Nitric oxide-dependent biodegradation of graphene oxide reduces inflammation in the gastrointestinal tract

Biological and environmental degradation of two-dimensional materials

As the use of two-dimensional materials continues to grow, so too does the need to understand the environmental and biological impact of such materials. Degradation is a critical step in the life cycle of any material, but the majority of such knowledge is obtained from test tube and in vitro studies. Therefore, there remains a gap in understanding the degradability of two-dimensional materials in complex systems (in vivo) and in different ambient environments. In this Review, we highlight the need for more data-driven studies on the degradation of two-dimensional materials, including their kinetics, by-products, stability and possible downstream effects. Although challenging, building an understanding of the degradation profiles of different advanced materials in various environments at the chemical and molecular level is essential.

Unveiling the Role of Fractionated Graphene Oxide in Nitric Oxide Scavenging

The feasibility of saturating aqueous anoxic solutions with in situ-generated high-purity nitric oxide (NO) is shown herein. A methemoglobin assay estimated the average nitric oxide concentration to be ca. 20 ± 3 µM. Graphene oxide aqueous dispersions were prepared by ultrasound-assisted extra exfoliation. These dispersions, including unpurified (pristine) samples and samples purified from transition metal impurities (bulk) fractions (bulkGO) and (nano) separated fractions (nanoGO) in a range of 0.5 to 14 kDa were prepared with ppm level concentrations. A robust and reproducible chemiluminescence (CL) assay validated the interaction between graphene oxide and NO in a luminol-based system. The results showed a significant increase in NO scavenging activity within the bulkGO fractions to nanofractions ranging from 14 to 3.5 kDa. The different reaction pathways underlying the transformation of nitric oxide are being evaluated, focusing on understanding how its presence or absence affects these processes. Our kinetic model suggests a significant difference in nitric oxide regulation; nanoGO demonstrates an interception rate seventy-times higher than that achieved through CL quenching.

Safety Assessment of Graphene-Based Materials

Graphene is the first 2D atomic crystal, and its isolation heralded a new era in materials science with the emergence of several other atomically thin materials displaying multifunctional properties. The safety assessment of new materials is often something of an afterthought, but in the case of graphene, the initial isolation and characterization of the material was soon followed by the assessment of its potential impact on living systems. The Graphene Flagship project addressed the health and environmental aspects of graphene and other 2D materials, providing an instructive lesson in interdisciplinarity - from materials science to biology. Here, the outcomes of the toxicological and ecotoxicological studies performed on graphene and its derivatives, and the key lessons learned from this decade-long journey, are highlighted.

Remotely Controlled Electrochemical Degradation of Metallic Implants

Biodegradable medical implants promise to benefit patients by eliminating risks and discomfort associated with permanent implantation or surgical removal. The time until full resorption is largely determined by the implant's material composition, geometric design, and surface properties. Implants with a fixed residence time, however, cannot account for the needs of individual patients, thereby imposing limits on personalization. Here, an active Fe-based implant system is reported whose biodegradation is controlled remotely and in situ. This is achieved by incorporating a galvanic cell within the implant. An external and wireless signal is used to activate the on-board electronic circuit that controls the corrosion current between the implant body and an integrated counter electrode. This configuration leads to the accelerated degradation of the implant and allows to harvest electrochemical energy that is naturally released by corrosion. In this study, the electrochemical properties of the Fe-30Mn-1C/Pt galvanic cell model system is first investigated and high-resolution X-ray microcomputed tomography is used to evaluate the galvanic degradation of stent structures. Subsequently, a centimeter-sized active implant prototype is assembled with conventional electronic components and the remotely controlled corrosion is tested in vitro. Furthermore, strategies toward the miniaturization and full biodegradability of this system are presented.

