Biomedical applications of the graphene-based materials

Graphene-Oxide Peptide-Containing Materials for Biomedical Applications

This review explores the application of graphene-based materials (GBMs) in biomedicine, focusing on graphene oxide (GO) and its interactions with peptides and proteins. GO, a versatile nanomaterial with oxygen-containing functional groups, holds significant potential for biomedical applications but faces challenges related to toxicity and environmental impact. Peptides and proteins can be functionalized on GO surfaces through various methods, including non-covalent interactions such as π-π stacking, electrostatic forces, hydrophobic interactions, hydrogen bonding, and van der Waals forces, as well as covalent bonding through reactions involving amide bond formation, esterification, thiol chemistry, and click chemistry. These approaches enhance GO's functionality in several key areas: biosensing for sensitive biomarker detection, theranostic imaging that integrates diagnostics and therapy for real-time treatment monitoring, and targeted cancer therapy where GO can deliver drugs directly to tumor sites while being tracked by imaging techniques like MRI and photoacoustic imaging. Additionally, GO-based scaffolds are advancing tissue engineering and aiding tissues' bone, muscle, and nerve tissue regeneration, while their antimicrobial properties are improving infection-resistant medical devices. Despite its potential, addressing challenges related to stability and scalability is essential to fully harness the benefits of GBMs in healthcare.

Synthesis of Multi-Functional Graphene Monolayers via Bipolar Electrochemistry

Graphene has gained substantial research interest in many fields due to its remarkable properties among many other two-dimensional materials. In this study, we propose a wireless electrochemical approach, bipolar electrochemistry, for the precise modification of single layers of graphene at predefined locations, such as distinct edges or corners, with a variety of metals or polymers, thus enabling the elaboration of multi-functional monolayer graphene sheets. We illustrate the concept e. g. by depositing multiple metals, or platinum and a catalyst-containing porous polymer on the same graphene sheet, but at separate corners. This configuration allows activating chemiluminescence on the polymer spot, and simultaneously generates the driving force for autonomous motion on the Pt side through the catalytic decomposition of hydrogen peroxide into oxygen bubbles. This integration of different chemical features on the same object, exemplified by these proof-of-principle experiments, enhances the functionality of two-dimensional materials, paving the way for the use of these hybrid materials for a variety of applications, ranging from sensing and catalysis to targeted delivery.

Pristine/folate-functionalized graphene oxide as two intrinsically radioiodinated nano-theranostics: self/dual in vivo targeting comparative study

Background

Nanomedicine offers great potentials for theranostic studies via providing higher efficacy and safety levels. This work aimed to develop and evaluate a new nanoplatform as a tumor theranostic probe.

Results

Carboxyl-functionalized graphene oxide nanosheets (FGO) was well synthesized from graphite powder and then conjugated with folic acid to act as a targeted nano-probe. Full characterization and in vitro cytotoxicity evaluation were conducted; besides, in vivo bio-evaluation was attained via intrinsic radioiodination approach in both normal and tumor-bearing Albino mice. The results indicated that FGO as well as conjugated graphene oxide nanosheets (CGO) are comparatively non-toxic to normal cells even at higher concentrations. Pharmacokinetics of FGO and CGO showed intensive and selective uptake in the tumor sites where CGO showed high T/NT of 7.27 that was 4 folds of FGO at 1 h post injection. Additionally, radioiodinated-CGO (ICGO) had declared a superior prominence over the previously published tumor targeted GO radiotracers regarding the physicochemical properties pertaining ability and tumor accumulation behavior.

Conclusions

In conclusion, ICGO can be used as a selective tumor targeting agent for cancer theranosis with aid of I-131 that has a maximum beta and gamma energies of 606.3 and 364.5 keV, respectively.

Regulation of astrocyte activity and immune response on graphene oxide-coated titanium by electrophoretic deposition

Introduction: Astrocytes play crucial role in modulating immune response in the damaged central nervous system. Numerous studies have investigated the relationship between immune responses in astrocytes and brain diseases. However, the potential application of nanomaterials for alleviating neuroinflammation induced by astrocytes remains unexplored. Method: In this study, we utilized electrophoretic deposition (EPD) to coat graphene oxide (GO) onto titanium (Ti) to enhance the bioactivity of Ti. Results: We confirmed that GO-Ti could improve cell adhesion and proliferation of astrocytes with upregulated integrins and glial fibrillary acidic protein (GFAP) expression. Moreover, we observed that astrocytes on GO-Ti exhibited a heightened immune response when exposed to lipopolysaccharide (LPS). Although pro-inflammatory cytokines increased, anti-inflammatory cytokines and brain-derived neurotrophic factors involved in neuroprotective effects were also augmented through nuclear localization of the yes-associated protein (YAP) and nuclear factor kappa B (NF-κB). Discussion: Taken together, GO-Ti could enhance the neuroprotective function of astrocytes by upregulating the expression of anti-inflammatory cytokines and neuroprotective factors with improved cell adhesion and viability. Consequently, our findings suggest that GO-Ti has the potential to induce neuroprotective effects by regulating cell activity.

Review article laser-induced hyperthermia on graphene oxide composites

BACKGROUND

Hyperthermia-based therapies have shown great potential for clinical applications such as for the antitumor and antipathogenic activities. Within all strategies, the so-called photothermal therapy proposes to induce the hyperthermia by the remote laser radiation on a photothermal conversion agent, in contact with the target tissue.

METHODS

This paper reviews the most relevant in vitro and in vivo studies focused on NIR laser-induced hyperthermia due to photoexcitation of graphene oxide (GO) and reduced graphene oxide (rGO). Relevant parameters such as the amount of GO/rGO, the influence of the laser wavelength and power density are considered. Moreover, the required temperature and exposure time for each antitumor/antipathogenic case are collected and unified in a thermal dose parameter: the CEM43.

