Category: Graphene

Over the past three decades, the cement industry has reduced CO2 emissions by 40% through clinkerization improvements. In 2021, Mexican cement companies aligned with a roadmap towards a low-carbon economy. Nanotechnologies like graphene oxide (GO) offer significant enhancements, increasing concrete durability, reducing cement use, and improving strength. These innovations benefit both energy efficiency and corrosion control, as well as material workability.

Innovation with Graphene

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Innovation with Graphene

Towards a More Sustainable and Efficient Cement Industry

Part 2

For the cement industry, reducing CO2 emissions is not a new topic. Over the past 30 years, producers have managed to reduce approximately 40% of the fuel needed for the clinkerization process, thus reducing CO2 emissions by the same proportion, given that around 900 g of CO2 are produced per kilogram of cement.

Over ten years ago, a collaboration between the International Energy Agency, the Global Cement and Concrete Association (GCCA), and the Inter-American Cement Federation (FICEM) established the first roadmap for emission reduction. This laid the groundwork for the National Chamber of Cement (CANACEM), FICEM, and companies such as CEMEX, Cruz Azul, Cementos Chihuahua, Cementos Fortaleza, Holcim México, and Cementos Moctezuma to evaluate emissions and determine strategies for low-carbon cement production.

According to the CANACEM roadmap, the main indicators for CO2 reduction are 1) the Clinker/Cement ratio, 2) co-processing, 3) energy efficiency, and 4) exploring new technologies such as CO2 capture, clinker reduction, and cement reinforcement.

In a previous article addressing environmental challenges in the construction industry and the goal of net-zero CO2 emissions by 2050, key opportunities for graphene nanotechnology in sustainable construction were highlighted, including:

  1. Cement reduction,
  2. Waste utilization,
  3. Cost reduction,
  4. Energy efficiency.

On September 4, the website https://www.graphene-info.com/ published the new edition of the Graphene-enhanced Construction Materials Market Report, which delves deeper into the advantages of using graphene in construction materials, related companies, ongoing projects, and research.

Graphene oxide (GO) is a carbon-based nanomaterial with sheet-like structures smaller than 100 nm or 0.1 microns in width and only one atom thick. It has hydroxyl (OH), epoxy (-O-), carboxyl (COOH), and carbonyl (C=O) functional groups on its surface that allow it to interact with cement C-S-H crystals, improving the hydration process. The properties of GO that make it attractive as a chemical modifier for cement include high tensile strength (130 GPa), large surface area (2630 m²/g), high thermal conductivity (5300 W/mK), and barrier properties. This interaction helps improve the properties of cement-based structures, such as concrete, resulting in the following:

  1. Reduced cement consumption in concrete structures while achieving similar mechanical properties, with compressive strength increased by 5% to 30%, tensile strength by 8% to 20%, elastic modulus by 4% to 12%, and abrasion resistance by 10% to 12%.
  2. Better quality and more durable concrete structures due to lower porosity, increasing impermeability by 12% to 60%, improving performance in aggressive environments.
  3. Enhanced thermal diffusivity of concrete, providing better thermal crack control, fire resistance, and de-icing capability for pavements.
  4. Improved workability, better appearance of structures, faster setting time, and easier mold release, as GO acts as a catalyst in the cement hydration reaction.
  5. Protection against microbiologically induced corrosion, as GO limits the conditions necessary for microbial attachment and reproduction.

Since 2018, Energeia-Graphenemex® has been exploring the benefits of graphene nanotechnology across various industrial sectors. As experts in the field, they recommend conducting validation tests, considering the multiple variables in the construction sector, especially those related to new cement compositions, to achieve optimal dosage results, always guided by trained personnel.

Authored by: EF/DHS

References

  1. M. Murali et al., Utilizing graphene oxide in cementitious composites: A systematic review. Case Studies in Construction Materials 17 (2022) e01359.
  2. Z. Pan, et al., Mechanical properties and microstructure of a graphene oxide–cement composite, Cem. Concr. Compos. vol. 58 (2015) 140–147, https://doi. org/10.1016/j.cemconcomp.2015.02.001
  3. E. Cuenca, L. D’Ambrosio, D. Lizunov, A. Tretjakov, O. Volobujeva, L. Ferrara, Mechanical properties and self-healing capacity of ultra high performance fibre reinforced concrete with alumina nano-fibres: tailoring ultra high durability concrete for aggressive exposure scenarios, Cem. Concr. Compos. vol. 118 (2021).
  4. N. Makul, Modern sustainable cement and concrete composites: review of current status, challenges and guidelines, Sustain. Mater. Technol. vol. 25 (2020); 5. L. Lu, P. Zhao, Z. Lu, A short discussion on how to effectively use graphene oxide to reinforce cementitious composites, Constr. Build. Mater. vol. 189 (2018) 33–41.
  5. Q. Wang, J. Wang, C.-x Lu, B.-w Liu, K. Zhang, C.-z Li, Influence of graphene oxide additions on the microstructure and mechanical strength of cement, N. Carbon Mater. vol. 30 (4) (2015) 349–356.
  6. https://canacem.org.mx/site/wp-content/uploads/2023/03/Hoja-de-Ruta-Mexico-FICEM.pdf.
  7. https://cdn.ymaws.com/www.thegraphenecouncil.org/resource/resmgr/case_studies/first_graphene__-_greening_c.pdf
  8. https://www.graphene-info.com

Innovations in Water Technologies

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Innovations in Water Technologies:

The Impact of Graphene

As of June 2024, the National Institute of Statistics and Geography (INEGI) recorded that around 50% of Mexican territory was in severe drought, 30% in extreme drought, and 11% in exceptional drought, significantly impacting not only the supply of drinking water—only 52.3% of the population in Mexico has this service—but also numerous economic activities such as the agricultural and livestock sectors.

However, the water crisis is not a national issue alone. According to WHO/UNICEF, over 2000 million people worldwide lack access to potable water. These organizations have defined sustainable development goals for 2030 to ensure water availability, critical for improving hygiene education; protecting and restoring ecosystems; using water resources efficiently; investing in infrastructure and sanitation facilities; and promoting new water technologies, such as irrigation systems, rainwater collection, and treatment and reuse methods.

One such technology is nanotechnology, revolutionized 20 years ago by the isolation of graphene, a multifunctional carbon-based nanomaterial in the diamond and graphite family. Numerous studies have evaluated its effects on materials used in water technologies, such as filtration membranes and flocculants. Graphene’s extraordinary physicochemical characteristics, which can be controlled and shared with other three-dimensional materials, sparked interest. Initial studies as a nanofiller in primarily polymeric matrices revealed significant mechanical, antiadhesive, antifriction, antimicrobial, and filtering improvements. These enhancements increased its lifespan, reduced organic matter buildup on surfaces, and maintained consistent water flow and filtration efficiency.