Two-dimensional molybdenum disulfide nanosheets evoke nitric oxide-dependent antibacterial effects

Nanomaterials are currently being explored as novel antimicrobial agents. In this study, we first investigated the ability of two-dimensional (2D) molybdenum disulfide (MoS2) nanosheets to trigger neutrophil extracellular traps (NETs) using neutrophil-differentiated HL-60 cells as well as primary human peripheral blood neutrophils. We then addressed whether the MoS2 nanosheets themselves function as antibacterial agents. We found that MoS2 and Na2MoO4 both triggered NETs, as evidenced by the quantification of neutrophil elastase (NE) activity and immunofluorescence staining of extracellular NE, as well as scanning electron microscopy. The release of NETs was found to be nitric oxide (NO)-dependent. We also found that the MoS2 nanosheets but not the soluble salt prompted acellular NO production in the presence of NaNO2. The acellular generation of NO, suggestive of nanozyme properties of the MoS2 nanosheets, was demonstrated by electron paramagnetic resonance analysis. Electrochemical analysis using cyclic voltammetry confirmed the redox transition of the MoS2 nanosheets. Finally, MoS2 nanosheets inhibited the growth of Escherichia coli in the presence of sodium nitrate. Taken together, MoS2 nanosheets triggered cellular effects as well as acellular antibacterial effects, and we provided evidence for nitrite reductase-like properties of MoS2.

Lung Persistence, Biodegradation, and Elimination of Graphene-Based Materials are Predominantly Size-Dependent and Mediated by Alveolar Phagocytes

Graphene-based materials (GBMs) have promising applications in various sectors, including pulmonary nanomedicine. Nevertheless, the influence of GBM physicochemical characteristics on their fate and impact in lung has not been thoroughly addressed. To fill this gap, the biological response, distribution, and bio-persistence of four different GBMs in mouse lungs up to 28 days after single oropharyngeal aspiration are investigated. None of the GBMs, varying in size (large versus small) and carbon to oxygen ratio as well as thickness (few-layers graphene (FLG) versus thin graphene oxide (GO)), induce a strong pulmonary immune response. However, recruited neutrophils internalize nanosheets better and degrade GBMs faster than macrophages, revealing their crucial role in the elimination of small GBMs. In contrast, large GO sheets induce more damages due to a hindered degradation and long-term persistence in macrophages. Overall, small dimensions appear to be a leading feature in the design of safe GBM pulmonary nanovectors due to an enhanced degradation in phagocytes and a faster clearance from the lungs for small GBMs. Thickness also plays an important role, since decreased material loading in alveolar phagocytes and faster elimination are found for FLGs compared to thinner GOs. These results are important for designing safer-by-design GBMs for biomedical application.

Label-free detection of polystyrene nanoparticles in Daphnia magna using Raman confocal mapping

Micro- and nanoplastic pollution has emerged as a global environmental problem. Moreover, plastic particles are of increasing concern for human health. However, the detection of so-called nanoplastics in relevant biological compartments remains a challenge. Here we show that Raman confocal spectroscopy-microscopy can be deployed for the non-invasive detection of amine-functionalized and carboxy-functionalized polystyrene (PS) nanoparticles (NPs) in Daphnia magna. The presence of PS NPs in the gastrointestinal (GI) tract of D. magna was confirmed by using transmission electron microscopy. Furthermore, we investigated the ability of NH₂-PS NPs and COOH-PS NPs to disrupt the epithelial barrier of the GI tract using the human colon adenocarcinoma cell line HT-29. To this end, the cells were differentiated for 21 days and then exposed to PS NPs followed by cytotoxicity assessment and transepithelial electrical resistance measurements. A minor disruption of barrier integrity was noted for COOH-PS NPs, but not for the NH₂-PS NPs, while no overt cytotoxicity was observed for both NPs. This study provides evidence of the feasibility of applying label-free approaches, i.e., confocal Raman mapping, to study PS NPs in a biological system.

