Nano Materials

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Nano Materials

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A titanium oxide nanowire-based air filter can trap and destroy pathogens

8/7/20

https://www.news-medical.net/news/20200 ... ogens.aspx


Filter “paper” made from titanium oxide nanowires is capable of trapping pathogens and destroying them with light. This discovery by an EPFL laboratory could be put to use in personal protective equipment, as well as in ventilation and air conditioning systems.

As part of attempts to curtail the Covid-19 pandemic, paper masks are increasingly being made mandatory. Their relative effectiveness is no longer in question, but their widespread use has a number of drawbacks. These include the environmental impact of disposable masks made from layers of non-woven polypropylene plastic microfibres. Moreover, they merely trap pathogens instead of destroying them. "In a hospital setting, these masks are placed in special bins and handled appropriately," says László Forró, head of EPFL's Laboratory of Physics of Complex Matter. "However, their use in the wider world - where they are tossed into open waste bins and even left on the street - can turn them into new sources of contamination."

Researchers in Forró's lab are working on a promising solution to this problem: a membrane made of titanium oxide nanowires, similar in appearance to filter paper but with antibacterial and antiviral properties.

Their material works by using the photocatalytic properties of titanium dioxide. When exposed to ultraviolet radiation, the fibers convert resident moisture into oxidizing agents such as hydrogen peroxide, which have the ability to destroy pathogens. "Since our filter is exceptionally good at absorbing moisture, it can trap droplets that carry viruses and bacteria," says Forró. "This creates a favorable environment for the oxidation process, which is triggered by light."

The researchers' work appears today in Advanced Functional Materials, and includes experiments that demonstrate the membrane's ability to destroy E. coli, the reference bacterium in biomedical research, and DNA strands in a matter of seconds. Based on these results, the researchers assert - although this remains to be demonstrated experimentally - that the process would be equally successful on a wide range of viruses, including SARS-CoV-2.

Their article also states that manufacturing such membranes would be feasible on a large scale: the laboratory's equipment alone is capable of producing up to 200 m2 of filter paper per week, or enough for up to 80,000 masks per month. Moreover, the masks could be sterilized and reused up a thousand times. This would alleviate shortages and substantially reduce the amount of waste created by disposable surgical masks. Finally, the manufacturing process, which involves calcining the titanite nanowires, makes them stable and prevents the risk of nanoparticles being inhaled by the user.

A start-up named Swoxid is already preparing to move the technology out of the lab.

The membranes could also be used in air treatment applications such as ventilation and air conditioning systems as well as in personal protective equipment."

-Endre Horváth, article's lead author and co-founder of Swoxid
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Re: A titanium oxide nanowire-based air filter can trap and destroy pathogens

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Love that - this is the time to be out of the box in our collective thinking.
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Graphene oxide-silver nanoparticles shown to rapidly neutralize RNA viruses

3/2/21


https://www.news-medical.net/news/20210 ... ruses.aspx


While the vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are administered, and extensive research is conducted for targeted therapeutics to control the COVID-19 (coronavirus disease 2019), it is equally crucial to develop more novel, broad-spectrum antiviral compounds.

Silver nanoparticles (AgNP) are well-established as antibacterial and antiviral agents. Another nanomaterial - graphene oxide (GO) - is also effective against microorganisms. Coupled with its high surface area, it acts as a potent ideal drug carrier. With high levels of antiviral agents, the combination with graphene oxide is found to show higher antiviral performance and reduced toxicity.

While many groups have investigated graphene oxide and silver nanoparticles, a recent study examined the antiviral properties of GO-AgNP composite materials developed by Graphene Composites as part of their patent-pending GC Ink antiviral formulations.

Researchers from Brown University, Rhode Island, and Graphene Composites Ltd., UK, collaborated to formulate a graphene oxide/silver nanoparticle ink with antiviral properties.

“Our finding that graphene oxide/silver nanoparticle ink can rapidly prevent in vitro infection with two different viruses is exciting, and suggests that the ink has the potential to be used in a variety of applications to help reduce the spread of viruses in the environment,” Dr. Meredith J. Crane, co-author of the research, published on the bioRxiv*preprint server, said.

