In vitro toxicity evaluation of graphene oxide on A549 cells

Carbon materials for effective purification of aqueous solutions from tributyl phosphate

This study investigates various sorbents for the effective sorption of dissolved organic substances, using tributyl phosphate (TBP) as a model compound. TBP is one of the most commonly used extractants in the nuclear industry. Four different carbon materials with high specific surface areas (2000-3000 m2 g-1) were selected for evaluation. The sorption of TBP from nitric acid solutions was examined over a wide range of concentrations. The samples with the largest specific surface areas showed the highest sorption capacity for organic matter. To enable repeated use, a purification scheme was developed to restore the sorbents' original properties. The samples were subjected to various treatments, analyzed using X-ray photoelectron spectroscopy, and used in subsequent sorption experiments.

Palladium-reduced graphene oxide nanocomposites enhance neurite outgrowth and protect neurons from Ishemic stroke

Currently, the construction of novel biomimetic reduced graphene oxide (RGO)-based nanocomposites to induce neurite sprouting and repair the injured neurons represents a promising strategy in promoting neuronal development or treatment of cerebral anoxia or ischemia. Here, we present an effective method for constructing palladium-reduced graphene oxide (Pd-RGO) nanocomposites by covalently bonding Pd onto RGO surfaces to enhance neurite sprouting of cultured neurons. As described, the Pd-RGO nanocomposites exhibit the required physicochemical features for better biocompatibility without impacting cell viability. Primary neurons cultured on Pd-RGO nanocomposites had significantly increased number and length of neuronal processes, including both axons and dendrites, compared with the control. Western blotting showed that Pd-RGO nanocomposites improved the expression levels of growth associate protein-43 (GAP-43), as well as β-III tubulin, Tau-1, microtubule-associated protein-2 (MAP2), four proteins that are involved in regulating neurite sprouting and outgrowth. Importantly, Pd-RGO significantly promoted neurite length and complexity under oxygen-glucose deprivation/re-oxygenation (OGD/R) conditions, an in vitro cellular model of ischemic brain damage, that closely relates to neuronal GAP-43 expression. Furthermore, using the middle cerebral artery occlusion (MCAO) model in rats, we found Pd-RGO effectively reduced the infarct area, decreased neuronal apoptosis in the brain, and improved the rats' behavioral outcomes after MCAO. Together, these results indicate the great potential of Pd-RGO nanocomposites as a novel excellent biomimetic material for neural interfacing that shed light on its applications in brain injuries.

Unraveling Nanomaterials in Biomimetic Mineralization of Dental Hard Tissue: Focusing on Advantages, Mechanisms, and Prospects

The demineralization of dental hard tissue imposes considerable health and economic burdens worldwide, but an optimal method that can repair both the chemical composition and complex structures has not been developed. The continuous development of nanotechnology has created new opportunities for the regeneration and repair of dental hard tissue. Increasingly studies have reported that nanomaterials (NMs) can induce and regulate the biomimetic mineralization of dental hard tissue, but few studies have examined how they are involved in the different stages, let alone the relevant mechanisms of action. Besides their nanoscale dimensions and excellent designability, NMs play a corresponding role in the function of the raw materials for mineralization, mineralized microenvironment, mineralization guidance, and the function of mineralized products. This review comprehensively summarizes the advantages of NMs and examines the specific mineralization mechanisms. Design strategies to promote regeneration and repair are summarized according to the application purpose of NMs in the oral cavity, and limitations and development directions in dental hard tissue remineralization are proposed. This review can provide a theoretical basis to understand the interaction between NMs and the remineralization of dental hard tissue, thereby optimizing design strategy, rational development, and clinical application of NMs in the field of remineralization.

Graphene oxide nanoparticles inhibit H9N2 influenza A virus infectivity by destroying viral coat proteins

Nanoparticles have gained attention as potential antiviral agents, but the effects of graphene oxide nanoparticles (GONPs) on influenza virus remain unclear. In this study, we evaluated the antiviral activity of GONPs against influenza virus strain A/Hunan-Lengshuitan/11197/2013(H9N2). Our results show that GONPs with a diameter of 4 nm exerted an antiviral effect, whereas those with a diameter of 400 nm had no effect. Treatment with 4-nm GONPs reduced viral titers by more than 99% and inhibited viral nucleoprotein expression in a dose-dependent manner. We also confirmed that 4-nm GONPs inhibited the infectivity of H9N2 in MDCK cells. A transmission electron microscopic analysis revealed morphological abnormalities in the GONP-treated virus, including the destruction of the envelope glycoprotein spikes and an irregular shape, suggesting that GONPs cause the destruction of the viral coat proteins. Our results highlight the potential utility of GONPs in the prevention and treatment of viral infections, especially those of emerging and re-emerging viruses.

Synthesis and characterization of fluorinated graphene oxide nanosheets derived from Lissachatina fulica snail mucus and their biomedical applications

The modern nanomedicine incorporates the multimodal treatments into a single formulation, offering innovative cancer therapy options. Nanosheets function as carriers, altering the solubility, biodistribution, and effectiveness of medicinal compounds, resulting in more efficient cancer treatments and reduced side effects. The non-toxic nature of fluorinated graphene oxide (FGO) nanosheets and their potential applications in medication delivery, medical diagnostics, and biomedicine distinguish them from others. Leveraging the unique properties of Lissachatina fulica snail mucus (LfSM), FGO nanosheets were developed to reveal the novel characteristics. Consequently, LfSM was utilized to create non-toxic, environmentally friendly, and long-lasting FGO nanosheets. Ultraviolet-visible (UV-vis) spectroscopy revealed a prominent absorbance peak at 235 nm. The characterization of the synthesized FGO nanosheets involved X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), and atomic force microscopy (AFM) analyses. The antimicrobial activity data demonstrated a broad spectrum of antibacterial effects against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The cytotoxicity efficacy of LfSM-FGO nanosheets against pancreatic cancer cell line (PANC1) showed promising results at low concentrations. The study suggests that FGO nanosheets made from LfSM could serve as alternate factors for in biomedical applications in the future.

In vitro cytotoxicity assessment of carbonaceous gels for bone marrow mesenchymal stem cells

The current work aimed to elucidate the potential applications of the carbonaceous gels and assess the in vitro cytotoxicity of these gels when suspended in a culture medium and exposed to bone marrow mesenchymal stem cells. Cellular viability, cell cycle distribution, apoptotic cell death, and mitochondrial membrane potential in bone marrow mesenchymal stem cells co-incubated with different concentrations of carbonaceous gels (0.1, 1, 10, 50, and 100 μg/mL) were evaluated. Flow cytometry and immunofluorescence were used to investigate apoptosis and cell cycle distribution. The expression of associated apoptotic proteins was analysed using Western Blot. Although the co-incubation of carbonaceous gels did not significantly affect cell viability, high dosages (100 μg/mL) of these gels led to cellular dysfunction. Specifically, cells exposed to high concentrations of these gels exhibited G2-phase arrest and increased levels of reactive oxygen species. However, the reported impacts did not cause considerable cell death. At the same time, carbonaceous gels did not significantly induce apoptosis. Compared to other carbon nanomaterials, carbonaceous gels' biotoxicity was relatively low, suggesting their potential for various biological applications. Nonetheless, caution should be exercised when considering the concentration of carbonaceous gels for future medical applications.

Exploring Mucoadhesive and Toxicological Characteristics Following Modification of Linear Polyethylenimine with Various Anhydrides

Linear polyethylenimine (L-PEI) has numerous applications, such as in pharmaceutical formulations, gene delivery, and water treatment. However, due to the presence of secondary amine groups, L-PEI shows a relatively high toxicity and low biocompatibility. Here, various organic anhydrides were used to modify L-PEI to reduce its toxicity and enhance its functionality. We selected methacrylic anhydride, crotonic anhydride, maleic anhydride, and succinic anhydride to modify L-PEI. The structure of the resulting derivatives was characterized using 1H NMR and FTIR spectroscopies, and their behavior in aqueous solutions was studied using turbidimetric and electrophoretic mobility measurements over a broad range of pHs. A fluorescence flow through method determined the mucoadhesive properties of the polymers to the bovine palpebral conjunctiva. Methacrylated L-PEI and crotonylated L-PEI showed strong mucoadhesive properties at pH 7.4, likely due to covalent bonding with mucin thiol groups. In contrast, maleylated and succinylated L-PEI were poorly mucoadhesive as the pH was above their isoelectric point, resulting in electrostatic repulsion between the polymers and mucin. The toxicity of these polymers was evaluated using in vivo assays with planaria and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cell viability assay in human alveolar epithelial cells. Moreover, the irritancy of polymers was assessed using a slug mucosa irritation assay. The results demonstrated that anhydride modification mitigated the adverse toxicity effects seen for parent L-PEI.