Graphene Oxide Nanosheets Reduce Astrocyte Reactivity to Inflammation and Ameliorate Experimental Autoimmune Encephalomyelitis

In neuroinflammation, astrocytes play multifaceted roles that regulate the neuronal environment. Astrocytes sense and respond to pro-inflammatory cytokines (CKs) and, by a repertoire of intracellular Ca2+ signaling, contribute to disease progression. Therapeutic approaches wish to reduce the overactivation in Ca2+ signaling in inflammatory-reactive astrocytes to restore dysregulated cellular changes. Cell-targeting therapeutics might take advantage by the use of nanomaterial-multifunctional platforms such as graphene oxide (GO). GO biomedical applications in the nervous system involve therapeutic delivery and sensing, and GO flakes were shown to enable interfacing of neuronal and glial membrane dynamics. We exploit organotypic spinal cord cultures and optical imaging to explore Ca2+ changes in astrocytes, and we report, when spinal tissue is exposed to CKs, neuroinflammatory-associated modulation of resident glia. We show the efficacy of GO to revert these dynamic changes in astrocytic reactivity to CKs, and we translate this potential in an animal model of immune-mediated neuroinflammatory disease.

Research Status and Prospect of Non-Viral Vectors Based on siRNA: A Review

Gene therapy has attracted much attention because of its unique mechanism of action, non-toxicity, and good tolerance, which can kill cancer cells without damaging healthy tissues. siRNA-based gene therapy can downregulate, enhance, or correct gene expression by introducing some nucleic acid into patient tissues. Routine treatment of hemophilia requires frequent intravenous injections of missing clotting protein. The high cost of combined therapy causes most patients to lack the best treatment resources. siRNA therapy has the potential of lasting treatment and even curing diseases. Compared with traditional surgery and chemotherapy, siRNA has fewer side effects and less damage to normal cells. The available therapies for degenerative diseases can only alleviate the symptoms of patients, while siRNA therapy drugs can upregulate gene expression, modify epigenetic changes, and stop the disease. In addition, siRNA also plays an important role in cardiovascular diseases, gastrointestinal diseases, and hepatitis B. However, free siRNA is easily degraded by nuclease and has a short half-life in the blood. Research has found that siRNA can be delivered to specific cells through appropriate vector selection and design to improve the therapeutic effect. The application of viral vectors is limited because of their high immunogenicity and low capacity, while non-viral vectors are widely used because of their low immunogenicity, low production cost, and high safety. This paper reviews the common non-viral vectors in recent years and introduces their advantages and disadvantages, as well as the latest application examples.

Elimination of Cancer Cells in Co-Culture: Role of Different Nanocarriers in Regulation of CD47 and Calreticulin-Induced Phagocytosis

Under healthy conditions, pro- and anti-phagocytic signals are balanced. Cluster of Differentiation 47 (CD47) is believed to act as an anti-phagocytic marker that is highly expressed on multiple types of human cancer cells including acute myeloid leukemia (AML) and lung and liver carcinomas, allowing them to escape phagocytosis by macrophages. Downregulating CD47 on cancer cells discloses calreticulin (CRT) to macrophages and recovers their phagocytic activity. Herein, we postulate that using a modified graphene oxide (GO) carrier to deliver small interfering RNA (siRNA) CD47 (CD47_siRNA) in AML, A549 lung, and HepG2 liver cancer cells in co-culture in vitro will silence CD47 and flag cancer cells for CRT-mediated phagocytosis. Results showed a high knockdown efficiency of CD47 and a significant increase in CRT levels simultaneously by using GO formulation as carriers in all used cancer cell lines. The presence of CRT on cancer cells was significantly higher than levels before knockdown of CD47 and was required to achieve phagocytosis in co-culture with human macrophages. Lipid nanoparticles (LNPs) and modified boron nitride nanotubes (BNPs) were used to carry CD47_siRNA, and the knockdown efficiency values of CD47 were compared in three cancer cells in co-culture, with an achieved knockdown efficiency of >95% using LNPs as carriers. Interestingly, the high efficiency of CD47 knockdown was obtained by using the LNPs and BNP carriers; however, an increase in CRT levels on cancer cells was not required for phagocytosis to happen in co-culture with human macrophages, indicating other pathways' involvement in the phagocytosis process. These findings highlight the roles of 2D (graphene oxide), 1D (boron nitride nanotube), and "0D" (lipid nanoparticle) carriers for the delivery of siRNA to eliminate cancer cells in co-culture, likely through different phagocytosis pathways in multiple types of human cancer cells. Moreover, these results provide an explanation of immune therapies that target CD47 and the potential use of these carriers in screening drugs for such therapies in vitro.

