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Ultrathin MoS2–MoO3–xheterojunction nanosheets with unique features were introduced as biocompatible, non-cytotoxic, and visible light-sensitive stimulator layers for the controlled differentiation of human neural progenitor cells (hNPCs) into nervous lineages. hNPC differentiation was also investigated on reduced graphene oxide (rGO)-containing scaffolds, that is, rGO and rGO/MoS2–MoO3–xnanosheets. In darkness, hNPC differentiation into neurons increased on MoS2–MoO3–xby a factor of 2.7 due to the excellent biophysical cues and further increased on rGO/MoS2–MoO3–xby a factor of 4.4 due to a synergistic effect induced by the rGO. The MoO3–xdomains with antioxidant activity and LSPR absorption induced p-type doping in MoS2–MoO3–x. Under photostimulation, the hNPCs on the MoS2–MoO3–xexhibited higher differentiation into glial cells by a factor of 1.4, and the decrease in photo-electron current to hNPCs due to the induction of more p-type doping in the MoS2–MoO3–x. While the increase in neuronal differentiation of hNPCs on rGO/MoS2–MoO3–xby a factor of 1.8 was ascribed to the presence of rGO as an ultrafast electron transferor which quickly transferred photogenerated electrons to hNPCs before their transfer to free radicals, these results demonstrated the promising potential of MoS2-based scaffolds for applying in the controllable repair and/or regeneration of diseases/disorders related to the nervous system.

An oxygen nanoshuttle based on a reduced graphene oxide/copper peroxide (rGO/CuO2) nanocomposite has been presented to deliver in situ oxygen nanobubbles (O2NBs) for combating bacterial infections. In the presence of rGO, the solid source of oxygen (i.e., CuO2) was decomposed (in response to environmental conditions such as pH and temperature) into O2NBs in a more controllable and long-lasting trend (from 60 to 144 h). In a neutral buffer, the O2NBs experienced growth and collapse evolutions, creating a dynamic micro–nanoenvironment around the nanocomposite. In addition to effective battling against methicillin-resistant Staphylococcus aureusbacteria, the O2NBs demonstrated superior antibacterial properties on Gram-positive S. aureusto those on Gram-negative Escherichia colibacteria, especially in the presence of rGO. In fact, the rGO contents could provide synergistic effects through harvesting some respiratory electrons (leading to striking interruption of the bacterial respiratory pathway) in one side and transferring them into the O2NBs, resulting in nanoscale reactive oxygen species (ROS) generation in another side. Moreover, near-infrared laser irradiation induced more damage to the cell membrane due to the synergistic effects of local heat elevation and catalyzing the release/collapse of NBs imposing mechanical disruptions. Our results show that the O2-containing nanoshuttles can effectively be used as intelligent and controllable anti-infection nanorobots in upcoming graphene-based nanobiomedical applications.

The reverse osmosis (RO) desalination capability of hydrogenated and hydroxylated graphene nanomesh membranes (GNMs) inspired by the morphology of carbon nitride (C2N) has been studied by using molecular dynamics simulation. As an advantage, water permeance of the GNMs is found to be several orders of magnitude higher than that of the available RO filters and comparable with highly strained C2N (S-C2N) as follows: 6,6-H,OH > 12-H > S-C2N > 5,5-H,OH > 10-H. The reverse order is found for salt rejection, regardless of S-C2N. The hydrophilic character of the incorporated −OH functional group is believed to be responsible for linking the water molecules in feed and permeate sides via the formation of strong hydrogen bonds. This leads to a remarkable reduction in resistance of water molecules during penetration across GNMs. In fact, water permeance and salt rejection of the GNMs are controllable by adjusting the effective size and chemistry of their nanopores, while these kinds of adjustments are principally impossible for C2N, resulting in limiting the water permeance. More importantly, the C2N nanofilter works efficiently only under high tensile strain, which is not so straightforward in practice. These observations are also verified by computing electrostatic potential map interaction and barrier energies for transportation of water molecules/ions through GNMs based on quantum chemistry aspects.