According to the study, the researchers generated various materials using three different production methods: reduction with silver salt, direct addition of Ag nanospheres, and direct addition of Ag nanospheres to thiolized graphene.

Followed by characterization of seven materials to test for the infectivity of two RNA viruses, influenza A virus (IAV) and the human coronavirus (HCoV) OC43, after short exposure periods, the researchers found that the composite with Ag nanospheres (that was added directly) completely reduced the viral infectivity.

The IAV is an enveloped virus of the orthomyxovirus family with a segmented single-stranded RNA genome; it causes flu pandemics. The HCoV-OC43 is an enveloped betacoronavirus with a single-stranded RNA genome associated with the common cold in humans. The researchers have used these viruses as representatives of viruses that circulate seasonally, such as the seasonal influenza viruses, and those with novel introductions into the population with pandemic potential, as experienced with the novel 2009 H1N1 influenza A virus lineage and the coronavirus SARS-CoV-2, the viral agent of COVID-19 disease.

The researchers found the antiviral activity consistent with the chemical and morphological differences in the materials, specifically the stabilization of the AgNPs, which is aided by a capping agent's presence. The researchers discussed the oxidation state, reactive surface groups of the GO and the size of the AgNPs.

The study identified two GO-AgNP materials with potent and rapid antiviral activity in solution against two enveloped RNA viruses associated with human respiratory infection. The remaining five materials possessed a range of modest to no antiviral effects against IAV, the researchers reported.

This study has reported a synergistic effect between the GO and the AgNPs. Most likely the mechanism of action may be by the rapid disruption of the viral envelope.

As opposed to targeted drugs, non-specific antivirals are advantageous. They act broad-spectrum; thus, the mutational variants are also killed. With new epidemics emerging in short periods, this formulation will be useful. With no or reduced toxicity, the formulation holds high promise and calls for further research to warrant it.

The SARS-CoV-2, the etiological agent of COVID-19, has infected over 114 million lives and caused over 2.53 million deaths, according to WHO reports. The need for an effective and successful therapeutic option is urgent - a broad-spectrum antiviral may fit the bill. This study here has revealed the potential for the GO-AgNP composite materials to function as antiviral nanosystems that may enhance current infection prevention measures and antiviral therapies, the researchers write.

Journal reference:

Graphene oxide/silver nanoparticle ink formulations rapidly inhibit influenza A virus and OC43 coronavirus infection in vitro, Meredith J. Crane, Stephen Devine, Amanda M. Jamieson, bioRxiv 2021.02.25.432893; doi: https://doi.org/10.1101/2021.02.25.432893, https://www.biorxiv.org/content/10.1101 ... 5.432893v1
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Fighting SARS-CoV-2 with materials science

3/18/21


https://www.news-medical.net/news/20210 ... ience.aspx


In a recent editorial in the journal Emergent Materials, Dr. Huseyin C. Yalcin from Qatar University Biomedical Research Center and Dr. Ajeet Kaushik from Florida Polytechnic University announce several important developments in their timely special issue entitled “Materials Science in the Battle against COVID-19”.

The pandemic of coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmitted via human to human, has resulted in the ongoing global health and economic crisis.

Despite the introduction of several vaccines (with varying success among different countries), our lives may still be revolving around other preventative measures for years to come. Although healthcare providers are on the front lines, scientists and engineers have their role in exploring better treatments, diagnostic approaches, and safety protocols.

In this unprecedented race against time, materials science can definitely be considered one of the fields contributing substantially, primarily due to a significant cumulative knowledge that can be swiftly translated to the clinical milieu.

Hence, as the Editors of the Springer journal Emergent Materials, Dr. Yalcin and Dr. Kaushik aimed to put forth a representative assembly of reviews and original studies that cover and highlight all relevant themes in the field of materials science – such as biosensors, nanomedicine, and nanoparticles, personal protective equipment, medical devices, additive manufacturing and biomaterials.

