A new capacity of gut microbiota: Fermentation of engineered inorganic carbon nanomaterials into endogenous organic metabolites.

Carbon-based nanomaterials (CNMs) have recently been found in humans raising a great concern over their adverse roles in the hosts. However, our knowledge of the in vivo behavior and fate of CNMs, especially their biological processes elicited by the gut microbiota, remains poor. Here, we uncovered the integration of CNMs (single-walled carbon nanotubes and graphene oxide) into the endogenous carbon flow through degradation and fermentation, mediated by the gut microbiota of mice using isotope tracing and gene sequencing. As a newly available carbon source for the gut microbiota, microbial fermentation leads to the incorporation of inorganic carbon from the CNMs into organic butyrate through the pyruvate pathway. Furthermore, the butyrate-producing bacteria are identified to show a preference for the CNMs as their favorable source, and excessive butyrate derived from microbial CNMs fermentation further impacts on the function (proliferation and differentiation) of intestinal stem cells in mouse and intestinal organoid models. Collectively, our results unlock the unknown fermentation processes of CNMs in the gut of hosts and underscore an urgent need for assessing the transformation of CNMs and their health risk via the gut-centric physiological and anatomical pathways.

Visualization of fullerenol nanoparticles distribution in Daphnia magna using Laser Ablation-isotope Ratio Mass (LA-IRMS) and Matrix-assisted Laser Desorption/Ionization Imaging Mass Spectrometry (MALDI-IMS).

Laser ablation-isotope ratio mass spectrometry (LA-IRMS) allows the mapping analysis of carbon isotope (δ13C) signature in organism samples.Matrix assisted laser desorption ionization time-of-flightimaging mass spectrometry (MALDI-TOF-IMS) enables image of target directly. In this study, the distribution of δ13C and fullerenol nanoparticles in Daphnia magna (D. magna) exposed to different fullerenol solution are mapped using the LA-IRSM and MALDI-TOF-IMS for comparison. We visualize thedistribution of fullerenol nanoparticles mainly in the intestine, also in other parts of the body as well. This is the first time that fullerenol nanoparticles was found outside the intestine of D. magna, which has been confirmed by the two imaging methods individually. Although the both imaging methods are applicable to in-situ visualize the localization and spatial distribution of fullerenol nanoparticles in organisms, MALDI-TOF-IMS is more suitable, in terms of sample preparation and image resolution. The results of our study will also provide a new idea and method for the research of environmental toxicology.

The Underlying Function and Structural Organization of the Intracellular Protein Corona on Graphdiyne Oxide Nanosheet for Local Immunomodulation.

Nanomaterial-biology interaction is the critical step in the fate of biomedical nanomedicines, influencing the consequent biological outcomes. Herein, we present two-dimensional carbon-based nanomaterials-graphdiyne oxide (GDYO) nanosheets that interact with an intracellular protein corona consisting of signal transducer and activator of transcription 3 (STAT3), inducing the reeducation of immunosuppressive macrophages. The interaction at the GDYO-STAT3 interface, driven by structure matching, hydrogen bonding, and salt bridges, simultaneously triggers the immune response in the tumor microenvironment, facilitating cancer immunotherapy. For the first time, our data reveal an interaction mechanism between the nanoparticle-protein interfaces inevitably formed inside the cells that determines the macrophage phenotype. Our results suggest that GDYO nanosheets could be applied for local immunomodulation due to their function and structural organization of the intracellular protein corona occurred inside macrophages.

Bioaccumulation, biodistribution，and depuration of 13C-labelled fullerenols in zebrafish through dietary exposure.