Guidance on the assessment of biocompatibility of biomaterials: Fundamentals and testing considerations

BACKGROUND

Assessing the biocompatibility of materials is crucial for ensuring the safety and well-being of patients by preventing undesirable, toxic, immune, or allergic reactions, and ensuring that materials remain functional over time without triggering adverse reactions. To ensure a comprehensive assessment, planning tests that carefully consider the intended application and potential exposure scenarios for selecting relevant assays, cell types, and testing parameters is essential. Moreover, characterizing the composition and properties of biomaterials allows for a more accurate understanding of test outcomes and the identification of factors contributing to cytotoxicity. Precise reporting of methodology and results facilitates research reproducibility and understanding of the findings by the scientific community, regulatory agencies, healthcare providers, and the general public.

AIMS

This article aims to provide an overview of the key concepts associated with evaluating the biocompatibility of biomaterials while also offering practical guidance on cellular principles, testing methodologies, and biological assays that can support in the planning, execution, and reporting of biocompatibility testing.

Development of antibacterial dual-cure dental resin composites via tetrapod-shaped zinc oxide incorporation

OBJECTIVES

This study aimed to evaluate the effects of incorporating the 0-20 wt% tetrapod-shaped zinc oxide (tZnO) whiskers on the mechanical, antibacterial, and cytotoxic properties exhibited by experimental dual-cure resin composites.

METHODS

Commercially obtained tZnO whiskers underwent surface modification using 3-methacryloxypropyltrimethoxysilane (γ-MPS). Subsequently, four groups of resin composites containing 0, 5, 10, and 20 wt% silanized tZnO along with barium borosilicate glass (BaBSG) fillers were fabricated while maintaining total filler loading at 60 wt%. Mechanical properties were examined utilizing specimens produced adhering to ISO 4049:2019 guidelines where applicable. Depth of cure was quantified immediately, while three-point flexural strength, flexural modulus, fracture toughness, Vickers hardness, compressive strength, and diametral tensile strength were assessed after 24 h of storage in 37 °C distilled water. Planktonic bacteria of Streptococcus mutans (S. mutans) were cultured and tested for antibacterial activity using disk diffusion and microbial anti-adhesion assays. Cytotoxicity was examined by preparing extracts from specimens in a cell culture medium and exposing stem cells from human exfoliated deciduous teeth (SHED) to serial dilutions of these extracts, then assessing cell viability and survival using CCK-8 assay and live/dead staining.

RESULTS

Elevating tZnO loading yielded significant reductions in depth of cure, compressive (from 296.4 to 254.6 MPa), and diametral tensile strength (from 42.7 to 31.0 MPa), while flexural strength (91.3-94.1 MPa), flexural modulus (6.4-6.6 GPa), fracture toughness (0.96-1.04 MPa·m0.5), and Vickers hardness (36.5-37.4 kgf·mm-2) remained the same. Composites integrating tZnO displayed markedly enhanced antibacterial activity against S. mutans, based on anti-adhesion tests and live/dead staining. No cytotoxicity was observed for SHED treated with extracts from resin composites possessing up to 20 wt% tZnO whiskers.

SIGNIFICANCE

This study demonstrates that incorporating up to 20 wt% silanized tZnO in place of traditional barium glass particles appreciably enhances dual-cure resin composite antibacterial function against S. mutans without compromising mechanical properties.

Biomimetic Antifungal Materials: Countering the Challenge of Multidrug-Resistant Fungi

In light of rising public health threats like antifungal and antimicrobial resistance, alongside the slowdown in new antimicrobial development, biomimetics have shown promise as therapeutic agents. Multidrug-resistant fungi pose significant challenges as they quickly develop resistance, making traditional antifungals less effective. Developing new antifungals is also complicated by the need to target eukaryotic cells without harming the host. This review examines biomimetic antifungal materials that mimic natural biological mechanisms for targeted and efficient action. It covers a range of agents, including antifungal peptides, alginate-based antifungals, chitosan derivatives, nanoparticles, plant-derived polyphenols, and probiotic bacteria. These agents work through mechanisms such as disrupting cell membranes, generating reactive oxygen species, and inhibiting essential fungal processes. Despite their potential, challenges remain in terms of ensuring biocompatibility, optimizing delivery, and overcoming potential resistance. Production scalability and economic viability are also concerns. Future research should enhance the stability and efficacy of these materials, integrate multifunctional approaches, and develop sophisticated delivery systems. Interdisciplinary efforts are needed to understand interactions between these materials, fungal cells, and the host environment. Long-term health and environmental impacts, fungal resistance mechanisms, and standardized testing protocols require further study. In conclusion, while biomimetic antifungal materials represent a revolutionary approach to combating multidrug-resistant fungi, extensive research and development are needed to fully realize their potential.

Emergence of graphene as a novel nanomaterial for cardiovascular applications

Cardiovascular diseases (CDs) are the foremost cause of death worldwide. Several promising therapeutic methods have been developed for this approach, including pharmacological, surgical intervention, cell therapy, or biomaterial implantation since heart tissue is incapable of regenerating and healing on its own. The best treatment for heart failure to date is heart transplantation and invasive surgical intervention, despite their invasiveness, donor limitations, and the possibility of being rejected by the patient's immune system. To address these challenges, research is being conducted on less invasive and efficient methods. Consequently, graphene-based materials (GBMs) have attracted a great deal of interest in the last decade because of their exceptional mechanical, electrical, chemical, antibacterial, and biocompatibility properties. An overview of GBMs' applications in the cardiovascular system has been presented in this article. Following a brief explanation of graphene and its derivatives' properties, the potential of GBMs to improve and restore cardiovascular system function by using them as cardiac tissue engineering, stents, vascular bypass grafts,and heart valve has been discussed.

Antibacterial Efficacy of Graphene Nanoparticles against Enterococcus faecalis: In Vitro Study

OBJECTIVE(S)

 This study compared the antimicrobial efficacy of nanographene (NG) particles with chlorhexidine (CHX) and calcium hydroxide (Ca(OH)2) against Enterococcus faecalis.

MATERIALS AND METHODS

 Forty extracted human mandibular premolar teeth were cleaned using a scaler, and the middle-third of the root (6 mm) was decoronated using a rotary diamond disk. The inner diameter of the teeth was made consistent using Gates Glidden Drills #3, treated with ethylene diamine tetra-acetic acid and sodium hypochlorite before sterilization. The samples were then contaminated with E. faecalis grown in Tryptic soy broth for 21 days. Tooth samples were then randomly divided into four groups: Group I (Control), untreated saline; Group II, Ca(OH)2; Group III, CHX; and Group IV, NG. The assessment of bacterial growth was carried out by harvesting dentin chips at the end of 1, 3, and 7 days. The colonies were physically counted and tabulated after 24 hours from seeding. Statistical analysis of the collected data was performed with analysis of variance and Tukey's post hoc test using SPSS Version 20.0.

RESULTS

 The contaminated dentine blocks irrigated with NG (0.5 µg) and CHX (0 ± 0; p < 0.001) had no growth of E. faecalis colonies compared to blocks of Ca(OH)2 (10 ± 21) and saline (927 ± 455). All concentrations of NG (0.5 and 1.0 µg) showed effectiveness higher (p < 0.001) than 2% CHX when measured by the zone of inhibition against E. faecalis. CONCLUSION:  It may be concluded that NG is effective against growth of E. faecalis and may be used as a promising antimicrobial agent during root canal treatment. However, further studies should be done to investigate the effect of NG against other dental pathogens.

