

  • Cassandra J. Porter: Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 
  • Jay R. Werber: Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut and Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 
  • Mingjiang Zhong: Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 
  • Corey J. Wilson: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
  • Menachem Elimelech: Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 

“Great Things from Small Things” Top 50 Nanotech Blog – Our Top Posts This Week


Happy Holiday (Labor Day) Weekend Everyone! Here are our Top Posts from this past week … Just in case you missed them! We hope all of you are well and safe and continuing to ‘get back to normal’ as the COVID-19 Pandemic of 2020 continues to restrain all of us in one way or another.

Thankfully however, COVID-19 has NOT restricted the Forward Advance of Innovation and Technology Solutions from the small worlds of Nanotechnology – “Great Things from Small Things” – Read and Enjoy and wonderful Holiday Weekend!Team GNT

Carbon Nanotube Second Skin Protects First Responders and Warfighters against Chem, Bio Agents – Lawrence Livermore National Laboratory

The same materials (adsorbents or barrier layers) that provide protection in current garments also detrimentally inhibit breathability.

Recent events such as the COVID-19 pandemic and the use of chemical weapons in the Syria conflict have provided a stark reminder of the plethora of chemical and biological threats that soldiers, medical personnel and first responders face during routine and emergency operations. Researchers have developed a smart, breathable fabric designed to protect the wearer against biological and chemical warfare agents. Material of this type could be used in clinical and medical settings as well.

Recent events such as the COVID-19 pandemic and the use of chemical weapons in the Syria conflict have provided a stark reminder of the plethora of chemical and biological threats that soldiers, medical personnel and first responders face during routine and emergency operations.

Read More … https://genesisnanotech.wordpress.com/2020/05/11/carbon-nanotube-second-skin-protects-first-responders-and-warfighters-against-chem-bio-agents-lawrence-livermore-national-laboratory/

MIT: Lighting the Way to Better Battery Technology

Supratim Das is determined to demystify lithium-ion batteries, by first understanding their flaws.  Photo: Lillie Paquette/School of Engineering

Doctoral candidate Supratim Das wants the world to know how to make longer-lasting batteries that charge mobile phones and electric cars.

Supratim Das’s quest for the perfect battery began in the dark. Growing up in Kolkata, India, Das saw that a ready supply of electric power was a luxury his family didn’t have. “I wanted to do something about it,” Das says. Now a fourth-year PhD candidate in MIT chemical engineering who’s months away from defending his thesis, he’s been investigating what causes the batteries that power the world’s mobile phones and electric cars to deteriorate over time.

Lithium-ion batteries, so-named for the movement of lithium ions that make them work, power most rechargeable devices today. The element lithium has properties that allow lithium-ion batteries to be both portable and powerful; the 2019 Nobel Prize in Chemistry was awarded to scientists who helped develop them in the late 1970s. But despite their widespread use, lithium-ion batteries, essentially a black box during operation, harbor mysteries that prevent scientists from unlocking their full potential. Das is determined to demystify them, by first understanding their flaws.

Read More … https://genesisnanotech.wordpress.com/2020/07/06/mit-lighting-the-way-to-better-battery-technology/

Nuclear Diamond Batteries could disrupt Energy/ Energy Storage as we know it … “Imagine a World where you wouldn’t need to charge your battery for …. Decades!”

Illustration of the NDB Battery in a Most Recognizable ‘18650’ Format

They will blow any energy density comparison out of the water, lasting anywhere from a decade to 28,000 years without ever needing a charge.”

“They will offer higher power density than lithium-ion. They will be nigh-on indestructible and totally safe in an electric car crash.”

And in some applications, like electric cars, they stand to be considerably cheaper than current lithium-ion packs despite their huge advantages.

In the words of Dr. John Shawe-Taylor, UNESCO Chair and University College London Professor: “NDB has the potential to solve the major global issue of carbon emissions in one stroke without the expensive infrastructure projects, energy transportation costs, or negative environmental impacts associated with alternate solutions such as carbon capture at fossil fuel power stations, hydroelectric plants, turbines, or nuclear power stations.

Read More … https://genesisnanotech.wordpress.com/2020/08/25/nano-diamond-self-charging-batteries-could-disrupt-energy-as-we-know-it-imagine-a-world-where-you-wouldnt-need-to-charge-your-battery-for-decades/

“Practical and Viable” Hydrogen Production from Solar – Long Sought Goal of Renewable Energy – Is Close … Oh So Close

Technology developed at the Technion: the oxygen and hydrogen are produced and stored in completely separate cells.

