Tag: Graphene materials

Graphene: The next revolution in biomedical applications

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Graphene:

The next revolution in biomedical applications

Part I. Tissue Engineering

Advances in medicine have reached levels unimagined until recently. Among them, tissue engineering has an important participation. With it is possible to combine cells, biomaterials and biologically active molecules with the aim of repairing or replicating tissues or organs with a function similar to that of the original structure. In principle, biomaterials are used as molecular scaffolds to act as a three-dimensional (3D) support or guide for the anchoring and growth of the cells that will be in charge of forming the new tissue.

The first molecular scaffolds were designed with natural materials such as collagen, glycosaminoglycans (GAGs), chitosan, and alginates; then with artificial compounds such as polylactic acid (PLA), polyglycolic acid (PGA), poly(lactic-co-glycolic) acid (PLGA), polyurethanes (PUs), polytetrafluoroethylene (PTFE), polyethyleneterephthalate (PET); bioceramics such as hydroxyapatite (HA) and tricalcium phosphate; metals such as stainless steel, chrome-cobalt alloys (Co-Cr) or titanium alloys (Ti) and recently, new research is oriented towards the use of nanotechnology.

The relationship between nanotechnology and tissue engineering is due to the fact, that the extracellular matrix (ECM) that helps cells unite and communicate with each other, is made up of a network of nanometer-sized fibers made up of bioactive molecules. It is at this point where nanotechnology opens new possibilities for regenerative medicine, since it has been proven that the use of materials that act on the same nanometric scale as the ECM favors mimicking the physiological environment of the organism to stimulate cell growth and differentiation in a more natural environment.

Among the most studied nanomaterials in recent years are graphene materials, which consist of nanometric sheets of carbon atoms organized in two-dimensional (2D) hexagonal networks. Among the most interesting properties for tissue engineering are: its large surface area, mechanical resistance, thermal conductivity, biocompatibility and finally, an extraordinary ability to share its properties with other materials to improve their original characteristics.

For example, the use of graphene materials within the 3D architecture of certain biopolymers in tests carried out on heart, liver, bone, cartilage, and skin tissues has shown substantial improvements in their physicochemical, mechanical, electrical and biological properties, achieving excellent response. for stem cell adhesion and differentiation.

In 2022, the Andaltec technology center (Spain) reported the development of a material from polymers derived from graphene by 3D printing with great potential for the regeneration of muscle tissue. They demonstrated that in the presence of graphene derivatives, cells contract and expand without an external stimulus, therefore, it has great potential for use in regenerative medicine.

On the other hand, the Division of Postgraduate Studies and Research (DEPeI) on Odontology, UNAM and the National School of Higher Studies (ENES) León Unit, Mx., through a study published in J Oral Res 2021 supports the possibilities of graphene oxide (GO) in the design of biomaterials for dental use. The results of the research carried out with Graphenemex® GO samples, concluded that this nanomaterial in combination with polymethylmethacrylate (PMMA), in addition to improving its physical-mechanical properties, also demonstrated good compatibility and an interesting stimulation of cell proliferation when being evaluated on cultures with gingival-fibroblasts, dental-pulp-cells and human osteoblasts.

In 2020, researchers from the University of Malaga (Spain) published another study that identified GO as the ideal material for regenerative medicine. The study carried out on an animal model, showed high biocompatibility of different types of graphene oxide with dopaminergic cells, favoring their maturation and protecting them from the toxic conditions of Parkinson’s disease. These results postulate GO as an adequate scaffold to test new drugs or develop constructs for cell replacement therapy of Parkinson’s disease.

Despite the large amount of research on the interactions of graphene materials with biological media, there is still a long way to go to have these biomaterials available and in clinical operation. Energeia- Graphenemex, the pioneering Mexican company in Latin America in the research and development of applications with graphene materials, in collaboration with other companies and research centers, seeks to contribute with science to understand these interactions in a security framework, to lay solid foundations on the use of graphene nanotechnology in the biomedical sector for the benefit of society.