For example, researchers from the Indian Institute of Technology Madras and Tel Aviv University in Israel successfully developed a silica aerogel with graphene oxide for wastewater decontamination. Meanwhile, scientists from Palacký University in Olomouc, Czech Republic, under the 2D-CHEM project funded by the European Research Council’s Graphene Flagship, designed acid graphene synthesized from fluorographene to remove heavy metals like lead and cadmium, as well as noble metals like palladium, gallium, and indium.

Notably, the promising research results on graphene in water technologies have moved from laboratories to the market. Companies exploiting its benefits include the Australian company CLEAN TEQ WATER, specializing in water treatment with presence in Melbourne, Beijing, Tianjin, and Africa. Its subsidiary NematiQ successfully developed graphene nanofiltration membranes that are more durable and energy-efficient, recently receiving the WaterMark certification as a safe product for water filtration. The British company EVOVE, formerly known as G2O Water Technologies, utilizes hydrophilic graphene oxide coatings to enhance the performance of conventional ceramic or polymeric membranes.

Finally, collaborative efforts between Graphene Flagship scientists and European leaders in water purification, such as Icon Lifesaver, Medica SpA, and Polymem S.A, through the GRAPHIL project, aim to introduce a new filtration system using hollow fiber polymer membranes mixed with graphene for safe potable water management, primarily for domestic use.

Graphene’s advancements are gradually gaining ground beyond academic borders to address one of the world’s most pressing issues. Energeia-Graphenemex®, a pioneering Mexican company in Latin America in the production and development of graphene materials applications, collaborates with other companies and research centers to find strategies to improve water availability and quality, aiming to bring new graphene applications to the market in the short term.

Author: EF/DHS

The Future of Batteries

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The Future of Batteries:

Graphene as a Sustainable Solution to the Lithium Crisis

In the last decade, the global increase in demand for lithium-ion batteries has been driven by the growing popularity of electronic devices, from portable devices such as tablets, consoles, and cell phones to electric vehicles. According to the International Monetary Fund, it is estimated that by 2050 the demand for batteries will exceed supply by 40%, posing a potential crisis for industries that depend on them if viable alternatives are not implemented.

The issues with lithium-ion batteries are not limited to supply-demand balance. Lithium is a finite resource whose extraction and disposal have negative impacts on the environment and human health. Additionally, batteries present significant safety risks such as instability, overcharging, overheating, and fires.

Graphene, a two-dimensional nanomaterial of carbon with an extremely thin, transparent, and strong sheet structure, has captured the attention of battery experts. Its unique architecture allows for high electrical conductivity and chemical stability, essential characteristics for improving the performance of lithium-ion batteries (LIB), lithium-sulfur batteries (LSB), and lithium-oxygen batteries (LOB).

Benefits of Graphene in Batteries:

  1. Increased Energy Storage Capacity: Graphene has a structure with an extensive surface area, facilitating a greater number of intercalation sites for lithium ions. This translates into a significant improvement in the energy storage capacity of batteries.
  2. Improved Electrical Conductivity: Graphene’s π-π bonds allow efficient electron transport between the active materials of the electrodes and the current collectors. This reduces the internal resistance of the batteries and improves their power output, which is crucial for applications requiring high charge and discharge rates.
  3. Enhanced Stability and Durability: Graphene promotes the stability of electrode materials by preventing premature degradation during charge and discharge cycles. This not only extends the lifespan of batteries but also ensures greater cyclic stability, maintaining consistent performance over time.

Future Perspectives and Alternatives: Despite the continuous growth of the lithium-ion battery market, their environmental risks and technical limitations are driving research towards more sustainable and efficient alternatives. Some of these alternatives include sodium/sulfur-based battery systems, chitin/zinc, silicon/carbon, and combinations of graphene with other advanced materials.

At Energeia-Graphenemex, we are proud to be at the forefront of these innovations, exploring how graphene and other nanotechnological materials can continue transforming the battery industry and contributing to a cleaner and more sustainable energy future.

Writing: EF/ DHS

References:

  1. A. Ali, P.K. Shen, Nonprecious metal’s graphene-supported electrocatalysts for hydrogen evolution reaction: fundamentals to applications, Carbon Energy 2 (2020) 99.
  2. A. Ali, P.K. Shen, Recent progress in graphene-based nanostructured electrocatalysts for overall water splitting, Electrochem. Energy Rev. 3 (2020) 370;
  3. A. Ali, P.K. Shen, Recent advances in graphene-based platinum and Palladium electrocatalysts for the methanol oxidation reaction, J. Mater. Chem. 7 (2019) 22189–22217; 4. Moreno-Brieva, Fernando, & Merino-Moreno, Carlos. (2020). Scientific and Technological Links from Samsung On Lithium Batteries and Graphene. Journal of technology management & innovation, 15(4), 81
  4. Yu Yang, Renjie Wang, Zhaojie Shen, Quanqing Yu, Rui Xiong, Weixiang Shen, Towards a safer lithium-ion batteries: A critical review on cause, characteristics, warning and disposal  strategy for thermal runaway, Advances in Applied Energy, 11, 2023, 100146
  5. https://www.hibridosyelectricos.com/coches/grafeno-baterias-coches-electricos_69751_102.html
  6. https://rpp.pe/columnistas/fernandoortegasanmartin/grafeno-vs-litio-el-futuro-de-las-baterias-automotrices-noticia-1391824
  7. https://www.energymonitor.ai/tech/energy-storage/graphene-is-set-to-disrupt-the-ev-battery-market/
  8. https://www.eleconomista.com.mx/opinion/Datos-sobre-el-mercado-de-smartphones-en-Mexico-20240131-0117.html

Graphene as the Driver of the Energy Revolution

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Graphene as the Driver of the Energy Revolution:

Advances in Efficiency and Renewable Energy Storage

In today’s context, environmental concerns and climate change have shifted from being a trend to a top priority. This has led to the formation of multidisciplinary teams globally, focused on finding more sustainable technological solutions for energy challenges, such as energy generation and storage, with the additional aim of minimizing emissions.

In this context, thermal energy management through passive technologies, like solar energy, has gained significant importance. Its utilization as an eco-friendly and energetically efficient alternative has seen substantial growth, from its application in domestic settings to electricity generation systems.