RESULTS

The calculated CEM43 thermal doses revealed a great variability for the same type of tumor/strain. In order to detect potential tendencies, the values were classified into four ranges, varying from CEM43 < 60 min to CEM43 ≥ 1 year. Thus, a preference for moderate thermal doses of CEM43 < 1 year was detected in antitumor activity, with temperatures ≤ 50 °C and exposure time ≤ 15 min. In case of the antipathogenic studies, the most used thermal dose was higher, CEM43 ≥ 1 year, with ablative hyperthermia (> 60ºC).

CONCLUSIONS

The ability of GO/rGO as effective photothermal conversion agents to promote a controlled hyperthermia is proven. The variability found for the CEM43 thermal doses on the reviewed studies reveals the potentiality to evaluate, for each application, the use of lower temperatures, by modulating time and/or repetitions in the doses.

Recent advances in modification of novel carbon-based composites: Synthesis, properties, and biotechnological/ biomedical applications

Nowadays, carbon-based materials owing to great interest in biomedical science/biotechnology and applied for effective diagnosis and treatment of disease. To enhance the effectiveness of carbon nanotubes (CNTs)/graphene-based materials for bio-medical science/technology applications, different kinds of surface modification/functionalization were developed for the attachment of metal oxides nanostructures, biomolecules and polymers. The attachment of pharmaceutical agents with CNTs/graphene, make it a favorable candidate in research field of bio-medical science/technology applications. Surface modified/functionalized CNTs and graphene derivatives materials integrated with pharmaceutical agents has been developed for the purpose of cancer therapy, antibacterial action, pathogens bio detection, drug and gene delivery. Surface modification or functionalization of CNT/graphene materials provides good platform for pharmaceutical agents attachment with improved surface Raman scattering, fluorescence and its quenching capability. Graphene-based biosensing and bioimaging technologies are widely applied to identify numerous trace level analytes. These fluorescent and electrochemical sensors are utilized primarily for detecting organic, inorganic, and biomolecules. In this article, we highlights and summarized overview of the current research progress concerned on the CNTs/graphene-based materials as a new generation materials for detection and treatment of diseases.

Xenogenic Implantation of Human Mesenchymal Stromal Cells Using a Novel 3D-Printed Scaffold of PLGA and Graphene Leads to a Significant Increase in Bone Mineralization in a Rat Segmental Femoral Bone Defect

Tissue-engineering technologies have the potential to provide an effective approach to bone regeneration. Based on the published literature and data from our laboratory, two biomaterial inks containing PLGA and blended with graphene nanoparticles were fabricated. The biomaterial inks consisted of two forms of commercially available PLGA with varying ratios of LA:GA (65:35 and 75:25) and molecular weights of 30,000-107,000. Each of these forms of PLGA was blended with a form containing a 50:50 ratio of LA:GA, resulting in ratios of 50:65 and 50:75, which were subsequently mixed with a 0.05 wt% low-oxygen-functionalized derivative of graphene. Scanning electron microscopy showed interconnected pores in the lattice structures of each scaffold. The cytocompatibility of human ADMSCs transduced with a red fluorescent protein (RFP) was evaluated in vitro. The in vivo biocompatibility and the potential to repair bones were evaluated in a critically sized 5 mm mechanical load-bearing segmental femur defect model in rats. Bone repair was monitored by radiological, histological, and microcomputed tomography methods. The results showed that all of the constructs were biocompatible and did not exhibit any adverse effects. The constructs containing PLGA (50:75)/graphene alone and with hADMSCs demonstrated a significant increase in mineralized tissues within 60 days post-treatment. The percentage of bone volume to total volume from microCT analyses in the rats treated with the PLGA + cells construct showed a 50% new tissue formation, which matched that of a phantom. The microCT results were supported by Von Kossa staining.

Graphene-Related Nanomaterials for Biomedical Applications

This paper builds on the context and recent progress on the control, reproducibility, and limitations of using graphene and graphene-related materials (GRMs) in biomedical applications. The review describes the human hazard assessment of GRMs in in vitro and in vivo studies, highlights the composition-structure-activity relationships that cause toxicity for these substances, and identifies the key parameters that determine the activation of their biological effects. GRMs are designed to offer the advantage of facilitating unique biomedical applications that impact different techniques in medicine, especially in neuroscience. Due to the increasing utilization of GRMs, there is a need to comprehensively assess the potential impact of these materials on human health. Various outcomes associated with GRMs, including biocompatibility, biodegradability, beneficial effects on cell proliferation, differentiation rates, apoptosis, necrosis, autophagy, oxidative stress, physical destruction, DNA damage, and inflammatory responses, have led to an increasing interest in these regenerative nanostructured materials. Considering the existence of graphene-related nanomaterials with different physicochemical properties, the materials are expected to exhibit unique modes of interactions with biomolecules, cells, and tissues depending on their size, chemical composition, and hydrophil-to-hydrophobe ratio. Understanding such interactions is crucial from two perspectives, namely, from the perspectives of their toxicity and biological uses. The main aim of this study is to assess and tune the diverse properties that must be considered when planning biomedical applications. These properties include flexibility, transparency, surface chemistry (hydrophil-hydrophobe ratio), thermoelectrical conductibility, loading and release capacity, and biocompatibility.