Drafting: EF/DHS

References

  1. Graphene and its derivatives: understanding the main chemical and medicinal chemistry roles for biomedical applications. J Nanostructure Chem, 2022, 12:693
  2. Biological and physico-mechanical properties of poly (methyl methacrylate) enriched with graphene oxide as a potential biomaterial. J Oral Res 2021; 10(2):1
  3. Graphene-Based Antimicrobial Biomedical Surfaces. ChemPhysChem 2021, 22, 250
  4. Functionalized Graphene Nanoparticles Induce Human Mesenchymal Stem Cells to Express Distinct Extracellular Matrix Proteins Mediating Osteogenesis. Int J Nanomed 2020:15 2501
  5. Graphene Oxide and Reduced Derivatives, as Powder or Film Scaffolds, Differentially Promote Dopaminergic Neuron Differentiation and Survival. Front. Neurosci., 21 December 2020. Sec. Neuropharmacology Volume 14
  6. International Journal of Nanomedicine 2019:14 5753
  7. Biocompatibility Considerations in the Design of Graphene Biomedical Materials. Adv. Mat. Interfaces 2019, 6, 1900229
  8. Graphene based scaffolds on bone tissue engineering. Bioengineered, 2018, 9:1, 38
  9. When stem cells meet graphene: Opportunities and challenges in regenerative medicine. Biomaterials, 2018, 155, 236
  10. Graphene-based materials for tissue engineering. Adv. Drug Deliv. Rev. 2016,105, 255

Chapter 92 e: Tissue Engineering, Anthony Atala. 2023 McGraw Hill.

Graphene as a sustainable alternative for water purification

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Graphene as a sustainable alternative

for water purification

Graphene materials, that is, Graphene, Graphene Oxide (GO) and Reduced Graphene Oxide (rGO), are carbon nanostructures that, thanks to their size, area, and surface chemistry, allow the design o new three-dimensional and multifunctional materials with high probabilities. to solve the problems associated with water scarcity.

For example, they are potential coagulant/flocculating agents, this is because they have a large surface area along which there are multiple anchor points capable of capturing a large amount of organic and inorganic matter, that is, they are highly useful for the capture of contaminants.

Main strategies for the use of graphene materials for the capture of contaminants.
  Taken from Environ. Sci. Technol., 2012, 46, 7717.

They are also chemically inert and by being immobilized in a substrate they prevent organic matter from adhering to surfaces. This property, when implemented in membrane technology, would allow a flow of water almost without friction, in other words, the use of graphene materials could make the flow of water remain constant for longer and therefore provide greater energy efficiency.

Likewise, their nanometric size, the arrangement of their sheets and the presence of millions of nanochannels between them make them highly impermeable, acting as a filter for molecules or contaminants.

Ion and water transport through graphene nanochannels.
Taken from J. Phys. Chem. C 2020, 124, 31, 17320.

Finally, the important antimicrobial and photocatalytic properties of graphene and its derivatives, in addition to reducing the microbial load by taking advantage of sunlight, would also help to reduce the requirements for biocidal agents.

Schematic representation of graphene in 3D structures for water purification.
Taken from Gels 2022, 8, 622.

The identification, understanding and use of the properties of graphene for the development of real products has not been an easy task. However, on November 3, 2022, the Graphene flagship, the multidisciplinary project in which almost 10 years ago the European Commission invested 1,000 million euros for Graphene research, announced the results of the Graphil Project, which consisted of the development of a new polysulfone filter with Graphene Oxide that acts as a more efficient mechanical network to trap polluting particles such as heavy metals, antibiotics, viruses, bacteria, toxins, etc., while allowing the passage of clean and safe water.

For its part, Energeia-Graphenemex®, the pioneering Mexican company in Latin America in the research and development of applications with graphene materials, in collaboration with other companies and research centers, joins this search for strategies to improve the availability and quality of water through the use of graphene, hoping in the short term to have all these benefits available to society.