However, the natural intermittence of solar energy due to diurnal and nocturnal cycles poses long-term challenges. Hence, it’s imperative to consider complementary technologies like Phase Change Materials (PCMs). These materials can absorb thermal energy from the surroundings to change their state, releasing stored energy for heating or cooling applications in various sectors, including construction, electronics, and aerospace.

Among the well-known PCMs is paraffin, which undergoes a solid-liquid phase change to store latent heat by absorbing thermal energy until reaching its melting point. While paraffins offer advantages such as being safe, reliable, economical, and having acceptable stability for long crystallization-fusion cycles, they also face challenges such as low thermal conductivity and leakage in the liquid state.

Fortunately, PCMs, including paraffin, benefit from advances in nanotechnology, especially when modified with nanoparticles like Graphene. Incorporating Graphene into PCMs like paraffin significantly enhances thermal conductivity and energy efficiency, facilitating solar-to-thermal energy conversion and storage.

What makes Graphene so special?

Graphene, with its exceptional physicochemical properties, is one of the most promising nanomaterials as a co-adjuvant in addressing energy-related challenges. Unlike other carbon nanostructures like diamond, graphite, activated carbon, fullerenes, or nanotubes, Graphene exhibits superior electrical and mechanical properties, with the added advantage of easy combination with other compounds like PCMs to share characteristics and enhance performance. For example, compared to nanotubes, one of the most well-known and studied carbon nanostructures, Graphene boasts higher charge mobility (200,000 cm2 V 1 s 1 Vs. 150,000 cm2 V 1 s 1), greater electrical conductivity (6.6 MS m -1 Vs. 0.35 MS m -1), and higher transmittance (97.0% Vs. 95.7%), making it highly attractive for energy-related applications.

How does Graphene relate to PCMs for solar energy utilization?

Historically, from a sustainable perspective and as a real-world application, architecture is a clear example of solar energy utilization. Starting from ancient times with the construction of adobe walls to trap daytime heat and release it at night, to modern infrastructure using heaters or solar panels, to Trombe walls as a passive heating tool. For instance, Trombe walls comprise materials like glass, wood, steel, aluminum, concrete, and PCMs like paraffin, arranged in special configurations that collectively absorb heat to slowly conduct it into the dwelling.

Through the identification of Graphene’s multifunctional properties and the exploration of its benefits in various sectors, it was found that its integration into paraffin used for passive heating systems can significantly improve thermal conductivity or driving force by up to 164%, showcasing clear superiority over highly efficient hybrid nanoparticles like Cu-TiO2 or Al2O3-MWCNT, whose normal benefits range between 50 and 70%. This means that integrating these technologies into passive heating systems, besides improving thermal comfort throughout the year, would also yield significant energy savings and reduce CO2 emissions.

Solar cells

Another well-known potential application of nanotechnology in the energy sector is the design of the fourth generation of solar panels, which includes the use of two-dimensional nanomaterials like molybdenum disulfide (MoS2), tungsten diselenide (WSe2), and again, Graphene.

Among the most representative advantages that Graphene has demonstrated over other materials are, in addition to its mechanical strength, its high charge mobility, great transmittance, lightness, flexibility, and stability, which have led to significant advances in its performance for solar panel design, increasing its efficiency from 1.5% to 15% in less than 10 years, almost comparable to the efficiency of current cells ranging from 20 to 22%. However, in pursuit of further improving these percentages, experts in the field continue to explore methodologies based on Graphene doping with other structures like silicon, molybdenum hexafluoride, molybdenum oxide, thionyl chloride, trioxionitric acid, gold chloride, boron, oxygen, nitrogen, phosphorus, or sulfur, to reduce its resistance and better harness solar energy.

At Energeia-Graphenemex, the leading company in Latin America in the design and development of graphene-based applications, we are aware of the challenges that Graphene, like any emerging technology, faces, and we are pleased to be part of the select group of researchers and industrialists globally seeking to benefit society, the economy, and the environment with the advantages these wonderful materials can offer.

Thanks to our multidisciplinary team, we have quickly overcome the obstacles that have hindered the arrival of this material to the market in real applications, starting with its large-scale production, with controlled quality and at an affordable cost, as well as with the development of new products with graphene nanoengineering, where controlling its stability and compatibility with compounds and processes used in each application or industry has been fundamental.

Graphene as an ally of renewable energies is still in its early stages, not necessarily due to its manipulation but because of the complexity this sector represents. However, the significant advances made over the past decade should not be underestimated, as they lay the groundwork for the next generations of equipment and technologies.

Redaction: EF/DHS

References

  1. Jafaryar M, Sheikholeslami M. Simulation of melting paraffin with graphene nanoparticles within a solar thermal energy storage system. Sci Rep. 2023, 26;13(1):8604;
  2. R. Bharathiraja, T. Ramkumar, M. Selvakumar. Studies on the thermal characteristics of nano-enhanced paraffin wax phase change material (PCM) for thermal storage applications. J. Energy Storage, 73, Part C, 2023, 109216;
  3. Li-Wu Fan, Xin Fang, Xiao Wang, Yi Zeng, Yu-Qi Xiao, Zi-Tao Yu, Xu Xu, Ya-Cai Hu, Ke-Fa Cen, Effects of various carbon nanofillers on the thermal conductivity and energy storage properties of paraffin-based nanocomposite phase change materials, Applied Energy, 110, 2013, 163;
  4. Top Khac Le., et al., Advances in solar energy harvesting integrated by van der Waals graphene heterojunctions. RSC Adv., 2023, 13, 31273

Textile Innovations II

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Textile Innovations:

Exploring Graphene Trends in the Industry

Part II

In the previous article on Textile Innovations, we explored the trends of graphene in the industry, focusing on its practical applications in textiles, leveraging its electrical, thermal, fire resistance, and mechanical properties. In this article, we will delve into the advantages of graphene, considering its multifunctional benefits such as its barrier effect with a focus on waterproofing and antimicrobial properties, as well as its contributions to UV protection and comfort.

Mechanical Resistance

The well-known high mechanical strength of graphene, with a Young’s modulus of ~1100 GPa and a tensile strength of 42 N/m, makes a single layer of graphene 200 times stronger than steel of equal thickness. This strength can be utilized in graphene-modified composites, enabling them to withstand significant forces without deformation, achieving greater strength with a smaller gauge. In wool fabrics, excellent linearity with over 20% elongation, moisture resistance from 30 to 90%, and good electrical and mechanical properties have been observed.

Barrier Properties

The hydrophobic nature of graphene, the size of its nanochannels, and the high electron density on its surface make it highly impermeable to particulate matter, liquids, and gases. Graphene compounds interact with other materials and molecularly organize their three-dimensional structure, creating compounds that are not only impermeable but also mechanically stronger and with significant recovery or deformation resistance.