Graphene Oxide Strengthens Gelatine through Non-Covalent Interactions with Its Amorphous Region

Graphene oxide (GO) has attracted huge attention in biomedical sciences due to its outstanding properties and potential applications. In this study, we synthesized GO using our recently developed 1-pyrenebutyric acid-assisted method and assessed how the GO as a filler influences the mechanical properties of GO-gelatine nanocomposite dry films as well as the cytotoxicity of HEK-293 cells grown on the GO-gelatine substrates. We show that the addition of GO (0-2%) improves the mechanical properties of gelatine in a concentration-dependent manner. The presence of 2 wt% GO increased the tensile strength, elasticity, ductility, and toughness of the gelatine films by about 3.1-, 2.5-, 2-, and 8-fold, respectively. Cell viability, apoptosis, and necrosis analyses showed no cytotoxicity from GO. Furthermore, we performed circular dichroism, X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses to decipher the interactions between GO and gelatine. The results show, for the first time, that GO enhances the mechanical properties of gelatine by forming non-covalent intermolecular interactions with gelatine at its amorphous or disordered regions. We believe that our findings will provide new insight and help pave the way for potential and wide applications of GO in tissue engineering and regenerative biomedicine.

Progresses and perspectives on natural polysaccharide based hydrogels for repair of infarcted myocardium

Myocardial infarction (MI) is serious health threat and impairs the quality of life. It is a major causative factor of morbidity and mortality. MI leads to the necrosis of cardio-myocytes, cardiac remodelling and dysfunction, eventually leading to heart failure. The limitations of conventional therapeutic and surgical interventions and lack of heart donors have necessitated the evolution of alternate treatment approaches for MI. Polysaccharide hydrogel based repair of infarcted myocardium have surfaced as viable option for MI treatment. Polysaccharide hydrogels may be injectable hydrogels or cardiac patches. Injectable hydrogels can in situ deliver cells and bio-actives, facilitating in situ cardiac regeneration and repair. Polysaccharide hydrogel cardiac patches reduce cardiac wall stress, and inhibit ventricular expansion and promote angiogenesis. Herein, we discuss about MI pathophysiology and myocardial microenvironment and how polysaccharide hydrogels are designed to mimic and support the microenvironment for cardiac repair. We also put forward the versatility of the different polysaccharide hydrogels in mimicking diverse cardiac properties, and acting as a medium for delivery of cells, and therapeutics for promoting angiogenesis and cardiac repair. The objectives of this review is to summarize the factors leading to MI and to put forward how polysaccharide based hydrogels promote cardiac repair. This review is written to enable researchers understand the factors promoting MI so that they can undertake and design novel hydrogels for cardiac regeneration.

Comparative toxicological analysis of two pristine carbon nanomaterials (graphene oxide and aminated graphene oxide) and their corresponding degraded forms using human in vitro models

Despite the wide application of graphene-based materials, the information of the toxicity associated to some specific derivatives such as aminated graphene oxide is scarce. Likewise, most of these studies analyse the pristine materials, while the available data regarding the harmful effects of degraded forms is very limited. In this work, the toxicity of graphene oxide (GO), aminated graphene oxide (GO-NH2), and their respective degraded forms (dGO and dGO-NH2) obtained after being submitted to high-intensity sonication was evaluated applying in vitro assays in different models of human exposure. Viability and ROS assays were performed on A549 and HT29 cells, while their skin irritation potential was tested on a reconstructed human epidermis model. The obtained results showed that GO-NH2 and dGO-NH2 substantially decrease cell viability in the lung and gastrointestinal models, being this reduction slightly higher in the cells exposed to the degraded forms. In contrast, this parameter was not affected by GO and dGO which, conversely, showed the ability to induce higher levels of ROS than the pristine and degraded aminated forms. Furthermore, none of the materials is skin irritant. Altogether, these results provide new insights about the potential harmful effects of the selected graphene-based nanomaterials in comparison with their degraded counterparts.

Compounding Methylene Blue with Selenium-decorated Graphene Quantum Dots to Improve Singlet Oxygen Production for Photodynamic Therapy Application

Graphene quantum dots (GQDs) are known as suitable material to be applied in different fields such as photodynamic therapy (PDT). Herein, GQDs were synthesized by the pyrolysis method and then decorated with selenium (Se). Afterward, they were combined with methylene blue (MB) to increase singlet oxygen generation as well as to apply them more effectively in the PDT method. Furthermore, GQDs were investigated by transmission electron microscope (TEM), photoluminescence spectrum (PL), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), reactive oxygen species (ROS) measurement, and cytotoxicity measurement. GQDs showed no dependence on the excitation wavelength. The result of ROS measurement proves that the combination of GQD-Se and MB increases singlet oxygen production. Moreover, afterglow measurement approved the beneficial effect of GQD-Se on even deep and near skin tumor treatment. Cytotoxicity measurements under dark conditions, cell viability, and the side effects on human cells were determined by (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay. Our findings show that under dark conditions, even high concentrations of nanoparticles have no significant effect on cell viability. These findings and the high biocompatibility of GQDs indicate the effective application of GQD-Se-MB in PDT.

Graphene oxide as inhibitor on the hydrolysis of fats under simulated in vitro duodenal conditions

Obesity is a global pandemic, thus novel developments that reduce the absorption of fats is of interest. We have evaluated the effect of graphene oxide (GO) on the lipase catalyzed hydrolysis of fats (tributyrin, sunflower and olive oil) under simulated duodenal conditions. Results indicate that the presence of GO in the digestion mixture can inhibit lipase activity up to a 90% of the initial reaction rate, and this inhibition lasts even during 2 h of digestion. The inhibition mechanism seems non competitive and could be opposite to the effect of bile salts, although the direct interaction between GO and the enzyme cannot be discarded. The inhibition is found also in alimentary fats suggesting that GO could be a strong inhibitor for fat hydrolysis.

Short term biodistribution and in vivo toxicity assessment of intravenously injected pristine graphene oxide nanoflakes in SD rats

The present study aimed to elucidate the short term biodistribution of nano sized graphene oxide (GO) along with the toxicological assessment under in-vivo condition with an intent to analyse the toxic effects of sudden accidental exposure of GO The synthesised GO was characterized using UV-Visible spectroscopy, XRD, FTIR, Raman spectroscopy, TGA and DLS. The morphological imaging was performed using SEM, TEM and AFM. With a lateral size of less than 300 nm, these nanoparticles exhibit significant organ barrier permeability of up to 20%. Upon acute exposure to 10 mg/kg dose of ICG-tagged GO nanoflakes through intravenous route, various organs such as kidney, spleen and liver were observed, and the nanoparticles predominantly accumulated in the liver upon 24 h of exposure. Upon confirming the accumulation of these particles in liver through IVIS imaging, our next attempt was to analyse various biochemical and serum parameters. An elevation in various serum parameters such as ALT, AST, Creatinine and Bilirubin was observed. Similarly, in the case of biochemical parameters tested in liver homogenates, an increase in NO, Catalase, GSH, SOD, ROS, LPO, GR, GPx, and GST was observed. This study highlights the potential toxicological risk associated with GO exposure which must be taken into account for any risk analysis associated with GO based consumer products and the occupational hazards.

Graphene Hybrid Tough Hydrogels with Nanostructures for Tissue Regeneration

Over the past few decades, hydrogels have attracted considerable attention as promising biomedical materials. However, conventional hydrogels require improved mechanical properties, such as brittleness, which significantly limits their widespread use. Recently, hydrogels with remarkably improved toughness have been developed; however, their low biocompatibility must be addressed. In this study, we developed a tough graphene hybrid hydrogel with nanostructures. The resultant hydrogel exhibited remarkable mechanical properties while representing an aligned nanostructure that resembled the extracellular matrix of soft tissue. Owing to the synergistic effect of the topographical properties, and the enhanced biochemical properties, the graphene hybrid hydrogel had excellent stretchability, resilience, toughness, and biocompatibility. Furthermore, the hydrogel displayed outstanding tissue regeneration capabilities (e.g., skin and tendons). Overall, the proposed graphene hybrid tough hydrogel may provide significant insights into the application of tough hydrogels in tissue regeneration.