Synergetic reinforcing effect of graphene oxide and nanosilver on carboxymethyl cellulose/sodium alginate nanocomposite films: Assessment of physicochemical and antibacterial properties

Incorporating single or combined nanofillers in polymeric matrices is a promising approach for developing antimicrobial materials for applications in wound healing and packaging etc. This study reports a facile fabrication of antimicrobial nanocomposite films using biocompatible polymers sodium carboxymethyl cellulose (CMC) and sodium alginate (SA) reinforced with nanosilver (Ag) and graphene oxide (GO) using the solvent casting approach. Eco-friendly synthesis of Ag nanoparticles within a size range of 20-30 nm was carried out within the polymeric solution. GO was introduced into the CMC/SA/Ag solution in different weight percentages. The films were characterized by UV-Vis, FT-IR, Raman, XRD, FE-SEM, EDAX, and TEM. The results indicated the enhanced thermal and mechanical performance of CMC/SA/Ag-GO nanocomposites with increased GO weight %. The antibacterial efficacy of the fabricated films was evaluated on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The CMC/SA/Ag-GO2% nanocomposite exhibited the highest zone of inhibition of 21.30 ± 0.70 mm against E. coli and 18.00 ± 1.00 mm against S. aureus. The CMC/SA/Ag-GO nanocomposites exhibited excellent antibacterial activity as compared to CMC/SA and CMC/SA-Ag due to the synergetic bacterial growth inhibition activities of the GO and Ag. The cytotoxic activity of the prepared nanocomposite films was also assessed to investigate their biocompatibility.

Subchronic Graphene Exposure Reshapes Skin Cell Metabolism

In recent years, the toxicity of graphene-related materials (GRMs) has been evaluated in diverse models to guarantee their safety. In most applications, sublethal doses of GRMs contact human barriers such as skin in a subchronic way. Herein, the subchronic effect (30 day exposure) of three GRMs (GO 1, GO 2, and FLG) with different oxidation degrees and sizes was studied. The effects of these materials on human skin cells, HaCaTs, were assayed through high-throughput metabolic-based readout and other cell-based assays. A differential effect was found between the different GRMs. GO 2 induced a metabolic remodeling in epithelial cells, increasing the level of tricarboxylic acid components, mirrored by increased cell proliferation and changes in cell phenotype. The oxidation degree, size, and method of manufacture of GRMs dictated harmful effects on cell metabolism and behavior generated by nontoxic exposures. Therefore, a “safe by design” procedure is necessary when working with these nanomaterials.

Nanoparticle-Mediated Photothermal Therapy Limitation in Clinical Applications Regarding Pain Management

The development of new effective cancer treatment methods has attracted much attention, mainly due to the limited efficacy and considerable side effects of currently used cancer treatment methods such as radiation therapy and chemotherapy. Photothermal therapy based on the use of plasmonically resonant metallic nanoparticles has emerged as a promising technique to eradicate cancer cells selectively. In this method, plasmonic nanoparticles are first preferentially uptaken by a tumor and then selectively heated by exposure to laser radiation with a specific plasmonic resonant wavelength, to destroy the tumor whilst minimizing damage to adjacent normal tissue. However, several parameters can limit the effectiveness of photothermal therapy, resulting in insufficient heating and potentially leading to cancer recurrence. One of these parameters is the patient's pain sensation during the treatment, if this is performed without use of anesthetic. Pain can restrict the level of applicable laser radiation, cause an interruption to the treatment course and, as such, affect its efficacy, as well as leading to a negative patient experience and consequential general population hesitancy to this type of therapy. Since having a comfortable and painless procedure is one of the important treatment goals in the clinic, along with its high effectiveness, and due to the relatively low number of studies devoted to this specific topic, we have compiled this review. Moreover, non-invasive and painless methods for temperature measurement during photothermal therapy (PTT), such as Raman spectroscopy and nanothermometry, will be discussed in the following. Here, we firstly outline the physical phenomena underlying the photothermal therapy, and then discuss studies devoted to photothermal cancer treatment concerning pain management and pathways for improved efficiency of photothermal therapy whilst minimizing pain experienced by the patient.

Fabrication, Structure, Performance, and Application of Graphene-Based Composite Aerogel

Graphene-based composite aerogel (GCA) refers to a solid porous substance formed by graphene or its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), with inorganic materials and polymers. Because GCA has super-high adsorption, separation, electrical properties, and sensitivity, it has great potential for application in super-strong adsorption and separation materials, long-life fast-charging batteries, and flexible sensing materials. GCA has become a research hotspot, and many research papers and achievements have emerged in recent years. Therefore, the fabrication, structure, performance, and application prospects of GCA are summarized and discussed in this review. Meanwhile, the existing problems and development trends of GCA are also introduced so that more will know about it and be interested in researching it.

Graphene quantum dots‐based targeted nanoprobes detecting drug delivery, imaging, and enhanced chemotherapy of nasopharyngeal carcinoma

One of the main clinical treatments for advanced nasopharyngeal carcinoma is chemotherapy, but systemic administration can cause serious adverse reactions. New type of nanomaterial which can actively targeting, imaging, and treating nasopharyngeal carcinoma at the same time to enhance the effect of chemotherapy, meanwhile monitoring the intracellular drug release process at the level of single cancer cell was urgently needed. GE11, an EGFR antagonist peptide, was used to target nasopharyngeal carcinoma which has positive expression of EGFR on its nucleus. GE11‐modified graphene quantum dots (GQDs@GE11) were used as drug carriers for clinical chemotherapeutics cisplatin (CDDP) and doxorubicin (DOX). The emission spectrum of GQDs (460 nm) and the excitation spectrum of DOX (470 nm) have a good overlap, thus the transfer and release process of DOX can be sensitively detected by the fluorescence resonance energy transfer (FRET). CDDP was used to enhance the chemotherapy effect of nanoprobe, and the loading amount of DOX and CDDP on GQDs@GE11 nanoprobe were up to 67 and 50 mg/g, respectively. In vivo experiments have confirmed that GQDs@GE11/CDDP/DOX nanoprobe can be enriched to tumor site through specific targeting effect, and significantly inhibit tumor cell proliferation. This new type of targeted therapy fluorescent probe provides new ideas for the study of drug release process and the treatment of nasopharyngeal carcinoma.