Graphene oxide elicits microbiome-dependent type 2 immune responses via the aryl hydrocarbon receptor

The gut microbiome produces metabolites that interact with the aryl hydrocarbon receptor (AhR), a key regulator of immune homoeostasis in the gut1,2. Here we show that oral exposure to graphene oxide (GO) modulates the composition of the gut microbiome in adult zebrafish, with significant differences in wild-type versus ahr2-deficient animals. Furthermore, GO was found to elicit AhR-dependent induction of cyp1a and homing of lck+ cells to the gut in germ-free zebrafish larvae when combined with the short-chain fatty acid butyrate. To obtain further insights into the immune responses to GO, we used single-cell RNA sequencing to profile cells from whole germ-free embryos as well as cells enriched for lck. These studies provided evidence for the existence of innate lymphoid cell (ILC)-like cells3 in germ-free zebrafish. Moreover, GO endowed with a 'corona' of microbial butyrate triggered the induction of ILC2-like cells with attributes of regulatory cells. Taken together, this study shows that a nanomaterial can influence the crosstalk between the microbiome and immune system in an AhR-dependent manner.

Biodegradation of Graphene Oxide by Insects (Tenebrio molitor Larvae): Role of the Gut Microbiome and Enzymes

Biodegradation of graphene materials is critical for understanding their environmental process and fate. Thus, biodegradation and mineralization of graphene oxide (GO) by an insect (yellow mealworms, Tenebrio molitor larvae) were investigated. Twenty mealworms could eat up a piece of GO film (1.5 × 1.5 cm) in 15 days. The ingested GO film underwent degradation, and the residual GO sheets were observed in the frass. Raman imaging confirmed that the residual GO (I_D/I_G, 1.16) was more defective than the pristine GO film (I_D/I_G, 0.95). ¹⁴C analysis showed that GO sheets were partially mineralized into CO₂ (0.26%) and assimilated into biomass compositions (e.g., lipid and protein) (0.36%). Gut microbes and extracellular enzymes in yellow mealworms played crucial roles in GO degradation, and the predominant gut microbes for GO biodegradation were identified as Enterobacteriaceae bacteria (e.g., Escherichia-Shigella sp.). Two biodegradation products belonging to hydroxylated or carboxylated aromatic compounds were formed with the assistance of electrons and hydroxyl radicals in mealworm guts. These findings are useful for better understanding the environmental and biological fate of graphene materials.

Advancement of cell-penetrating peptides in combating triple-negative breast cancer

Extensive research efforts have been made and are still ongoing in the search for an ideal anti-cancer therapy. Almost all chemotherapeutics require a carrier or vehicle, a drug delivery system that can transport the drug specifically to the targeted cancer cells, sparing normal cells. Cell-penetrating peptides (CPPs) provide an effective and efficient pathway for the intra-cellular transportation of various bioactive molecules in several biomedical therapies. They are now well-recognized as facilitators of intracellular cargo delivery and have excellent potential for targeted anti-cancer therapy. In this review, we explain CPPs, recent progress in the development of new CPPs, and their utilization to transport cargoes such as imaging agents, chemotherapeutics, and short-interfering RNAs (siRNA) into tumor cells, contributing to the advancement of novel tumor-specific delivery systems.

