Raman spectroscopic quantification of graphene oxide in soil: Transport, surficial enrichment and environmental effects.

The transport and retention data in environmental media are indispensable for the hazard evaluations of graphene materials. Due to the complexity of soil, the transport of graphene is hard to quantify without isotope labeling. Herein, we developed 2D Raman mapping as a label-free technique to quantify graphene oxide (GO) in soil. After pre-treatment by hydrazine hydrate to quench its fluorescence, the quantification of GO in soil was achieved in the range of 0.1-1000 mg/L by measuring the average G-band intensity. In column transport experiment, the transport and retention of GO in soil depended on the solution chemistry. Lower pH and higher ionic strength hindered the transport of GO. In particular, Ca2+ showed the most obvious retardation on the transport of GO. GO enriched in the surficial soil layer by several folds of the initial concentrations, and higher GO concentration led to more surficial enrichment. The sowing manner of seeds affected the soil enrichment of GO, too. The surficial enrichment of GO reduced its direct contact with seedling roots, resulting in the alleviation of GO toxicity. Our results provided a facile method to study the environmental behaviors of graphene and highlighted the crucial impacts of environmental media on the graphene toxicity.

Photothermal therapy of xenografted tumor by carbon nanoparticles-Fe(II) complex.

Due to the unique structure, carbon nanomaterials could convert near-infrared (NIR) light into heat efficiently in tumor ablation using photothermal therapy (PTT). However, none of them has been applied in clinical treatment, because they have not been approved for clinical evaluations and the precise temperature control facility is scarce. In this study, we designed a temperature-responsive controller for PTT and used carbon nanoparticles-Fe(II) complex (CNSI-Fe) as photothermal conversion agent (PTA) for PTT of tumor in vitro and in vivo. CNSI-Fe was an innovative drug under the evaluations in clinical trials. CNSI-Fe showed excellent photothermal conversion ability in water to increase the water temperature by 40 °C within 5 min under irradiation of 808 nm laser at 0.5 W/cm2. The temperature was precisely controlled at 52 °C for both in vitro and in vivo tumor inhibition. CNSI-Fe with NIR irradiation showed higher tumor cell inhibition than CNSI. In tumor bearing mice, CNSI-Fe with NIR irradiation achieved an inhibition rate of 84.7 % and 71.4 % of them were completely cured. Mechanistically, CNSI-Fe under NIR irradiation induced the radical generation, oxidative damage and ferroptosis to kill tumor. In addition, CNSI-Fe showed good biosafety during PTT according to hematological, serum biological and histopathological examinations. These results indicated that the combination of chemotherapy and PTT provided higher antitumor efficiency using CNSI-Fe as PTA.

Reduced graphene oxide promotes the biodegradation of sulfamethoxazole by white-rot fungus Phanerochaete chrysosporium under cadmium stress.

The biodegradation of antibiotics in aquatic environment is consistently impeded by the widespread presence of heavy metals, necessitating urgent measures to mitigate or eliminate this environmental stress. This work investigated the degradation of sulfamethoxazole (SMX) by the white-rot fungus Phanerochaete chrysosporium (WRF) under heavy metal cadmium ion (Cd2+) stress, with a focus on the protective effects of reduced graphene oxide (RGO). The pseudo-first-order rate constant and removal efficiency of 5 mg/L SMX in 48 h by WRF decrease from 0.208 h-1 and 55.6% to 0.08 h-1 and 28.6% at 16 mg/L of Cd2+, while these values recover to 0.297 h-1 and 72.8% by supplementing RGO. The results demonstrate that RGO, possessing excellent biocompatibility, effectively safeguard the mycelial structure of WRF against Cd2+ stress and provide protection against oxidative damage to WRF. Simultaneously, the production of manganese peroxidase (MnP) by WRF decreases to 38.285 U/L in the presence of 24 mg/L Cd2+, whereas it recovers to 328.51 U/L upon the supplement of RGO. RGO can induce oxidative stress in WRF, thereby stimulating the secretion of laccase (Lac) and MnP to enhance the SMX degradation. The mechanism discovered in this study provides a new strategy to mitigate heavy metal stress encountered by WRF during antibiotic degradation.