Drug Release Kinetics of DOX-Loaded Graphene-Based Nanocarriers for Ovarian and Breast Cancer Therapeutics

Cancer remains one of the leading causes of death worldwide despite extensive efforts at developing curative treatments. Chemotherapy, one of the most common forms of treatment, lacks specificity and can induce collateral damages to healthy surrounding tissues/cells and elicit off-target toxic side effects. The carbon-based nanomaterial graphene, can load aromatic drugs with high efficiency, has good biocompatibility, and can be easily functionalised with targeting ligands, antibodies, and biomolecules to increase the accuracy of targeting specific areas; graphene has therefore been explored as a nanocarrier for classical chemotherapy drugs. In this work, seventeen publications that report the release of doxorubicin (DOX) from 2D graphene-based nanohybrids (graphene oxide and reduced graphene oxide) for the treatment of breast and ovarian cancers have been identified based on a range of inclusion and exclusion criteria. To aid in the clinical translation of proof-of-concept studies, this work identifies the pre-clinical experimental protocols and analyses the release kinetics of these publications. Fifteen of the papers utilised a change in pH as the stimulus for drug release, and two utilised either near infrared (NIR) or ultrasound as the stimulus. The extracted drug release data from these publications were fit to four known kinetic models. It was found that the majority of these data best fit the Weibull kinetic model. The agreement between the kinetic data in previously published literature provides a predictable estimation of DOX release from graphene-based nanocarriers. This study demonstrates the potential conjugation of graphene and DOX in drug delivery applications, and this knowledge can help improve to the design and formulation of future graphene-based nanocarriers. In addition, the use of further experimental testing and the standardisation of experimental protocols will be beneficial for future work. The incorporation of computational modelling prior to pre-clinical testing will also aid in the development of controlled and sustained DOX release systems that offer efficient and efficacious results.

Towards the Use of Adsorption Methods for the Removal of Purines from Beer

Beer corresponds to a fermented alcoholic beverage composed of several components, including purine compounds. These molecules, when ingested by humans, can be catabolized into uric acid, contributing to uric acid’s level increase in serum, which may lead to hyperuricemia and gout. To assure a proper management of this disease, physicians recommend restrictive dietary measures, particularly by avoiding the consumption of beer. Therefore, it is of relevance to develop efficient methods to remove purine compounds from alcoholic beverages such as beer. In this review, we provide an introduction on fermented alcoholic beverages, with emphasis on beer, as well as its purine compounds and their role in uric acid metabolism in the human body in relation to hyperuricemia and gout development. The several reported enzymatic, biological and adsorption methods envisaging purine compounds’ removal are then reviewed. Some enzymatic and biological methods present drawbacks, which can be overcome by adsorption methods. Within adsorption methods, adsorbent materials, such as activated carbon or charcoal, have been reported and applied to beer or wort samples, showing an excellent capacity for adsorbing and removing purine compounds. Although the main topic of this review is on the removal of purine compounds from beer, other studies involving other matrices rather than beer or wort that are rich in purines are included, since they provide relevant clues on designing efficient removal processes. By ensuring the selective removal of purine compounds from this beverage, beer can be taken by hyperuricemic and gouty patients, avoiding restrictive dietary measures, while decreasing the related healthcare economic burden.

A Review of Graphene: Material Synthesis from Biomass Sources

Single-atom-thick graphene is a particularly interesting material in basic research and applications owing to its remarkable electronic, mechanical, chemical, thermal, and optical properties. This leads to its potential use in a multitude of applications for improved energy storage (capacitors, batteries, and fuel cells), energy generation, biomedical, sensors or even as an advanced membrane material for separations. This paper provided an overview of research in graphene, in the area of synthesis from various sources specially from biomass, advanced characterization techniques, properties, and application. Finally, some challenges and future perspectives of graphene are also discussed.

A case study of SARS-CoV-2 transmission behavior in a severely air-polluted city (Delhi, India) and the potential usage of graphene based materials for filtering air-pollutants and controlling/monitoring the COVID-19 pandemic

Globally, humanity is facing its most significant challenge in 100 years due to the novel coronavirus, SARS-CoV-2, which is responsible for COVID-19. Under the enormous pressure created by the pandemic, scientists are studying virus transmission mechanisms in order to develop effective mitigation strategies. However, no established methods have been developed to control the spread of this deadly virus. In addition, the ease in lockdown has escalated air pollution which may affect SARS-CoV-2 transmission through attachment to particulates. The present review summarizes the role of graphene nanomaterials, which show antimicrobial behavior and have antiviral efficacy, in reducing the spread of COVID-19. Graphene and its derivatives have excellent antimicrobial efficacy, providing both physical and chemical mechanisms of damage. Coupled with their lightness, optimal properties, and ease of functionalization, they are optimal nanomaterials for coating onto fabrics such as personal protection equipment, face masks and gloves to control the transmission of SARS-CoV-2 effectively. Biosensors using graphene can effectively detect the virus with high accuracy and sensitivity, providing rapid quantification. It is envisioned that the present work will boost the development of graphene-based highly sensitive, accurate and cost-effective diagnostic tools for efficiently monitoring and controlling the spread of COVID-19 and other air-borne viruses.