Presently, clinical nanomedicine and nanobiotechnology have impressively demanded the generation of new organic/inorganic analogues of graphene (as one of the intriguing biomedical research targets) for stem-cell-based tissue engineering. Among different shapes of graphene, three-dimensional (3D) graphene foams (GFs) are highly promising candidates to provide conditions for mimicking in vivo environments, affording effective cell attachment, proliferation,and differentiation due to their unique properties. These include the highest biocompatibility among nanostructures, high surface-to-volume ratio, 3D porous structure (to provide a homogeneous/isotropic growth of tissues), highly favorable mechanical characteristics, and rapid mass and electron transport kinetics (which are required for chemical/physical stimulation of differentiated cells). This review aims to describe recent and rapid advances in the fabrication of 3D GFs, together with their use in tissue engineering and regenerative nanomedicine applications. Moreover, we have summarized a broad range of recent studies about the behaviors, biocompatibility/toxicity,and biodegradability of these materials, both in vitro and in vivo. Finally, the highlights and challenges of these 3D porous structures, compared to the current polymeric scaffold competitors, are discussed.

In this work, graphene oxide (GO) aqueous suspensions prepared by a chemical exfoliation method showed a fluorescence peak at ∼615 nm. Photoluminescence spectroscopy determined that functionalization of the GO sheets by 3-(2-Aminoethylamino) propyltrimethoxysilane molecules significantly quench the fluorescence property of the GO sheets. Fourier transform infrared spectroscopy confirmed proper functionalization of the GO sheets. Curcumin was applied as a fluorescent natural material with an emission peak at ∼550 nm wavelength for green fluorescent labeling of the functionalized-GO sheets. The curcumin-labeled functionalized-GO sheets showed an intense emission band fluorescent property with an emission peak at ∼540 nm. These results can provide applications of natural fluorescent materials (such as curcumin) in green fluorescent labeling of functionalized-GO sheets, which has attracted much attention for utilizing in upcoming bioapplications.

This paper reports on a novel low-temperature method for preparing curcumin-reduced graphene oxide (Cur-rGO) from graphene oxide (GO) and investigates their cyclic voltammetry (CV) and photoluminescence (PL) properties. GO sheets were synthesized using modified Hummers’ method and then were chemically reduced using polyphenol curcumin into graphene sheets. Atomic force microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy were used to confirm the formation of Cur-rGO and revealed their functionalization with polyphenol curcumin. The electrochemical and optical properties of the Cur-rGO sheets were investigated using CV and PL spectroscopy. According to the PL and CV characterization for the Cur-rGO sheets, charges and resonant energy were transferred from curcumin molecules to the GO sheets’ surfaces. This arises from the bonding of the fluorescence curcumin molecules to the Cur-rGO surfaces, through π–π stacking of their aromatic rings. It should be noted that curcumin molecules act as electron donors, suppressing the fluorescence of the GO sheets while improving their electrochemical activities.

Nanoscale graphene oxide (NGO) sheets were synthesized and used as carbocatalysts for effective oxidation of benzylic alcohols and aromatic aldehydes. For oxidation of alcohols in the presence of H2O2at 80 °C, the NGOs (20% mass fraction) as carbocatalysts showed selectivity toward aldehyde. The rate and yield of this reaction strongly depended on the nature of substituents on the alcohol. For 4-nitrobenzyl alcohol, <10% of it was converted into the corresponding carboxylic acid after 24 h. By contrast, 4-methoxybenzyl alcohol and diphenylmethanol were completely converted into the corresponding carboxylic acid and ketone after only 9 and 3 h, respectively. The conversion rates for oxidation of aromatic aldehydes by NGO carbocatalysts were higher than those for alcohol oxidation. For all the aldehydes, complete conversion to the corresponding carboxylic acids was achieved using 7% (mass fraction) of NGO at 70 °C within 2–3 h. Possible mechanisms for NGO carbocatalyst structure-dependent oxidation of benzyl alcohols and structure-independent oxidation of aromatic aldehydes are discussed.