Adhesion States Greatly Affect Cellular Susceptibility to Graphene Oxide: Therapeutic Implications for Cancer Metastasis

Graphene oxide (GO) has received increasing attention in the life sciences because of its potential for various applications. Although GO is generally considered biocompatible, it can negatively impact cell physiology under some circumstances. Here, we demonstrate that the cytotoxicity of GO greatly varies depending on the cell adhesion states. Human HCT-116 cells in a non-adhered state were more susceptible to GO than those in an adherent state. Apoptosis was partially induced by GO in both adhered and non-adhered cells to a similar extent, suggesting that apoptosis induction does not account for the selective effects of GO on non-adhered cells. GO treatment rapidly decreased intracellular ATP levels in non-adhered cells but not in adhered ones, suggesting ATP depletion as the primary cause of GO-induced cell death. Concurrently, autophagy induction, a cellular response for energy homeostasis, was more evident in non-adhered cells than in adhered cells. Collectively, our observations provide novel insights into GO's action with regard to cell adhesion states. Because the elimination of non-adhered cells is important in preventing cancer metastasis, the selective detrimental effects of GO on non-adhered cells suggest its therapeutic potential for use in cancer metastasis.

β-Carotene laden antibacterial and antioxidant gelatin/polyglyceryl stearate nano-hydrogel system for burn wound healing application

Worldwide, burn wounds are severe health issues prone to bacterial infections and challenging to treat with traditional wound dressings. Therefore, a highly desirable biological macromolecules-based wound dressing with good antioxidant, antibacterial, biocompatible, and a large surface area is required. Herein, aim to develop a biological macromolecules-based physically cross-linked gelatin/polyglyceryl stearate/graphene oxide (GPGO) hydrogel to treat burn wounds. Four sets of hydrogels were prepared by varying GO concentrations. FT-IR, FE-SEM, viscosity analysis, mechanical and thermal stability confirmed the successful preparation of hydrogels with desired properties. Further, β-carotene (0.5 mg/mL) was encapsulated in hydrogels to enhance the antioxidant activity, and a cumulative release as well as kinetics at pH 6.4 and 7.4 was performed. With an increase in GO concentration, hydrogels showed sustained release of β-carotene. Among all, GPGO-3 β hydrogel showed the highest antioxidant potency (57.75 %), hemocompatible (<5 %), cytocompatible (viable with NIH 3T3 cells), cell migration, proliferation, and in vitro wound healing. Also, GPGO-3 β hydrogel showed efficient antibacterial activity (%inhibition of 85.5 % and 80.2 % and zone of 11 mm and 9.8 mm against S. aureus and E. coli). These results demonstrated the ability of GPGO-3 β hydrogel as a promising candidate for burn wound healing applications.

A review of carbon nanomaterials/bacterial cellulose composites for nanomedicine applications

Carbon nanomaterials (CNMs) mainly include fullerene, carbon nanotubes, graphene, carbon quantum dots, nanodiamonds, and their derivatives. As a new type of material in the field of nanomaterials, it has outstanding physical and chemical properties, such as minor size effects, substantial specific surface area, extremely high reaction activity, biocompatibility, and chemical stability, which have attracted widespread attention in the medical community in the past decade. However, the single use of carbon nanomaterials has problems such as self-aggregation and poor water solubility. Researchers have recently combined them with bacterial cellulose to form a new intelligent composite material to improve the defects of carbon nanomaterials. This composite material has been widely synthesized and used in targeted drug delivery, biosensors, antibacterial dressings, tissue engineering scaffolds, and other nanomedicine fields. This paper mainly reviews the research progress of carbon nanomaterials based on bacterial cellulose in nanomedicine. In addition, the potential cytotoxicity of these composite materials and their components in vitro and in vivo was discussed, as well as the challenges and gaps that need to be addressed in future clinical applications.

Evaluating Gelatin-Based Films with Graphene Nanoparticles for Wound Healing Applications

In this study, gelatin-based films containing graphene nanoparticles were obtained. Nanoparticles were taken from four chosen commercial graphene nanoplatelets with different surface areas, such as 150 m2/g, 300 m2/g, 500 m2/g, and 750 m2/g, obtained in different conditions. Their morphology was observed using SEM with STEM mode; porosity, Raman spectra and elemental analysis were checked; and biological properties, such as hemolysis and cytotoxicity, were evaluated. Then, the selected biocompatible nanoparticles were used as the gelatin film modification with 10% concentration. As a result of solvent evaporation, homogeneous thin films were obtained. The surface's properties, mechanical strength, antioxidant activity, and water vapor permeation rate were examined to select the appropriate film for biomedical applications. We found that the addition of graphene nanoplatelets had a significant effect on the properties of materials, improving surface roughness, surface free energy, antioxidant activity, tensile strength, and Young's modulus. For the most favorable candidate for wound dressing applications, we chose a gelatin film containing nanoparticles with a surface area of 500 m2/g.

Graphene oxide as novel vaccine adjuvant

To improve antigen immunogenicity and promote long-lasting immunity, vaccine formulations have been appropriately supplemented with adjuvants. Graphene has been found to enhance the presentation of antigens to CD8+ T cells, as well as stimulating innate immune responses and inflammatory factors. Its properties, such as large surface area, water stability, and high aspect ratio, make it a suitable candidate for delivering biological substances. Graphene-based nanomaterials have recently attracted significant attention as a new type of vaccine adjuvants due to their potential role in the activation of immune responses. Due to the limited functionality of some approved human adjuvants for use, the development of new all-purpose adjuvants is urgently required. Research on the immunological and biomedical use of graphene oxide (GO) indicates that these nanocarriers possess excellent physicochemical properties, acceptable biocompatibility, and a high capacity for drug loading. Graphene-based nanocarriers also could improve the function of some immune cells such as dendritic cells and macrophages through specific signaling pathways. However, GO injection can lead to significant oxidative stress and inflammation. Various surface functionalization protocols have been employed to reduce possible adverse effects of GO, such as aggregation of GO in biological liquids and induce cell death. Furthermore, these modifications enhance the properties of functionalized-GO's qualities, making it an excellent carrier and adjuvant. Shedding light on different physicochemical and structural properties of GO and its derivatives has led to their application in various therapeutic and drug delivery fields. In this review, we have endeavored to elaborate on different aspects of GO.

Recent advances in nanoantibiotics against multidrug-resistant bacteria

Multidrug-resistant (MDR) bacteria-caused infections have been a major threat to human health. The abuse of conventional antibiotics accelerates the generation of MDR bacteria and makes the situation worse. The emergence of nanomaterials holds great promise for solving this tricky problem due to their multiple antibacterial mechanisms, tunable antibacterial spectra, and low probabilities of inducing drug resistance. In this review, we summarize the mechanism of the generation of drug resistance, and introduce the recently developed nanomaterials for dealing with MDR bacteria via various antibacterial mechanisms. Considering that biosafety and mass production are the major bottlenecks hurdling the commercialization of nanoantibiotics, we introduce the related development in these two aspects. We discuss urgent challenges in this field and future perspectives to promote the development and translation of nanoantibiotics as alternatives against MDR pathogens to traditional antibiotics-based approaches.

Progress in the application of graphene and its derivatives to osteogenesis

As bone and joint injuries from various causes become increasingly prominent, how to effectively reconstruct and repair bone defects presents a difficult problem for clinicians and researchers. In recent years, graphene and its derivatives have been the subject of growing body of research and have been found to promote the proliferation and osteogenic differentiation of stem cells. This provides a new idea for solving the clinical problem of bone defects. However, as as numerous articles address various aspects and have not been fully systematized, there is an urgent need to classify and summarize them. In this paper, for the first time, the effects of graphene and its derivatives on stem cells in solution, in 2D and 3D structures and in vivo and their possible mechanisms are reviewed, and the cytotoxic effects of graphene and its derivatives were summarized and analyzed. The toxicity of graphene and its derivatives is further reviewed. In addition, we suggest possible future development directions of graphene and its derivatives in bone tissue engineering applications to provide a reference for further clinical application.