Graphdiyne-Related Materials in Biomedical Applications and Their Potential in Peripheral Nerve Tissue Engineering

Graphdiyne (GDY) is a new member of the family of carbon-based nanomaterials with hybridized carbon atoms of sp and sp², including α, β, γ, and (6,6,12)-GDY, which differ in their percentage of acetylene bonds. The unique structure of GDY provides many attractive features, such as uniformly distributed pores, highly π-conjugated structure, high thermal stability, low toxicity, biodegradability, large specific surface area, tunable electrical conductivity, and remarkable thermal conductivity. Therefore, GDY is widely used in energy storage, catalysis, and energy fields, in addition to biomedical fields, such as biosensing, cancer therapy, drug delivery, radiation protection, and tissue engineering. In this review, we first discuss the synthesis of GDY with different shapes, including nanotubes, nanowires, nanowalls, and nanosheets. Second, we present the research progress in the biomedical field in recent years, along with the biodegradability and biocompatibility of GDY based on the existing literature. Subsequently, we present recent research results on the use of nanomaterials in peripheral nerve regeneration (PNR). Based on the wide application of nanomaterials in PNR and the remarkable properties of GDY, we predict the prospects and current challenges of GDY-based materials for PNR.

Co-assembled perylene/graphene oxide photosensitive heterobilayer for efficient neuromorphics

Neuromorphic electronics, which use artificial photosensitive synapses, can emulate biological nervous systems with in-memory sensing and computing abilities. Benefiting from multiple intra/interactions and strong light-matter coupling, two-dimensional heterostructures are promising synaptic materials for photonic synapses. Two primary strategies, including chemical vapor deposition and physical stacking, have been developed for layered heterostructures, but large-scale growth control over wet-chemical synthesis with comprehensive efficiency remains elusive. Here we demonstrate an interfacial coassembly heterobilayer films from perylene and graphene oxide (GO) precursors, which are spontaneously formed at the interface, with uniform bilayer structure of single-crystal perylene and well-stacked GO over centimeters in size. The planar heterostructure device exhibits an ultrahigh specific detectivity of 3.1 × 10¹³ Jones and ultralow energy consumption of 10⁻⁹ W as well as broadband photoperception from 365 to 1550 nm. Moreover, the device shows outstanding photonic synaptic behaviors with a paired-pulse facilitation (PPF) index of 214% in neuroplasticity, the heterosynapse array has the capability of information reinforcement learning and recognition.

Layered heterostructures are promising photosensitive materials for advanced optoelectronics. Here, the authors introduce an interfacial coassembly method to construct large-scale perylene/grahene oxide (GO) heterobilayer for broadband photoreception and efficient neuromorphics.

Understanding the bidirectional interactions between two-dimensional materials, microorganisms, and the immune system

Two-dimensional (2D) materials such as the graphene-based materials, transition metal dichalcogenides, transition metal carbides and nitrides (MXenes), black phosphorus, hexagonal boron nitride, and others have attracted considerable attention due to their unique physicochemical properties. This is true not least in the field of medicine. Understanding the interactions between 2D materials and the immune system is therefore of paramount importance. Furthermore, emerging evidence suggests that 2D materials may interact with microorganisms - pathogens as well as commensal bacteria that dwell in and on our body. We discuss the interplay between 2D materials, the immune system, and the microbial world in order to bring a systems perspective to bear on the biological interactions of 2D materials. The use of 2D materials as vectors for drug delivery and as immune adjuvants in tumor vaccines, and 2D materials to counteract inflammation and promote tissue regeneration, are explored. The bio-corona formation on and biodegradation of 2D materials, and the reciprocal interactions between 2D materials and microorganisms, are also highlighted. Finally, we consider the future challenges pertaining to the biomedical applications of various classes of 2D materials.