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Antimicrobial Barrier

Graphene’s antimicrobial capability is advantageous in the textile industry, considering the persistent challenge of microorganism anchoring, proliferation, and spread on garments, especially in the medical sector.

Antimicrobial Barrier Mechanisms

– Size Exclusion: The interatomic distance of carbon atoms in graphene (0.142 nm – 0.9 nm) provides a barrier that microorganisms, with sizes ranging from 10 nm to 3 micrometers, cannot permeate.

– Oxidative Stress: Interactions between the polar ends of phospholipids in cell membranes and graphene generate irreversible oxidative stress and microbial death. Its strong protein anchoring capability can inhibit the enzymatic capacity of some microorganisms.

– Membrane Damage: The sharp edges of graphene layers physically damage the structure of microorganisms, preventing microbial adhesion to surfaces without adverse effects on the skin.

UV Protection

Graphene’s absorption spectrum covers the entire electromagnetic spectrum, with a peak absorption around 281 nm, allowing it to absorb UV radiation with a wavelength between 100 and 281 nm. For wavelengths longer than 281 nm, graphene’s reflective properties play a crucial role in UV radiation resistance and, consequently, in the increased durability of materials exposed to the elements.

Comfort

Traditional textiles like cotton, linen, or silk are highly hydrophilic but have limited water molecule transport capacity. The hydrophobicity of graphene compounds prevents water transport to the inner layer and simultaneously transports water inversely to its outer surface. Its excellent thermal regulation capability prevents the concentration of heat and moisture, creating an environment inhospitable for the proliferation of microorganisms, thus preventing infections, stains, and unpleasant odors.

At Energeia-Graphenemex®, leaders in Latin America in graphene production and development, we are convinced of the tremendous potential of this material to meet the needs of industrial sectors such as the textile industry. We are committed to addressing the scientific, technical, economic, and ethical needs of each project, serving as a strategic ally for companies seeking to innovate and improve their products and processes through the integration of graphene technologies. We look forward to introducing the first graphene textiles in Mexico soon.

Redaction: EF/DH

References:

  1. Graphene Modified Multifunctional Personal Protective Clothing. Adv. Mater. Interfaces 2019, 6, 1900622;
  2. Graphene-based fabrics and their applications: a review. RSC Advances. 2016, 6:68261;
  3. Fabrication of a graphene coated nonwoven textile for industrial applications. Australian Institute for Innovative Materials – Papers. 2016, 2173;
  4. New Perspectives on Graphene/ Polymer Fibers and Fabrics for Smart Textiles: The Relevance of the Polymer/Graphene Interphase. Front. Mater. 2018, 5:18;
  5. Graphene applied textile materials for wearable e-textile. 5 th International Istanbul Textile Congress 2015: Innovative Technologies Inspire to Innovate‖ September 11th -12th 2015 Istanbul, Turkey;
  6. The Effect of Graphene Oxide on Flame Retardancy of Polypropylene and Polystyrene. Materials Performance and Characterization 2020, 9, 1, 284;
  7. Engineering Graphene Flakes for Wearable Textile Sensors via Highly Scalable and Ultrafast Yarn Dyeing Technique. ACS Nano 2019, 13, 4, 3847;
  8. Highly Conductive, Scalable, and Machine Washable Graphene-Based E-Textiles for Multifunctional Wearable Electronic Applications. Adv. Funct. Mater. 2020, 30, 2000293;
  9. Moisture- Resilient graphene – dyed wool fabric for strain sensing. ACS App. Mater. Interfaces. 2020, 12, 11,13265;
  10. Creating Smart and Functional Textile Materials with Graphene. Nanomaterials and Nanotechnology Biomedical, Environmental, and Industrial Applications. 2021, Chapter 13.;
  11. Graphene oxide incorporated waste wool/PAN hybrid fibres. Sci Rep 2021, 11, 12068;
  12. Moisture-Resilient Graphene-Dyed Wool Fabric for Strain Sensing. ACS Applied Materials & Interfaces 2020, 12, 11, 13265;
  13. Thermal Degradation and Flame-Retardant Mechanism of the Rigid Polyurethane Foam Including Functionalized Graphene Oxide. Polymers 2019, 11, 78;
  14. Tuning sound absorbing properties of open cell polyurethane foam by impregnating graphene oxide. App Acoustics. 151, 2019, 10;
  15. Intumescent flame-retardant polyurethane/reduced graphene oxide composites with improved mechanical, thermal, and barrier properties. Journal of Materials Science. 2014, 49, 243;
  16. Production and characterization of Graphene Nanoplatelet-based ink for smart textile strain sensors via screen printing technique. Materials & Design. 198, 15 2021, 109306;
  17. Caracterización de un tejido mezcla poliéster/ algodón aplicando grafeno mediante el proceso de adsorción. Tesis 2020;
  18. Síntesis y formulación de nuevas espumas de poliuretano flexibles con propiedades mejoradas. Tesis 2018.

Textile Innovations

Posted on | by Energeia Graphenemex

Textile Innovations:

Exploring Graphene Trends in the Industry

Part I

Graphene, a two-dimensional nanomaterial made of carbon atoms, is revolutionizing materials science and nanotechnology. It stands as the only known material that combines a myriad of thermal, electrical, mechanical, optical, and other properties. Moreover, it can integrate with other structures, sharing and significantly enhancing their original characteristics. Since its isolation in 2004, researchers and industries worldwide have sought to leverage its extraordinary benefits. However, high production costs and challenges in obtaining sufficient quantities for industrial applications have hindered widespread market adoption.

Despite these challenges, the textile industry has not remained idle in the face of the opportunities presented by graphene nanotechnology. Over the last decade, it has explored not only graphene but also other nanomaterials like copper nanoparticles (CuNp’s), silver (AgNp’s), gold (AuNp’s), zinc oxide (ZnO), titanium dioxide (TiO2), and carbon nanotubes, among others. The goal is to imbue textiles with antimicrobial properties, flame retardancy, mechanical strength, electrical conductivity, and various other attributes. The key difference lies in graphene’s multifunctional capabilities; it can provide or enhance more than one benefit simultaneously.

What Benefits Does Graphene Offer in the Textile Industry?

Graphene boasts an extensive and complex list of properties, ranging from mechanical to barrier-related, making it highly attractive for numerous applications. In the textile industry, initial interest focused on its electrical and thermal conductivity. However, extensive research has unveiled a wide array of benefits correlating with its multifunctionality.