Noncovalent Functionalized Graphene Nanocarriers from Graphite for Treating Thyroid Cancer Cells

Here, biocompatible graphene (G) nanocarriers decorated with iron oxide nanoparticles (IONPs) were prepared using 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and poly(ethylene glycol) monomethacrylate (PEGMA). For this, we report the use of graphite directly instead of graphene oxide or reduced graphene oxide. Graphene nanocarrier (in situ GIOPMPC) was prepared in one-pot by in situ copolymerization of MPC and PEGMA monomers in the presence of IONPs and G. GIOPMCP nanocarriers were prepared by sonication using PMPC-co-PEGMA copolymers in the presence of IONPs and G. The prepared graphene nanocarriers were thoroughly characterized by various techniques. The analyses confirmed the successful preparation of nanocarriers with even distributions of PMPC-co-PEGMA and IONPs on surface G. The IONPs were coordinated through the phosphate groups in PMPC. Excellent dispersibility of the graphene nanocarriers in water enabled drug delivery applications. The prepared nanocarriers did not show significant cytotoxicity to the thyroid cancer cells up to 8 mg/mL (IC₅₀: 38.26 mg/mL). Thyroid cancer cells were stably transduced with a bioluminescent reporter to monitor cell cytotoxicity. Doxorubicin (DOX) was loaded onto in situ GIOPMPC nanocarriers at two different concentrations and was successfully delivered to thyroid cancer cells, resulting in strong cytotoxicity. Moreover, signaling mechanistic analyses showed apoptosis activation, inhibition of anti-apoptosis and proliferation, and increased DNA damage in the thyroid cancer cells.

Factors affecting the biological response of Graphene

Nanotechnology has gained significant importance in different fields of medical, electronic, and environmental science. This technology is founded on the use of materials at the nanoscale scale (1-100 nanometers) for various purposes, particularly in the biomedical area, where its application is growing daily due to the need of materials with advanced properties. Over the past few years, there has been a growing use for graphene and its derivative composite materials. However, different physico-chemical properties influence its biological response; therefore, further studies to explain the interactions of these nanomaterials with biological systems are critical. This review presents the current advances in the applications of graphene in biomedicine with a focus on the physico-chemical characteristics of the graphene family and their influences on biological interactions.

Graphene Oxide and Reduced Graphene Oxide Exhibit Cardiotoxicity Through the Regulation of Lipid Peroxidation, Oxidative Stress, and Mitochondrial Dysfunction

Objective

Graphene has been widely used for various biological and biomedical applications due to its unique physiochemical properties. This study aimed to evaluate the cardiotoxicity of graphene oxide (GO) and reduced GO (rGO) in vitro and in vivo, as well as to investigate the underlying toxicity mechanisms.

Methods

GO was reduced by gamma irradiation to prepare rGO and then characterized by UV/visible light absorption spectroscopy. Rat myocardial cells (H9C2) were exposed to GO or rGO with different absorbed radiation doses. The in vitro cytotoxicity was evaluated by MTT assay, cell apoptosis assay, and lactate dehydrogenase (LDH) activity assay. The effects of GO and rGO on oxidative damage and mitochondrial membrane potential were also explored in H9C2 cells. For in vivo experiments, mice were injected with GO or rGO. The histopathological changes of heart tissues, as well as myocardial enzyme activity and lipid peroxidation indicators in heart tissues were further investigated.

Results

rGO was developed from GO following different doses of gamma irradiation. In vitro experiments in H9C2 cells showed that compared with control cells, both GO and rGO treatment inhibited cell viability, promoted cell apoptosis, and elevated the LDH release. With the increasing radiation absorbed dose, the cytotoxicity of rGO gradually increased. Notably, GO or rGO treatment increased the content of ROS and reduced the mitochondrial membrane potential in H9C2 cells. In vivo experiments also revealed that GO or rGO treatment damaged the myocardial tissues and changed the activities of several myocardial enzymes and the lipid peroxidation indicators in the myocardial tissues.

Conclusion

GO exhibited a lower cardiotoxicity than rGO due to the structure difference, and the cardiotoxicity of GO and rGO might be mediated by lipid peroxidation, oxidative stress, and mitochondrial dysfunction.

Graphene-based hybrid materials as promising scaffolds for peripheral nerve regeneration

Peripheral nerve injury (PNI) is a serious clinical health problem caused by the damage of peripheral nerves which results in neurological deficits and permanent disability. There are several factors that may cause PNI such as localized damage (car accident, trauma, electrical injury) and outbreak of the systemic diseases (autoimmune or diabetes). While various diagnostic procedures including X-ray, magnetic resonance imaging (MRI), as well as other type of examinations such as electromyography or nerve conduction studies have been efficiently developed, a full recovery in patients with PNI is in many cases deficient or incomplete. This is the reason why additional therapeutic strategies should be explored to favor a complete rehabilitation in order to get appropriate nerve injury regeneration. The use of biomaterials acting as scaffolds opens an interesting approach in regenerative medicine and tissue engineering applications due to their ability to guide the growth of new tissues, adhesion and proliferation of cells including the expression of bioactive signals. This review discusses the preparation and therapeutic strategies describing in vitro and in vivo experiments using graphene-based materials in the context of PNI and their ability to promote nerve tissue regeneration.

Improved nanomechanical and in-vitro biocompatibility of graphene oxide-carbon nanotube hydroxyapatite hybrid composites by synergistic effect

Hydroxyapatite (HAP) is an attractive bio-material for new bone growth process, hard tissue repair, bioactivity, osteoblast adhesion and proliferation due to its physicochemical resembles natural apatite. The intrinsic brittleness and poor mechanical properties of HAP restrict it for potential clinical applications. This problem is undertaken by exploiting the unique properties of carbon nanofillers (carbon nanotube (CNTs), graphene oxide (GO), graphene oxide-carbon nanotube (GCNTs) hybrid) which are used as reinforcement for preparing the carbon nanofillers based HAP composites. The nanomechanical and in-vitro biocompatibility of carbon nanofiller reinforced HAP composites have been studied. Carbon nanofiller reinforced HAP composites led to an improvement in nanomechanical and biocompatibility properties. The nanoindentation hardness and elastic modulus of GCNTs-HAP composites are significantly higher than other carbon nanofiller reinforced composites and pristine HAP powder. The in-vitro cytotoxicity of the prepared carbon nanofillers reinforced HAP composites is examined using MTT-assay on the MDCK cell line. The prepared GCNTs-HAP composites containing 2% of GCNTs nanofiller show higher cell viability, improved compatibility, and superior one cell proliferation induction than the other carbon nanofillers and HAP. These findings will provide the new prospects for utilizing the GO and its hybrid in HAP composites in bone repair, regeneration, augmentation and implantation.