In aquatic organisms, dietary exposure to nanomaterials is not only one of the important uptake pathways, but it is also one method to assess the transmission risk of the food chain. To address this concern, we quantitatively investigated the accumulation and depuration of fullerenols in the tissues of zebrafish after exposure to fullerenols-contaminated Daphnia magna. After exposure to 13C-labelled fullerenol solution at a concentration of 2.5 mg/L for 72 h, the steady state concentration of fullerenols in D. magna was 31.20 ± 1.59 mg/g dry weight. During the 28 d uptake period for zebrafish, fullerenols in the tissues increased in a tissue- and day-dependent manner, and the major target tissues of fullerenols were the intestines and liver, followed by the gill, muscle, and brain. The kinetic parameters of uptake and depuration were also quantitatively analyzed. After depuration for 15 d, a certain amount of residual fullerenols remained in the tissues, especially the brain, where approximately 64 d may be needed to achieve 90% of the cumulative concentration depuration. The calculated distribution-based trophic transfer factors (TTFd values) (from 0.26 to 0.49) indicated that the tissue biomagnification of fullerenols by zebrafish through dietary exposure may not occur. Transmission electron microscopy (TEM) confirmed the presence of fullerenols in D. magna and the tissues of zebrafish. Our research data are essential for thoroughly understanding of the fate of nanoparticles through the dietary exposure pathway and directing future tissue bioeffect studies regarding target tissues for further research.

Uptake and Transfer of 13C-Fullerenols from Scenedesmus obliquus to Daphnia magna in an Aquatic Environment.

Fullerenol, a water-soluble polyhydroxylated fullerene nanomaterial, enters aquatic organisms and ecosystems through different ingestion exposures and may pose environmental risks. The study of their uptake routes and transfer in aquatic systems is scarce. Herein, we quantitatively investigated the aquatic uptake and transfer of 13C-fullerenols from Scenedesmus obliquus to Daphnia magna using 13C-skeleton-labeling techniques. The bioaccumulation and depuration of fullerenol in Daphnia magna increased with exposure doses and time, reaching steady state within 16 h in aqueous and feeding-affected aqueous routes. The capacity of Daphnia magna to ingest fullerenol via the aqueous route was much higher than that via the dietary route. From the aqueous to feeding-affected aqueous, the kinetic analysis demonstrated the bioaccumulation factors decreases, which revealed that algae suppressed Daphnia magna uptake of fullerenols. The aqueous route was the primary fullerenols ingestion pathway for Daphnia magna. Kinetic analysis of the accumulation and transfer in Daphnia magna via the dietary route indicated low transfer efficiency of fullerenol along the Scenedesmus obliquus-Daphnia magna food chain. Using stable isotope labeling techniques, these quantitative data revealed that carbon nanomaterials underwent complex aquatic accumulation and transfer from primary producers to secondary consumers and algae inhibited their transfer in food chains.

Bioaccumulation and Toxicity of 13C-Skeleton Labeled Graphene Oxide in Wheat.

Graphene nanomaterials have many diverse applications, but are considered to be emerging environmental pollutants. Thus, their potential environmental risks and biosafety are receiving increased attention. Bioaccumulation and toxicity evaluations in plants are essential for biosafety assessment. In this study, 13C-stable isotope labeling of the carbon skeleton of graphene oxide (GO) was applied to investigate the bioaccumulation and toxicity of GO in wheat. Bioaccumulation of GO was accurately quantified according to the 13C/12C ratio. Wheat seedlings were exposed to 13C-labeled GO at 1.0 mg/mL in nutrient solution for 15 d. 13C-GO accumulated predominantly in the root with a content of 112 µg/g at day 15, hindered the development and growth of wheat plants, disrupted root structure and cellular ultrastructure, and promoted oxidative stress. The GO that accumulated in the root showed extremely limited translocation to the stem and leaves. During the experimental period, GO was excreted slowly from the root. GO inhibited the germination of wheat seeds at high concentrations (≥0.4 mg/mL). The mechanism of GO toxicity to wheat may be associated with oxidative stress induced by GO bioaccumulation, reflected by the changes of malondialdehyde concentration, catalase activity, and peroxidase activity. The results demonstrate that 13C labeling is a promising method to investigate environmental impacts and fates of carbon nanomaterials in biological systems.

Bioaccumulation, Depuration, and Transfer to Offspring of 13C-Labeled Fullerenols by Daphnia magna.