Graphene oxide had adverse effects on sperm motility and morphology through oxidative stress

Graphene oxide (GO) is a new type of graphene material, but its effects on the male reproductive system are unclear. Here, we investigated the effects of GO on human sperm in vitro. Sperms were incubated with various doses of GO (0, 10, 20, or 40 μg/mL) for different times (1, 3, or 6 h) at 37 °C, followed by analyses of the sperm motility, viability, abnormalities, and DNA fragmentations. GO exposure significantly decreased sperm motility and viability, increased sperm abnormalities, and DNA fragmentation. Moreover, GO exposure resulted in a significant reduction of sperm mitochondrial membrane potential (MMP), which was confirmed by the ultrastructural changes of chromatin and mitochondria caused by GO. These data revealed the adverse effects of GO on sperm. Further research showed that GO exposure led to a significant increase in malondialdehyde (MDA) and reactive oxygen species (ROS) in sperm cells and a significant decrease in total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px). In addition, western blot analysis showed that the levels of Nrf-2 and HO-1 protein expression in GO-treated sperm cells were significantly increased compared to the control. These results indicated that GO had adverse effects on human sperm through oxidative stress, which was associated with Nrf-2/HO-1 signaling pathway.

Graphene Oxide Nanostructures as Nanoplatforms for Delivering Natural Therapeutic Agents: Applications in Cancer Treatment, Bacterial Infections, and Bone Regeneration Medicine

Graphene, fullerenes, diamond, carbon nanotubes, and carbon dots are just a few of the carbon-based nanomaterials that have gained enormous popularity in a variety of scientific disciplines and industrial uses. As a two-dimensional material in the creation of therapeutic delivery systems for many illnesses, nanosized graphene oxide (NGO) is now garnering a large amount of attention among these materials. In addition to other benefits, NGO functions as a drug nanocarrier with remarkable biocompatibility, high pharmaceutical loading capacity, controlled drug release capability, biological imaging efficiency, multifunctional nanoplatform properties, and the power to increase the therapeutic efficacy of loaded agents. Thus, NGO is a perfect nanoplatform for the development of drug delivery systems (DDSs) to both detect and treat a variety of ailments. This review article's main focus is on investigating surface functionality, drug-loading methods, and drug release patterns designed particularly for smart delivery systems. The paper also examines the relevance of using NGOs to build DDSs and considers prospective uses in the treatment of diseases including cancer, infection by bacteria, and bone regeneration medicine. These factors cover the use of naturally occurring medicinal substances produced from plant-based sources.

Phosphorylcholine-grafted graphene oxide loaded with irinotecan for potential oncology therapy

2-Methacryloyloxyethyl phosphorylcholine (MPC) zwitterions were modified onto self-made graphene oxide (GO) through the atom transfer radical polymerization method. The chemical structures of the products were verified using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), etc. It was found that the modified GO (GO-PCn) is well dispersed in water with an average hydrodynamic diameter of about 170 nm. By utilizing the 2D planar structure of this modified graphene, the irinotecan@GO-PCn composite can be loaded with about 20% of irinotecan via π-π stacking interaction and exhibit pH-sensitive drug release performance, releasing faster in the acidic environment. The in vitro cytotoxicity assessments confirmed that GO-PCn composed of phosphorylcholine moiety represented low cytotoxicity and acted as a certain effect on reducing the acute toxicity of irinotecan, which established a foundation for further studies of the system in oncology therapy.

Production of Reduced Graphene Oxide by Using Three Different Microorganisms and Investigation of Their Cell Interactions

Despite the huge and efficient functionalities of reduced graphene oxide (RGO) for bioengineering applications, the use of harsh chemicals and unfavorable techniques in their production remains a major challenge. Microbial production of reduced graphene oxide (RGO) using specific bacterial strains has gained interest as a sustainable and efficient method. The reduction of GO to RGO by selected bacterial strains was achieved through their enzymatic activities and resulted in the removal of oxygen functional groups from GO, leading to the formation of RGO with enhanced structural integrity. The use of microorganisms offers a sustainable approach, utilizing renewable carbon sources and mild reaction conditions. This study investigates the production of RGO using three different bacterial strains: Lactococcus lactis (L. Lactis), Lactobacillus plantarum (L. plantarum), and Escherichia coli (E. coli) and evaluates its toxicity for safe utilization. The aim is to assess the quality of the produced RGO and evaluate its toxicity for potential applications. Thus, this study focused on the microbial production of reduced graphene oxides well as the investigation of their cellular interactions. Graphite-derived graphene oxide was used as a starting material and microbially reduced GO products were characterized using the FTIR, Raman, XRD, TGA, and XPS methods to determine their physical and chemical properties. FTIR shows that the epoxy and some of the alkoxy and carboxyl functional groups were reduced by E. coli and L. lactis, whereas the alkoxy groups were mostly reduced by L. plantarum. The ID/IG ratio from Raman spectra was found as 2.41 for GO. A substantial decrease in the ratio as well as defects was observed as 1.26, 1.35, and 1.46 for ERGO, LLRGO, and LPRGO after microbial reduction. The XRD analysis also showed a significant reduction in the interlayer spacing of the GO from 0.89 to 0.34 nm for all the reduced graphene oxides. TGA results showed that reduction of GO with L. lactis provided more reduction than other bacteria and formed a structure closer to graphene. Similarly, analysis with XPS showed that L lactis provides the most effective reduction with a C/O ratio of 3.70. In the XPS results obtained with all bacteria, it was observed that the C/O ratio increased because of the microbial reduction. Toxicity evaluations were performed to assess the biocompatibility and safety of the produced RGO. Cell viability assays were conducted using DLD-1 and CHO cell lines to determine the potential cytotoxic effects of RGO produced by each bacterial strain. Additionally, apoptotic, and necrotic responses were examined to understand the cellular mechanisms affected by RGO exposure. The results indicated that all the RGOs have concentration-dependent cytotoxicity. A significant amount of cell viability of DLD-1 cells was observed for L. lactis reduced graphene oxide. However, the highest cell viability of CHO cells was observed for L. plantarum reduced graphene oxide. All reduced graphene oxides have low apoptotic and necrotic responses in both cell lines. These findings highlight the importance of considering the specific bacterial strain used in RGO production as it can influence the toxicity and cellular response of the resulting RGO. The toxicity and cellular response to the final RGO can be affected by the particular bacterial strain that is employed to produce it. This information will help to ensure that RGO is used safely in a variety of applications, including tissue engineering, drug delivery systems, and biosensors, where comprehension of its toxicity profile is essential.

Bioscaffolds of graphene based-polymeric hybrid materials for myocardial tissue engineering

Introduction

Biomaterials currently utilized for the regeneration of myocardial tissue seem to associate with certain restrictions, including deficiency of electrical conductivity and sufficient mechanical strength. These two factors play an important role in cardiac tissue engineering and regeneration. The contractile property of cardiomyocytes depends on directed signal transmission over the electroconductive systems that happen inside the innate myocardium. Because of their distinctive electrical behavior, electroactive materials such as graphene might be used for the regeneration of cardiac tissue.

Methods

In this review, we aim to provide deep insight into the applications of graphene and graphene derivative-based hybrid polymeric scaffolds in cardiomyogenic differentiation and cardiac tissue regeneration.

Results

Synthetic biodegradable polymers are considered as a platform because their degradation can be controlled over time and easily functionalized. Therefore, graphene-polymeric hybrid scaffolds with anisotropic electrical behavior can be utilized to produce organizational and efficient constructs for macroscopic cardiac tissue engineering. In cardiac tissue regeneration, natural polymer based-scaffolds such as chitosan, gelatin, and cellulose can provide a permissive setting significantly supporting the differentiation and growth of the human induced pluripotent stem cells -derived cardiomyocytes, in large part due to their negligible immunogenicity and suitable biodegradability.

Conclusion

Cardiac tissue regeneration characteristically utilizes an extracellular matrix (scaffold), cells, and growth factors that enhance cell adhesion, growth, and cardiogenic differentiation. From the various evaluated electroactive polymeric scaffolds for cardiac tissue regeneration in the past decade, graphene and its derivatives-based materials can be utilized efficiently for cardiac tissue engineering.

Management and Mitigation of Vibriosis in Aquaculture: Nanoparticles as Promising Alternatives

Vibriosis is one of the most common diseases in marine aquaculture, caused by bacteria belonging to the genus Vibrio, that has been affecting many species of economically significant aquatic organisms around the world. The prevention of vibriosis in aquaculture is difficult, and the various treatments for vibriosis have their limitations. Therefore, there is an imperative need to find new alternatives. This review is based on the studies on vibriosis, specifically on the various treatments and their limitations, as well as the application of nanoparticles in aquaculture. One of the promising nanoparticles is graphene oxide (GO), which has been used in various applications, particularly in biological applications such as biosensors, drug delivery, and potential treatment for infectious diseases. GO has been shown to have anti-bacterial properties against both Gram-positive and Gram-negative bacteria, but no research has been published that emphasizes its impact on Vibrio spp. The review aims to explore the potential use of GO for treatment against vibriosis.