Graphene Oxide and Biomolecules for the Production of Functional 3D Graphene-Based Materials

Graphene and its derivatives have been widely employed in the manufacturing of novel composite nanomaterials which find applications across the fields of physics, chemistry, engineering and medicine. There are many techniques and strategies employed for the production, functionalization, and assembly of graphene with other organic and inorganic components. These are characterized by advantages and disadvantages related to the nature of the specific components involved. Among many, biomolecules and biopolymers have been extensively studied and employed during the last decade as building blocks, leading to the realization of graphene-based biomaterials owning unique properties and functionalities. In particular, biomolecules like nucleic acids, proteins and enzymes, as well as viruses, are of particular interest due to their natural ability to self-assemble via non-covalent interactions forming extremely complex and dynamic functional structures. The capability of proteins and nucleic acids to bind specific targets with very high selectivity or the ability of enzymes to catalyse specific reactions, make these biomolecules the perfect candidates to be combined with graphenes, and in particular graphene oxide, to create novel 3D nanostructured functional biomaterials. Furthermore, besides the ease of interaction between graphene oxide and biomolecules, the latter can be produced in bulk, favouring the scalability of the resulting nanostructured composite materials. Moreover, due to the presence of biological components, graphene oxide-based biomaterials are more environmentally friendly and can be manufactured more sustainably compared to other graphene-based materials assembled with synthetic and inorganic components. This review aims to provide an overview of the state of the art of 3D graphene-based materials assembled using graphene oxide and biomolecules, for the fabrication of novel functional and scalable materials and devices.

Biocompatible reduced graphene oxide stimulated BMSCs induce acceleration of bone remodeling and orthodontic tooth movement through promotion on osteoclastogenesis and angiogenesis

We has synthesized the biocompatible gelatin reduced graphene oxide (GOG) in previous research, and in this study we would further evaluate its effects on bone remodeling in the aspects of osteoclastogenesis and angiogenesis so as to verify its impact on accelerating orthodontic tooth movement. The mouse orthodontic tooth movement (OTM) model tests in vivo showed that the tooth movement was accelerated in the GOG local injection group with more osteoclastic bone resorption and neovascularization compared with the PBS injection group. The analysis on the degradation of GOG in bone marrow stromal stem cells (BMSCs) illustrated its good biocompatibility in vitro and the accumulation of GOG in spleen after local injection of GOG around the teeth in OTM model in vivo also didn't influence the survival and life of animals. The co-culture of BMSCs with hematopoietic stem cells (HSCs) or human umbilical vein endothelial cells (HUVECs) in transwell chamber systems were constructed to test the effects of GOG stimulated BMSCs on osteoclastogenesis and angiogenesis in vitro. With the GOG stimulated BMSCs co-culture in upper chamber of transwell, the HSCs in lower chamber manifested the enhanced osteoclastogenesis. Meanwhile, the co-culture of GOG stimulated BMSCs with HUVECs showed a promotive effect on the angiogenic ability of HUVECs. The mechanism analysis on the biofunctions of the GOG stimulated BMSCs illustrated the important regulatory effects of PERK pathway on osteoclastogenesis and angiogenesis. All the results showed the biosecurity of GOG and the biological functions of GOG stimulated BMSCs in accelerating bone remodeling and tooth movement.

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Here we observed the phenomenon of tooth movement acceleration induced by GOG in vivo.

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We hypothesized the pivotal role of BMSCs in the tooth movement acceleration induced by GOG.

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The effects of the GOG stimulated BMSCs on the osteoclastogenesis and angiogenesis were investigated in vitro.

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The potential mechanism of the GOG stimulated BMSCs were also analyzed in vitro and in vivo.

Cell-Penetrating Peptide-Modified Graphene Oxide Nanoparticles Loaded with Rictor siRNA for the Treatment of Triple-Negative Breast Cancer

Introduction

Breast cancer is a malignant tumor that seriously threatens women's life and health.

Methods

In this study, we proposed to use graphene nanoparticles loaded with siRNA that can silence Rictor molecules essential for the mammalian target of rapamycin (mTOR) complex 2 (mTORC2) complex to enhance gene delivery to tumor cells through modification of cell-penetrating peptide (CPP) for the treatment of breast cancer.

