Nanoscience & Nanotechnology Letters by Abu Faisal Hasan

Space debris and space waste management

"From year 1957, 70% of launched satellites are now debris and getting a better view on the problem through space debris tracking and reporting is just the first step in resolving the space debris problem..."

‘Nanomagnetic’ computing can provide low-energy AI'

It is possible to perform artificial intelligence using tiny nanomagnets that interact like neurons in the brain.

It could slash the energy cost of artificial intelligence (AI), which is currently doubling globally every 3.5 months.

"How the magnets interact gives us all the information we need; the laws of physics themselves become the computer."

Nanotech in Space

Samples of novel nanocomposite materials, seen above, mounted to the hull of the space station, and tested to see how they weather the perils of space.

Solid State Physics

A CdSe nano forest using templated assisted electro chemical deposition (Each wire is approx. 200nm is diameter)

Nanochemistry and Solid-state chemistry

Safety Concerns with Nanotechnology in Medicine

Toxicity of Nanomaterials:
Nanoparticles can behave very differently from their bulk counterparts. Their small size and large surface area can increase their reactivity and potentially cause harmful interactions with human cells. This could lead to toxicity, inflammatory responses, or other adverse effects.
Example: Some nanomaterials, like certain metals (e.g., silver nanoparticles), can generate reactive oxygen species (ROS) that may damage cells, tissues, or DNA.

Long-Term Health Effects:
The long-term effects of exposure to nanomaterials are still not fully understood. Since nanoparticles can easily enter cells and tissues, there is concern that they might accumulate over time in vital organs such as the liver, kidneys, or brain, potentially leading to chronic toxicity or even carcinogenesis.
Example: In animal studies, the accumulation of certain nanoparticles in the liver has been observed, raising concerns about potential long-term organ damage.

Environmental Impact:
Aside from direct health concerns, there are questions about the environmental impact of nanomaterials. The production, use, and disposal of nanoparticles could lead to contamination, with nanoparticles potentially entering ecosystems and affecting wildlife.
Example: Nanoparticles used in drug delivery systems or medical imaging might accumulate in water supplies if not properly disposed of, posing potential risks to aquatic life.

Bioaccumulation:
Given their small size, nanoparticles can travel through biological barriers (such as the blood-brain barrier), but they may also accumulate in unintended areas, potentially causing adverse effects on healthy tissues.
Example: Nanoparticles intended for targeted drug delivery may inadvertently accumulate in non-target organs or tissues, causing toxicity or unwanted side effects

Filtration/separation by Nanofilters Another approach for air pollution control is nanostructured membranes that have pores small enough to separate different pollutants from exhaust. Research focuses on the improvement and optimization of nano-structured membranes to capture several gas polluants. Nanofibre-coated filter media are used for air filtration (e.g. dust removal) at industrial plants and for filtration of the inlet air for gas turbines ). In particulate, filteration by nano-structured membranes is suitable for several VOCs vapors.For example, formaldehyde (HCHO) imposes great challenges for its removal. Traditional photochemical techniques utilizing photocatalysts are not appropriate for the indoor HCHO removal due to the necessity of UV light illuminations and the danger of destructive ozone liberation. Hence, the removal of formaldehyde has been improved through many techniques, for example, electrospun polyacrylonitrile (PAN)- based carbon nanofiber (CNF) membrane with high microporosity and abundant nitrogen-containing functional groups as effective adsorption sites was produced. A reasonable quantity of formaldehyde even at a low concentration was adsorbed onto the PAN-activated carbon nanofiber (ACNF). An additional example in indoor air pollutants is bioaerosols (aerosols of biological origin such as viruses, bacteria, and fungi), they can rapidly grow and provoke several diseases, such as allergies and infections. Silver nanoparticles and copper nanoparticles filters are widely used in the air filtration technology as antimicrobial materials to remove bioaerosols through air conditional processes. In this, many studies have cited that silver nanoparticles could successfully eliminate bacterial bioaerosols. One of the most environmental challenges is the removing of particulate matter (PM) which causes serious harm to public health. Metal−organic frameworks (M*Fs) are crystalline materials with high porosity, tunable pore size, and rich functionalities, holding the promise for contaminant capture. Here, nanocrystals of four unique M*F structures are processed into nanofibrous filters. The M*Filters show high removal efficiencies for PM2.5 and PM10. These M*Filters can also be effective and selective to adsorb toxic gases such as SO2 when exposed in a stream of SO2/N2 mixture.