Technion Israel Institute of Technology

Israeli and Italian scientists have developed a renewable energy technology that converts solar energy to hydrogen fuel — and it’s reportedly at the threshold of “practical” viability.The new solar tech would offer a sustainable way to turn water and sunlight into storable energy for fuel cells, whether that stored power feeds into the electrical grid or goes to fuel-cell powered trucks, trains, cars, ships, planes or industrial processes.Think of this research as a sort of artificial photosynthesis, said Lilac Amirav, associate professor of chemistry at the Technion — Israel Institute of Technology in Haifa. (If it could be scaled up, the technology could eventually be the basis of “solar factories” in which arrays of solar collectors split water into stores of hydrogen fuel——as well as, for reasons discussed below, one or more other industrial chemicals.)Read More … https://genesisnanotech.wordpress.com/2020/09/02/practical-and-viable-hydrogen-production-from-solar-long-sought-goal-of-renewable-energy-is-close-oh-so-close/

Watch More … The EV ‘Revolution and Evolution’ … Will the Era of the ICE be over in 2025? 2030?

Tony Seba, Silicon Valley entrepreneur, Author and Thought Leader, Lecturer at Stanford University, Keynote The reinvention and connection between infrastructure and mobility will fundamentally disrupt the clean transport model. It will change the way governments and consumers think about mobility, how power is delivered and consumed and the payment models for usage.

“Practical and Viable” Hydrogen Production from Solar – Long Sought Goal of Renewable Energy – Is Close … Oh So Close


Technion Israel Institute of Technology

Israeli and Italian scientists have developed a renewable energy technology that converts solar energy to hydrogen fuel — and it’s reportedly at the threshold of “practical” viability.

The new solar tech would offer a sustainable way to turn water and sunlight into storable energy for fuel cells, whether that stored power feeds into the electrical grid or goes to fuel-cell powered trucks, trains, cars, ships, planes or industrial processes.

Think of this research as a sort of artificial photosynthesis, said Lilac Amirav, associate professor of chemistry at the Technion — Israel Institute of Technology in Haifa. (If it could be scaled up, the technology could eventually be the basis of “solar factories” in which arrays of solar collectors split water into stores of hydrogen fuel——as well as, for reasons discussed below, one or more other industrial chemicals.)

“We [start with] a semiconductor that’s very similar to what we have in solar panels,” says Amirav. But rather than taking the photovoltaic route of using sunlight to liberate a current of electrons, the reaction they’re studying harnesses sunlight to efficiently and cost-effectively peel off hydrogen from water molecules.

The big hurdle to date has been that hydrogen and oxygen just as readily recombine once they’re split apart—that is, unless a catalyst can be introduced to the reaction that shunts water’s two component elements away from one another.

Enter the rod-shaped nanoparticles Amirav and co-researchers have developed. The wand-like rods (50-60 nanometers long and just 4.5 nm in diameter) are all tipped with platinum spheres 2–3 nm in diameter, like nano-size marbles fastened onto the ends of drinking straws.

Since 2010, when the team first began publishing papers about such specially tuned nanorods, they’ve been tweaking the design to maximize its ability to extract as much hydrogen and excess energy as possible from “solar-to-chemical energy conversion.”

Which brings us back to those “other” industrial chemicals. Because creating molecular hydrogen out of water also yields oxygen, they realized they had to figure out what to do with that byproduct.

“When you’re thinking about artificial photosynthesis, you care about hydrogen—because hydrogen’s a fuel,” says Amirav. “Oxygen is not such an interesting product. But that is the bottleneck of the process.”

There’s no getting around the fact that oxygen liberated from split water molecules carries energy away from the reaction, too. So, unless it’s harnessed, it ultimately represents just wasted solar energy—which means lost efficiency in the overall reaction.

Technology developed at the Technion: the oxygen and hydrogen are produced and stored in completely separate cells.

Prof. Avner Rothschild from the Faculty of Materials Science and Engineering

Read More About “Hydrogen on Demand Technology” from Technion

So, the researchers added another reaction to the process. Not only does their platinum-tipped nanorod catalyst use solar energy to turn water into hydrogen, it also uses the liberated oxygen to convert the organic molecule benzylamine into the industrial chemical benzaldehyde (commonly used in dyes, flavoring extracts, and perfumes).

All told, the nanorods convert 4.2 percent of the energy of incoming sunlight into chemical bonds. Considering the energy in the hydrogen fuel alone, they convert 3.6 percent of sunlight energy into stored fuel.

These might seem like minuscule figures. But 3.6 percent is still considerably better than the 1-2 percent range that previous technologies had achieved.

And according to the U.S. Department of Energy, 5-10 percent efficiency is all that’s needed to reach what the researchers call the “practical feasibility threshold” for solar hydrogen generation.

Between February and August of this year, Amirav and her colleagues published about the above innovations in the journals NanoEnergy and Chemistry Europe. They also recently presented their research at the fall virtual meeting of the American Chemical Society.

In their presentation, which hinted at future directions for their work, they teased further efficiency improvements courtesy of new new work with AI data mining experts.