Toxicity of VO2 micro/nanoparticles to nitrogen-fixing bacterium Azotobacter vinelandii.

Vanadium dioxide (VO2) has been used in a variety of products due to its outstanding phase transition properties. However, as potential heavy metal contaminants, the environmental hazards and risks of VO2 should be systematically investigated. Biological nitrogen fixation is one of the most dominant processes in biogeochemical cycle, which is associated with nitrogen-fixing bacteria. In this study, we reported the environmental bio-effects of VO2 micro/nanoparticles on the nitrogen-fixing bacterium Azotobacter vinelandii. VO2 at 10 and 30 mg/L caused severe hazards to A. vinelandii, such as cell apoptosis, oxidative damage, physical damage, genotoxicity, and the loss of nitrogen fixation activity. The up-regulated differentially expressed genes of A. vinelandii were related to stress response, and the down-regulated genes were mainly related to energy metabolism. Surprisingly, VO2 of 10 mg/L decreased the nif gene expression but elevated the vnf gene expression, which enhanced the ability of A. vinelandii to reduce acetylene in anaerobic environment. In addition, under tested conditions, VO2 nanoparticles exhibited insignificantly higher toxicity than VO2 microparticles.

Organic ligands regulate the environmental impacts of metal-organic frameworks on nitrogen-fixing bacterium Azotobacter vinelandii.

Metal-organic frameworks (MOFs) are rapidly developed materials with fantastic properties and wide applications. The increasing studies highlighted the potential threats of MOF materials to the environment. Comparing to the limited species of metal elements, the organic ligands have much higher diversity, but the influence of organic ligands on the environmental impacts of MOFs has not been revealed. Herein, we synthesized three Cu-MOFs with different organic ligands, namely Cu-BDC (1,4-terephthalic acid), Cu-IM (imidazole) and Cu-TATB (2,4,6-tris(4-carboxyphenyl)- 1,3,5-triazine), and evaluated their environmental toxicity to the nitrogen-fixing bacterium Azotobacter vinelandii. Cu-BDC inhibited the bacterial growth at lower concentrations than Cu-IM and Cu-TATB. The transcriptomes suggested the changes of membrane components by Cu-MOFs, consistent with the membrane leakage and cell wall damages. Cu-MOFs inhibited the nitrogen fixation activity through energy metabolism disturbance according to Gene Ontology functional annotation of ATP binding, Ca2+Mg2+-ATPase activity and ATP content. Only Cu-IM lowered the nitrogen fixation related nif genes, and affected the ribosome, purine metabolism and oxidative phosphorylation pathways. Otherwise, Cu-BDC and Cu-TATB mainly affected the flagellar assemblies and bacterial chemotaxis pathways. Our results collectively indicated that organic ligands regulated the environmental toxicity of MOFs through different metabolism pathways.

GSH-Activatable Aggregation-Induced Emission Cationic Lipid for Efficient Gene Delivery.

The key to gene therapy is the design of biocompatible and efficient delivery systems. In this work, a glutathione (GSH)-activated aggregation-induced-emission (AIE) cationic amphiphilic lipid, termed QM-SS-KK, was prepared for nonviral gene delivery. QM-SS-KK was composed of a hydrophilic biocompatible lysine tripeptide headgroup, a GSH-triggered disulfide linkage, and a hydrophobic AIE fluorophore QM-OH (QM: quinoline-malononitrile) tail. The peptide moiety could not only efficiently compact DNA but also well modulate the dispersion properties of QM-SS-KK, leading to the fluorescence-off state before GSH treatment. The cleavage of disulfide in QM-SS-KK by GSH generated AIE signals in situ with a tracking ability. The liposomes consisted of QM-SS-KK, and 1,2-dioleoylphosphatidylethanolamine (DOPE) (QM-SS-KK/DOPE) delivered plasmid DNAs (pDNAs) into cells with high efficiency. In particular, QM-SS-KK/DOPE had an enhanced transfection efficiency (TE) in the presence of 10% serum, which was two times higher than that of the commercial transfection agent PEI25K. These results highlighted the great potential of peptide and QM-based fluorescence AIE lipids for gene delivery applications.