An easy method for preparing CuO nanoparticles incorporated in a mesoporous structure was presented based on the thermal decomposition of a copper complex. The novel copper coordination compound of [Cu(anic)2]·0.75H2O (anic= 2-aminonicotinate) with the microflake morphology was synthesized through the reaction of 2-aminonicotinic acid (Hanic) and copper(II) nitrate. Using elemental analysis and Fourier transform infrared (FTIR) spectroscopy, the chemical composition of CuC12H11.5N4O4.75was proposed. Calcination process at 550 °C for 4 h transformed the microflakes into CuO nanoparticles incorporated in a mesoporous structure. The FTIR peaks assigned to 2-aminonicotinate were completely removed after calcination, confirming CuO formation. X-ray diffraction (XRD) analysis also confirmed the generation of pure and crystalline CuO. SEM showed CuO nanoparticles with the average diameter of 75 nm. The diffuse reflectance spectrum (DRS) of the CuO nanoparticles showed a band gap energy of −1.58 eV. The degradation efficiency toward rhodamine B was almost 100 % after 5 h illumination when both CuO and H2O2were utilized. The results show that the product can be used as an efficient photocatalyst for water treatment.

Hollow microblocks of [Zn(anic)2], as a novel coordination compound, were synthesized using 2-aminonicotinic acid (Hanic) and zinc (II) nitrate tetrahydrate. The chemical composition of the zinc complex, ZnC12H10N4O4, was determined by Fourier transform infrared (FTIR) spectroscopy and elemental analysis. The synthesized zinc complex was used as a precursor to produce ZnO nanostructures by calcination at 550 °C for 4 h. Morphological studies by scanning electron microscopy and transmission electron microscopy revealed the formation of porous microbricks of ZnO nanoparticles. N2adsorption-desorption analysis showed that the obtained ZnO microbricks possess a mesoporous structure with a surface area of 8.13 m2/g and a pore size of 22.6 nm. The X-ray diffraction pattern of the final product proved the formation of a pure ZnO composition with a hexagonal structure. Moreover, FTIR analyses showed that the 2-aminonicotinic acid ligand peaks were absent after the calcination step. Diffuse reflectance spectroscopy was used to determine the band gap energy of the produced ZnO and it was about 3.19 eV. To investigate the photocatalytic activity of the porous ZnO nanostructure, a series of photocatalytic tests were carried out to remove Congo red, as a representative toxic azo dye, from aqueous solution. The results show that the product can be used as an efficient photocatalyst for waste water treatment with high degradation efficiency.

Graphene oxide nanowalls with extremely sharp edges and preferred vertical orientation were deposited on a graphite electrode by using electrophoretic deposition in an Mg2+-GO electrolyte. Using differential pulse voltammetry (DPV), reduced graphene nanowalls (RGNWs) were applied for the first time, in developing an ultra-high-resolution electrochemical biosensor for detection of the four bases of DNA (G, A, T, and C) by monitoring the oxidation signals of the individual nucleotide bases. The extremely enhanced electrochemical reactivity of the four free bases of DNA, single-stranded DNA, and double-stranded DNA (dsDNA) at the surface of the RGNW electrode was compared to electrochemical performances of reduced graphene nanosheet (RGNS), graphite, and glassy carbon electrodes. By increasing the number of DPVs up to 100 scans, the RGNW electrode exhibited an excellent stability with only 15% variation in the oxidation signals, while for the RGNS electrode no detectable signals relating to T and C of 0.1 μM dsDNA were observed. The linear dynamic detection range of the RGNW electrode for dsDNA was checked in the wide range of 0.1 fM to 10 mM, while for the RGNS electrode, it was from 2.0 pM to <10 mM. The lower limits of dsDNA detection of the RGNW and RGNS electrodes were estimated as 9.4 zM (∼5 dsDNA/mL) and 5.4 fM, respectively. The RGNWs were efficient in label-free detection of single nucleotide polymorphisms of 20 zM oligonucleotides (∼10 DNA/mL) having a specific sequence. Therefore, the RGNWs can effectively contribute to the development of ultra-high-sensitive electrochemical biosensors with single-DNA resolutions.

Bacterial toxicity of graphene nanosheets in the form of graphene nanowalls deposited on stainless steel substrates was investigated for both Gram-positive and Gram-negative models of bacteria. The graphene oxide nanowalls were obtained by electrophoretic deposition of Mg2+-graphene oxide nanosheets synthesized by a chemical exfoliation method. On the basis of measuring the efflux of cytoplasmic materials of the bacteria, it was found that the cell membrane damage of the bacteria caused by direct contact of the bacteria with the extremely sharp edges of the nanowalls was the effective mechanism in the bacterial inactivation. In this regard, the Gram-negative Escherichia colibacteria with an outer membrane were more resistant to the cell membrane damage caused by the nanowalls than the Gram-positive Staphylococcus aureuslacking the outer membrane. Moreover, the graphene oxide nanowalls reduced by hydrazine were more toxic to the bacteria than the unreduced graphene oxide nanowalls. The better antibacterial activity of the reduced nanowalls was assigned to the better charge transfer between the bacteria and the more sharpened edges of the reduced nanowalls, during the contact interaction.