Fullerenols have wide application in the field of life sciences as a result of their extensive biocompatibility and biofunctionality. However, their environmental fate and ecotoxicological risks are largely unknown. In this study, stable isotope (13C) labeling was applied to investigate the bioaccumulation and depuration of fullerenols in Daphnia magna. By incorporation of 13C on the skeleton of fullerenols, the concentrations of fullerenols in the samples could be precisely determined on the basis of carbon isotope ratios (13C/12C). After exposure to 13C-labeled fullerenols in artificial freshwater for 48 h, the steady concentrations of fullerenols in D. magna were nearly 0.39 and 1.37% of the dry body weight in the 0.1 and 1.0 mg/L exposure groups, respectively. After 48 h of depuration, D. magna could excrete 97.34 and 89.56% of the accumulated fullerenols in 0.1 and 1.0 mg/L exposure group, respectively. The depuration of fullerenols from D. magna followed first-order kinetics. Moreover, accumulated fullerenols in gravid D. magna could be transferred to the next generation of neonates. The results in present study demonstrated that stable isotope (13C) labeling is a powerful tool to investigate the environmental fate and the potential impacts of fullerenols in ecological systems.

Surface modification-mediated biodistribution of ¹³C-fullerene C60 in vivo.

BACKGROUND: Functionalization is believed to have a considerable impact on the biodistribution of fullerene in vivo. However, a direct comparison of differently functionalized fullerenes is required to prove the hypothesis. The purpose of this study was to investigate the influences of surface modification on the biodistribution of fullerene following its exposure via several routs of administration. METHODS: (13)C skeleton-labeled fullerene C60 ((13)C-C60) was functionalized with carboxyl groups ((13)C-C60-COOH) or hydroxyl groups ((13)C-C60-OH). Male ICR mice (~25 g) were exposed to a single dose of 400 µg of (13)C-C60-COOH or (13)C-C60-OH in 200 µL of aqueous 0.9% NaCl solution by three different exposure pathways, including tail vein injection, gavage and intraperitoneal exposure. Tissue samples, including blood, heart, liver, spleen, stomach, kidneys, lungs, brain, large intestine, small intestine, muscle, bone and skin were subsequently collected, dissected, homogenized, lyophilized, and analyzed by isotope ratio mass spectrometry. RESULTS: The liver, bone, muscle and skin were found to be the major target organs for C60-COOH and C60-OH after their intravenous injection, whereas unmodified C60 was mainly found in the liver, spleen and lung. The total uptakes in liver and spleen followed the order: C60 > > C60-COOH > C60-OH. The distribution rate over 24 h followed the order: C60 > C60-OH > C60-COOH. C60-COOH and C60-OH were both cleared from the body at 7 d post exposure. C60-COOH was absorbed in the gastrointestinal tract following gavage exposure and distributed into the heart, liver, spleen, stomach, lungs, intestine and bone tissues. The translocation of C60-OH was more widespread than that of C60-COOH after intraperitoneal injection. CONCLUSIONS: The surface modification of fullerene C60 led to a decreased in its accumulation level and distribution rate, as well as altering its target organs. These results therefore demonstrate that the chemical functionalization of fullerene had a significant impact on its translocation and biodistribution properties. Further surface modifications could therefore be used to reduce the toxicity of C60 and improve its biocompatibility, which would be beneficial for biomedical applications.

Toxicological properties of nanomaterials.

The development of engineered nanomaterials opens tremendous opportunities for their application as therapeutic and diagnostic tools, as well as in the fields of consumer products. As the newly developed material subtype, they exhibit great activities for the high ratio of surface to total atoms. In the bio-system, the activity can render nanomaterials some negative outcomes for their unexpected deposition in organs and cells, the cellular response to the exogenous substance and the interfacial reaction with biomolecules. In this review, we have discussed the evolution of nanotoxicology studies in the past ten years mainly emerging from our laboratory. The early in vivo studies mainly focused on the biokinetic of inhaled nanoparticles and their impacts on mammal tissues, such as the central nervous system, respiratory system, cardiovascular system and so on. Then the scope extended to engineered nanomaterials used as food additives and medicines, as well as their influence on alimentary and reproductive systems. In vitro experiments to study the nanoparticle-cell interaction and nanoparticle-biomolecule interplay are indispensable to reveal the mechanisms behind the macroscopic phenomenon. In addition, novel tools such as new model organisms and synchrotron radiation-based techniques are used to facilitate our understanding of the toxicology profile of nanomaterials.

Effects of green tea powder on production performance, egg quality, and blood biochemical parameters in laying hens.