It’s crucial to note that the extraordinary characteristics of graphene, as described in the literature, often pertain to measurements conducted on nanomaterials in their pure form. To truly capitalize on their benefits in tangible applications, it’s necessary to combine them with three-dimensional materials capable of transferring their properties. Polymeric matrices have proven highly efficient as a support for graphene materials, with interfaces that are strong and stable facilitating superior property transfer.

How Does Graphene Interact with Textile Materials?

At the nanoscale, interaction mechanisms depend on multiple factors and generally involve electrostatic interactions, Van der Waals forces, hydrogen bonding, π-π interactions, or hydrophobic interactions. On the macroscale, understanding this interaction is contingent on the type of graphene, textile material, and the integration method or timing. The latter is particularly crucial because having the right graphene is not sufficient; anchoring and permanence throughout the structure of natural or synthetic textile fibers are variables that increase complexity.

In many cases, additional chemical modifications to graphene are necessary, and the implementation of other additives for charge modification is considered. Various technologies, such as vacuum infiltration, pressing, or dyeing methods, may be employed to improve interaction. However, these methods may be superficial, and achieving mechanical or flame-retardant benefits may require further chemical modifications or the use of specific technologies.

Due to the breadth of the topic, this article is divided into two sections. In this first part, we will discuss the uses of electrical, thermal (fire resistance), and mechanical properties of graphene in textiles. The next publication will conclude the description of barrier properties, protection against UV radiation, and comfort.

Electrical Conductivity

Graphene’s high electrical conductivity is fascinating for manufacturing smart textiles incorporating sensors, microprocessors, light indicators, fiber optics, etc. Applications extend to textiles with electromagnetic and antistatic protection, with potential uses in industries like oil, mining, military, and medicine. Graphene’s corrosion-free, lightweight, and flexible nature sets it apart from metallic fibers.

Studies have explored incorporating digital or electronic components into garments, such as glucose monitors, heart rate monitors, gas sensors, tension and torsion monitors, motion sensors, acoustic sensors, pulse sensors, or even solar energy harvesting.

Thermal Conductivity

Graphene’s well-known thermal conductivity benefits the rapid dissipation of heat in various materials, including textiles. Its integration into viscoelastic materials for mattresses or textiles used in summer garments helps maintain thermal balance associated with comfort and rest. Therapeutic applications are also being studied to stimulate blood circulation and aid muscle recovery from fatigue.

Graphene textiles have been used as heating elements in industrial and residential heating components such as carpets, car seats, and de-icing systems for aircraft access routes. Graphene, being corrosion-free and allowing for lower weight, offers additional advantages over metallic heating elements.

Fire Resistance

The thermal stability of graphene materials depends on their chemical structure and can range from 500°C to 3000°C. However, these conditions may vary when functionalized or combined with other materials. In certain cases, graphene can increase the decomposition temperature and ignition time. Graphene acts as a gas barrier due to its tortuous internal structure, reducing the diffusion of combustible gas to the flame source, inhibiting oxygen diffusion, delaying initial combustion, and preventing re-ignition. Graphene improves the thermal stability of polymers by decreasing the heat release rate, preventing fire spread, and reducing ignition time.

While some polymers with graphene may accelerate ignition time, once a carbon layer forms, it covers the polymer’s external surface and protects the sublayer from fire spread. Graphene’s chemical composition is free of halogens, eliminating the release of furans and dioxins that cause environmental issues.

At Energeia-Graphenemex®, leaders in Latin America in graphene production and development, we believe in the tremendous potential of this material to meet the needs of industrial sectors such as the textile industry. We are also aware of the scientific, technical, economic, and ethical needs inherent in each project. As a strategic ally, we collaborate with companies interested in innovating and improving their products and processes by forming multidisciplinary teams to pave the way for the introduction of new technologies like graphene into the market. We look forward to soon seeing the first graphene textiles in Mexico.

Redaction: EF/DH

References:

  1. Graphene Modified Multifunctional Personal Protective Clothing. Adv. Mater. Interfaces 2019, 6, 1900622;
  2. Graphene-based fabrics and their applications: a review. RSC Advances. 2016, 6:68261;
  3. Fabrication of a graphene coated nonwoven textile for industrial applications. Australian Institute for Innovative Materials – Papers. 2016, 2173;
  4. New Perspectives on Graphene/ Polymer Fibers and Fabrics for Smart Textiles: The Relevance of the Polymer/Graphene Interphase. Front. Mater. 2018, 5:18;
  5. Graphene applied textile materials for wearable e-textile. 5 th International Istanbul Textile Congress 2015: Innovative Technologies Inspire to Innovate‖ September 11th -12th 2015 Istanbul, Turkey;
  6. The Effect of Graphene Oxide on Flame Retardancy of Polypropylene and Polystyrene. Materials Performance and Characterization 2020, 9, 1, 284;
  7. Engineering Graphene Flakes for Wearable Textile Sensors via Highly Scalable and Ultrafast Yarn Dyeing Technique. ACS Nano 2019, 13, 4, 3847;
  8. Highly Conductive, Scalable, and Machine Washable Graphene-Based E-Textiles for Multifunctional Wearable Electronic Applications. Adv. Funct. Mater. 2020, 30, 2000293;
  9. Moisture- Resilient graphene – dyed wool fabric for strain sensing. ACS App. Mater. Interfaces. 2020, 12, 11,13265;
  10. Creating Smart and Functional Textile Materials with Graphene. Nanomaterials and Nanotechnology Biomedical, Environmental, and Industrial Applications. 2021, Chapter 13.;
  11. Graphene oxide incorporated waste wool/PAN hybrid fibres. Sci Rep 2021, 11, 12068;
  12. Moisture-Resilient Graphene-Dyed Wool Fabric for Strain Sensing. ACS Applied Materials & Interfaces 2020, 12, 11, 13265;
  13. Thermal Degradation and Flame-Retardant Mechanism of the Rigid Polyurethane Foam Including Functionalized Graphene Oxide. Polymers 2019, 11, 78;
  14. Tuning sound absorbing properties of open cell polyurethane foam by impregnating graphene oxide. App Acoustics. 151, 2019, 10;
  15. Intumescent flame-retardant polyurethane/reduced graphene oxide composites with improved mechanical, thermal, and barrier properties. Journal of Materials Science. 2014, 49, 243;
  16. Production and characterization of Graphene Nanoplatelet-based ink for smart textile strain sensors via screen printing technique. Materials & Design. 198, 15 2021, 109306;
  17. Caracterización de un tejido mezcla poliéster/ algodón aplicando grafeno mediante el proceso de adsorción. Tesis 2020;
  18. Síntesis y formulación de nuevas espumas de poliuretano flexibles con propiedades mejoradas. Tesis 2018.