Porous Carbon Sponge from White-Rot Fungus Phanerochaete chrysosporium for the Removal of Oils and Organic Solvents.

Oil leakage incidentally occurs and leads to environmental disasters. Because of their porous and hydrophobic characteristics, graphene sponges are often studied as an oil adsorbent to repair oil spills at sea. Graphene materials are very expensive, and their biological toxicity has been given serious concerns; however, the easier preparation and eco-friendly, biomass-derived porous carbon materials can be used as an alternative to graphene materials. In this study, we prepared a porous carbon sponge (PCS) for oil and organic solvent removal by carbonizing white-rot fungus Phanerochaete chrysosporium, a fast-growing microorganism for the production of lignin-degrading enzymes and the environmental remediation. P. chrysosporium fungus balls were converted into black PCS by carbonization at high temperatures, where PCS was light (density of 56 g/L), hydrophobic (contact angle of 115°) and porous. According to the results of BET and XPS analysis, the surface area of PCS was 14.43 m2/g, and the carbon in PCS is mainly sp2 carbon. PCS could adsorb pure oils and organic solvents within seconds. The adsorption capacities of PCS were 20.7 g/g for gasoline, 30.1 g/g for peanut oil, 27.7 g/g for toluene, 18.5 g/g for dodecane, 32.5 g/g for chloroform, 27.1 g/g for tetrahydrofuran, 23.7 g/g for acetone and 13.7 g/g for ethanol. According to the reusability study, there was no obvious capacity loss after recycling up to 10 cycles. Our results indicated that white-rot fungi could be adopted as a cheap carbon resource for oil and organic solvent removal.

Particulate toxicity of metal-organic framework UiO-66 to white rot fungus Phanerochaete chrysosporium.

Metal-organic frameworks (MOF) are emerging materials with fantastic properties and wide applications. The release of metal ions from MOF materials is usually regarded as the origin of soluble MOF toxicity. However, whether the stable MOF particulates would induce environmental hazards is not clear. Herein, we aimed to reveal the particulate toxicity of MOF materials using the insoluble UiO-66 as the representative MOF and Phanerochaete chrysosporium as the model microorganism. UiO-66 nanoparticles (NPs) were synthesized by solvothermal method and their diameter was 68.4 ± 8.5 nm. UiO-66 NPs were stable in the culture system and the dissolution rate of 500 mg/L group was 0.26% after 14 d incubation. UiO-66 NPs did not affect the fungus growth according to the fresh weight increases and unchanged dry weights. Fungus mycelia kept even at concentrations up to 500 mg/L. Ultrastructural observation showed that UiO-66 NPs did not enter the fungal cells, but slightly destroyed the cell wall. UiO-66 NPs inhibited the laccase activity and promoted the activity of manganese peroxidase. The overall impact on the decomposition activity of P. chrysosporium was low in dye coloration test and sawdust degradation assay. Meaningful oxidative stress was aroused by UiO-66 NPs, as indicated by the decreases of catalase, glutathione, and total superoxide dismutase, and the increases of H2O2. Our results collectively suggested that the MOF particulates could induce mild mechanical damage to fungi and the toxicity was low comparing to other instable MOF materials.

Low Toxicity of Metal-Organic Framework MOF-74(Co) Nano-Particles In Vitro and In Vivo.