“We are looking for alternative organic transformations,” says Amirav. This way, she and her collaborators hope, their solar factories can produce hydrogen fuel plus an array of other useful industrial byproducts.

In the future, their artificial photosynthesis process could yield low-emission energy, plus some beneficial chemical extracts as a “practical” and “feasible” side-effect.

Nuclear Diamond Batteries could disrupt Energy/ Energy Storage as we know it … “Imagine a World where you wouldn’t need to charge your battery for …. Decades!”


Nano-Diamond-Self-Charging-Battery-FB
Illustration of the NDB Battery in a Most Recognizable ‘18650’ Format

They will blow any energy density comparison out of the water, lasting anywhere from a decade to 28,000 years without ever needing a charge.”

“They will offer higher power density than lithium-ion. They will be nigh-on indestructible and totally safe in an electric car crash.”

And in some applications, like electric cars, they stand to be considerably cheaper than current lithium-ion packs despite their huge advantages.

In the words of Dr. John Shawe-Taylor, UNESCO Chair and University College London Professor: “NDB has the potential to solve the major global issue of carbon emissions in one stroke without the expensive infrastructure projects, energy transportation costs, or negative environmental impacts associated with alternate solutions such as carbon capture at fossil fuel power stations, hydroelectric plants, turbines, or nuclear power stations.

 

So What is NDB’s Story and How Do They Work?

The heart of each cell is a small piece of recycled nuclear waste. NDB (nuclear diamond battery) uses graphite nuclear reactor parts that have absorbed radiation from nuclear fuel rods and have themselves become radioactive.

Untreated, it’s high-grade nuclear waste: dangerous, difficult and expensive to store, with a very long half-life.

This graphite is rich in the carbon-14 radioisotope, which undergoes beta decay into nitrogen, releasing an anti-neutrino and a beta decay electron in the process. NDB takes this graphite, purifies it and uses it to create tiny carbon-14 diamonds.

nuclear-waste-diamond-batteries-768x403

The diamond structure acts as a semiconductor and heat sink, collecting the charge and transporting it out. Completely encasing the radioactive carbon-14 diamond is a layer of cheap, non-radioactive, lab-created carbon-12 diamond, which contains the energetic particles, prevents radiation leaks and acts as a super-hard protective and tamper-proof layer.

To create a battery cell, several layers of this nano-diamond material are stacked up and stored with a tiny integrated circuit board and a small supercapacitor to collect, store and instantly distribute the charge. NDB says it’ll conform to any shape or standard, including AA, AAA, 18650, 2170 or all manner of custom sizes.

And so what you get is a tiny miniature power generator in the shape of a battery that never needs charging – and that NDB says will be cost-competitive with, and sometimes significantly less expensive than – current lithium batteries. That equation is helped along by the fact that some of the suppliers of the original nuclear waste will pay NDB to take it off their hands. 

img_1875

Shown here as a small, circuit board mounted design, the nano diamond battery has the potential to totally upend the energy equation since it never needs charging and lasts many, many years

Radiation levels from a cell, NDB tells us, will be less than the radiation levels produced by the human body itself, making it totally safe for use in a variety of applications. At the small scale, these could include things like pacemaker batteries and other electronic implants, where their long lifespan will save the wearer from replacement surgeries. They could also be placed directly onto circuit boards, delivering power for the lifespan of a device.

In a consumer electronics application, NDB’s Neel Naicker gives us an example of just how different these devices would be: “Think of it in an iPhone. With the same size battery, it would charge your battery from zero to full, five times an hour. Imagine that.

Imagine a world where you wouldn’t have to charge your battery at all for the day. Now imagine for the week, for the month… How about for decades? That’s what we’re able to do with this technology.”

And it can scale up to electric vehicle sizes and beyond, offering superb power density in a battery pack that is projected to last as long as 90 years in that application – something that could be pulled out of your old car and put into a new one. If part of a cell fails, the active nano diamond part can be recycled into another cell, and once they reach the end of their lifespan – which could be up to 28,000 years for a low-powered sensor that might, for example, be used on a satellite – they leave nothing but “harmless byproducts.”

In the words of Dr. John Shawe-Taylor, UNESCO Chair and University College London Professor: “NDB has the potential to solve the major global issue of carbon emissions in one stroke without the expensive infrastructure projects, energy transportation costs, or negative environmental impacts associated with alternate solutions such as carbon capture at fossil fuel power stations, hydroelectric plants, turbines, or nuclear power stations.

Their technology’s ability to deliver energy over very long periods of time without the need for recharging, refueling, or servicing puts them in an ideal position to tackle the world’s energy requirements through a distributed solution with close to zero environmental impact and energy transportation costs.”