Graphene and Tribology

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Graphene and Tribology:

The Future of Lubricants and Energy Efficiency in the Industry

Tribology is the science that studies friction, wear, and lubrication, both of natural and artificial systems in relative motion. Its study is important since all the mechanical systems in motion that surround us consume large amounts of energy due to friction. This can lead to structural deformation and fatigue, or cause crack initiation and propagation that ultimately leads to the formation of loose wear debris in the mechanisms.

As surfaces wear, they become rougher and highly reactive due to the formation of defects, causing greater energy dissipation, becoming a highly damaging cycle. This is because when one surface slides tangentially over another, there is resistance to movement caused mainly by interference between the roughness, sometimes macroscopic, between two surfaces. This resistance is called friction and occurs in the form of wear, increased temperature, and deformation. Even in the presence of a lubricating film, when the load capacity is large or the sliding time is long, the lubricating film loses thickness breaks, generating heat and friction, causing significant failures in the parts of metallurgical equipment.

“Friction and wear not only affect the operation and maintenance of industrial equipment, but the energy loss caused by these phenomena accounts for 1/3 of the world’s industrial energy consumption, while 80% of failures in pieces result in important economic impacts.”

Extensive research on the tribological properties of graphene and its derivatives has positioned it as an important two-dimensional nano-lubricant element, with anti-friction, anti-wear and anti-corrosive effects due to the following mechanisms:

• Nanometric Protective Layer: Graphene sheets, thanks to their lamellar morphology and surface energy, form a protective film that prevents direct contact between sliding surfaces. This shield minimizes friction and wear, even at micro and nano levels.

• Continuous Sliding: The weak bonds between graphene sheets allow continuous sliding, avoiding contact between moving surfaces. When these bonds are broken, the sheets are redistributed, maintaining the integrity of the protective film.

• Suppression of Degradations: Graphene suppresses abrasive, adhesive and corrosive degradation, reducing friction and preventing wear.

• Energy Dissipation Mechanisms: The stretching and bending of graphene compounds act as efficient energy dissipation mechanisms.

Theoretical studies suggest that, as temperature increases, the friction force decreases due to the accumulation of charge between carbon and hydrogen atoms, generating electrostatic repulsion. These properties have led to friction coefficients from 0.05 to 0.0003, without significant surface wear.

Energeia-Graphenemex®: Leader in Development of Technologies with Graphene

Energeia-Graphenemex®, a pioneer company in Latin America, stands out for its focus on the industrial development of graphene. Its experience in creating affordable, large-scale production methods ensures the availability of graphene materials for various applications, from its own products to strategic collaborations with other companies seeking to incorporate graphene technology into their products.

An important point to consider is that the effectiveness of graphene materials does not only lie in their simple presence within a new material, but that is also, to improve their performance as a lubricant, additional chemical modifications may be required, e.g., with nitrogen, elements. metals and their oxides, polymers, compounds such as molybdenum disulfide, boron nitride, dimanganese tetraoxide, stearic acid, oleic acid, alkylamine, among others that are being studied. At Energeia-Graphenemex® we hope to soon have the first graphene lubricant available in Mexico.

Drafting: EF/DH

References

  1. Bao Jin. Lubrication properties of graphene under harsh working conditions. Mater. Today Adv. 2023, 18, 100369;
  2. Liu. Yanfei, Xiangyu Ge, Jinjin Li, Graphene Lubrication, Appl. Mater. Today. 2020, 20, 100662;
  3. Jianlin Sun and Shaonan Du. Application of graphene derivatives and their nanocomposites in tribology and lubrication: a review. RSC Adv., 2019, 9, 40642;
  4. Zhiliang Li, Chonghai Xu, Guangchun Xiao, Jingjie Zhang, Zhaoqiang Chen and Mingdong Yi. Lubrication Performance of Graphene as Lubricant Additive in 4-n-pentyl-40 -cyanobiphyl Liquid Crystal (5CB) for Steel/Steel Contacts. Mater. 2018, 11, 2110;
  5. J. Li, X. Ge, J Luo, Random occurrence of macroscale superlubricity of graphite enabled by tribo-transfer of multilayer graphene nanoflakes, Carbon. 2018, 138, 154;
  6. T. Arif, G. Colas, T Filleter, Effect of humidity and water intercalation on the tribological behavior of graphene and graphene oxide, ACS Appl. Mater. Inter- faces, 2018, 10,26, 22537;
  7. Y. Liu, J. Li, X. Chen, J Luo, Fluorinated graphene: A promising macroscale solid lubricant under various environments, ACS Appl. Mater. Interfaces, 2019, 11, 43, 40470;
  8. O.L. Luévano-Cabrales, M. Alvarez-Vera, H.M. Hdz-García, R. Muñoz-Arroyo, A.I. Mtz-Enriquez, J.L. Acevedo-Dávila, et al., Effect of graphene oxide on wear resistance of polyester resin electrostatically deposited on steel sheets, Wear 2019, 426, 296;
  9. R.K. Upadhyay, A. Kumar, Effect of humidity on the synergy of friction and wear properties in ternary epoxy-graphene-MoS 2 composites, Carbon, 2019, 146, 717.

Graphene and nanomedicine: the perfect combination for improved health

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Graphene and nanomedicine:

the perfect combination for improved health

Part III. Dentistry- Implantology

The application of nanotechnology in nanomedicine is based on the fact that most biological molecules, from DNA, amino acids and proteins to constituents such as hydroxyapatite and collagen fibrils, among others, exist and function at the nanometric scale.

Nanometer (nm): millionth of 1 millimeter.

Graphene materials are two-dimensional (2D) sheet-shaped carbon nanoparticles that have gained popularity in the field of biomedical sciences not only for their incredible mechanical, thermal, electrical, optical, and biological properties, but also for their ability to transfer these properties to other materials allowing the possibility of creating new compounds with advanced characteristics. In Odontology, and particularly in relation to implantology, this transfer of properties has opened numerous lines of research with great expectations due to the interesting synergistic effect between infection control and its regenerative capacity.1

Nanoparticle: particle that measures between 1 and 100 nm.

Graphene as a new strategy for the design and manipulation of dental implants and tissue regeneration. Taken from Tissue Eng Regen Med. 2017; 14(5):481

What are the problems that graphene could solve?

Osseointegration

One of the main concerns after the placement of an implant is the failure of its osseointegration. This can occur because instead of bone cells growing at the bone-implant interface, fibrous tissue grows that does not allow implant stabilization. An alternative to favor site conditions where cell interactions will occur is modification of the implant surface by physical or chemical methods to create nanoporosities that increase surface area and favor cell activity. 2

Osseointegration: Firm, stable, and long-lasting connection between an implant and the surrounding bone. Its success depends on biological and systemic factors of the patient, in addition to the characteristics of the implant.