References:

  1. Yu Z, Wei L, Lu L, Shen Y, Zhang Y, Wang J, Tan X. Structural Manipulation of 3D Graphene-Based Macrostructures for Water Purification. Gels. 2022, 29; 8(10):622.
  2. Alessandro Kovtun, Antonio Bianchi, Massimo Zambianchi, Cristian Bettini, Franco Corticelli Giampiero Ruani, Letizia Bocchi,Francesco Stante,Massimo Gazzano, Tainah Dorina Marforio, Matteo Calvaresi, Matteo Minelli,Maria Luisa Navacchia, Vincenzo Palermo and Manuela Melucci. Core–shell graphene oxide– polymer hollow fibers as water filters with enhanced performance and selectivity. Faraday Discuss., 2021, 227, 274.
  3. Sebastiano Mantovani,Sara Khaliha, Laura Favaretto, Cristian Bettini,Antonio Bianchi, Alessandro Kovtun, Massimo Zambianchi, Massimo Gazzano,  Barbara Casentini, Vincenzo Palermo and Manuela Melucci. Scalable synthesis and purification of functionalized graphene nanosheets for water remediation. Chem. Commun., 2021, 57, 3765
  4. Sara Khaliha, Tainah D. Marforio, Alessandro Kovtun, Sebastiano Mantovani, Antonio Bianchi, Maria Luisa Navacchia, Massimo Zambianchi, Letizia Bocchi. Nicoals Boulanger. Artem Iakunkov, Matteo Calvaresi, Alexandr V. Talyzin, Vincenzo Palermo, Manuela Melucci. Defective graphene nanosheets for drinking water purification: Adsorption mechanism, performance, and recovery. FlatChem., 2021, 29 100283.
  5. Yunzhen Zhao, Decai Huang, Jiaye Su, and Shiwu Gao. Coupled Transport of Water and Ions through Graphene Nanochannels. J. Phys. Chem. C 2020, 124, 31, 17320
  6. F. Guo, G. Silverberg, S. Bowers, S.-P. Kim, D. Datta, V. Shenoy and R. H. Hurt, Environmental Applications of Graphene-Based Nanomaterials. Environ. Sci. Technol., 2012, 46, 7717
  7. https://graphene-flagship.eu/graphene/news/graphene-applications-graphil/

Graphene: a revolution in the paper industry

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Graphene:

a revolution in the paper industry


The paper industry represents a very broad and versatile market, in fact and despite the challenges it faces due to the impact of digital media and its competition with plastic, its world production continues to be considerable, exceeding 400 million tons distributed in products for containers and packaging, for hygienic and sanitary use, as well as paper for printing, writing and the press.

“It is estimated that by the end of 2022 cardboard will represent two thirds of world paper production”

On the other hand, the continuous need for innovation as well as the search for solutions to the problems inherent in these products, such as their easy contamination and permeability, have made nanotechnology remain an important tool with the use of different nanomaterials such as nano- cellulose crystals and nanofibers, nanoparticles of silicon oxide (SiO2), titanium dioxide (TiO2), zinc dioxide (ZrO2) and recently graphene materials such as graphene and graphene oxide (GO) 1 with the aim of design nano-scale building blocks to obtain denser and less porous networks that, in addition to improving the quality of the final product, also diversify its use.

“Cellulose, in addition to being one of the most abundant natural polymers on earth, is also the main raw material for the paper industry. Graphene is obtained from graphite, a very abundant carbon mineral in Mexico”

How do graphene materials benefit the paper industry?


When talking about graphene, the main points of reference are its resistance, impermeability, flexibility, conductivity, lightness, biocompatibility, etc., all in a single material. Given this, it is important to understand that the behavior of graphene materials will depend, among other things, on the type of graphene, functionalization and concentration, but also on the processes involved in each industry and the nature of the materials with which it will be combined to transfer its properties and therefore there is no exact formula for each usage target, for example:


Mechanical strength- In the case of cellulose films, the presence of as little as 0.5% GO can significantly improve tensile strength, elongation at break and fracture energy by 78%, 172% and 397%, respectively; useful for its application in high performance bioplastic films2.


Antimicrobial protection- Among the benefits of interest to the paper industry are its biocompatibility, its physical barrier properties and its antimicrobial activity. For example, a study that prepared a paper coating with 0.05% GO reduced the growth rate of bacteria such as E. coli and S. aureus by 73% and 53%, respectively3,4. This is because GO helps limit microbial adhesion, replication and penetration.