The paper aimed to evaluate the effects of dietary inclusion of green tea powder (GTP) on laying performance, egg quality, and blood biochemical parameters of laying hens. A total of 240 Jingfen No. 6 laying hens (age, 24 wk) were randomly allocated into 4 groups: control group (CON, basal diet), GTP0.5, GTP0.75, and GTP1.0 (basal diet included 0.5, 0.75, and 1.0% GTP, respectively). Each group has 5 replicates with 12 birds each. The feeding trial lasted 8 wk. The results showed that the hen-day egg production rate in GTP0.5 and GTP 0.75 group was higher than that of GTP1.0 group (P < 0.05), hen-day egg production rate in the GTP1.0 group was lower compared to the CON group (P > 0.05), the feed conversion ratio (FCR) in the GTP0.75 group was lower than that in CON and GTP 1.0 group (P < 0.05) during the entire experimental period. Albumen height and Haugh unit were higher in the GTP0.75 and GTP1.0 group compared to the CON group at d 56 (P < 0.05). At the end of experiment, plasma TG content in the GTP0.75 and GTP1.0 group was lower than that in the CON group (P < 0.05), the T-CH concentration in the GTP0.5 and GTP0.75 group was lower compared to the CON group (P < 0.05), plasma LDL-C and CORT concentrations were decreased by dietary GTP supplementation (P < 0.05), the HDL-C and BUN concentrations in the GTP0.75 and GTP1.0 group were higher than that in the CON group (P < 0.05). The antibody titers of H5N1 in the GTP0.75 and GTP1.0 group, and H7N9 in the GTP1.0 group were lower than that in the CON group (P < 0.05). In conclusion, dietary GTP inclusion could affect laying performance, regulate lipid metabolism, and have no favorable influence on antibody titers of H5N1 and H7N9, herein, dietary 0.5% GTP inclusion is suggested for Jingfen No. 6 laying hens during the peak laying period.

Surface functionalized gold nanorods: tracking and observing live cell via three optical signals.

Surface functionalized gold nanorods (GNRs) with three optical signals and the ability to track and observe live cells was investigated. The Cetyltrimethyl Ammonium Bromide (CTAB) was used as the shape-directing agent to develop GNRs with uniform size and aspect ratio. The as-synthesized GNRs can strongly enhance the Raman signal of the attached MGITC on the GNRs. Polyethylene glycol (SH-PEG-COOH) and SH-PEG-FITC were attached with GNRs through ligand exchange with CTAB. They can stabilize the GNRs, reduce the cytotoxicity and provide fluorescence signal. A cell-penetrating peptide was covalently conjugated with SH-PEG-COOH to assist the GNRs to enter living cell. After cultured with the MCF-7 cells, the surfaced functionalized Au nanorods can enter the MCF-7 cells and be tracking with enhanced MGITC Raman signal, FITC fluorescence, and Rayleigh scatter signal.

Cellular uptake, intracellular trafficking, and cytotoxicity of nanomaterials.

The interactions of nanoparticles with the soft surfaces of biological systems like cells play key roles in executing their biomedical functions and in toxicity. The discovery or design of new biomedical functions, or the prediction of the toxicological consequences of nanoparticles in vivo, first require knowledge of the interplay processes of the nanoparticles with the target cells. This article focusses on the cellular uptake, location and translocation, and any biological consequences, such as cytotoxicity, of the most widely studied and used nanoparticles, such as carbon-based nanoparticles, metallic nanoparticles, and quantum dots. The relevance of the size and shape, composition, charge, and surface chemistry of the nanoparticles in cells is considered. The intracellular uptake pathways of the nanoparticles and the cellular responses, with potential signaling pathways activated by nanoparticle interactions, are also discussed.

Sorting the unique chirality, right handed single wall carbon nanotubes via the dye modified ssDNA.

The unique (n, m) SWCNTs have both left- and right-handed helicity and they are enantiomers, and unique chiral SWCNTs with single helicity haven't achieved yet. In our studies the aromatic fluorescence molecule, (R+) 5'-Hexachloro-Fluorescein Phosphoramidite (HEX), was linked to DNA, and this new polymer could help us to get unique chiral SWCNT (11,1) with only right-handed species, and this result is confirmed by AFM, HRTEM, NIR, SRCD, and Raman studies.