With the rapid development of metal-organic frameworks (MOF), the toxicity and environmental safety of MOF materials should be thoroughly investigated. The behaviors and bio-effects of MOF materials after oral exposure are largely unknown. In this study, we performed a pilot toxicity evaluation of MOF-74(Co) nanoparticles (NPs) both in vitro and in vivo. The cell viability and cell cycle were monitored after LO2 cells were incubated with MOF-74(Co). The Co contents, bodyweight, serum biochemistry, histopathological changes, and oxidative stress parameters were measured after oral exposure to MOF-74(Co) NPs in mice. LO2 cells showed viability loss at 100 mg/L. The cell cycle arrest was more sensitive, which was observed even at 12.5 mg/L. MOF-74(Co) NPs led to a significant accumulation of Co in the liver and kidneys. No bodyweight loss was observed and the serum biochemical index was mainly unchanged. Except for slight inflammation, the histopathological images of the liver and kidneys after oral exposure to MOF-74(Co) NPs were normal compared to the control. Meaningful oxidative stress was found in the liver and kidneys. The results collectively indicated the low toxicity of MOF-74(Co) NPs after oral exposure in mice.

Phytotoxicity of VO2 nanoparticles with different sizes to pea seedlings.

Vanadium dioxide nanoparticles (VO2 NPs) have been massively produced due to their excellent metal-insulator transition characteristics for various applications. Pilot studies indicated the toxicity of VO2 NPs to bacteria and mammalian cells, but the environmental hazards of VO2 NPs to plants have been unrevealed to date. In this study, we reported the inhibitive effects of VO2 NPs to the growth and photosynthesis of pea seedlings. Laboratory synthesized monoclinic VO2 NPs (N-VO2), commercial nanosized VO2 NPs (S-VO2), and commercial microsized VO2 particles (M-VO2) were carefully characterized for environmental toxicity evaluations. VO2 particles were supplemented to culture medium for seed germination and seedling growth. All three VO2 samples did not affect the germination rates of pee seeds, while serious growth inhibition of pea seedlings was observed at 10 mg/L for S-VO2 and N-VO2, and 100 mg/L for M-VO2. VO2 particles had no impact on the chlorophyll contents, but the photosynthesis of leaf was significantly decreased following the consequence of N-VO2 > S-VO2 > M-VO2. The inhibition of photosynthesis was attributed to the damage of acceptor side of photosystem II by VO2 particles at high concentrations. Abundant bioaccumulations of vanadium in roots aroused oxidative damage and changed the root structure. Our results collectively indicated that the phytotoxicity of VO2 NPs was related to the concentration, size and crystalline degree.

Stimulating effects of reduced graphene oxide on the growth and nitrogen fixation activity of nitrogen-fixing bacterium Azotobacter chroococcum.

Graphene has found important applications in various areas and hundred tons of graphene materials are annually produced. It is crucial to investigate both the negative and positive environmental effects of graphene materials to ensure the safe applications and develop environmental applications. In this study, we reported the stimulating effects of reduced graphene oxide (RGO) to nitrogen-fixing bacterium Azotobacter chroococcum. RGO stimulated the cell growth of A. chroococcum at 0.010-0.500 mg/mL according to the growth curves and the colony-forming unit (CFU) increases. RGO wrapped over the A. chroococcum cells without inducing ultrastructural changes. RGO decreased the leakage of cell membrane, but slight oxidative stress was observed in A. chroococcum. RGO promoted the nitrogen fixation activity of A. chroococcum at 0.5 mg/mL according to both isotope dilution method and acetylene reduction activity measurements. Consequently, the increases of soil nitrogen contents were evidenced, in particular about 30% increase of organic nitrogen occurred at 0.5 mg/mL of RGO. In addition, RGO might possibly benefit the plant growth through enhancing the indoleacetic acid production of A. chroococcum. These results highlighted the positive environmental effects of graphene materials to nitrogen-fixing bacteria in nitrogen cycle.

[Effects of Three Illuminants on the Color of High Translucent Multilayered Zirconia].