Nanotechnology for Air Pollution Prevention Prevention of air pollution refers to a reduction in pollution sources and other practices that utilize raw materials, energy, utilities and other resources effectively in order to reduce or eliminate waste generation. Nanotechnology offers many innovative strategies to reduce waste production in various processes such as improving manufacturing processes, reducing hazardous chemicals, reducing greenhouse gas emissions and reducing the use of synthetic plastics. The application of nanotechnology is able to create an environmentally friendly substance or material, replacing widely used toxic materials. The advantage of this technology is the increased efficiency, reduced system costs and whole replacement, as well as reduced environmental impact. Examples of environmentally friendly materials that can be produced using nanotechnology are biodegradable plastics have specific structure for degradation, non-toxic-nanocrystalline composite materials to substitute the electrodes of lithium-graphite in rechargeable batteries, and new types of nanomaterials having better performance and less toxicity instead of traditional materials. As an example, carbon nanotubes can provide better functionality than the conventional cathode tubes that contain many toxic metals. Other example of environmentally friendly substance is self-cleaning glasses, for example, Activ Glass, market product from Pilkington. The glass has an extraordinary covering made of TiO2 nanocrystals which, when exposed to sunlight, interacts in two pathways: the first one is the degradation of any organic pollutants deposited on the glass, The second way, under rain, water droplets form a sheet, then the pollutants on the surface are picked up by water and wash off the glass

Cell-selective nanotherapy prevents vessel renarrowing and promotes healing of arteries opened by angioplasty

The nanotherapy comprised of a nontoxic peptide known as p5RHH and a synthetic messenger RNA (mRNA) that carries the genetic instructions, or code, needed by cells to make proteins. By simply mixing up the p5RHH with the mRNA, they spontaneously self assemble into compacted nanoparticles that specifically target the injured regions of the arteries in mouse models mimicking angioplasty. The nanoparticles contain an microRNA switch added to the mRNA.

“One of the main challenges of cardiovascular disease remains the delivery of targeted therapies specifically to the plaque regions and the cells that form plaques, including the smooth muscle cells and inflammatory cells — without affecting the endothelial cells or the healthy regions,”

With the help of mRNA that encodes for p27 protein, which blocks cell growth, and added to the mRNA an endothelial cell-specific microRNA to generate a microRNA switch. The design of this microRNA switch allowed the researchers to turn on the mRNA in smooth muscle cells to inhibit their growth and the formation of restenosis. It also enabled them to turn off the mRNA in endothelial cells so these cells could grow uninhibited and quickly heal the damaged blood vessel.

A microRNA-based therapy worked better than drug-eluting stents in a rat model of angioplasty. That work used an adenovirus vector to carry the cell-selective therapy to injured arteries. For that the viral vector was replaced with a nanoparticle alternative – a change needed to avoid safety concerns and advance the therapy toward use in patients.

The investigational nanoparticles were injected into mice with arteries mimicking post-angioplasty vessel injury every three days for two weeks (5 doses total). Mice treated with the nanoparticles containing the miRNA switch had significantly reduced restenosis and completely restored endothelial cell growth in the injured artery, compared to animals treated with nanoparticles containing mRNA without the miRNA switch.

Overall, the findings suggest that the miRNA-switch nanoparticles could be applied clinically to selectively prevent restenosis after PCI by specifically targeting areas of endothelial cell damage to allow quicker cell regrowth and repair of injured arteries.