Protection against UV radiation- According to another report, the use of 2% GO in cellulose films blocks UVA and UVB radiation by 66.7% and 54.2% respectively, without affecting the transmission of visible light, an interesting property for the design of protection and packaging materials.5


Barrier properties- Graphene materials present nano-channels between their sheets that represent a tortuous path for the passage of large molecules and, therefore, it is widely investigated both for its great impermeability against liquids and gases, but also for its potential benefits for the decontamination, purification and even desalination of seawater. Research carried out on cellulose acetate (CA) membranes for desalination described that the use of 1% GO improves morphology, hydrophilicity, porosity, roughness, mechanical resistance, thermal stability and, therefore, its operating efficiency, as well as it has happened with other types of membranes such as polysulfone, in which a concentration of 0.2% GO can be enough to improve their performance by up to 72%, in terms of water flow and salt rejection in tests with sodium sulfate. sodium6,7. The foregoing is not only reflected in the efficiency of filtration and/or desalination, but also the optimization of maintenance resources and energy consumption of said systems.


Energeia- Graphenemex®, the leading company in Latin America in the design and development of applications with graphene materials, continuously works to solve the obstacles that graphene faces to reach the market and, through strategic alliances with other industries, seeks to make this technology available to the industry for solving various problems.


References

  1. Trache, D., Thakur, V. K., & Boukherroub, R. 2020., Cellulose nanocrystals/graphene hybrids—a promising new class of materials for advanced applications. Nanomaterials, 10(8), 1523.
  2. M. Akhtari, M. Dehghani-Firouzabadi, M. Aliabadi, M. Arefkhani. Effect of graphene oxide nanoparticle coatings on the strength of packaging paper and its barrier and antibacterial properties. 2019., Bois et Forêts des Tropiques. 342, 69.
  3. W. Hu, Ch. Peng, W. Luo, M. Lv, X. Li, D. Li, Q. Huang, and Ch. Fan. Graphene-Based Antibacterial Paper. 2010. ACS Nano, 4, 7, 4317–4323
  4. X. Liu, T. Zhang, K. Pang, Y. Duan and J. Zhang. Graphene oxide/cellulose composite films with enhanced UV-shielding and mechanical properties prepared in NaOH/urea aqueous solution. 2016., RSC Adv., 6, 73358
  5. Zhang, X. F., Song, L., Wang, Z., Wang, Y., Wan, L., & Yao, J. 2020., Highly transparent graphene oxide/cellulose composite film bearing ultraviolet shielding property. International journal of biological macromolecules, 145, 663.
  6. S. M. Ghaseminezhad, M. Barikani, M. Salehirad.  Development of graphene oxide-cellulose acetate nanocomposite reverse osmosis membrane for seawater desalination. Composites Part B: Engineering. 2019., 161, 15, 320.
  7. B.M. Ganesh, Arun M. Isloor, A.F.Ismail., Enhanced hydrophilicity and salt rejection study of graphene oxide-polysulfone mixed matrix membrane. 2013., Desalination., 313, 199.

Graphene oxide: a promising alternative in nanotechnology

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Graphene oxide:

a promising alternative in nanotechnology

Since graphene was isolated for the first time in 2004 by the Manchester group, this nanomaterial has proven to be the most revolutionary for the development of new applications at an industrial level.

Graphene has extraordinary electrical, optical, thermal properties and high mechanical resistance. The properties of graphene are attributed to its structure in the form of two-dimensional (2D) sheets, made up of hexagonally bonded carbon atoms and a thickness of one carbon atom.

Currently there are different methods of graphene production, these can be classified into two methods, according to their origin, the “bottom-up” method and the “top down” method. The “bottom-Up” method consists in the creation of graphene structures through building blocks (atoms, molecules), for example, by Chemical Vapor Deposition (CVD); and the “top down” method involves the production of graphene from the oxidation of graphite. Graphite is made up of sheets of graphene that are stacked on top of each other. The following diagram represents the process for obtaining graphene from the oxidation of graphite.

Schematic diagram of the process for obtaining GO, through the oxidation of graphite.