OBJECTIVE: To evaluate the effects of three common illuminants on the color of four brands of high translucent multilayered zirconia (HTMZ) ceramics so as to provide reference for clinical practice and dental restoration fabrication, and to reduce the risks for illuminant change causing color mismatch between the natural teeth and the restorations made of HTMZ. METHODS: Four brands of commonly used HTMZ were selected and ten cuboid samples ( n=10/group) of 12 mm×10 mm×0.8 mm were prepared for each type of HTMZ. The L*, a*, and b* values of the samples were measured under D65, A and F2, three standard illuminants. Then, the L*, a*, and b* values were statistically analyzed by using factors of the type of the illuminant and the brand of the zirconia. Color difference (ΔE) of samples of the same brand under exposure to changed illuminants was also calculated. RESULTS: When the same samples were exposure to different illuminants, there was no significant difference in the L* value, the a* value for the different iluminants was shown to be illuminant A>illuminant F2>illuminant D65, and the b* value was shown to be illuminant F2>illuminant D65>illuminant A. The L*, a*, and b* values of samples of different brands showed statistically significant difference when they were exposed to the same illuminant ( P<0.0001). Samples of the same brand showed ΔE when they were under the three different illuninants, and all ΔE were clinically acceptable. CONCLUSION: The types of illuminant used, to a certain degree, affected the hue and chroma of HTMZ. There were colorimetric differences between restorations made of different brands of HTMZ ceramics of the same color. The types of illuminants most common to the daily life of patients and the color characteristics of materials of different brands should be taken into consideration to facilitate the selection of restoration materials and dental restoration fabrication, and to reduce the risks for color mismatch between the restorations and the adjacent teeth caused by the change of illuminants.

Toxicity and activity inhibition of metal-organic framework MOF-199 to nitrogen-fixing bacterium Azotobacter vinelandii.

Metal-organic framework (MOF) materials with fantastic properties have found important applications in various areas. Learning the lessons from plastics and microplastics, it is urgent to investigate the environmental impacts of emerging materials to avoid potential pollution. However, the environmental toxicity and risks of MOF materials are seldom reported. Herein, we studied the toxicity and activity inhibition of MOF-199 to nitrogen-fixing bacterium Azotobacter vinelandii. MOF-199 significantly suppressed the growth of A. vinelandii and led to cell death at 40 mg/L. MOF-199 penetrated the cell wall and induced the shrinking of bacterial cells. MOF-199 reduced the nitrogen fixation activity of A. vinelandii at 40 mg/L by decreasing the gene nifH levels and inhibiting the Ca2+Mg2+-ATPase activity, which was further confirmed by the changes in oxidative phosphorylation related genes. Complete growth inhibition and activity loss of A. vinelandii occurred at 60 mg/L of MOF-199. The toxicological mechanism of MOF-199 to A. vinelandii was assigned to the oxidative stress, which occurred at 20 mg/L and higher. Both Cu2+ release and particulates themselves contributed to the toxicity of MOF-199 to A. vinelandii. These findings highlighted the environmental hazards and risks of MOF materials to nitrogen-fixing bacteria and nitrogen fixation in the biogeochemical cycle.

Biocompatible zinc gallogermanate persistent luminescent nanoparticles for fast tumor drainage lymph node imaging in vivo.

Tumor drainage lymph node identification and dissection are crucial for the oncological surgery to prevent/delay the recurrence. However, commercial imaging reagents distinguish the lymph nodes by staining them dark, which would be seriously interfered by blood and surrounding tissues. In this study, we reported the Cr3+/Pr3+-doped zinc gallogermanate persistent luminescent nanoparticles (PLNPs) for fast tumor drainage lymph node imaging with high contrast. PLNPs were synthesized by citrate sol-gel method and dispersed in Tween 80 for in vivo applications. PLNPs were well dispersed in water with hydrodynamic radii of 5 nm and emitted strong persistent luminescence at 696 nm upon the irradiation of UV light. The advantage of afterglow imaging over fluorescent imaging of PLNPs was first established after subcutaneous injection to mice with much higher contrast and less interference of autofluorescence. PLNPs quickly migrated to sentinel lymph nodes after the interdermal injection to extremity of mice. The tumor drainage lymph node imaging was achieved within 5 min upon the intratumoral injection to H460 tumor bearing mice and the signal to noise ratio was 462. Due to the lack of targeting moieties, the intravenous injected PLNPs mainly accumulated in liver. There were no statistical changes in serum biochemistry and abnormal histopathological characteristic, indicating the low toxicity of PLNPs. These findings highlighted the great potential of PLNPs as high-performance imaging reagent for lymph node identification.