An integrated and multi-technique approach to characterize airborne graphene flakes in the workplace during production phases

Graphene is a one-atom-thick sheet of carbon atoms arranged in a honeycomb pattern and its unique and amazing properties make it suitable for a wide range of applications ranging from electronic devices to food packaging. However, the biocompatibility of graphene is dependent on the complex interplay of its several physical and chemical properties. The main aim of the present study is to highlight the importance of integrating different characterization techniques to describe the potential release of airborne graphene flakes in a graphene processing and production research laboratory. Specifically, the production and processing (i.e., drying) of few-layer graphene (FLG) through liquid-phase exfoliation of graphite are analysed by integrated characterization techniques. For this purpose, the exposure measurement strategy was based on the multi-metric tiered approach proposed by the Organization for Economic Cooperation and Development (OECD) via integrating high-frequency real-time measurements and personal sampling. Particle number concentration, average diameter and lung deposition surface area time series acquired in the worker's personal breathing zone (PBZ) were compared simultaneously to background measurements, showing the potential release of FLG. Then, electron microscopy techniques and Raman spectroscopy were applied to characterize particles collected by personal inertial impactors to investigate the morphology, chemical composition and crystal structure of rare airborne graphene flakes. The gathered information provides a valuable basis for improving risk management strategies in research and industrial laboratories.

Ru x Pd y Alloy Nanoparticles Uniformly Anchored on Reduced Graphene Oxide Nanosheets (Ru x Pd y @rGO): A Recyclable Catalyst

In this work, Ru _x Pd _y alloy nanoparticles were uniformly decorated on a two-dimensional reduced graphene oxide (rGO) sheet by an in situ chemical co-reduction process. The resulting products were characterized by various physiochemical techniques such as X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic absorption spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Further, the synthesized Ru _x Pd _y @rGO nanocomposites have been employed as a heterogeneous catalyst for three different catalytic reactions: (1) dehydrogenation of aqueous ammonia borane (AB); (2) hydrogenation of aromatic nitro compounds using ammonia borane as the hydrogen source, and (3) for the synthesis of aromatic azo derivatives. The present work illustrates the sustainable anchoring of metal nanoparticles over the surface of rGO nanosheets, which could be used for multifarious catalytic reactions.

Graphene-laden hydrogels: A strategy for thermally triggered drug delivery

The synthesis of graphene-based materials has attracted considerable attention in drug delivery strategies. Indeed, the conductivity and mechanical stability of graphene have been investigated for controlled and tunable drug release via electric or mechanical stimuli. However, the design of a thermo-sensitive scaffold using pristine graphene (without distortions related to the oxidation processes) has not been deeply investigated yet, although it may represent a promising approach for several therapeutic treatments. Here, few-layer graphene was used as a nanofiller in a hydrogel system with a thermally tunable drug release profile. In particular, varying the temperature (25 °C, 37 °C and 44 °C), responsive drug releases were noticed and hypothesized depending on the formation and perturbation of π-π interactions involving graphene, the polymeric matrix and the model drug (diclofenac). As a result, these hybrid hydrogels show a potential application as thermally triggered drug release systems in several healthcare scenarios.

Potential of carbohydrate-conjugated graphene assemblies in biomedical applications

Graphene displays various properties like optical, electrical, mechanical, etc. resulting in a large range of applications in biosensing, bio-imaging, medical and electronic devices. The graphene-based nanomaterials show disadvantages like hydrophobic surface, degradation of biomolecules (proteins and amino acids) and toxicity to the human and microbes by permeating into the cells and thus, limiting the use in the biomedical field. Conjugation of carbohydrates like chitin, cyclodextrins and cellulose with graphene results in thermal stability, oxygen repulsive ability, fire-retardant and gelling properties with better biodegradability, biocompatibility and safety leading to the formation of environment-friendly biopolymers. This article delivers an overview of the molecular interaction of different carbohydrates-derived from natural sources like marine, plants and microbes with graphene nanosheets to extend the applications in tissue engineering, surgical materials, biosensing and novel drug delivery for prolonged action in the treatment of breast and hepatic cancers.

Polyethylene Glycol-Coated Graphene Oxide Loaded with Erlotinib as an Effective Therapeutic Agent for Treating Nasopharyngeal Cancer Cells

Introduction

Nasopharyngeal carcinoma (NPC) is a common cancer in southern China and Taiwan, and radiation therapy combined with or without chemotherapy is its mainstay treatment. Although it is highly sensitive to radiotherapy, local recurrence and distant metastasis remain difficult unsolved problems. In recent years, graphene oxide (GO) has been found to be a promising novel anticancer drug carrier. Here, we present our designed functionalized GO, polyethylene glycol-coated GO (GO-PEG), as a drug carrier, which was loaded with erlotinib and showed promising anticancer effects on NPC cells.

Methods

The effects of GO-PEG-erlotinib on the proliferation, migration, and invasion of NPC cells were investigated by WST-8 assay, wound healing assay, and invasion assay, respectively. RNA sequencing was conducted and analyzed to determine the molecular mechanisms by which GO-PEG-erlotinib affects NPC cells.

Results

Our results showed that GO-PEG-erlotinib reduced NPC cell viability in a dose-dependent manner and also inhibited the migration and invasion of NPC cells. The RNA sequencing revealed several related molecular mechanisms.