In the case of graphene materials, in addition to their extensive and extremely thin surface area one atom thick, another of their added values is the cloud of electrons that surrounds them, and the presence of some oxygenated groups allows them to interact with proteins serum to form a focal adhesion. In other words, the hydrophobic/hydrophilic nature of these nanomaterials in combination with the roughness of the surface contributes to the interaction with proteins and later with cells, acting as a scaffold to promote the growth, differentiation, and anchorage of bone cells in the implant, paving the way for a stable and predictable osseointegration with a better projection of useful life.3,4

The regenerative impact of graphene materials lies in their great ability to adsorb proteins, creating a layer between cells and the surfaces of the materials to promote cell adhesion and proliferation.1

Infection control

Another cause for implant failure is the appearance of peri-prosthetic or peri-implant infections; to avoid them, it is common to use techniques such as antibiotic impregnation, local drug delivery systems, and the coating of implants with titanium nanotubes, silver nanoparticles, or polypeptide nanofilms for the controlled release of antibiotics.5 However, the worrying increase of antibiotic resistance has made these strategies less and less effective.

Graphene materials, in addition to their biocompatibility, have intrinsic antimicrobial properties with advantages over traditional antibiotics as they have less chance of developing microbial resistance. Odontology has been exploring these effects for several years on bioceramic materials such as alumina and zirconium, metals such as titanium, restorative materials such as glass ionomer, and polymeric materials such as polymethyl methacrylate (PMMA), to name a few. In general, the antimicrobial mechanisms accepted for these nanostructures are: 1) physical damage to the membrane, 2) oxidative stress, 3) inactivation by electron withdrawal, 4) isolation against the passage of nutrients and finally, 5) in the case of coatings, control of hydrophobicity and surface energy can also prevent cell attachment with low affinity and prevent biofilm formation.6,7

Biofilm: Layer of microorganisms that grow and adhere to the surface of a natural structure such as teeth (dental plaque) or artificial such as a medical device (intravascular catheters).

In 2021, a group of scientists from the University of Gwangju, Korea, published a study in which they coated zirconium implants with graphene oxide using the argon plasma method. Their results reported that this modification reduced by 58.5% the presence of Streptococcus mutans, the bacterium with the greatest influence on the formation of dental plaque and dental caries, agreeing with a significant reduction in biofilm thickness of 43.4%. In addition to the antimicrobial effect, they also showed a statistically significant increase of 3.2% and 15.7% in the proliferation and differentiation of bone cells.8 These results are consistent with what was reported by the Jiao Tong University, Shanghai, on a hybrid material of titanium with graphene. synthesized by the spark plasma sintering (SPS) technique. Similarly, the research demonstrated an interesting decrease in the formation of multibacterial biofilms composed of Streptococcus mutans, Fusobacterium nucleatum and Porphyromonas gingivalis, accompanied by an improvement in the activity of human gingival fibroblasts, one of the most important cell groups involved in healing.9 In addition to the synergy between infection control and its regenerative capacity, other studies related to dental implantology are also focusing their attention on the mechanical properties for the design of new implants or restorative materials. 10-12

Energeia-Graphenemex, the pioneering Mexican company in Latin America in the research and development of applications with graphene materials, throughout its 10-year career has overcome numerous scientific and commercial challenges to reach the market with products for different industries. And being aware that to reach the health sector it is essential to carry out exhaustive evaluations, kindly invites all those companies and/or research centers that are interested in continuing to explore the benefits of graphene materials and laying increasingly solid foundations on their safe use for biomedical applications.

Drafting: EF/DHS

References

  1. ¿Can Graphene Oxide Help to Prevent Peri-Implantitis in the Case of Metallic Implants? Coatings 2022, 12, 1202.
  2. New design of a cementless glenoid component in unconstrained shoulder arthroplasty: a prospective medium term analysis of 143 cases. Eur J Orthop Surg Traumatol 2013. 23(1):27–34 7.
  3.  European Journal of Orthopaedic Surgery & Traumatology (2018) 28:1257
  4. Graphene-Based Biomaterials for Bone Regenerative Engineering: A Comprehensive Review of the Field and Considerations Regarding Biocompatibility and Biodegradation. Adv. Healthc. Mater. 2021, 2001414.
  5. Nanotechnology and bone regeneration: a mini review. 2014 Int Orthop 38(9):1877–1884 /1. European Journal of Orthopaedic Surgery & Traumatology (2018) 28:1257
  6. Graphene: ¿An Antibacterial Agent or a Promoter of Bacterial Proliferation? iSciencie. 2020.  23, 101787
  7. Graphene: The game changer in dentistry. IP Annals of Prosthodontics and Restorative Dentistry 2022;8(1):10
  8. Antibacterial Activity of Graphene Depends on Its Surface Oxygen Content.
  9. Direct-Deposited Graphene Oxide on Dental Implants for Antimicrobial Activities and OsteogenesisInt. J. Nanomedicine 2021 :16 5745
  10. Graphene-Reinforced Titanium Enhances Soft Tissue Seal. Front. Bioeng. Biotechnol. 2021. 9:665305.
  11. Graphene-Doped Polymethyl Methacrylate (PMMA) as a New Restorative Material in Implant-Prosthetics: In Vitro Analysis of Resistance to Mechanical Fatigue. J. Clin. Med. 2023, 12, 1269.
  12. Mechanical Characterization of Dental Prostheses Manufactured with PMMA–Graphene Composites. Materials 2022, 15, 5391
  13. Fabrication and properties of in situ reduced graphene oxide-toughened zirconia composite ceramics. J. Am. Ceram. Soc. 2018, 101, 8

The safety of graphene in human health: what science says about it

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The safety of graphene in human health:

what science says about it

Part II. Are graphene materials safe for humans?

The family of graphene materials comprises a wide range of two-dimensional (2D) carbon nanostructures in the form of sheets that differ from each other by the particularities derived from the production method or by the innumerable functionalizations that can be performed after its obtaining. In 2022, Nature magazine, one of the most important scientific journals in the world, published a study in which 36 products from graphene suppliers from countries such as the United States, Norway, Italy, Canada, India, China, Malaysia and England were analyzed, concluding that graphenes represent a heterogeneous class of materials with variable characteristics and properties, whether mechanical, thermal, electrical, optical, biological, etc., which can be transferred to a large number of three-dimensional (3D) compounds to modify or create new products.