Single photon counting compressive imaging using a generative model optimized via sampling and transfer learning.

Single photon counting compressive imaging, a combination of single-pixel-imaging and single-photon-counting technology, is provided with low cost and ultra-high sensitivity. However, it requires a long imaging time when applying traditional compressed sensing (CS) reconstruction algorithms. A deep-learning-based compressed reconstruction network refrains iterative computation while achieving efficient reconstruction. This paper proposes a compressed reconstruction network (OGTM) based on a generative model, adding sampling sub-network to achieve joint-optimization of sampling and generation for better reconstruction. To avoid the slow convergence caused by alternating training, initial weights of the sampling and generation sub-network are transferred from an autoencoder. The results indicate that the convergence speed and imaging quality are significantly improved. The OGTM validated on a single-photon compressive imaging system performs imaging experiments on specific and generalized targets. For specific targets, the results demonstrate that OGTM can quickly generate images from few measurements, and its reconstruction is better than the existing compressed sensing recovery algorithms, compensating defects of the generative models in compressed sensing.

Toxicity and photosynthetic inhibition of metal-organic framework MOF-199 to pea seedlings.

Metal-organic framework (MOF) materials are star materials with unique structures and properties. To ensure safe production and applications, the toxicity and environmental hazards of MOF materials should be thoroughly investigated. However, the environmental impact of MOF materials on plants is completely unknown. Herein, we reported the toxicity and photosynthetic inhibitory properties of MOF-199 to pea plants (Pisum sativum L.). MOF-199 was synthesized by hydrothermal method. MOF-199 was copper containing double-pyramid of high surface area (668 m2/g). MOF-199 accelerated the germination of pea seeds, but the total germination rates were unchanged. MOF-199 inhibited the seedling growth at high concentrations. The net photosynthetic rate increased, while the total photosynthesis capability decreased. Damage to the acceptor side of photosystem II was evidenced by chlorophyll fluorescence. Mechanistically, MOF-199 released Cu2+ in the nutrient solution, led to Cu2+ accumulations in seedlings, and promoted oxidative stress. In addition, the photosynthetic inhibitions of MOF-199 were stronger than equivalent concentrations of Cu(NO3)2, implying that MOF-199 particles also contributed to the environmental hazards. Our results highlighted the potential threat of MOF materials to plant growth and photosynthesis.

Effects of blocking mGluR5 on primate dorsolateral prefrontal cortical neuronal firing and working memory performance.

RATIONALE: Metabotropic glutamate type 5 receptor (mGluR5) antagonists are under development for treating cognitive disorders such as Fragile X syndrome and Alzheimer's disease, largely based on success in mouse models, where post-synaptic mGluR5 stimulation weakens synaptic functions in hippocampus. However, human trials of mGluR5 antagonists have yet to be successful. This may be due in part to the differing effects of mGluR5 in hippocampus vs. prefrontal cortex, as mGluR5 are primarily post-synaptic in rodent hippocampus, but are both pre- and post-synaptic in the dorsolateral prefrontal cortical (dlPFC) circuits known to subserve working memory. OBJECTIVES AND METHODS: The current study examined the effects of the selective mGluR5 negative allosteric modulator, MTEP (3-((2-Methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride), on neuronal firing and working memory performance in aging rhesus monkeys with naturally occurring impairments in neuronal firing and cognitive performance. RESULTS: We found that iontophoresis of MTEP directly onto dlPFC "Delay cells" had an inverted U dose-response, where low doses tended to enhance task-related firing, but higher doses suppressed neuronal firing. Similar effects were seen on cognitive performance following systemic MTEP administration (0.0001-0.1 mg/kg), with MTEP producing erratic dose-response curves. In the subset of monkeys (50%) that showed replicable improvement with MTEP, co-administration with the mGluR5 PAM, CDPPB (3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide), blocked MTEP beneficial effects, consistent with mGluR5 actions. CONCLUSIONS: The mixed effects of MTEP on cognitive performance may arise from opposing actions at pre- vs. post-synaptic mGluR5 in dlPFC. These data from monkeys suggest that future clinical trials should include low doses, and identification of potential subgroup responders.