Smart masks and deactivating surfaces


One notable example is the study that highlights the importance of blending new biomaterials within “smart” face masks to prevent the transmission and subsequent enhancement of antiviral activity, where environmentally acceptable material usage in order to minimize the long-lasting effect on the environment is also accentuated. This was done with the use of computer-aided design tools and computational fluid dynamics.

Furthermore, antimicrobial surfaces can potentially halt the spread of SARS-CoV-2 and other viral infections. A study that is also included in this special issue highlights gold hard anodized (GHA) materials with antimicrobial surface traits, but also with enhanced tribological and mechanical properties suitable for various biomedical applications.

Likewise, conducting polymers with antiviral/antimicrobial properties can be introduced in personal protective equipment (most notably gloves, coverall suits and face shields) for frontline health workers in order to ward off not only COVID-19, but also bacterial infections that are pervasive in hospital settings.

The potential of using 3D printing in applications relevant to the COVID-19 pandemic has also been highlighted, such as printing personal protective equipment, swabs, but also whole isolation wards. This may be a part of additive manufacturing to tackle the growing demand for supplies.

Speeding up the detection of SARS-CoV-2


This pandemic reminded us once again of the importance of testing that enables rapid and direct detection of respiratory viruses. On top of that, polymerase chain reaction (PCR) tests require well-trained personnel and expensive equipment, and this can also be extended to instances when cell culture is used.

On the other hand, microfluidic technologies may open the door for precise detection of respiratory tract viruses, which is why several papers have been included in this special issue that delineates novel biosensor technologies for improved diagnostics of SARS-COV-2.

For example, one paper elegantly explains the use of different nanomaterials in diagnostic microfluidic platforms for COVID-19, while another describes in-depth how high-affinity biosensors could be developed with quantum dots for SARS-CoV-2 detection.

Moreover, electrochemical, plasmonic, and magnetic biosensors that focus on SARS-COV-2 protein detection are also highlighted, and one study goes into extraordinary depth when describing biosensing for microfluidic platforms for viral diagnostics.

“We strongly believe that this issue will serve as a best platform of knowledge transfer and help the multidisciplinary community to identify a key direction for the science and technology towards advanced emergent materials applications to fight the SARS-COV-2 and relevant complications”, conclude the authors of this Editorial.

Journal reference:

Yalcin, H.C. & Kaushik, A. (2021). Support of intelligent emergent materials to combat COVID-19 pandemic. Emergent Materials. https://doi.org/10.1007/s42247-021-00189-3, https://link.springer.com/article/10.10 ... 21-00189-3
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The role of nanomaterials during the COVID-19 pandemic

9/22/21


https://www.news-medical.net/news/20210 ... demic.aspx


The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China, in 2019. Subsequently, the global outbreak of the novel virus was announced to be a pandemic by the World Health Organization (WHO) in March 2020. The pandemic is popularly known as coronavirus disease 2019 (COVID-19). SARS-CoV-2 is extremely virulent with a high rate of transmission. To date, it has claimed more than 4.71 million lives worldwide.

Nanotechnology has been widely applied in biomedicine, especially for controlled drug delivery, diagnosis, and treatment of various diseases. In response to the current pandemic, many laboratories around the world applied this technology. The applications include developing facemasks bearing filters coated with nanomaterials, vaccines with nanometer adjuvants, affordable and rapid COVID-19 diagnostic kits.

A new review published in Rare Metals has focused on the applications of nanomaterials to fight the ongoing COVID-19 pandemic. This article revealed that nanomaterials help to prevent, diagnose, and provide treatment to SARS-CoV-2 infected individuals.

Nanomaterials and virus prevention


Scientists revealed that typically SARS-CoV-2 is transmitted via droplets of an infected person when they cough or sneeze. Sometimes, these droplets adhere to surrounding surfaces like doorknobs and onto healthcare workers' protective gear. A study reported that SARS-CoV-2 remains active for seven days on a facemask worn by an infected person. When healthy individuals touch these contaminated spots, they are at a high risk of COVID-19 infection.

Nanotechnology has helped develop facemasks with dual functions, i.e., protection against SARS-CoV-2 virus and excellent self-disinfection properties. Also, the use of nanomaterials in the development of surface disinfectants with self-disinfection properties has been immensely beneficial for hospital and healthcare settings.