Nanotoxicology: From Past Lights and Shadows to Current Concerns

The term nanotoxicology has only gained interest from the last two decades onwards . Since that time, many advances have been made in this area. Two important factors led to a rapid progress in this branch of science . Firstly, “the large-scale production of diversified nanomaterials and remarkable progress in the development of new types of nanomaterials with disconcerting physical and chemical characteristics” . Second, many studies based on constantly improving NMs have stimulated research in Physics, Chemistry, and Bioengineering, leading to new interdisciplinary progress in Nanoscience and its applications. For example, there has been huge progress in the bioapplication of Nanomaterials(NMs)

Nanomedicine and nanotoxicology are strictly linked, since both can explore the same mechanisms and affect identical metabolic pathways . Bearing in mind that newly NMs can exhibit specific toxicity, it is necessary to summarize and reassess the data accumulated from time to time, thereby ensuring safety . The development of current nanotoxicology studies is surprising, mainly in the biological area . For example, the biosynthesis of insecticidal nanoparticles mediated by plants and other botanical products is constantly developed .

Nanotoxicology has become a subdiscipline at the interface of toxicology and NMs . Due to their extremely small size and large surface area to volume ratio, NMs have different properties compared to their larger equivalents that may enable unpredictable interactions with cells and tissues. Nanotoxicology tends to highlight the possible toxic interactions between NMs and different biological systems (cells, tissues, and living organisms). Several years of research have showed that the interactions of NMs with the environment and with cells of living organisms are highly complex . However, it has not been revealed how the properties (both physicochemical and morphological) of NMs can influence these interactions .

The morphological and physicochemical properties of NMs have a great impact on the interaction with biological cells and may influence their toxicity. Nanotoxicology is responsible for the analysis of the toxic effects of NMs, especially since the materials’ size plays a significant role in the toxicity of NMs . The concept of nanotoxicology is based on different parameters, such as the size, surface area, morphology, composition, surface chemistry, agglomeration/aggregation phenomena, etc. In fact, all of these parameters have a critical impact on the determination of the nanoparticles’ dose and consequently, the precise assessment of their toxicity. However, determining the maximum exposure values of toxic NMs would be impossible without in vitro and in vivo tests. Many strategies to study the nanotoxicology and the interaction of NMs with biological systems are already in place . Initial studies on the toxicity of NMs were carried out in the last decade of the 20th century, already revealing that materials of a micrometric scale did not present toxicity, while materials at a nanometric scale might have some toxic effect .

Toxicity Tests
Toxicity tests can be performed on cell cultures (in vitro) and in living organisms (in vivo) such as fish, mice, or rats. There are several standardized toxicological tests that are available to assess the biological response of a chemical substance. However, there is no standardization for the assessment of nanoparticles toxicity. It causes many difficulties in the comparison of the results regarding the toxicity of the tested ingredients. Most of the toxicity tests for NMs have been performed in vitro, using cultures of mammalian cells that were extracted from the most different parts of the body (e.g.,: brain, lungs, heart, skin and liver). Although in vitro tests are less expensive than in vivo and the results may be obtained in a shorter time, it is not possible to infer potential implications related with the human health based on the in vitro only .
Since continental and marine waters would be the main receiving compartment, in vivo tests were mainly carried out in aquatic organisms that would reflect the impact of nanomaterials on the environment. During the contact with animals, the variation of the NMs concentration allows to calculate statistically the indicators that will allow the comparison of toxicity between different nanomaterials and/or between nanomaterials and traditional chemical substances. The most used evaluation parameters are the LC50 (i.e., concentration of nanomaterial that causes the death of 50% of the population, LOEC (i.e., low concentration that causes a noticeable effect on the organism), and NOEC (i.e., maximum concentration, at which no effect is observed on the organisms). Moreover, experimental animal trials have advantages, with one of the important ones being the assessment of the kinetics of nanoparticles through absorption, distribution, metabolism, and excretion (ADME).

"Retina cell breakthrough could help treat blindness
by harness nanotechnology to help tackle a common cause of sight loss...,

Nanotechnology to create a 3D ‘scaffold’ to grow cells from the retina –paving the way for potential new ways of treating a common cause of blindness.