Local photodegradation of graphene oxide sheets at the tip of ZnO nanorods was used to achieve semiconducting graphene nanomeshes. The chemically exfoliated graphene oxide sheets, with a thickness of ∼0.9 nm, were deposited on quartz substrates. Vertically aligned ZnO nanorod arrays with diameters of 140 nm and lengths of <1 μm were grown on a glass substrate by using a hydrothermal method. The graphene oxide sheets were physically attached to the tip of the ZnO nanorods by assembling the sheets on the nanorods. UV-assisted photodegradation of the graphene oxide sheets (with dimension of ∼5 × 5 μm) at a contact place with the ZnO nanorods resulted in graphene nanomeshes with a pore size of ∼200 nm. The graphene nanomeshes prepared by using the photocatalytic property of the ZnO nanorods contained smaller oxygen-containing carbonaceous bonds and higher defects as compared to the as-prepared graphene oxide sheets. When chemical reduction of the graphene nanomeshes by hydrazine was used, the oxygen bonds of the nanomeshes more decreased while their graphitization increased. Based on X-ray photoelectron spectroscopy at low binding energies, the graphene nanomeshes reduced by hydrazine exhibited as a broad sheet a p-type semiconductor with an ∼1.2 eV energy gap between the valence band and the Fermi level.

Organ-on-a-chip (OOC) systems are engineered nanobiosystems to mimic the physiochemical environment of a specific organ in the body. Among various components of OOC systems, biomimetic membranes have been regarded as one of the most important key components to develop controllable biomimetic bioanalysis systems. Here, we review the preparation and characterization of biomimetic membranes in comparison with the features of the extracellular matrix. After that, we review and discuss the latest applications of engineered biomimetic membranes to fabricate various organs on a chip, such as liver, kidney, intestine, lung, skin, heart, vasculature and blood vessels, brain, and multiorgans with perspectives for further biomedical applications.

Breast cancer is the most prevalent type of cancer in women; hence, many researches have been focused on developing effective treatment protocols. In this study, a novel nanocarrier was fabricated for gene and photothermal combination cancer therapy by conjugating histone methyltransferase complex subunit SET1 (hSET1) on reduced polydopamine coated graphene oxide nanosheets (rGO-PDA).

The first perspective regarding the application of nano-micro size aggregations on the prevascularizations and biomedicine.This perspective provides an in-depth discussion regarding the use of these prevascularized nano-micro size aggregates in biomedicine and regenerative medicine.

Viral diseases have long been among the biggest challenges for healthcare systems around the world. The recent Coronavirus Disease 2019 (COVID-19) pandemic is an example of how complicated the situation can get if we are not prepared to combat a viral outbreak in time, which brings up the need for quick and affordable biosensing platforms and vast knowledge of potential antiviral effects and drug/gene delivery opportunities. The same challenges have also existed for nonviral immunogenic disorders. Nanomedicine is considered a novel candidate for effectively overcoming these worldwide challenges. Among the versatile nanomaterials commonly used in biomedical applications, graphene has recently earned much attention thanks to its special and inspiring physicochemical properties, such as its large surface area, efficient thermal/electrical properties, carbon-based chemical purity with controllable biocompatibility, easy functionalization, capability of single-molecule detection, anticancer characteristics, 3D template feature in tissue engineering, and, in particular, antibacterial/antiviral activities. In this Review, the most important and challenging viruses of our era, such as human immunodeficiency virus, Ebola, SARS-CoV-2, norovirus, and hepatitis virus, and immunogenic disorders, such as asthma, Alzheimer’s disease, and Parkinson’s disease, in which graphene-based nanomaterials can effectively take part in the prevention, detection, treatment, medication, and health effect issues, have been covered and discussed.