The graphite oxidation process begins with the addition of graphite in sulfuric acid (H2SO4), with constant mechanical stirring. Subsequently, potassium permanganate (KMnO4) is slowly added, producing a chemical reaction that allows the graphite (graphene sheets stacked on top of each other) to be chemically modified in its structure. When KMnO4 reacts with H2SO4, it forms manganese oxide VII (Mn2O7), which is a very selective oxidizing agent on double bond aromatic compounds, such as graphite. The oxidizing agent molecularly attacks the structure of each graphene sheet in the graphite, grafting oxygenated functional groups (with oxygen), such as epoxide groups (C-O-C) and hydroxyl groups (-OH), on each sheet, and carboxyl groups (-COOH, CO2H ) on the edges of each sheet, obtaining graphite oxide and graphene oxide (GO), see Figure 1.

Figure 1. Structure of graphene oxide

The incorporation of oxygenated functional groups allows a material such as graphite, which is highly hydrophobic (which repels water) and a good electrical conductor, to become graphite oxide and graphene oxide (GO), highly hydrophilic materials, that is, they mix and disperse easily with water (See Figure 2). GO is chemically similar to graphite oxide, but structurally differs in the arrangement and number of stacked sheets.

Figure 2. (a and b) Behavior of graphite and graphene oxide (GO) in water, c) GO sheet, Transmission Electron Microscopy (TEM).

The GO can be defined as a single exfoliated graphene sheet or stack of few sheets (3-4) that is functionalized with different oxygenated groups. Among its main characteristics is that it is hydrophilic, insulating and hygroscopic (absorbs moisture). On the other hand, graphene oxide sheets possess a large surface area and exhibit high mechanical strength and flexibility.

Applications

Graphene oxide has attracted great interest in various fields of science and technology, due to its remarkable mechanical, chemical, and thermal properties, among others. So numerous investigations began, to take advantage of the properties of graphene oxide.

In 2011, the first investigations of the use of GO as a precursor in the large-scale production of graphene emerged, for use as filler/reinforcement material/in polymeric matrices, such as high-density polyethylene (HDPE) and low-density polyethylene (HDPE). density (LDPE).

By 2014, GO was considered feasible for use as a flame retardant agent. Research is still ongoing to functionalize it with different polymeric materials.

In 2017, the first reports of the manufacture of GO-based membranes began, since it is impermeable to gases and liquids, showing its ability to filter small particles, organic molecules and even its use for seawater desalination.

In 2018, Energeia-Graphenemex started research on graphene oxide as a new additive for the production of anticorrosive and antimicrobial coatings. By 2019, studies of graphene oxide in coatings with antibacterial behavior increased, associated with the fact that GO is capable of penetrating the cell membrane of bacteria, producing oxidative stress and inhibiting their reproduction.

In particular, the functionalization of GO allows it to be applicable in biological systems, development of biosensors for the identification of specific molecules, drug delivery systems, among others.

Energeia – Graphenemex®, a leading Mexican company in Latin America in research and production of graphene materials for the development of industrial applications. It has extensive experience in the production of graphene oxide (GO) on a large scale, with different degrees of oxidation and high quality for use in different applications and industries. Currently, it uses graphene oxide in the production of concrete additives and anticorrosive and antimicrobial coatings that are marketed under the Graphenergy brand.

References

  1. M. Fang, K. Wang, H. Lu, Y. Yang y S. Nutt, «Covalent polymer functionalization of graphene nanosheets and mechanical properties of composites,» Journal of Materials Chemistry, vol. 19, pp. 7098-7105, 2009.
  2. B. Dittrich, K.-a. Wartig, R. Mülhaupt y B. Schartel, «Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene,» Polymers, vol. 6, pp. 2875-2895, 2014.
  3. Y.-j. Wan, L.-x. Gong, L.-c. Tang, L.-b. Wu y J.-x. Jiang, «Mechanical properties of epoxy composites filled with silane-functionalized graphene oxide,» COMPOSITES PART A, vol. 64, pp. 79-89, 2014.
  4. J. Wang, C. Xu, H. Hu, L. Wan, R. Chen, H. Zheng, F. Liu, M. Zhang, X. Shang y X. Wang, «Synthesis , mechanical , and barrier properties of LDPE / Graphene nanocomposites using vinyl triethoxysilane as a coupling agent,» J. Nanopart Res, vol. 13, pp. 869-878, 2011.

