Antimicrobial Graphene Coatings

Antimicrobial Graphene

Coatings


In less than 20 years the world has faced a series of abnormal phenomena caused by highly infectious pathogens. The easy and rapid transmission of infections forces us to seek increasingly efficient strategies to strengthen health services, in addition to representing a radical change in our lifestyle, where extreme hygiene techniques are in first place of importance to avoid the spread and massive contagion inside and outside hospitals.

Viral diseases of greater impact.

  • 2002-2003. Severe acute respiratory syndrome (SARS-Cov).
  • 2012. Middle East Respiratory Syndrome (MERS-Cov).
  • 2014- 2016. Ebola.
  • 2019- 2022. SARS-Cov-2.

>6.5 million deaths.

Dangerous bacteria for human health:

  • Staphylococcus aureus.
  • Streptococcus pneumoniae.
  • Pseudomonas aeruginosa.
  • Haemophilus influenzae.
  • Helicobacter pylori.

Hongos frecuentes en ambiente doméstico:

  • Aspergillus spp.
  • Cladosporium spp.
  • Alternaria spp.
  • Acremonium spp.
  • Epiccocum spp.
  • Penicillium spp.
  • Stachybotrys spp.


Graphene as an adjuvant in infection control


In 2018, Energeia- Graphenemex® launched the antimicrobial Graphenergy line, made up of two specialized vinyl- and vinyl-acrylic-based coatings with graphene oxide, whose antimicrobial potential is 400 times higher than common products, helping to keep surfaces free of fungi and bacteria for a long time.

In vitro studies and in a relevant environment carried out by the Laboratory of Pathology, Biochemistry and Microbiology of the Faculty of Stomatology of the U.A.S.L.P., showed that surfaces protected with antimicrobial Graphenergy remain free of microorganisms for more than 6 months, without the need for additional chemicals. Figure 1.

Fig. 1. Results at 2, 4 and 6 months on the protection of antimicrobial Graphenergy compared to a control group (No Graphene Oxide).
Important: A clean surface is in the range of 1-10 CFU/cm2.


In 2022, the strategic alliance between the companies Energeia-Graphenemex® and Oxical® is preparing to launch a new 100% natural coating, without toxic compounds (VOCs), highly waterproof, breathable and highly antimicrobial, made from high-quality and purity lime modified with Graphene nanoparticles, under the ecological Graphenecal brand.

Its extraordinary antimicrobial capacity is not only a great aid in keeping spaces free of microorganisms, but also protects surfaces against biodeterioration, particularly those with high historical value. Figure 2.

Fig. 2. Graphene-free lime paint has a microbial biofilm on more than 90% of its surface. The area covered with organic Graphenecal remained free of contamination for more than 100 days of incubation. The antimicrobial effect of organic Graphenecal is highly effective, with a reduction of microorganisms of 7 Log10.

Is graphene nanotechnology safe?


Yes, Graphenergy and Graphenecal antimicrobial coatings are as safe as any conventional paint or coating. The graphene and graphene oxide nanoparticles contained in its formulations do not shed or release toxic substances into the environment.

“Not all microorganisms are dangerous, but it is better to keep them away”

How do graphene materials work?


  1. Physical barrier- High impermeability. Graphene materials are usually presented in millions of blocks composed of 1 to 10 nanometric sheets similar to a pack of cards, with multiple sinuous paths between each sheet that act as an external barrier that suppresses the entry of essential nutrients for microbial growth.

  2. Graphene and its derivatives can act as electron donors or acceptors, altering the respiratory chain of the microorganism or extracting its electrons. This imbalance in the form of a nano-circuit is so fast that it does not give the microorganism time to recover and, therefore, inactivates it before adhering to the surface.

  3. Structural damage. The edges of the nanomaterial sheets act like small knives that damage or break the cell membrane of the microorganism, altering its functioning and preventing its viability.

Do graphene materials have antiviral activity?


The antiviral effect of graphene materials seems not to be very different from that described against fungi and bacteria. The hypotheses are directed towards an interesting synergistic effect between impermeability, structural damage and electrostatic interactions due to the positive polarity of some viruses (SARS-Cov-2) and the negative polarity of graphene oxide, in addition to its great protein-anchoring capacity.



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. In addition to adding value to its products with the multifunctional properties of Graphene and its derivatives, the company also aims to create strategic alliances to support innovative developments with graphene nanotechnology.


References

  1. García-Contreras R, Guzmán Juárez H, López-Ramos D & Alvarez Gayosso C. Biological and physico-mechanical properties of poly (methyl methacrylate) enriched with graphene oxide as a potential biomaterial. J Oral Res 2021; 10(2):1-9. Doi:10.17126/joralres. 2021.019
  2. UM.D. Giulio, R. Zappacosta, S.D. Lodovico, E.D. Campli, G. Siani, A. Fontana, L. Cellini, Antimicrobial and antibiofilm eficacy of graphene oxide against chronic wound microorganisms. Antimicrob. Agents Chemother. 62(7), e00547-18 (2018). https://doi.org/10.1128/AAC.00547-18
  3. H.E. Karahan, C. Wiraja, C. Xu, J. Wei, Y. Wang, L. Wang, F. Liu, Y. Chen, Graphene materials in antimicrobial nanomedicine: current status and future perspectives. Adv. Healthc. Mater. 7(13), 1701406 (2018). https://doi.org/10.1002/ adhm.201701406
  4. Sydlik SA, Jhunjhunwala S, Webber MJ, Anderson DG, Langer R. In vivo compatibility of graphene oxide with differing oxidation states. ACS Nano. 2015. 9: 3866
  5. Yang K, Zhang S, Zhang G, Sun X, Lee ST, Liu Z. Graphene in mice: ultrahigh in vivo tumor uptake and efficient photothermal therapy. Nano Lett. 2010. 10: 3318.
  6. Bhattacharya K, Farcal LR, Fadeel B. Shifting identities of metal oxide nanoparticles: focus on inflammation. 2014. MRS Bull; 39: 970
  7. Huang PJ, Pautler R, Shanmugaraj J, Labbé G, Liu J. Inhibiting the VIM-2 metallo-β-lactamase by graphene oxide and carbon nanotubes. ACS Appl Mater Interfaces 2015; 7: 9898.
  8. Moghimi SM, Wibroe PP, Wu L, Farhangrazi ZS. Insidious pathogen-mimicking properties of nanoparticles in triggering the lectin pathway of the complement system. Eur J Nanomedicine. 2015; 7: 263.
  9. Bhattacharya K, Mukherjee SP., Gallud A., Burkert SC., Bistarelli S., Bellucci S., Bottini, M., Star A., Fadeel B. Biological interactions of carbon-based nanomaterials: From coronation to degradation. Nanomedicine: Nanotechnology, Biology, and Medicine. 2016. 12. 333

Graphene in the paper industry

Graphene

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.