Conclusion

GO-PEG-erlotinib effectively suppressed NPC cell proliferation, migration, and invasion, likely by several mechanisms. GO-PEG-erlotinib may be a potential therapeutic agent for treating NPC in the future.

Preparation, characterization and anti-cancer activity of graphene oxide-‑silver nanocomposite

This work reported the preparation, characterization, cytotoxicity of green synthesized Lespedeza cuneate mediated silver nanoparticles (Lc-AgNPs) and graphene oxide‑silver nanocomposite (GO-AgNComp) using Lc-AgNPs. The UV absorption spectrum at 419 nm indicated the successful formation of GO-AgNComp. The TEM analysis displayed the thin sheet of graphene decorated Lc-AgNPs in GO-AgNComp. Zeta potential was -13.2 mV for Lc-AgNPs and -30.5 mV for GO-AgNComp. The photothermal conversion efficiency was calculated as 31.09% for GO-AgNComp. The negatively charged zeta potential of GO-AgNComp enhanced its cellular penetration through enhanced permeability and retention (EPR) effect. The near-infrared laser (NIR) induced the anticancer activity of Lc-AgNPs and GO-AgNComp in human lung cancer cells (A549) and brain tumour (LN229). The results indicated that about 50% of A549 cells and LN229 cells were ablated by treatment of 24.73 ± 2.98 μg/mL and 27.34 ± 1.62 μg/mL of Lc-AgNPs, as well by 15.46 ± 2.31 μg/mL and 20.95 ± 1.35 μg/mL of GO-AgNComp respectively. Moreover, GO-AgNComp was not cytotoxic to normal mouse fibroblast cells (NIH3T3), but it caused the cancer cell death in A549 and LN229 through ROS generation, nuclear damage, and mitochondrial membrane potential (∆ψm) loss. This work reported the anticancer potential of GO-AgNComp, which deserves further study on the molecular elucidation of GO-AgNComp mediated human lung and tumour therapy.

Carbon nanostructures: The drug and the delivery system for brain disorders

Neurodegenerative disorders and brain tumors are major pathological conditions affecting the brain. The delivery of therapeutic agents into the brain is not as easy as to other organs or systems. The presence of the blood-brain barrier (BBB) makes the drug delivery into the brain more complicated and challenging. Many techniques have been developed to overcome the difficulties with BBB and to achieve brain-targeted drug delivery. Incorporation of the drugs into nanocarriers capable to penetrate BBB is a simple technique. Different nanocarriers have been developed including polymeric nanoparticles, carbon nanoparticles, lipid-based nanoparticles, etc. Carbon nanostructures could make a superior position among them, because of their good biocompatibility and easy penetration of BBB. Carbon-family nanomaterials consist of different carbon-based structures including zero-dimensional fullerene, one-dimensional carbon nanotube, two-dimensional graphene, and some other related structures like carbon dots and nanodiamonds. They can be used as efficient carriers for drug delivery into the brain. Apart from the drug delivery applications, they can also be used as a central nervous system (CNS) therapeutic agent; some of the carbon nanostructures have neuroregenerative activity. Their influence on neuronal growth and anti-amyloid action is also interesting. This review focuses on different carbon nanostructures for brain-targeted drug delivery and their CNS activities. As a carrier and CNS therapeutic agent, carbon nanostructures can revolutionize the treatment of brain disorders.

Functionalized Graphene Nanoparticles Induce Human Mesenchymal Stem Cells to Express Distinct Extracellular Matrix Proteins Mediating Osteogenesis

PURPOSE

The extracellular matrix (ECM) labyrinthine network secreted by mesenchymal stem cells (MSCs) provides a microenvironment that enhances cell adherence, proliferation, viability, and differentiation. The potential of graphene-based nanomaterials to mimic a tissue-specific ECM has been recognized in designing bone tissue engineering scaffolds. In this study, we investigated the expression of specific ECM proteins when human fat-derived adult MSCs adhered and underwent osteogenic differentiation in the presence of functionalized graphene nanoparticles.

METHODS

Graphene nanoparticles with 6-10% oxygen content were prepared and characterized by XPS, FTIR, AFM and Raman spectroscopy. Calcein-am and crystal violet staining were performed to evaluate viability and proliferation of human fat-derived MSCs on graphene nanoparticles. Alizarin red staining and quantitation were used to determine the effect of graphene nanoparticles on osteogenic differentiation. Finally, immunofluorescence assays were used to investigate the expression of ECM proteins during cell adhesion and osteogenic differentiation.

RESULTS

Our data show that in the presence of graphene, MSCs express specific integrin heterodimers and exhibit a distinct pattern of the corresponding bone-specific ECM proteins, primarily fibronectin, collagen I and vitronectin. Furthermore, MSCs undergo osteogenic differentiation spontaneously without any chemical induction, suggesting that the physicochemical properties of graphene nanoparticles might trigger the expression of bone-specific ECM.

CONCLUSION

Understanding the cell-graphene interactions resulting in an osteogenic niche for MSCs will significantly improve the application of graphene nanoparticles in bone repair and regeneration.

A simple scheme for finding magnetic aromatic hydrocarbon molecules

Polycyclic aromatic hydrocarbon (PAH) molecules such as quasi-unidimensional oligo-acene and fused azulene display interesting properties for increasing chain length. However, these molecules can be hard to explore computationally due to the number of atoms involved and the fast-increasing numerical cost when using many-body methods. The identification of magnetic PAH molecules is most relevant for technological applications and hence it would be of particular interest to develop rapid preliminary checks to identify likely candidates for both theoretical and experimental pursuits. In this article, we show that an analysis based on a second-order perturbation treatment of electronic correlations for the Hubbard model qualitatively predicts the outcome of more extensive and accurate methods. Based on these results we propose a simple computational protocol for screening molecules and identifying those worthy of a more sophisticated analysis on the magnetic nature of their ground states. Using this protocol we were able to identify two new magnetic molecules made from the combination of only two naphthalene monomers and two azulene ones (both isomers with formula C₃₄H₂₀). For further confirmation of this result, these molecules were also studied by means of density matrix renormalization group and density functional theory.