Biocompatibility of graphene oxide nanosheets functionalized with various amino acids towards mesenchymal stem cells

Graphene and its derivatives have gained popularity due to their numerous applications in various fields, such as biomedicine. Recent reports have revealed the severe toxic effects of these nanomaterials on cells and organs. In general, the chemical composition and surface chemistry of nanomaterials affect their biocompatibility. Therefore, the purpose of the present study was to evaluate the cytotoxicity and genotoxicity of graphene oxide (GO) synthesized by Hummer's method and functionalized by different amino acids such as lysine, methionine, aspartate, and tyrosine. The obtained nanosheets were identified by FT-IR, EDX, RAMAN, FE-SEM, and DLS techniques. In addition, trypan blue and Alamar blue methods were used to assess the cytotoxicity of mesenchymal stem cells extracted from human embryonic umbilical cord Wharton jelly (WJ-MSCs). The annexin V staining procedure was used to determine apoptotic and necrotic death. In addition, COMET and karyotyping techniques were used to assess the extent of DNA and chromosome damage. The results of the cytotoxicity assay showed that amino acid modifications significantly reduced the concentration-dependent cytotoxicity of GO to varying degrees. The GO modified with aspartic acid had the lowest cytotoxicity. There was no evidence of chromosomal damage in the karyotyping method, but in the comet assay, the samples modified with tyrosine and lysine showed the greatest DNA damage and rate of apoptosis. Overall, the aspartic acid-modified GO caused the least cellular and genetic damage to WJ-MSCs, implying its superior biomedical applications such as cell therapy and tissue engineering over GO.

Role of Chemical Reduction and Formulation of Graphene Oxide on Its Cytotoxicity towards Human Epithelial Bronchial Cells

Graphene-based materials may pose a potential risk for human health due to occupational exposure, mainly by inhalation. This study was carried out on bronchial epithelial 16HBE14o- cells to evaluate the role of chemical reduction and formulation of graphene oxide (GO) on its cytotoxic potential. To this end, the effects of GO were compared to its chemically reduced form (rGO) and its stable water dispersion (wdGO), by means of cell viability reduction, reactive oxygen species (ROS) generation, pro-inflammatory mediators release and genotoxicity. These materials induced a concentration-dependent cell viability reduction with the following potency rank: rGO > GO >> wdGO. After 24 h exposure, rGO reduced cell viability with an EC50 of 4.8 μg/mL (eight-fold lower than that of GO) and was the most potent material in inducing ROS generation, in contrast to wdGO. Cytokines release and genotoxicity (DNA damage and micronucleus induction) appeared low for all the materials, with wdGO showing the lowest effect, especially for the former. These results suggest a key role for GO reduction in increasing GO cytotoxic potential, probably due to material structure alterations resulting from the reduction process. In contrast, GO formulated in a stable dispersion seems to be the lowest cytotoxic material, presumably due to its lower cellular internalization and damaging capacity.

New insight into the biocompatibility/toxicity of graphene oxides and their reduced forms on Chlamydomonas reinhardtii

Graphene oxides (GOs) and their reduced forms are often discussed both positively and negatively due to the lack of information about their chemistry and structure. This study utilized GOs with two sheet sizes that were further reduced by two reducing agents (sodium borohydride and hydrazine) to obtain two different degrees of reduction. The synthesized nanomaterials were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), elemental analysis (EA), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy (RA) to understand their chemistry and structure. The second focus of our investigation included in vitro testing of the biocompatibility/toxicity of these materials on a model organism, the freshwater microalga Chlamydomonas reinhardtii. The effects were studied on the basis of biological endpoints complemented by biomass investigation (FTIR spectroscopy, EA, and atomic absorption spectrometry (AAS)). The results showed that the biocompatibility/toxicity of GOs is dependent on their chemistry and structure and that it is impossible to generalize the toxicity of graphene-based nanomaterials.

Cost-effective one-spot hydrothermal synthesis of graphene oxide nanoparticles for wastewater remediation: AI-enhanced approach for transition metal oxides

This investigation presents a cost-efficient hydrothermal synthesis technique for producing graphene oxide nanoparticles (GO-NPs) that exhibit promising potential in wastewater treatment. The synthesis process involves a facile and expandable hydrothermal reactor that can be regulated using an AI-empowered methodology. The generated GO-NPs were characterised using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM), confirming their successful synthesis and high quality. The high degree of crystallinity observed in the GO-NPs can be attributed to the favourable reaction conditions facilitated by the hydrothermal synthesis. The TEM analysis showed that the GO-NPs had a homogeneous dispersion pattern and a consistent size distribution of approximately 10 nm. Carboxylation was employed to functionalize the GO-NPs, enhancing their reactivity towards diverse contaminants present in wastewater. The remediation potential of the GO-NPs for transition metal oxides, which are frequently found in wastewater, was assessed. The GO-NPs exhibited notable efficacy in remediating the transition metal oxides that were subjected to testing. The heightened efficacy of remediation can be attributed to the substantial surface area and elevated reactivity of the GO-NPs, in addition to their functionalization using carboxylic groups. The cost-effective and efficient synthesis method, coupled with the high remediation potential of the GO-NPs, makes them a highly promising contender for employment in wastewater remediation applications. The use of AI in regulating the hydrothermal synthesis procedure enables accurate manipulation of the reaction parameters, thereby augmenting the quality and uniformity of the resultant GO-NPs. The proposed method exhibits scalability potential for large-scale production of GO-NPs, presenting a viable remedy for the challenges associated with wastewater remediation.

Effects of Graphene Oxide Nanosheets in Freshwater Biofilms

Graphene oxide (GO) properties make it a promising material for graphene-based applications in areas such as biomedicine, agriculture, and the environment. Thus, its production is expected to increase, reaching hundreds of tons every year. One GO final destination is freshwater bodies, possibly affecting the communities of these systems. To clarify the effect that GO may impose in freshwater communities, a fluvial biofilm scraped from submerged river stones was exposed to a range (0.1 to 20 mg/L) of GO concentrations during 96 h. With this approach, we hypothesized that GO can: (1) cause mechanical damage and morphological changes in cell biofilms; (2) interfere with the absorption of light by biofilms; (3) and generate oxidative stress, causing oxidative damage and inducing biochemical and physiological alterations. Our results showed that GO did not inflict mechanical damage. Instead, a positive effect is proposed, linked to the ability of GO to bind cations and increase the micronutrient availability to biofilms. High concentrations of GO increased photosynthetic pigment (chlorophyll a, b, and c, and carotenoids) content as a strategy to capture the available light more effectively as a response to the shading effect. A significant increase in the enzymatic (SOD and GSTs activity) and low molecular weight (lipids and carotenoids) antioxidant response was observed, that efficiently reduced oxidative stress effects, reducing the level of peroxidation, and preserving membrane integrity. Being complex entities, biofilms are more similar to environmental communities and may provide more accurate information to evaluate the impact of GO in aquatic systems.

Nanomaterial-Based Scaffolds for Tissue Engineering Applications: A Review on Graphene, Carbon Nanotubes and Nanocellulose

Nanoscale biomaterials have garnered immense interest in the scientific community in the recent decade. This review specifically focuses on the application of three nanomaterials, i.e., graphene and its derivatives (graphene oxide, reduced graphene oxide), carbon nanotubes (CNTs) and nanocellulose (cellulose nanocrystals or CNCs and cellulose nanofibers or CNFs), in regenerating different types of tissues, including skin, cartilage, nerve, muscle and bone. Their excellent inherent (and tunable) physical, chemical, mechanical, electrical, thermal and optical properties make them suitable for a wide range of biomedical applications, including but not limited to diagnostics, therapeutics, biosensing, bioimaging, drug and gene delivery, tissue engineering and regenerative medicine. A state-of-the-art literature review of composite tissue scaffolds fabricated using these nanomaterials is provided, including the unique physicochemical properties and mechanisms that induce cell adhesion, growth, and differentiation into specific tissues. In addition, in vitro and in vivo cytotoxic effects and biodegradation behavior of these nanomaterials are presented. We also discuss challenges and gaps that still exist and need to be addressed in future research before clinical translation of these promising nanomaterials can be realized in a safe, efficacious, and economical manner.