Previous studies have revealed metals such as silver and copper have excellent antiviral properties. As expected, silver and copper nanomaterials showed high surface-to-volume ratios and improved biological functions. Similarly, gold nanoparticles can deactivate viruses and bacteria by catalyzing specific reactions to generate reactive oxygen species (ROS) under light irradiation with a specific wavelength.

Scientists have also developed non-metallic nanomaterials, e.g., hydrophobic graphene nanomaterial, for facemasks with self-disinfection properties. Additionally, nanoscale TiO2 fiber coating enhances the filtering property of facemasks. Inorganic nanoclusters (NCs) possess intrinsic bactericidal and antiviral activity to minimize the accumulation of harmful pathogens in the nanofiber pores.

Nanomaterials and COVID-19 diagnosis


Nanomaterials, especially nanobiosensors, can augment the quality and efficiency of the detection process. The rapid detection and immediate response characteristics make these sensors ideal for medical applications. Currently, the detection of COVID-19 is critical for major preventative applications.

Scientists have developed a COVID-19 biosensor system based on nanomaterials combined with one-step reverse transcription loop-mediated isothermal amplification. This biosensor can successfully diagnose COVID-19. Another biosensor device, based on a field-effect transistor (FET), can efficiently detect the COVID-19 virus in medical samples. The latter class of biosensors has been synthesized from graphene nanosheets, modified with the COVID-19 spike antibody, and can efficiently identify the COVID-19 spike protein.

Recently, scientists developed a novel biosensor by coating graphene sheets of FET with an antibody to the COVID-19 spike protein. The limit of detection for the COVID-19 target antigenic protein is 1 fg·ml−1. As this is significantly lower than traditional detection concentrations, the difficulty of sampling is immensely reduced. Another group of researchers developed a bioassay based on gold nanoparticles coated with thiol-modified antisense oligonucleotides. This can accurately diagnose COVID-19 in a few minutes.

Nanoparticles in COVID-19 Vaccines

Vaccines trigger the immune system via the introduction of antigens. Conventional vaccines possess many challenges, such as low blood flow stability and the inability to elicit a sustained and adequate immune response. Vaccines that produce higher levels of antibodies are regarded as effective, but in most cases, these vaccines also have higher side effects.

Recently, nanoparticle vaccines have been regarded to be good alternatives to traditional vaccines. The main advantages of nanomaterial-based vaccines are controllable drug kinetics, high payloads, and high stability. Also, in the DNA- and RNA-based vaccines, an additional vector is required. Scientists revealed that vaccine adjuvants derived from nanoparticles possess many advantageous properties, including slow-release, robust humoral and cellular responses induction and improved vaccine efficacy.

Sinopharm, a Pharmaceutical Group in China, in collaboration with the Wuhan Institute of Biological Products, used aluminum salts, graphene, silica nanoparticles, gold nanoparticles, liposomes, and polymerized nanoparticles as vaccine adjuvants. Moderna used lipid encapsulation for the development of their COVID-19 vaccine. Based on immunogenicity, several studies have indicated that gold nanoparticles, spike protein nanoparticles, and hollow polymeric nanoparticles could effectively induce a human immune response against coronaviruses.

Nanomaterials and antiviral drugs


Nanomaterials, e.g., liposomes and PLGA nanoparticles, can be used to encapsulate antiviral drugs, which promote long-term circulation and sustained release of the drugs. This technology improves the therapeutic effect. Researchers believe that nanomaterials could be used to deliver angiogenic factors in combination with antiviral drugs to treat COVID-19 disease. Nanocarriers could significantly transport drugs with greater efficiency than conventional methods.

Journal reference:


Xiao, M. et al. (2021) "Applications of nanomaterials in COVID-19 pandemic", Rare Metals. doi: 10.1007/s12598-021-01789-y.
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New nanomaterial for treatment of skin infections

9/30/21

https://www.eurekalert.org/news-releases/929997


Peer-Reviewed Publication

Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague)


Researchers at the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague) and the Technical University of Liberec in collaboration with researchers from the Institute of Microbiology of the CAS, the Department of Burns Medicine of the Third Faculty of Medicine at Charles University (Czech Republic), and P. J. Šafárik University in Košice (Slovakia) have developed a novel antibacterial material combining nonwoven nanotextile and unique compounds with antibacterial properties. Called NANO-LPPO, the new material can fulfill a wide range of applications as a dressing for wounds, such as burn injuries, by preventing infection and thus facilitating treatment and healing.