Overview of the application of inorganic nanomaterials in cancer photothermal therapy

Cancer photothermal therapy (PTT) has captured the attention of researchers worldwide due to its localized and trigger-activated therapeutic effect.

Externally predictive quantum-mechanical models for the adsorption of aromatic organic compounds by graphene-oxide nanomaterials

Graphene oxide is most often chosen as an alternative to graphene in the applications of carbon-based nanomaterials where adsorption is the primary process. However, its adsorption properties are poorly understood. The existing reports on the adsorption mechanism of graphene oxide rely on the linear free-energy/solvation-energy relationship (LFER/LSER) models. This computational work explores the role of quantum mechanical descriptors in the adsorption of aromatic organic compounds by graphene-oxide. For this, externally predictive quantitative models based on quantum-mechanical descriptors are developed and compared with the existing LSERs for the prediction of adsorption coefficients of organic compounds at three different adsorbate concentrations. The predictivity of the models is assessed using an external prediction set of compounds not used for developing the models. Notably, the mean polarizability, but originating from the quantum mechanical exchange interactions (between electrons of parallel spin), is found to be the most significant factor in driving the adsorption on graphene oxide. The present work also proposes quantum-mechanical-LSER models based on a combination of quantum-mechanical and LSER descriptors, which are in fact found to be equally predictive as the existing LSERs. The quantum-mechanical models proposed in this work are further utilized for the prediction of adsorption coefficients of aliphatic compounds.

Antibacterial Property of Composites of Reduced Graphene Oxide with Nano-Silver and Zinc Oxide Nanoparticles Synthesized Using a Microwave-Assisted Approach

Graphene oxide (GO) composites with various metal nanoparticles (NPs) are attracting increasing interest owing to their broad scope in biomedical applications. Here, microwave-assisted chemical reduction was used to deposit nano-silver and zinc oxide NPs (Ag and ZnO NPs) on the surface of reduced GO (rGO) at the following weight percentages: 5.34% Ag/rGO, 7.49% Ag/rGO, 6.85% ZnO/rGO, 16.45% ZnO/rGO, 3.47/34.91% Ag/ZnO/rGO, and 7.08/15.28% Ag/ZnO/rGO. These materials were tested for antibacterial activity, and 3.47/34.91% Ag/ZnO/rGO and 7.08/15.28% Ag/ZnO/rGO exhibited better antibacterial activity than the other tested materials against the gram-negative bacterium Escherichia coli K12. At 1000 ppm, both these Ag/ZnO/rGO composites had better killing properties against both E. coli K12 and the gram-positive bacterium Staphylococcus aureus SA113 than Ag/rGO and ZnO/rGO did. RedoxSensor flow cytometry showed that 3.47/34.91% Ag/ZnO/rGO and 7.08/15.28% Ag/ZnO/rGO decreased reductase activity and affected membrane integrity in the bacteria. At 100 ppm, these two composites affected membrane integrity more in E. coli, while 7.08/15.28% Ag/ZnO/rGO considerably decreased reductase activity in S. aureus. Thus, the 3.47/34.91% and 7.08%/15.28% Ag/ZnO/rGO nanocomposites can be applied not only as antibacterial agents but also in a variety of biomedical materials such as sensors, photothermal therapy, drug delivery, and catalysis, in the future.

Photodynamic Therapy Based on Graphene and MXene in Cancer Theranostics

Cancer is one of the leading causes of death in the world. Therefore, the development of new advanced and targeted strategies in cancer research for early diagnosis and treatment has become essential to improve diagnosis outcomes and reduce therapy side effects. Graphene and more recently, MXene, are the main representatives of the family of two-dimensional (2D) materials and are widely studied as multimodal nanoplatforms for cancer diagnostics and treatment, in particular leveraging their potentialities as photodynamic therapeutic agents. Indeed, due to their irreplaceable physicochemical properties, they are virtuous allies for photodynamic therapy (PDT) in combination with bioimaging, photothermal therapy, as well as drug and gene delivery. In this review, the rapidly progressing literature related to the use of these promising 2D materials for cancer theranostics is described in detail, highlighting all their possible future advances in PDT.

Characterization of polycaprolactone/rGO nanocomposite scaffolds obtained by electrospinning

The incorporation of nanoparticles inside polymeric matrices has led to the development of multifunctional composites necessary to repair human tissues. The addition of nanoparticles may improve the properties of the composite materials such as surface area, mechanical properties, flexibility, hydrophilicity, electrical conductivity, etc. These properties can help in cellular growth, proliferation and/or differentiation. In this work, scaffolds of polycaprolactone (PCL) and reduced graphite oxide (rGO) were built by electrospinning technique. The ratios of rGO/PCL employed were 0.25, 0.5, 0.75 and 1 wt%. Two different voltage setup (10 and 15 kV) and distance of 10 cm were used for electrospinning. Thermal, mechanical, morphological, electrical, porosity and absorption water tests were made to the scaffolds. Samples electrospun at 10 kV with rGO showed improvement in mechanical properties with an increase of 190% of Young's Modulus in comparison with sample without rGO. Furthermore, samples electrospun at 15 kV showed an important deterioration with the addition of rGO but had an increase in the electrical conductivity and porosity. Overall, the addition of 0.75 and 1 wt% of rGO led to a detriment on properties due to formation of aggregates. The voltage on the electrospinning process plays a very important role in the final properties of the nanocomposites scaffolds of PCL-rGO.