Surface Area of Graphene Governs Its Neurotoxicity

Due to their unique physicochemical properties, graphene and its derivatives are widely exploited for biomedical applications. It has been shown that graphene may exert different degrees of toxicity in in vivo or in vitro models when administered via different routes and penetrated through physiological barriers, subsequently being distributed within tissues or located within cells. In this study, in vitro neurotoxicity of graphene with different surface areas (150 and 750 m²/g) was examined on dopaminergic neuron model cells. SH-SY5Y cells were treated with graphene possessing two different surface areas (150 and 750 m²/g) in different concentrations between 400 and 3.125 μg/mL, and the cytotoxic and genotoxic effects were investigated. Both sizes of graphene have shown increased cell viability in decreasing concentrations. Cell damage increased with higher surface area. Lactate dehydrogenase (LDH) results have concluded that the viability loss of the cells is not through membrane damage. Neither of the two graphene types showed damage through lipid peroxidation (MDA) oxidative stress pathway. Glutathione (GSH) values increased within the first 24 and 48 h for both types of graphene. This increase suggests that graphene has an antioxidant effect on the SH-SY5Y model neurons. Comet analysis shows that graphene does not show genotoxicity on either surface area. Although there are many studies on graphene and its derivatives on their use with different cells in the literature, there are conflicting results in these studies, and most of the literature is focused on graphene oxide. Among these studies, no study examining the effect of graphene surface areas on the cell was found. Our study contributes to the literature in terms of examining the cytotoxic and genotoxic behavior of graphene with different surface areas.

Effect of Melittin Complexes with Graphene and Graphene Oxide on Triple-Negative Breast Cancer Tumors Grown on Chicken Embryo Chorioallantoic Membrane

One of the components of bee venom is melittin (M), which has strong lysing properties on membranes. M has high toxicity to cancer cells, but it also affects healthy cells, making it necessary to use methods for targeted delivery to ensure treatment. This research is a continuation of previous studies using graphene nanomaterials as M carriers to breast cancer cells. The studies described below are conducted on a more organized biological structure than what is found in vitro cells, namely, cancerous tumors grown on a chicken embryo chorioallantoic membrane. Caspase 3 and 8 levels are analyzed, and the level of oxidative stress markers and changes in protein expression for cytokines are examined. The results show that M complexes with nanomaterials reduce the level of oxidative stress more than M alone does, but the use of graphene (GN) as a carrier increases the level of DNA damage to a greater extent than the increase caused by M alone. An analysis of cytokine levels shows that the use of the M and GN complex increases the level of proteins responsible for inhibiting tumor progression to a greater extent than the increase occasioned by a complex with graphene oxide (GO). The results suggest that the use of GN as an M carrier may increase the toxic effect of M on structures located inside a cell.

The antimicrobial efficacy of nanographene oxide and double antibiotic paste per se and in combination: part II

BACKGROUND

Finding strategies to overcome the rising trends of antimicrobial resistance against currently available antimicrobial agents has become increasingly relevant. Graphene oxide has recently emerged as a promising material due to its outstanding physicochemical and biological properties. This study aimed to validate previous data on the antibacterial activity of nanographene oxide (nGO), double antibiotic paste (DAP), and their combination (nGO-DAP).

METHODS

The antibacterial evaluation was performed against a wide range of microbial pathogens. Synthesis of nGO was achieved using a modified Hummers' method, and loading it with ciprofloxacin and metronidazole resulted in nGO-DAP. The microdilution method was utilized to assess the antimicrobial efficacy of nGO, DAP, and nGO-DAP against two gram-positive bacteria (S. aureus and E. faecalis), two gram-negative bacteria (E. coli, and S. typhi), and an opportunistic pathogenic yeast (C. albicans). Statistical analysis was conducted using one-sample t-test and one-way ANOVA (α = 0.05).

RESULTS

All three antimicrobial agents significantly increased the killing percent of microbial pathogens compared to the control group (P < 0.05). Furthermore, the synthesized nGO-DAP exhibited higher antimicrobial activity than nGO and DAP per se.

CONCLUSION

The novel synthesized nGO-DAP can be used as an effective antimicrobial nanomaterial for use in dental, biomedical, and pharmaceutical fields against a range of microbial pathogens, including gram-negative and gram-positive bacteria, as well as yeasts.

Effect of graphene-based nanomaterials on corneal wound healing in vitro

Graphene-based nanomaterials (GBNs) are widely used due to their chemical and physical properties for multiple commercial and environmental applications. From an occupational health perspective, there is concern regarding the effects of inhalation on the respiratory system, and many studies have been conducted to study inhalation impacts on lung. Similar to the respiratory system, the eyes may also be exposed to GBNs and thus impacted. In this study, immortalized human corneal epithelial (hTCEpi) cells and rabbit corneal fibroblasts (RCFs) were used to investigate the toxicity of eight types of GBN: graphene oxide (GO; 400 nm), GO (1 μm), partially reduced graphene oxide (PRGO; 400 nm), reduced graphene oxide (RGO; 400 nm), RGO (2 μm), graphene (110 nm), graphene (140 nm), and graphene (1 μm). We next examined the effects of these GBNs on hTCEpi cell migration. We also determined whether the expression of α-smooth muscle actin (αSMA), a myofibroblast marker, is altered by the GBNs using RCFs. We found that RGO (400 nm) and RGO (2 μm) were highly toxic to hTCEPi cells and RCFs meanwhile, PRGO (400 nm) was toxic only to hTCEpi cells. In addition, PRGO (400 nm), RGO (400 nm), and RGO (2 μm) inhibited hTCEpi cell migration and significantly increased αSMA mRNA expression. Further study in vivo is required to determine if RGO nanomaterials delay corneal epithelial healing and induce scar formation.

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.

The Cultivation Modality and Barrier Maturity Modulate the Toxicity of Industrial Zinc Oxide and Titanium Dioxide Nanoparticles on Nasal, Buccal, Bronchial, and Alveolar Mucosa Cell-Derived Barrier Models

As common industrial by-products, airborne engineered nanomaterials are considered important environmental toxins to monitor due to their potential health risks to humans and animals. The main uptake routes of airborne nanoparticles are nasal and/or oral inhalation, which are known to enable the transfer of nanomaterials into the bloodstream resulting in the rapid distribution throughout the human body. Consequently, mucosal barriers present in the nose, buccal, and lung have been identified and intensively studied as the key tissue barrier to nanoparticle translocation. Despite decades of research, surprisingly little is known about the differences among various mucosa tissue types to tolerate nanoparticle exposures. One limitation in comparing nanotoxicological data sets can be linked to a lack of harmonization and standardization of cell-based assays, where (a) different cultivation conditions such as an air-liquid interface or submerged cultures, (b) varying barrier maturity, and (c) diverse media substitutes have been used. The current comparative nanotoxicological study, therefore, aims at analyzing the toxic effects of nanomaterials on four human mucosa barrier models including nasal (RPMI2650), buccal (TR146), alveolar (A549), and bronchial (Calu-3) mucosal cell lines to better understand the modulating effects of tissue maturity, cultivation conditions, and tissue type using standard transwell cultivations at liquid-liquid and air-liquid interfaces. Overall, cell size, confluency, tight junction localization, and cell viability as well as barrier formation using 50% and 100% confluency was monitored using trans-epithelial-electrical resistance (TEER) measurements and resazurin-based Presto Blue assays of immature (e.g., 5 days) and mature (e.g., 22 days) cultures in the presence and absence of corticosteroids such as hydrocortisone. Results of our study show that cellular viability in response to increasing nanoparticle exposure scenarios is highly compound and cell-type specific (TR146 6 ± 0.7% at 2 mM ZnO (ZnO) vs. ~90% at 2 mM TiO2 (TiO2) for 24 h; Calu3 93.9 ± 4.21% at 2 mM ZnO vs. ~100% at 2 mM TiO2). Nanoparticle-induced cytotoxic effects under air-liquid cultivation conditions declined in RPMI2650, A549, TR146, and Calu-3 cells (~0.7 to ~0.2-fold), with increasing 50 to 100% barrier maturity under the influence of ZnO (2 mM). Cell viability in early and late mucosa barriers where hardly influenced by TiO2 as well as most cell types did not fall below 77% viability when added to Individual ALI cultures. Fully maturated bronchial mucosal cell barrier models cultivated under ALI conditions showed less tolerance to acute ZnO nanoparticle exposures (~50% remaining viability at 2 mM ZnO for 24 h) than the similarly treated but more robust nasal (~74%), buccal (~73%), and alveolar (~82%) cell-based models.