The graphene revolution in the automotive industry: innovation in vehicle care and protection

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The graphene revolution in the automotive industry:

innovation in vehicle care and protection

Just as continuous exposure to solar radiation is harmful to our skin, it also affects the appearance of cars, in particular it causes damage to paint, moldings, tires and other auto parts. In fact, the sun, acid rain and temperature changes are three of its main enemies, for that reason there are countless product options on the market for its care.

Graphene is the most interesting form in which Carbon can occur and consists of sheets of carbon atoms extracted mainly from Graphite or from some gases. The great scientific and technological relevance of this material is due to the particular organization of its atoms, which gives it surprising and numerous properties that have captured the attention of a large number of industries, including the automotive industry.

The potential uses attributed to Graphene for this industry are the manufacture of coatings for chassis and bodies, plastics for auto parts, either to improve their quality or to totally or partially replace metal parts, tires, textiles, greases, lubricants and products for car care.

Energeia- Graphenemex® dedicated to the research and production of graphene materials as well as the development of applications at an industrial level, in 2018 under the Nanocar® brand, placed on the market the first line of products with Graphene for automotive care.

Benefits:

Nanocar® products form a protective and nano-filling film for defects that allows the atomic sheets of Graphene to adhere to the surfaces of the bodywork, protecting against dust and moisture, delaying the effects of corrosion, as well as acting as a barrier against UV radiation and as a temperature dissipator to limit the long-term deterioration of the paint. In addition, the continuous use of Nanocar® products facilitates subsequent cleaning, without leaving a trace of drying, even when washing is carried out with hot surfaces.

Relationship of the properties of Graphene and its effects on Nanocar® products

Drafting: EF/DHS

The rise of graphene: advances and developments in the last decade

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The rise of graphene:

advances and developments in the last decade

Graphene is the most revolutionary nanomaterial of the 21st century and is considered the basic pillar for carbon nanochemistry, that is, the main element of all organic compounds.

Its versatility derives from its structure in the form of two-dimensional (2D) sheets, made up of carbon atoms linked in a hexagonal manner, and its importance lies in the extraordinary properties attributed to it and that have been conceived as the solution to innumerable social, environmental, scientific, technological and of course, economic needs.

Graphene sheet. High Resolution Transmission Electron Microscopy.
Energeia Collection – Graphenemex

Graphene allows matter to be modified to design compounds with new or improved characteristics, since it transfers its properties to the materials to which it is incorporated. This has allowed it to be used in the development of applications that seek to potentiate these properties, as shown in the following image.

Evolution – Graphene was first isolated in 2004 by Russian researchers Andre Geim and Konstantin Novoselov from the University of Manchester; subsequently, and thanks to their experiments, in 2010 they were awarded the Nobel Prize in Physics, as it was considered one of the most important discoveries of the century.

So important was the finding that in 2013 the European Union (EU) granted a budget of one billion euros to create the Graphene Flagship, an ambitious project valid for ten years with the aim of linking academia with industry, not only to understand its properties theoretically, but to fully exploit its benefits in real applications or products.

From that moment on, the progress of the investigations was so fast, and the expectations were higher and higher that, in 2017, the first edition of the ISO/TS 80004-13:2017 standard emerged (Ratified by the Spanish Association for Standardization in October 2020) for the normalization and standardization of Nanotechnology in new materials, including Graphene.

In the same 2020, a group of 70 researchers who are members of the Graphene Flagship, published the first manual with more than 500 pages on countless types of Graphene. By 2021, around 50 “spin-offs” and “startups” with different visions were registered within the organization, making the possibility of having a greater number of applications with Graphene or graphene materials at more affordable costs a reality by 2022.

In 2021 again the EU through the Federal Institute for Materials Research and Testing (BAM) with the new ISO-G-SCoPe project, set the objective of standardizing the methods to transfer Graphene to the industry, this as a result of the non-existence of production and quality standards, while, through the Versailles Project on Advanced Materials and Standards, under the direction of BAM, it seeks to validate the processes in a global test to convert them into standards.

Energeia Graphenemex® is the pioneer Mexican company in Latin America focused on the research and production of graphene materials for the development of applications at an industrial level. Among its strengths is the creation of patented methods and processes for replicable and large-scale production that ensures the availability of the appropriate graphene materials in accordance with the requirements of the applications it develops, either for its own products or as a strategic ally of other companies interested in innovating and improving their products with these materials.