By successfully grow retinal pigment epithelial (RPE) cells that stay healthy and viable for up to 150 days. RPE cells sit just outside the neural part of the retina and, when damaged, can cause vision to deteriorate.

It is the first time this technology, called ‘electrospinning’, has been used to create a scaffold on which the RPE cells could grow, and could revolutionise treatment for one of age-related macular degeneration, one of the world’s most common vision complaints.

When the scaffold is treated with a steroid called fluocinolone acetonide, which protects against inflammation, the resilience of the cells appears to increase, promoting growth of eye cells. These findings are important in the future development of ocular tissue for transplantation into the patient’s eye.

Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world and is expected to increase in the coming years due to an ageing population

AMD can be caused by changes in the Bruch’s membrane, which supports the RPE cells, and breakdown of the choriocapillaris, the rich vascular bed that is adjacent to the other side of the Bruch’s membrane.

The most common way sight deteriorates is due to an accumulation of lipid deposits called drusen, and the subsequent degeneration of parts of the RPE, the choriocapillaris and outer retina. In the developing world, AMD tends to be caused by abnormal blood vessel growth in the choroid and their subsequent movement into the RPE cells, leading to haemorrhaging, RPE or retinal detachment and scar formation.

The replacement of the RPE cells is among several promising therapeutic options for effective treatment of sight conditions like AMD, and researchers have been working on efficient ways to transplant these cells into the eye.

How the Physicochemical Properties of Manufactured Nanomaterials Affect Their Performance in Dispersion and Their Applications in Biomedicine

Example -

Dispersibility of Carbon Nanomaterials

More so than the dispersion of inorganic, metallic, or metal oxide nanoparticles, the prevention of aggregation in carbon nanomaterials is of utmost importance, since their agglomeration may hinder the realization of their excellent properties. Enhanced dispersion and stabilization of carbon nanomaterials (CNMs), such as graphene oxide, graphene, carbon nanotubes, and fullerenes, especially in water, is a critical challenge, because of their tendency to aggregate, particularly in aqueous systems, due to significant van der Waals attractions and their specific hydrophobic interactions. It is both the physicochemical properties of the carbon nanomaterials and the properties of the dispersion medium that influence the dispersion stability, which is further enhanced in aqueous media with NOM, due to the enhanced interactions assisted by the CNMs hydrophobic surfaces. Both single- and multi-wall carbon nanotubes (SWCNTs and MWCNTs) were found to disperse better in media with NOM than in natural water ); nevertheless, functionalization of the MWCNTs Dispersibility of Carbon Nanomaterials

More so than the dispersion of inorganic, metallic, or metal oxide nanoparticles, the prevention of aggregation in carbon nanomaterials is of utmost importance, since their agglomeration may hinder the realization of their excellent properties. Enhanced dispersion and stabilization of carbon nanomaterials (CNMs), such as graphene oxide, graphene, carbon nanotubes, and fullerenes, especially in water, is a critical challenge, because of their tendency to aggregate, particularly in aqueous systems, due to significant van der Waals attractions and their specific hydrophobic interactions. It is both the physicochemical properties of the carbon nanomaterials and the properties of the dispersion medium that influence the dispersion stability, which is further enhanced in aqueous media with NOM, due to the enhanced interactions assisted by the CNMs hydrophobic surfaces. Both single- and multi-wall carbon nanotubes (SWCNTs and MWCNTs) were found to disperse better in media with NOM than in natural water, nevertheless, functionalization of the MWCNTs can improve the dispersion and lead to differences among the different media. The presence of proteins, lipids, or protein/lipid components is crucial for the dispersion of carbon nanomaterials such as fullerenes and single- and multi-wall carbon nanotubes in various media as well whereas vehicles lacking lipids or proteins lead to the formation of the largest agglomerates.can improve the dispersion and lead to differences among the different media. The presence of proteins, lipids, or protein/lipid components is crucial for the dispersion of carbon nanomaterials such as fullerenes and single- and multi-wall carbon nanotubes in various media as well, whereas vehicles lacking lipids or proteins lead to the formation of the largest agglomerates.