Results

Remarkably, we successfully synthesized graphene oxide (GO)/polyethyleneimine (PEI)/polyethylene glycol (PEG)/CPP/small interfering RNA (siRNA) system, and the results were observed by atomic force microscopy (AFM) and ultraviolet visible (UV-Vis) absorption spectra. The optimum mass ratio of siRNA to GO-PEI-PEG-CPP was 1:0.5. We screened out Rictor siRNA-2 from 9 candidates, which presented the highest inhibition rate, and this siRNA was selected for the subsequent experiments. We validated that Rictor siRNA-2 significantly reduced the Rictor expression in triple negative breast cancer (TNBC) cells. Confocal fluorescence microscope and flow cytometry analysis showed that GO-PEI-PEG-CPP/siRNA was able to be effectively uptake by TNBC cells. GO-PEI-PEG-CPP/siRNA improved the effect of siRNA on the inhibition of TNBC cell viability and the induction of TNBC cell apoptosis. The expression of Rictor and the phosphorylation of Akt and p70s6k were inhibited by GO-PEI-PEG-CPP/siRNA. Tumorigenicity analysis in nude mice showed that GO-PEI-PEG-CPP/siRNA significantly repressed the tumor growth of TNBC cells in vivo. The levels of ki-67 were repressed by GO-PEI-PEG-CPP/siRNA, and the apoptosis was induced by GO-PEI-PEG-CPP/siRNA in the system.

Discussion

Therefore, we concluded that CPP-modified GO nanoparticles loaded with Rictor siRNA significantly repressed TNBC progression by the inhibition of PI3K/Akt/mTOR signaling. Our finding provides a promising therapeutic strategy for the treatment of TNBC.

Tuning the Reduction of Graphene Oxide Nanoflakes Differently Affects Neuronal Networks in the Zebrafish

The increasing engineering of biomedical devices and the design of drug-delivery platforms enriched by graphene-based components demand careful investigations of the impact of graphene-related materials (GRMs) on the nervous system. In addition, the enhanced diffusion of GRM-based products and technologies that might favor the dispersion in the environment of GRMs nanoparticles urgently requires the potential neurotoxicity of these compounds to be addressed. One of the challenges in providing definite evidence supporting the harmful or safe use of GRMs is addressing the variety of this family of materials, with GRMs differing for size and chemistry. Such a diversity impairs reaching a unique and predictive picture of the effects of GRMs on the nervous system. Here, by exploiting the thermal reduction of graphene oxide nanoflakes (GO) to generate materials with different oxygen/carbon ratios, we used a high-throughput analysis of early-stage zebrafish locomotor behavior to investigate if modifications of a specific GRM chemical property influenced how these nanomaterials affect vertebrate sensory-motor neurophysiology-exposing zebrafish to GO downregulated their swimming performance. Conversely, reduced GO (rGO) treatments boosted locomotor activity. We concluded that the tuning of single GRM chemical properties is sufficient to produce differential effects on nervous system physiology, likely interfering with different signaling pathways.

Biodegradation of graphdiyne oxide in classically activated (M1) macrophages modulates cytokine production

Graphdiyne oxide (GDYO) is a carbon-based nanomaterial possessing sp² and sp-hybridized carbon atoms with many promising applications. However, its biocompatibility and potential biodegradability remain poorly understood. Using human primary monocyte-derived macrophages as a model we show here that GDYO elicited little or no cytotoxicity toward classically activated (M1) and alternatively activated (M2) macrophages. Moreover, GDYO reprogrammed M2 macrophages towards M1 macrophages, as evidenced by the elevation of specific cell surface markers and cytokines and the induction of NOS2 expression. We could also show inducible nitric oxide synthase (iNOS)-dependent biodegradation of GDYO in M1 macrophages, and this was corroborated in an acellular system using the peroxynitrite donor, SIN-1. Furthermore, GDYO elicited the production of pro-inflammatory cytokines in a biodegradation-dependent manner. Our findings shed new light on the reciprocal interactions between GDYO and human macrophages. This is relevant for biomedical applications of GDYO such as the re-education of tumor-associated macrophages or TAMs.