“Undoubtedly, graphene and nanotechnology in general continue to be controversial issues as they confront us with a world that is difficult to see and understand, but with simply amazing effects”

Are graphene materials safe?

Graphene materials promise to be an important tool within biomedical technologies. In principle, its benefits can be used for the design of diagnostic elements such as sensors and devices for images up to neural interfaces, gene therapy, drug delivery, tissue engineering, infection control, phototherapy for cancer treatment, bioelectronic and dental medicine, among other. But for them to be truly used in this type of technology, their interactions with the biological environment must first be understood or, failing that, ensure that their presence does not alter the natural environment of the cells. In this sense, numerous studies have been carried out with the different forms, presentations, and available concentrations of graphene whose findings have gradually paved the way for its safe use in biomedical technologies:

i) Graphene materials in their free form. In in vitro tests, exposure of human lung epithelial cells to graphene sheets at concentrations lower than 0.005 mg/ml did not cause significant changes in their morphology or adhesion,2,3 nor was cytotoxic activity identified in stem cells derived from adipose tissue. human, periodontal ligament and dental pulp exposed to 0.5 mg/ml of GO,4 even and understanding a possible dose-size dependent effect, other investigations report safe concentrations below 40 mg/ml or, that do not exceed 1, 5% w/v. 5-8

Finally, one of the most recent in vivo studies published by the University of Manchester, United Kingdom, on the pulmonary response of mice exposed to graphene oxide (GO) in the respiratory tract, did not identify significant damage or pulmonary fibrosis at 90-day follow-up. These results provide solid grounds for the safety of these nanostructures without underestimating basic safety measures, such as avoiding their inhalation.9 Likewise, scientists from the University of Trieste, Italy, analyzed the impact of graphene materials on the skin, reporting low toxicity on cells.10

“It is unlikely that graphene materials in their free form are used to be in contact with the biological environment, they are generally functionalized or immobilized in other materials to develop an application”

ii) Functionalized graphene materials. Functionalization is the term that refers to the chemical modification of a nanomaterial to give it a “function”, that is, to facilitate its incorporation with other compounds or to benefit its biocompatibility and better direct its use by anchoring functional groups, molecules, or nanoparticles. A study published in the journal Nature Communications on graphene bioapplications highlights the importance of its functionalization with amino groups to make it more compatible with human immune cells.11,12

“The most common functionalization of graphene is the anchoring of oxygenated groups on its surface, this material is known as graphene oxide”

iii) Immobilization in polymers. The use of graphene materials as nano-filling for plastics, resins, coatings, etc., is the most common way in which these nanostructures are used. For the biomedical sector, its immobilization in polymers has shown good biocompatibility and stimulation of cell proliferation; antimicrobial activity and improvement of the mechanical properties of polymers, being classified as excellent candidates for the manufacture of bone fixation devices, molecular scaffolds, orthopedic implants, or dental materials.13-15

Given the great potential of graphene materials in health sciences, but also due to the many questions about their safety, an international research team from the European Graphene Flagship project, led by EMPA (German acronym for the Federal Institute for Testing and Materials Research), conducted a study to assess the potential health effects of graphene materials immobilized within a polymer; the results showed that the graphene particles released from said polymeric compounds after abrasion induce insignificant effects.16

“It is reassuring to see that this study shows negligible effects, confirming the viability of graphene for mass applications. Andrea C. Ferrari, Graphene Flagship Science and Technology Officer.” 17,18

Energeia-Graphenemex, the pioneering Mexican company in Latin America in the research and development of applications with graphene materials, throughout its 10-year career has overcome numerous scientific and industrial challenges to reach the market with products for industrial use. In 2018, it began to explore the antimicrobial capabilities of its products with excellent results in vitro and in a relevant environment; currently, and in conjunction with other research centers, it is carrying out evaluations to explore the potential of its materials as nano-reinforcement of biopolymers.

Drafting: EF/DHS

References

  1. Cytotoxicity survey of commercial graphene materials from worldwide. npj 2D Materials and Applications (2022) 6:65
  2. Biocompatibility of Pristine Graphene Monolayers, Nanosheets and Thin Films. 2014, 1406.2497.
  3. Preliminary In Vitro Cytotoxicity, Mutagenicity and Antitumoral Activity Evaluation of Graphene Flake and Aqueous Graphene Paste. Life 2022, 12, 242
  4. Biological and physico-mechanical properties of poly (methyl methacrylate) enriched with graphene oxide as a potential biomaterial. J Oral Res 2021; 10(2):1
  5.  Graphene substrates promote adherence of human osteoblasts and mesenchymal stromal cells. Carbon. 2010; 48: 4323–9
  6. Multi-layer Graphene oxide in human keratinocytes: time-dependent cytotoxicity. Prolifer Gene Express Coat 2021; 11:1
  7. Cytotoxicity assessment of graphene-based nanomaterials on human dental follicle stem cells. Colloids Surf B Biointerfaces. 2015; 136:791
  8. Arabinoxylan/graphene-oxide/nHAp-NPs/PVA bionano composite scaffolds for fractured bone healing. 2021. J. Tissue Eng. Regen. Med. 15, 322.
  9. Size-Dependent Pulmonary Impact of Thin Graphene Oxide Sheets in Mice: Toward Safe-by-Design. Adv. Sci. 2020, 7, 1903200
  10. Differential cytotoxic effects of graphene and graphene oxide on skin keratinocytes. 2017. Sci Rep 7, 40572
  11. Amine-Modified Graphene: Thrombo-Protective Safer Alternative to Graphene Oxide for Biomedical Applications. ACS Nano 2012, 6, 2731
  12. Single-cell mass cytometry and transcriptome profiling reveal the impact of graphene on human immune cells. Nature Communications, 2017, 8: 1109,
  13. In-vitro cytotoxicity of zinc oxide, graphene oxide, and calcium carbonate nano particulates reinforced high-density polyethylene composite. J. Mater Res. Technol. 2022. 18: 921
  14. Graphene-Doped Polymethyl Methacrylate (PMMA) as a New Restorative Material in Implant-Prosthetics: In Vitro Analysis of Resistance to Mechanical FatigueJ. Clin. Med. 2023, 12, 1269
  15. High performance of polysulfone/ Graphene oxide- silver nanocomposites with excellent antibacterial capability for medical applications. Matter today commun. 2021. 27
  16. Hazard assessment of abraded thermoplastic composites reinforced with reduced graphene oxide. J. Hazard Mater. 2022. 435. 129053
  17. https://www.empa.ch/web/s604/graphene-dust
  18. https://www.graphene-info.com/researchers-asses-health-hazards-graphene-enhanced-composites