Because the number of bacterial strains resistant to common antibiotics is steadily increasing, there is a growing need for new substances with antibacterial properties. A very promising class of substances are the so-called lipophosphonoxins (LPPO) developed by the team of Dominik Rejman of IOCB Prague in collaboration with Libor Krásný of the Institute of Microbiology of the CAS.

“Lipophosphonoxins hold considerable promise as a new generation of antibiotics. They don’t have to penetrate the bacteria but instead act on the surface, where they disrupt the bacterial cell membrane. That makes them very efficient at destroying bacteria,” says Rejman.

“A big advantage of LPPO is the limited ability of bacteria to develop resistance to them. In an experiment lasting several weeks, we failed to find a bacteria resistant to these substances, while resistance to well-known antibiotics developed relatively easily,” explains Krásný.

The potential of LPPO is especially evident in situations requiring immediate targeted intervention, such as skin infections. Here, however, the substances must be combined with a suitable material that ensures their topical efficacy without the need to enter the circulatory system. This reduces the burden to the body and facilitates use.

One such suitable material is a polymer nanofiber developed by the team of David Lukáš of the Faculty of Science, Humanities and Education at the Technical University of Liberec. The researchers combined it with LPPO to prepare a new type of dressing material for bacteria-infected skin wounds. The material’s main benefit is that the antibacterial LPPO are released from it gradually and in relation to the presence and extent of infection.

“The research and development of the material NANO-LPPO is a continuation of the work carried out in a clinical trial on the NANOTARDIS medical device, which we recently successfully completed in collaboration with Regional Hospital Liberec, University Hospital Královské Vinohrady, and Bulovka University Hospital. With its morphological and physical-chemical properties, the device promotes the healing of clean acute wounds,” says Lukáš. “This collaboration with colleagues from IOCB Prague is really advancing the possibilities for use of functionalized nanofiber materials in the areas of chronic and infected wounds.”

“Enzymes decompose the nanomaterial into harmless molecules. The LPPO are an integral component of the material and are primarily released from it during this decomposition. Moreover, the process is greatly accelerated by the presence of bacteria, which produce lytic enzymes. This means that the more bacteria there are in the wound, the faster the material decomposes, which in turn releases more of the active substances into the affected site to promote healing and regeneration of soft tissues,” says Rejman in describing the action of the material.

“Our experiments on mice confirmed the ability of NANO-LPPO to prevent infection in the wound and thus accelerate healing and regeneration. There was practically no spread of infection where we used the material. If clinical trials go well, this could be a breakthrough in the treatment of burns and other serious injuries where infection poses an acute threat and complication to treatment,” explains wound care specialist Peter Gál of the Department of Burns Medicine at Charles University’s Third Faculty of Medicine, the Faculty of Medicine at P. J. Šafárik University in Košice, and the East Slovak Institute for Cardiovascular Diseases.

In terms of applications, NANO-LPPO is an interesting material for manufacturers of medicinal products and medical devices. Its commercialization is being coordinated through a collaborative effort between IOCB TECH, a subsidiary of IOCB Prague, and Charles University Innovations Prague, a subsidiary of Charles University, both of which were created for the purpose of transferring results of academic research to practice. The companies are currently seeking a suitable commercial partner.

The findings of the extensive interdisciplinary study were published in Scientific Reports.