Does black phosphorus hold potential to overcome graphene oxide? A comparative review of their promising application for cancer therapy

Although graphene oxide (GO) is leading the way in the biomedical field of 2D materials, nanosized black phosphorus (NBP) has recently come to attention for use in this challenging field. A direct comparison between these two materials, in this context, has never been described. Therefore, in this mini-review, we will critically compare the applications of NBP and GO in cancer therapy. Material functionalisation, biodegradation by design, phototherapy and immunotherapy will be summarised. This work aims to inspire researchers in designing the next generation of safe NBP platforms for cancer treatment, taking advantage of the vast experience gained with GO.

"Fishing" nano-bio interactions at the key biological barriers

Understanding nano-bio interactions is pivotal to the safe implementation of nanotechnology for both biological and environmental applications. Zebrafish as a model organism provides unique opportunities to dissect nano-bio interactions occurring at different biological barriers. In this review, we focus on four key biological barriers, namely cell membrane, blood-brain barrier (BBB), skin and gill epithelia, and gastrointestinal tract (GIT), and highlight recent advancement achieved by using zebrafish to conduct both visualized observations and mechanistic investigations on a diversity of nano-bio interactions.

Recent advances in nanomaterials for therapy and diagnosis for atherosclerosis

Atherosclerosis is a chronic inflammatory disease driven by lipid accumulation in arteries, leading to narrowing and thrombosis. It affects the heart, brain, and peripheral vessels and is the leading cause of mortality in the United States. Researchers have strived to design nanomaterials of various functions, ranging from non-invasive imaging contrast agents, targeted therapeutic delivery systems to multifunctional nanoagents able to target, diagnose, and treat atherosclerosis. Therefore, this review aims to summarize recent progress (2017-now) in the development of nanomaterials and their applications to improve atherosclerosis diagnosis and therapy during the preclinical and clinical stages of the disease.

Gelatin reduced Graphene Oxide Nanosheets as Kartogenin Nanocarrier Induces Rat ADSCs Chondrogenic Differentiation Combining with Autophagy Modification

Biocompatible reduced graphene oxide (rGO) could deliver drugs for synergistically stimulating stem cells directed differentiation with influences on specific cellular activities. Here, we prepared a biodegradable gelatin reduced graphene oxide (rGO@Ge) to evaluate its functions in promoting rat adipose derived mesenchymal stem cells (ADSCs) chondrogenic differentiation through delivering kartogenin (KGN) into the stem cell efficiently. The optimum KGN concentration (approximately 1 μM) that promoted the proliferation and chondrogenic differentiation of ADSCs was clarified by a series of experiments, including immunofluorescent (IF) staining (Sox-9, Col II), alcian blue (Ab) staining, toluidine blue (Tb) staining and real-time quantitative PCR analysis of the chondrogenic markers. Meanwhile, the biocompatibility of rGO@Ge was evaluated to clearly define the nonhazardous concentration range, and the drug loading and releasing properties of rGO@Ge were tested with KGN for its further application in inducing ADSCs chondrogenic differentiation. Furthermore, the mechanism of rGO@Ge entering ADSCs was investigated by the different inhibitors that are involved in the endocytosis of the nanocarrier, and the degradation of the rGO@Ge in ADSCs was observed by transmission electron microscopy (TEM). The synergistic promoting effect of rGO@Ge nanocarrier on ADSCs chondrogenesis with KGN was also studied by the IF, Ab, Tb stainings and PCR analysis of the chondrogenic markers. Finally, the intracellular Reactive Oxygen Species (ROS) and autophagy induced by KGN/rGO@Ge complex composites were tested in details for clarification on the correlation between the autophagy and chondrogenesis in ADSCs induced by rGO@Ge. All the results show that rGO@Ge as a biocompatible nanocarrier can deliver KGN into ADSCs for exerting a pro-chondrogenic effect and assist the drug to promote ADSCs chondrogenesis synergistically through modification of the autophagy in vitro, which promised its further application in repairing cartilage defect in vivo.