石墨烯纳米材料对哺乳动物的毒性及其作用机制

石墨烯是一种新兴纳米材料,具有独特的电学和光学性质、超大的比表面积以及潜在的生物相容性,在材料和电子产业、能源、环境以及生物医学等领域得到广泛应用。与此同时,石墨烯的环境行为和生物毒性也随之引起日益广泛的关注。本文通过对石墨烯纳米材料的生物毒性、细胞毒性、毒性影响因素和毒性机制等相关研究进展进行总结。石墨烯纳米材料可通过气管滴注、吸入、静脉注射、腹腔注射以及口服等方式进入体内,通过机械屏障、血脑屏障和血液胎盘屏障等积累在肺、肝、脾等部位引起急性或者慢性损伤;目前有关石墨烯毒性机制的研究主要集中于线粒体损伤、DNA损伤、炎性反应、凋亡等终点及氧化应激参与的复杂信号通路,不同石墨烯纳米材料的浓度、尺寸、表面结构和官能团等对石墨烯的生物毒性影响不同。鉴于当前该领域研究的局限性,对石墨烯纳米材料生物毒性研究的发展方向进行了展望,进而为石墨烯材料的安全应用提供理论借鉴和实践参考。     

石墨烯纳米材料对哺乳动物的毒性及其作用机制

石墨烯是一种应用广泛的新兴非金属纳米材料，具有独特的电学机械性能、超大的比表面积以及潜在的生物相容性，在材料、电子、能源、光学以及生物医学等领域得到广泛应用。与此同时，石墨烯的环境行为和生物毒性也随之引起日益广泛的关注。本文通过对石墨烯纳米材料的动物毒性、细胞毒性、毒性影响因素和毒性机制等相关研究进展进行总结。石墨烯纳米材料可通过气管滴注、吸入、静脉注射、腹腔注射以及口服等方式进入体内，通过机械屏障、血脑屏障和血液胎盘屏障等积累在肺、肝、脾等部位引起急性或者慢性损伤；目前有关石墨烯毒性机制的研究主要集中于线粒体损伤、DNA损伤、炎性反应、凋亡等终点及氧化应激参与的复杂信号通路，不同石墨烯纳米材料的浓度、尺寸、表面结构和官能团等对石墨烯的生物毒性影响不同。鉴于当前该领域研究的局限性，对石墨烯纳米材料生物毒性研究的发展方向进行了展望，进而为石墨烯材料的安全应用提供理论借鉴和实践参考。     

氧化石墨烯抗菌性及生物安全性研究进展

氧化石墨烯是一种表面有丰富含氧官能团的石墨烯衍生物,具有与石墨烯相似的二维蜂窝状晶格结构,从而导致了其具有电学、光学、力学特性和良好的生物相容性,被广泛应用于材料学、生物医学和药物传递等诸多领域。因氧化石墨烯日益增多的生产和使用,其在空气、水和土壤中大量积累,引发了人们对其生物安全性的高度关注。以微生物、陆生动植物和水生动植物为分类标准,综述了近几年氧化石墨烯对微生物、动物和植物的毒性影响,总结并分析了三者的毒性机理,比较了不同生存环境下其对动植物毒性影响的不同,旨在更加全面地揭示氧化石墨烯的生物安全性,为氧化石墨烯安全使用剂量和其功能化应用提供一定的参考。     

石墨烯在环境有机污染物分析中的应用进展

石墨烯是一种全部由碳六元环构成的新型二维碳纳米材料.从2004年发现至今,其在能源、电子、复合材料、生物医学等领域中的应用都取得了重大研究进展.近年来,石墨烯在分析化学领域也表现出了巨大的应用潜力,尤其是在环境有机污染物分析方面,涌现了大量相关报道.本文简要回顾了近期石墨烯在环境有机污染物分析中的应用情况,涵盖了样品前处理、色谱、传感器、质谱等不同的技术方向,并对石墨烯在环境分析中的应用前景进行了展望.     

氧化石墨烯纳米材料的制备及其对Eu(Ⅲ)吸附性能

通过改良的Hummers法制备了氧化石墨烯纳米材料,用于水中核素的吸附.通过调节氧化剂用量,改变了氧化石墨烯的微观结构进而获得了良好的核素吸附性能.研究发现随着氧化剂用量的提高,氧化石墨烯结构的无序度逐渐增大,结构层缺陷增多,晶面间距增加,微晶尺寸减少,氧化石墨烯片层出现褶皱.静态单核素吸附实验表明,氧化石墨烯对核素有着良好的吸附效果,高氧化度的氧化石墨烯纳米材料对Eu(Ⅲ)的吸附性能良好,最大吸附容量为76.46 mg·g~(-1),吸附规律更接近于Langmuir模型.此外,本文还对氧化石墨烯的吸附动力学、固液比影响进行了研究.研究结果表明,氧化石墨烯在核电厂放射性废水的处理方面具有广阔的应用前景.     