Cellular uptake of biotransformed graphene oxide into lung cells

Due to its high surface area and convenient functionalization, graphene oxide has many potential applications in biomedicine, especially as a drug carrier. However, knowledge about its internalization inside mammalian cells is still limited. Graphene oxide cellular uptake is a complex phenomenon affected by factors such as the size of the particle and modifications of its surface. Moreover, nanomaterials introduced into living organisms interact with biological fluids' components. It may further alter its biological properties. All these factors must be considered when the cellular uptake of potential drug carriers is considered. In this study, the effect of graphene oxide particle sizes on internalization efficiency into normal (LL-24) and cancerous (A549) human lung cells was investigated. Moreover, one set of samples was incubated with human serum to determine how the interaction of graphene oxide with serum components affects its structure, surface, and interaction with cells. Our findings indicate that samples incubated with serum enhance cell proliferation but enter the cells with lesser efficiency than their counterparts not incubated with human serum. What is more affinity towards the cells was higher for larger particles.

Graphene oxide nanoarchitectures in cancer biology: Nano-modulators of autophagy and apoptosis

Nanotechnology is a growing field, with many potential biomedical applications of nanomedicine for the treatment of different diseases, particularly cancer, on the horizon. Graphene oxide (GO) nanoparticles can act as carbon-based nanocarriers with advantages such as a large surface area, good mechanical strength, and the capacity for surface modification. These nanostructures have been extensively used in cancer therapy for drug and gene delivery, photothermal therapy, overcoming chemotherapy resistance, and for imaging procedures. In the current review, we focus on the biological functions of GO nanoparticles as regulators of apoptosis and autophagy, the two major forms of programmed cell death. GO nanoparticles can either induce or inhibit autophagy in cancer cells, depending on the conditions. By stimulating autophagy, GO nanocarriers can promote the sensitivity of cancer cells to chemotherapy. However, by impairing autophagy flux, GO nanoparticles can reduce cell survival and enhance inflammation. Similarly, GO nanomaterials can increase ROS production and induce DNA damage, thereby sensitizing cancer cells to apoptosis. In vitro and in vivo experiments have investigated whether GO nanomaterials show any toxicity in major body organs, such as the brain, liver, spleen, and heart. Molecular pathways, such as ATG, MAPK, JNK, and Akt, can be regulated by GO nanomaterials, leading to effects on autophagy and apoptosis. These topics are discussed in this review to shed some lights towards the biomedical potential of GO nanoparticles and their biocompatibility, paving the way for their future application in clinical trials.

Effect of gamma-ray irradiated reduced graphene oxide (rGO) on environmental health: An in-vitro and in-vivo studies

The unique properties of reduced graphene oxide (rGO) have drawn the attention of scientists worldwide since the last decade and it is explored for a wide range of applications. However, the rapid expansion of rGO use in various products will eventually lead to environenal exposure and rises a safety concern on the environment and humal health risk. Moreover, the utilization of toxic chemicals for the reduction of graphene oxide (GO) into rGO is not environmentally friendly, warranting the exploration of non-toxic approaches. In the present work, rGO was synthesized using a different dose of gamma-ray irradiation and characterized. The in-vitro and in-vivo analysis indicated that the gamma-irradiated rGO induced toxicity depending on its degree of reduction and dosage. In the L929 cells, rGO-30 KGy significantly induced cytotoxicity even at low concentration (1 mg L^-1) by inducing reactive oxygen species (ROS), lactate dehydrogenase (LDH) enzyme production, nuclear fragmentation and apoptosis. The change in morphology of the cells like membrane blebbing and cell rounding was also observed via FESEM. In the in-vivo model Caenorhabditis elegans, rGO-30 KGy significantly affected the functioning of primary and secondary targeted organs and also negatively influenced the nuclear accumulation of transcription factors (DAF-16/FOXO and SKN-1/Nrf2), neuronal health, and antioxidant defense mechanism of the nematodes. The real-time PCR analysis showed significant up-regulation (ced-3, ced-4, cep-1, egl-1, and hus-1) and down-regulation (ced-9) of the gene involved in germ-line and DNA damage-induced apoptosis. The detailed toxicity mechanism of gamma irradiated rGO has been elucidated. This work highlights the toxicity of rGO prepared by gamma-ray radiation and paves way for understating the toxicity mechanism.

Insights of Platinum Drug Interaction with Spinel Magnetic Nanocomposites for Targeted Anti-Cancer Effect

In nanotherapeutics, gaining insight about the drug interaction with the pore architecture and surface functional groups of nanocarriers is crucial to aid in the development of targeted drug delivery. Manganese ferrite impregnated graphene oxide (MnFe₂O₄/GO) with a two-dimensional sheet and spherical silica with a three-dimensional interconnected porous structure (MnFe₂O₄/silica) were evaluated for cisplatin release and cytotoxic effects. Characterization studies revealed the presence of Mn²⁺ species with a variable spinel cubic phase and superparamagnetic effect. We used first principles calculations to study the physisorption of cisplatin on monodispersed silica and on single- and multi-layered GO. The binding energy of cisplatin on silica and single-layer GO was ~1.5 eV, while it was about double that value for the multilayer GO structure. Moreover, we treated MCF-7 (breast cancer cells) and HFF-1 (human foreskin fibroblast) with our nanocomposites and used the cell viability assay MTT. Both nanocomposites significantly reduced the cell viability. Pt⁴⁺ species of cisplatin on the spinel ferrite/silica nanocomposite had a better effect on the cytotoxic capability when compared to GO. The EC50 for MnFe₂O₄/silica/cisplatin and MnFe₂O₄/GO/cisplatin on MCF-7 was: 48.43 µg/mL and 85.36 µg/mL, respectively. The EC50 for the same conditions on HFF was: 102.92 µg/mL and 102.21 µg/mL, respectively. In addition, immunofluorescence images using c-caspase 3/7, and TEM analysis indicated that treating cells with these nanocomposites resulted in apoptosis as the major mechanism of cell death.

Poria cocos polysaccharide-functionalized graphene oxide nanosheet induces efficient cancer immunotherapy in mice

Introduction: Tumor vaccines that induce robust humoral and cellular immune responses have attracted tremendous interest for cancer immunotherapy. Despite the tremendous potential of tumor vaccines as an effective approach for cancer treatment and prevention, a major challenge in achieving sustained antitumor immunity is inefficient antigen delivery to secondary lymphoid organs, even with adjuvant aid. Methods: Herein, we present antigen/adjuvant integrated nanocomplexes termed nsGO/PCP/OVA by employing graphene oxide nanosheet (nsGO) as antigen nanocarriers loaded with model antigen ovalbumin (OVA) and adjuvant, Poria cocos polysaccharides (PCP). We evaluated the efficacy of nsGO/PCP/OVA in activating antigen-specific humoral as well as cellular immune responses and consequent tumor prevention and rejection in vivo. Results: The optimally formed nsGO/PCP/OVA was approximately 120-150 nm in diameter with a uniform size distribution. Nanoparticles can be effectively engulfed by dendritic cells (DCs) through receptor-mediated endocytosis, induced the maturation of DCs and improved the delivery efficiency both in vitro and in vivo. The nsGO/PCP/OVA nanoparticles also induced a significant enhancement of OVA antigen-specific Th1 and Th2 immune responses in vivo. In addition, vaccination with nsGO/PCP/OVA not only significantly suppressed tumor growth in prophylactic treatments, but also achieved a therapeutic effect in inhibiting the growth of already-established tumors. Conclusion: Therefore, this potent nanovaccine platform with nanocarrier nsGO and PCP as adjuvants provides a promising strategy for boosting anti-tumor immunity for cancer immunotherapy.