Original paper:

Do Pham, D.D., Jenčová, V., Kaňuchová, M., Bayram, J., Grossová. I., Šuca, H., Urban, L., Havlíčková, K., Novotný, V., Mikeš, P., Mojr, V., Asatiani, N., Kuželová Košťáková, E., Maixnerová, M., Vlková, A., Vítovská, D., Šanderová, H., Nemec, A., Krásný, L., Zajíček, R., Lukáš, D., Rejman, D. & Gál, P. Novel lipophosphonoxin-loaded polycaprolactone electrospun nanofiber dressing reduces Staphylococcus aureus induced wound infection in mice. Sci Rep 11, 17688 (2021). https://doi.org/10.1038/s41598-021-96980-7

Journal


Scientific Reports

DOI


10.1038/s41598-021-96980-7

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Novel lipophosphonoxin-loaded polycaprolactone electrospun nanofiber dressing reduces Staphylococcus aureus induced wound infection in mice
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TimGDixon
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Love nano research...
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by TimGDixon » Thu Sep 30, 2021 4:37 am
Love nano research...


me too !

The applications of nanomaterials against viral disease

9/30/21


https://www.news-medical.net/news/20210 ... sease.aspx

Nano-based therapeutics and diagnostic systems are being increasingly applied to various fields of medicine, acting as sensors, delivery vehicles, immunostimulants, radiation sensitizers, and viral inhibitors. In a paper recently published in the journal Pharmaceutics, the application of nanomaterials in the diagnosis, prevention, and treatment of viral diseases is reviewed in detail, highlighting areas of significant progress or stagnation from the past few decades.

Nanomaterials in diagnosis

Nanomaterials encompass any engineered structure with a monomeric unit in the size range of 1-100 nm. They, therefore, include macroscopic materials with nano-scale surface features and microscopic particles in the nano-size range.

Carbon nanotubes are hollow cylindrical structures with intriguing electric properties that facilitate use in biosensors by incorporation of a specific protein or nucleic acid probes. For example, conjugation with complementary DNA or RNA to the virus being detected creates a high-speed virus sensor with a very low detection limit, where fluctuations in current through the sensor can be used to infer viral load. Flat graphene sheets of carbon can similarly be bound with antibodies or DNA to create sensors that can interact with larger biomolecules than carbon nanotubes owing to a lower degree of curvature exhibited.

Gold nanoparticles exhibit unique light interactions that result in intense adsorption across a narrow range of wavelengths, a phenomenon known as surface plasmon resonance. The wavelength of light most strongly absorbed by the particles is dependent on particle shape and size and can be tuned from the visible to the near infra-red.

Near infra-red light is maximally penetrating through biological tissue, and therefore sensors that rely on optical signaling in this range are ideal as a diagnostic platform. As with carbon nanotubes, relevant complementary molecules can be attached to the particles that will only bind with the virus or antibody under investigation.

Similarly, the specific wavelength of light in resonance with the particles can also be influenced by proximity with other particles. Thus, by inducing inter-particle bonding, the presence of a compound of interest can be determined colorimetrically by the eye. Many lateral flow severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection assays are based on the use of gold nanoparticles, where particles bearing a DNA reporter probe are combined with viral RNA in the sample to generate a visible red line.

Nanomaterials in disease prevention

Nanomaterials have been intrinsic to the development of coronavirus disease 2019 (COVID-19) vaccines, the mRNA-based vaccines utilizing liposomes or lipid nanoparticles as a delivery vehicle. Outside of the cytoplasm, mRNA degrades quickly, and thus liposomes ensure that the payload enters the cell and is available for transcription. An mRNA-based vaccine utilizing liposomes was first developed in 1993 against the influenza virus. Since then, liposomes have been exploited to deliver sensitive biomolecules into the cell in several capacities, such as during CRISPR-Cas9 gene editing.

Nanomaterials are also frequently used as adjuvants in vaccine formulations to stimulate an intense immune response, first employed in a seasonal flu vaccine in 1997 with the incorporation of squalene droplets coated in biocompatible surfactants. Since then, the conjugation of viral antigens onto the surface of nanoparticles has shown great success in stimulating an immune response in several vaccine formulations.
Nanomaterials in disease treatment

Drug delivery is the major purpose of nanomaterials in disease treatment, generally offering improved pharmacokinetics, drug retention time, and the "drug-likeness" of the compound being delivered.

The physical and chemical properties of the nanoparticle strongly influence the biodistribution of the nanomedicine in the body and the ability and propensity of the particle to enter target cells.