氧化石墨烯对水环境中金属离子的吸附作用研究进展

氧化石墨烯是一种具有2D晶型独立片层结构的新型碳纳米材料,其厚度仅为一个碳原子的高度.由于其具有吸附率高、易制得、可生物降解和可回收再利用等特点,近年来在水处理研究中受到越来越多的关注.本文围绕氧化石墨烯的结构和性质,阐述了氧化石墨烯对水环境中金属离子的主要吸附机制,讨论并总结了影响氧化石墨烯吸附能力的主要环境因素,并对氧化石墨烯的应用前景及研究趋势进行了展望.     

氧化石墨烯纳米颗粒在饱和砂土中的迁移特性

氧化石墨烯纳米颗粒在饱和砂土中的迁移特性氧化石墨烯是近年来科学界研究的热点之一,由于其独特的物理化学性质,使得它在材料、能源、工程、生物医学等领域引起了广泛的关注.氧化石墨烯一个很重要的特性就是含有大量的羟基、羧基、环氧基等含氧官能团(p Ka从4.3到9.8),使得它具有很好的水溶性和稳定性;相对于其他碳纳米颗粒(如碳纳米管、C60),氧化石墨烯纳米颗粒(GONPs)具有更强的迁移特性,随着其产量的增加,必然会导致在环境中的释放,从而产生一系列环境问题.因此研究     

碳纳米材料在环境中的转化

碳纳米材料主要包括富勒烯、碳纳米管和石墨烯.随着碳纳米材料的研究和应用范围不断扩大,其对环境的影响和在环境中的行为也逐渐受到关注,而在环境中的转化是环境行为的一个重要方面.首先,环境转化会改变碳纳米材料的性质,从而影响其它行为如聚集沉降和生态毒性.同时,作为一种以碳为骨架的材料,能否被自然界转化、从而进入碳循环是评价碳纳米材料长期环境影响的必要信息.因此,本文重点总结了碳纳米材料在自然环境条件和水处理条件下可能发生的生物或非生物转化,并分析影响碳纳米材料转化的因素,和转化过程对其环境行为的影响.     

氧化石墨烯的环境行为和毒性效应研究进展

由于具有优异的光学、力学、电学特性,氧化石墨烯纳米材料被广泛应用于传感、航空航天、新能源、疾病诊断等方面。随着氧化石墨烯的大量生产和广泛应用,其对环境的健康风险也日益引起关注。阐明氧化石墨烯的潜在毒性效应及其作用机制,对于科学客观评价其对人体和生态环境健康风险具有十分重要的意义。文章在总结了纳米氧化石墨烯在不同环境介质中的迁移、转化行为基础上、系统综述了氧化石墨烯对水生生物、陆生植物、大鼠以及微生物的毒害效应并探讨了氧化石墨烯生物毒害效应的可能机制。研究发现,氧化石墨烯在环境介质中主要形成稳定胶体且具有难以降解和易于多介质间迁移等特点;同时,氧化石墨烯还可以进入藻类、鱼类、植物、大鼠以及微生物细胞内并引起氧化应激反应导致炎症发生、多种细胞器损伤和组织器官形态异常。此外,研究还发现纳米氧化石墨烯还会导致DNA氧化损伤和DNA断裂等遗传毒性和诱导生殖毒性相关的小RNA异常表达。因此,对不同环境介质中纳米氧化石墨烯的环境行为和毒性效应进行深入研究具有十分重要的意义。今后可在纳米氧化石墨烯的暴露定量分析,纳米氧化石墨烯与生物大分子间的交互作用及长期低剂量下纳米氧化石墨烯的毒性效应3个方面加强研究。文章可为进一步阐明氧化石墨烯的健康风险提供理论参考。     

磺化石墨烯对小麦幼苗生长及生理生化指标的影响

随着石墨烯生产量和使用量的不断增大,其对生态环境的风险逐渐引起了环境学家的关注。采用水培试验,探究了磺化石墨烯(SGO)对小麦幼苗的生长、抗氧化酶活性及脂质过氧化的影响。结果表明:在培养10 d后,低浓度磺化石墨烯对小麦根系的生长有显著促进作用(P0.05),200 mg·L-1浓度处理与对照处理相比提高了84.3%,随着浓度增加促进作用逐渐减弱,1 000 mg·L-1时与对照相比提高了19.9%。但对小麦地上部的生长没有影响。磺化石墨烯处理的小麦幼苗根系和叶片组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)及丙二醛(MDA)都呈现先下降后上升的趋势。当磺化石墨烯浓度低于200 mg·L-1时,处理组小麦抗氧化酶的活性及MDA含量相对于对照处理大都有所降低,说明低浓度时磺化石墨烯没有对小麦的生长产生氧化胁迫,这与磺化石墨烯可能具有一定的抗氧化能力有关,而高浓度时由于产生氧化胁迫使各项生理生化指标逐渐上升。本实验结果为石墨烯材料对植物的毒理学研究提供了基础数据。     