Absorption of Carbon-13 Labelled Fullerene (C60) on Rice Seedlings and Effect of Phytohormones on Growth.

This study explores the effects of nanomaterials in rice seedlings using carbon 13 (13C)-labelled fullerene (C60). The experiment consisted of three groups, one CK and two nano particle groups with C60: 100 mg L-1 and 20 mg L-1. Mass spectrometry indicated higher 13C abundances in the nano particle groups compared with the CK. The 13C abundances of the 20 mg L-1 group, 100 mg L-1 group and CK were 1.0718%, 1.0715% and 1.0704%, respectively. We analyzed phytohormone concentrations in the rice at harvest time. Decreases in the concentrations of dihydrozeatin riboside (23% and 18% for the 20 mg L-1 and 100 mg L-1 group, respectively), zeatin riboside (23% and 18%, respectively), abscisic acid (11.1% and 12.7%, respectively), brassinolide (12.9% and 13.1%, respectively) and gibberellic acid 4 (12.9% and 13.1%, respectively) were observed compared with the CK. The gibberellic acid 3 concentrations in the 20 mg L-1 and 100 mg L-1 group increased by 12% and 7% compared with the CK, respectively. The methyl jasmonate concentration in the 100 mg L-1 group increased by 19.4% compared with the CK. The concentration of indole-3-acetic acid in the 100 mg L-1 group decreased by 13.5% compared with the CK. There was no change on isopentenyl adenosine concentration. This study indicates that C60 can be absorbed by rice and its effect on the growth of rice via phytohormones, including ABA, IAA, IPA, BR, GA3, GA4, DHZR, ZR and JA-ME. The results showed that, under the treatments of C60 NMs, the contents of some phytohormone in rice were decreased in comparison with CK.

Transmembrane delivery of aggregated [Gd@C82(OH)22]n nanoparticles.

We investigated whether multi-hydroxyl metallofullerenes can penetrate into erythrocyte and whether this potential transmembrane delivery requires aggregated nanostructure of these particles. The metal atom encapsulated in metallofullerenes was used as a quantitative marker to investigate body distribution of aggregated nanoparticles in cytomembrane and cytoplasm. Image of atomic force microscopy (AFM) and assay of inductively coupled plasma-mass spectrometry (ICP-MS) suggested that aggregated [Gd@C82(OH)22]n particles traversed through cytomembrane into cytoplasm. Aggregated Gd nanostructure belonged to small sphere with average diameter of 22.4 +/- 0.5 nm. For pristine Gd@C82 molecule, due to the electron donation from Gd atom, the distribution of electrons on the surface of carbon cage was localized. The electrophilic additive reaction of polyhydroxyl on the surface of Gd@C82 was directly affected by local distribution of electrons. This resulted in local distribution of hydroxyls on the surface of Gd nanoparticles. Local distribution of hydroxyls brought about polar and nonpolar domains on particle surface, which induced Gd@C82(OH)22 to be amphiphilic molecule with due hydrophilic and hydrophobic properties. Amphiphilic properties of these molecules promoted their mutual aggregation in water. In the process of aggregation, amphiphilic properties of aggregated nanoparticles were well maintained, and besides, hydrophilic and hydrophobic domains were also regularly distributed on the surface of [Gd@C82(OH)22]n particles. The amphiphilic nanoparticles attached externally to cytomembrane of erythrocyte might be effectively driven by hydrophobic effect when they directly contacted cytomembrane of erythrocyte. The number of [Gd@C82(OH)22]n nanoparticles attached to cytomembrane reached up to a certain critical threshold, a significant curvature tension of membrane would occur. The shape of cell was accordingly changed. Increased membrane tension triggered the sudden opening of specific pores as a result of cytmembrane response to nanoparitcle effect and the [Gd@C82(OH)22]n nanoparticles gained entry to cell via these pores. This process was biologically independent of caveolar-mediated endocytosis or transportation pathway via ion channels.

Ag nanoparticles coated SWCNT with surface enhanced Raman scattering (SERS) signals.