Tuning the surface charge, size, and outwardly presenting the chemical character of the particle can encourage uptake specifically to areas of inflammation, and further specificity can be imparted by incorporating target ligands onto the particle's surface. For example, attaching an antibody against the spike protein of SARS-CoV-2 can encourage the uptake of the particle into infected cells that are presenting the relevant antigen.

The large surface-to-volume ratio of nanomaterials provides an ample platform on which both targeting ligands and drug payloads may be loaded, allowing for the simultaneous delivery of large quantities of multiple compounds with synergistic effects.

Besides use as a delivery vehicle, nanoparticles themselves may be utilized as virus therapeutics, acting to block the viral replication cycle or cell entry. Silica nanoparticles designed to bind with the influenza virus have shown efficacy in blocking viral entry into cells in this way. Particles constructed from copper, silver, and gold are also capable of generating reactive oxygen species. Besides being directly damaging to viral genetic material can induce apoptosis in infected cells, thereby preventing viral propagation. Such materials can also be coated on high-traffic surfaces such as handrails to destroy any virus or bacteria by exposure to reactive oxygen species.

Journal reference:


Lim, J. et al. (2021) "Application of Nanomaterials as an Advanced Strategy for the Diagnosis, Prevention, and Treatment of Viral Diseases", Pharmaceutics, 13(10), p. 1570. doi: 10.3390/pharmaceutics13101570.
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Bioinspired electromechanical nanogenerators to regulate cell activity

10/11/21


https://phys.org/news/2021-10-bioinspir ... -cell.html


The extracellular matrix (ECM) including three-dimensional (3D) network and bioelectricity can profoundly influence cell development, migration, and functional expression. In a new report now published on Science Advances, Tong Li and a research team in chemistry, nanotechnology, bioelectronics and advanced materials in China, developed an electromechanical coupling bio-nanogenerator abbreviated bio-NG inspired by biophysical cues of the extracellular matrix. The device contained highly discrete piezoelectric fibers to generate piezo potential of up to millivolts to provide in situ electrical stimulation for living cells.

The unique 3D space within the bio-NGs provided an ECM-like environment to promote cell growth. The bio-NGs effectively promoted cell viability and development to maintain its specific functional expression. Researchers expect the new and advanced bio-NGs to mimic the complexity of the extracellular matrix and provide a physiologically relevant in vivo biological system. The device effectively promoted cell viability and development to maintain its specific functional expression. Li et al. expect the new and advanced version of bio-nanogenerators to provide a physiologically relevant in vivo biological system to replace inaccurate 2D systems and animal models.

Guidance for cells


In this work, Li et al. outlined a practical strategy for wireless electrical stimulation of cells and tissues to repair and sustain cell function. Bioelectricity is a biophysical cue that provides guidance for cell growth and differentiation during embryonic development and tissue regeneration. Endogenous bioelectricity exists in the cytoplasm and extracellular space, providing scientists a resource for electrical stimulation of excitable cells and regulating cellular activity for biomedical applications. Most treatment methods require an external energy input and wire connection to apply external electrical pulses through implanted microdevices. Recent developments in nanotechnology have allowed electrode-less and battery-free treatments, which include the use of nanogenerators for brain stimulation, hair regeneration and wound healing. However, most of them require a well-accepted solution to electrically stimulate the functional cells. Li et al. were therefore inspired by the biological function and microstructure of collagen fibers in the extracellular matrix to form bio-NGs composed of highly discrete piezoelectric electrospun fibers to provide cells with a physically relevant microenvironment. The bio-NG-cell interaction applies to in vivo environments to reduce inflammation, induce hepatocyte proliferation, and accelerate angiogenesis, as well as promote liver repair.

Forming the bioinspired electromechanical bio-NGs.