Deep-learning-based single-photon-counting compressive imaging via jointly trained subpixel convolution sampling.

The combination of single-pixel-imaging and single-photon-counting technology can achieve ultrahigh-sensitivity photon-counting imaging. However, its applications in high-resolution and real-time scenarios are limited by the long sampling and reconstruction time. Deep-learning-based compressive sensing provides an effective solution due to its ability to achieve fast and high-quality reconstruction. This paper proposes a sampling and reconstruction integrated neural network for single-photon-counting compressive imaging. To effectively remove the blocking artefact, a subpixel convolutional layer is jointly trained with a deep reconstruction network to imitate compressed sampling. By modifying the forward and backward propagation of the network, the first layer is trained into a binary matrix, which can be applied to the imaging system. An improved deep-reconstruction network based on the traditional Inception network is proposed, and the experimental results show that its reconstruction quality is better than existing deep-learning-based compressive sensing reconstruction algorithms.

Carbon Nanoparticles-Fe(II) Complex for Efficient Tumor Inhibition with Low Toxicity by Amplifying Oxidative Stress.

The Fe element is essential for human beings, but overdose of Fe leads to unwanted toxicity. However, overwhelming Fe accumulation in tumor cells could arouse strong oxidative stress for cancer therapy. Therefore, the fast and specific accumulation of Fe in tumor cells without systemic toxicity is critical for this purpose. Herein, we report that a carbon nanoparticles-Fe(II) complex (CNSI-Fe) could efficiently load Fe into tumor cells and inhibit tumor growth with low toxicity in H22 tumor-bearing mice. Upon intratumoral injection, CNSI-Fe only induced meaningful Fe increase in the tumor to significantly inhibit tumor growth with competitive efficiency to cis-dichlorodiammineplatinum(II). Fe accumulation stimulated the hydroxyl radical generation and serious oxidative stress in the tumor. Due to the lack of Fe accumulation in other tissues, CNSI-Fe was of low systemic toxicity to tumor-bearing mice. With the clinical success of CNSI for decades, CNSI-Fe might be used for cancer therapy through "off label" use to benefit patients immediately.

Fast Identification and Quantification of Graphene Oxide in Aqueous Environment by Raman Spectroscopy.

Today, graphene nanomaterials are produced on a large-scale and applied in various areas. The toxicity and hazards of graphene materials have aroused great concerns, in which the detection and quantification of graphene are essential for environmental risk evaluations. In this study, we developed a fast identification and quantification method for graphene oxide (GO) in aqueous environments using Raman spectroscopy. GO was chemically reduced by hydrazine hydrate to form partially reduced GO (PRGO), where the fluorescence from GO was largely reduced, and the Raman signals (G band and D band) were dominating. According to the Raman characteristics, GO was easily be distinguished from other carbon nanomaterials in aqueous environments, such as carbon nanotubes, fullerene and carbon nanoparticles. The GO concentration was quantified in the range of 0.001-0.6 mg/mL with good linearity. Using our technique, we did not find any GO in local water samples. The transport of GO dispersion in quartz sands was successfully quantified. Our results indicated that GO was conveniently quantified by Raman spectroscopy after partial reduction. The potential applications of our technique in the environmental risk evaluations of graphene materials are discussed further.