Indeed, the NDB battery offers an outstanding 24-hour energy proposition for off-grid living, and the NDB team is adamant that it wishes to devote a percentage of its time to providing it to needy remote communities as a charity service with the support of some of the company’s business customers.

Should the company chew right through the world’s full supply of carbon-14 nuclear waste – a prospect that would take some extremely serious volume – NDB says it can create its own carbon-14 raw material simply and cost-effectively.

The company has completed a proof of concept, and is ready to begin building its commercial prototype once its labs reopen after COVID shutdown. A low-powered commercial version is expected to hit the market in less than two years, and the high powered version is projected for five years’ time. NDB says it’s well ahead of its competition with patents pending on its technology and manufacturing processes. 

Should this pan out as promised, it’s hard to see how this won’t be a revolutionary power source. Such a long-life battery will fundamentally challenge the disposable ethos of many modern technologies, or lead to battery packs that consumers carry with them from phone to phone, car to car, laptop to laptop across decades. NDB-equipped homes can be grid-connected or not. Each battery is its own near-inexhaustible green energy source, quietly turning nuclear waste into useful energy. 

Sounds like remarkable news to us!

We spoke with several members of the NDB executive team. Check out the full edited transcript of that interview for more information, or watch the cartoon video below.

Nano Diamond Battery Explainer Video – NDB

Source: NDB

Want to Know More? Listen to Professor Simon Holland Explain Pros and Cons

Fuel cells for hydrogen vehicles are lasting longer and longer and … Promising Research from the University of Copenhagen


The new electrocatalyst for hydrogen fuel cells consists of a thin platinum-cobalt alloy network and, unlike the catalysts commonly used today, does not require a carbon carrier. Credit: Gustav Sievers

Roughly 1 billion cars and trucks zoom about the world’s roadways. Only a few run on hydrogen.

This could change after a breakthrough achieved by researchers at the University of Copenhagen.

The breakthrough? A new catalyst that can be used to produce cheaper and far more sustainable hydrogen powered vehicles.

Hydrogen vehicles are a rare sight. This is partly because they rely on a large amount of platinum to serve as a catalyst in their fuel cells—about 50 grams. Typically, vehicles only need about five grams of this rare and precious material. Indeed, only 100 tons of platinum are mined annually, in South Africa.

Now, researchers at the University of Copenhagen’s Department of Chemistry have developed a catalyst that doesn’t require such a large quantity of platinum.

“We have developed a catalyst which, in the laboratory, only needs a fraction of the amount of platinum that current  fuel cells for cars do. We are approaching the same amount of platinum as needed for a conventional .

At the same time, the new catalyst is much more stable than the catalysts deployed in today’s hydrogen powered vehicles,” explains Professor Matthias Arenz from the Department of Chemistry.

A paradigm shift for hydrogen vehicles

Sustainable technologies are often challenged by the limited availability of the rare materials that make them possible, which in turn, limits scalability.

Due to this current limitation, it is impossible to simply replace the world’s vehicles with hydrogen models overnight. As such, the new technology a game-changer.

“The new catalyst can make it possible to roll out hydrogen vehicles on a vastly greater scale than could have ever been achieved in the past,” states Professor Jan Rossmeisl, center leader of the Center for High Entropy Alloy Catalysis at UCPH’s Department of Chemistry.

The new catalyst improves fuel cells significantly, by making it possible to produce more horsepower per gram of platinum. This in turn, makes the production of hydrogen  vehicles more sustainable.

More durable, less platinum

Because only the surface of a catalyst is active, as many platinum atoms as possible are needed to coat it. A catalyst must also be durable. Herein lies the conflict.

To gain as much surface area as possible, today’s catalysts are based on -nano-particles which are coated over carbon. Unfortunately, carbon makes catalysts unstable. The new catalyst is distinguished by being carbon-free.

Instead of nano-particles, the researchers have developed a network of nanowires characterized an abundance of surface area and high durability.

“With this breakthrough, the notion of hydrogen vehicles becoming commonplace has become more realistic. It allows them to become cheaper, more sustainable and more durable,” says Jan Rossmeisl.

Dialogue with the automotive industry

The next step for the researchers is to scale up their results so that the technology can be implemented in hydrogen vehicles.

“We are in talks with the  about how this breakthrough can be rolled out in practice. So, things look quite promising,” says Professor Matthias Arenz.

The research results have just been published in Nature Materials, one of the leading scientific journals for materials research. It is the first article in which every researcher at the basic research center, “Center for High Entropy Alloy Catalysis (CHEAC)”, has collaborated.

The center is a so-called Center of Excellence, supported by the Danish National Research Foundation.

“At the center, we develop new materials to create sustainable chemicals and fuels that help society make the chemical industry greener. That it is now possible to scale up the production of hydrogen vehicles, and in a sustainable way, is a major step forward,” says center leader Jan Rossmeisl.