During the experiments, the research team introduced iron oxide magnetic nanoparticles into polyacrylonitrile to prepare highly discrete fibers for use as a magnetic-assisted electrospinning device. During electrospinning, the setup enabled the formation of scaffolds with well-interconnected pores and discrete fibers for cell-free migration. To prepare a closer-to-in-vivo microenvironment, the team also imparted bioelectricity as a biophysical cue. To accomplish this, the scientists developed a target scaffold to promote cell interaction and adhesion with fibers. The electromechanical coupling of bio-NGs assembled by the scaffold promoted the transmission and communication of signals between cells to mimic the bioelectric effects of collagen fibrils or fibers in the extracellular matrix. The team simulated and studied the piezoelectric potential generated from cell force in bio-NGs using finite element analysis. To accomplish this, they applied a load force to the cell-fiber contact and first measured the piezoelectricity of a single fiber within bio-NGs using piezoelectric force microscopy. The experimental voltage signals validated the theoretical piezoelectricity of the bio-NGs.

Characterizing the bio-NGs and regulating cell activity


To investigate the information of the fibers in bio-NGs, the team used Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) spectra. They then studied the thermodynamic properties of the piezoelectric fibers in bio-NGs using differential scanning calorimetry (DSC) thermograms and conducted cyclic voltammogram studies to test the charge storage and transmission properties of the piezoelectric fibers in bio-NGs. The team then tested the compressive resilience and mechanical properties of the fibers by first forming cylindrical shapes of them and compressing the scaffolds to understand the excellent resilience of the constructs. The mechanical properties and resilience of the fibers ensured the bio-NGs could effectively maintain a large enough pore size and stable 3D growth microenvironment for cell movement and growth. The team also investigated the NG-cell interaction in 3D space with two different cell lines including

retinal ganglion cell 5 (RGC5) and primary hepatocytes. The cells contained voltage-gated calcium channels in their membranes and others were motile cells with high metabolic functions. Using two-dimensional nanogenerators (NGs) and non-piezoelectric 3D fibers the team studied the effects of 3D space and electrical stimulation on cells. The data showed how the bio-NGs could provide a biofriendly cell culture microenvironment for further experiments.

Promoting in vivo liver repair with bio-NGs


The scientists then implanted the bio-NGs into an area of liver injury relative to hepatocyte regeneration to reflect their practicality. To accomplish this, they used Sprague-Dawley rats to induce liver injury. After four weeks of implanting the bio-NGs, the team removed the implants and studied inflammation using histology staining. They noted mild inflammation in the first week, which improved by the second week and reduced to normal levels by the fourth week. All other organs did not show deformation or abnormal lymphatic cell invasion to indicate good health conditions without systematic side effects. The observed regenerative process highlighted a new blood circulation system that formed inside regenerated liver tissue to suggest the interaction of bio-NGs with cells to reduce inflammation and promote tissue repair.

Long term stability and biocompatibility of bio-NGs in vivo


The NG-cell interaction efficiently promoted cell viability and maintained its functional expression in vitro and in vivo to provide a treatment strategy for clinical trials. For tissue regeneration, it is most effective to directly transplant functional cells into the damaged site in vivo. For additional studies, the team implanted the bio-NGs into the gastrocnemius muscle area around the sciatic nerve of rats to detect the stability of the bio-NGs in vivo. Li et al. then removed the implants after eight weeks and analyzed inflammation to show good biocompatibility of bio-NGs for prolonged periods of time in biological environments without any systemic side effects. The constructs are promising as implants for in vivo regenerative repair.

Outlook

In this way, Tong Li and colleagues developed extracellular matrix-like electromechanical coupling bio-nanogenerators (bio-NGs) to regulate cell activity and maintain its specific functional expression. The product created a local voltage potential to stimulate living cells as long as they remained motile. The unique environment facilitated cell culture in bio-NGs to trigger the opening of ion channels present in the cellular plasma membrane to achieve electrical stimulation at the single-cell level. The process offers great potential for bioelectronic medicine and cell-targeted local electrical impulses. The new method can replace inaccurate 2D systems and time-consuming animal models to provide a biomimetic, physiological microenvironment for accelerated tissue regeneration and bioinspired electronic medicine.

More information:
Tong Li et al, Cell activity modulation and its specific function maintenance by bioinspired electromechanical nanogenerator, Science Advances (2021). DOI: 10.1126/sciadv.abh2350
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