We report here a simple method to fabricate the silver nanoparticles (AgNPs) coated DNA-SWCNTs that give SERS signals. Dynamic light scattering (DLS), atomic force microscopy (AFM), and high resolution transmission electron microscopy (HRTEM) suggested the products are dispersive and soluble in aqueous solution. The Raman scattering spectra show AgNPs coated SWCNTs have enhanced the Raman signal when compared with pure SWCNT. From the radial breathing mode (RBM) of the Raman spectra, we can disclose that this DNA-SWCNT has unique chirality, which implies that it could be a good nanoprobe for cell marking.

Toxicity of graphene oxide to naked oats (Avena sativa L.) in hydroponic and soil cultures.

Graphene nanomaterials are emerging environmental pollutants and their toxicity to plants requires careful investigation in environmental matrixes. Actually, the transportation of graphene in hydroponic systems is completely different to that in soil, which might affect the interaction between graphene and plants. In this study, we compared the toxicity of graphene oxide (GO) to naked oats (Avena sativa L.) in hydroponic and soil cultures. Serious toxicity of GO was only observed in hydroponic culture. GO induced the inhibition of biomass gain, seedling length and photosynthesis of naked oats. The root structure was disturbed by GO and oxidative stress was aroused in the root. In contrast, the soil (vermiculite) interacted strongly with GO and restricted the transportation of GO in soil. This reduced the contact between GO and the roots and largely alleviated its toxicity. Our results collectively suggested that environmental biosafety evaluation should consider the impact of environmental behaviors of nanomaterials to better reflect the real bioeffect of nanomaterials.

Hydrogel-thickened microemulsion for topical administration of drug molecule at an extremely low concentration.

In this work, a hydrogel-thickened microemulsion (HTM) was investigated for delivering an extremely low concentration of drug molecule. The pseudo-ternary phase diagrams were constructed using isopropyl myristate (IPM), Tween 80, propylene glycol and water. The various HTM were prepared and characterized. We described that HTM has the combination of o/w microstructure of microemulsion and the three-dimensional gel network of hydrogel in continuous phase using transmission electron microscope. The stability tests showed that HTM had good stability. The influence of the addition of hydrogel into microemulsions on the viscosity and permeation ability is investigated. The abilities of HTM to deliver an extremely low concentration of triptolide as a model drug were evaluated using the in vitro permeation studies. The permeation rates of triptolide from various HTM were 2.2-3.6 times over that from the control hydrogel. The addition of 2% menthol into HTM consisting of 3% IPM, 30% Tween 80, 15% propylene glycol, 0.75% carbomer 940 resulted in the highest permeation rate of 0.105+/-0.006microcm(-2)h(-1), which was 5.8 times over control gel. The powerful permeation enhancing ability of HTM with a suitable viscosity makes it promising alternative carrier for transdermal administration of drug molecule at an extremely low concentration.

Podophyllotoxin-loaded solid lipid nanoparticles for epidermal targeting.

The purpose of this study was to evaluate solid lipid nanoparticles as the topical carrier for epidermal targeting of podophyllotoxin (POD). The high pressure homogenization was employed to prepare drug-loaded solid lipid nanoparticles. The POD-loaded SLN stabilized by 0.5% poloxamer 188 and 1.5% soybean lecithin (P-SLN) and 2% polysorbate 80 (T-SLN) was characterized by photon correlation spectroscopy (PCS). P-SLN showed an average diameter of 73.4 nm and a zeta potential of -48.36 mV. The imaging of AFM indicated that the P-SLN had a spherical shape. DSC and X-ray diffraction analysis showed that POD was dispersed in SLN in an amorphous state. The in vitro permeation study showed that P-SLN increased the accumulative amount of POD in porcine skin 3.48 times over 0.15% tincture. But T-SLN with a diameter of 123.1 nm and a zeta potential of -17.4 mV did not show a high accumulative amount of POD when compared with P-SLN, though both P-SLN and T-SLN could avoid the systemic uptake of POD. Because of the fluorescence property of POD, fluorescence microscopy imaging was employed to visualize the penetration of POD into skin from SLN. The penetration of POD from P-SLN seemed to follow two pathways along the stratum corneum and hair follicle route. The imaging revealed that P-SLN had a strong localization of POD within epidermis. The penetration of P-SLN with low particle size into stratum corneum along the skin surface 'furrow' and the consequent controlled release of POD might lead to the epidermal targeting. P-SLN provides a good epidermal targeting effect and may be a promising carrier for topical delivery of POD.