Exigency for fusion of graphene and carbon nanotube with biomaterials

Biomaterial industry is a widely growing field that is closely related to advanced materials. With development in fabrication techniques new materials are being created by researchers daily. The currently used biomaterials for biomedical applications have some limitations. This review examines those limitations such as corrosion, short fatigue life, less wear resistance, and inadequate mechanical properties. These limitations may lead to adverse effects. To overcome these limitations carbon-based nanomaterials may be incorporated such that these biomaterials reach the level of ideal biomaterials. Upgrade of biomaterials with graphene and carbon nanotubes (CNTs) needs to be done only after checking the safety profile of these materials. Biocompatibility of functionalized graphene and CNT is found to be adequate for the use in many applications such as drug delivery, biosensing and imaging, cancer therapeutics, and tissue regeneration whereas pristine graphene and CNT may produce adverse effects. The potential of carbon-based nanomaterials and graphene (and its derivatives) in overcoming those limitations and enhancing biological activities of ongoing biomaterials by acting as composites and coating material is examined. In addition, nanomaterials employ new techniques in biomedical application such as cancer therapy for more efficient results.     

石墨烯对高等植物幼苗的毒性及机理探究

随着石墨烯产品的广泛应用和潜在的环境释放,其对生态环境的影响已引起广泛关注。为探讨石墨烯对高等植物生长的影响,探究了其对黄瓜幼苗和玉米幼苗生长的影响及其致毒机理。结果表明,水培条件下,不同浓度的石墨烯(10、50、100、500、1 000和2 000 mg·L~(-1))处理植物幼苗15 d后,对植物幼苗的生长具有抑制作用。且随着处理时间和石墨烯浓度的增加,植物幼苗生长的所有指标,包括根/地上部鲜重和干重、根长、根尖数、株高和叶面积均相应降低。另外,黄瓜幼苗比玉米幼苗对石墨烯更加的敏感。进一步研究发现,石墨烯与黄瓜幼苗根部直接接触导致的物理损伤、氧化损伤,以及营养耗竭是其致毒机理。而石墨烯对玉米幼苗的致毒机理包括物理损伤和营养耗竭。本研究为石墨烯的环境风险评价提供了基础数据。     

One-step ball milling-prepared nano Fe2O3 and nitrogen-doped graphene with high oxygen reduction activity and its application in microbial fuel cells

• Nano Fe₂O₃ and N-doped graphene was prepared via a one-step ball milling method. • The maximum power density of Fe-N-G in MFC was 390% of that of pristine graphite. • Active sites like nano Fe₂O₃, pyridinic N and Fe-N groups were formed in Fe-N-G. • The improvement of Fe-N-G was due to full exposure of active sites on graphene. Developing high activity, low-cost and long durability catalysts for oxygen reduction reaction is of great significance for the practical application of microbial fuel cells. The full exposure of active sites in catalysts can enhance catalytic activity dramatically. Here, novel Fe-N-doped graphene is successfully synthesized via a one-step in situ ball milling method. Pristine graphite, ball milling graphene, N-doped graphene and Fe-N-doped graphene are applied in air cathodes, and enhanced performance is observed in microbial fuel cells with graphene-based catalysts. Particularly, Fe-N-doped graphene achieves the highest oxygen reduction reaction activity, with a maximum power density of 1380±20 mW/m² in microbial fuel cells and a current density of 23.8 A/m² at –0.16 V in electrochemical tests, which are comparable to commercial Pt and 390% and 640% of those of pristine graphite. An investigation of the material characteristics reveals that the superior performance of Fe-N-doped graphene results from the full exposure of Fe₂O₃ nanoparticles, pyrrolic N, pyridinic N and excellent Fe-N-G active sites on the graphene matrix. This work not only suggests the strategy of maximally exposing active sites to optimize the potential of catalysts but also provides promising catalysts for the use of microbial fuel cells in sustainable energy generation.     

Carbon nanotube- and graphene-based advanced membrane materials for desalination

The development of membrane-based desalination and water purification technologies offers new alternatives to meet the global freshwater demand. Rapid advancement in carbon nanotube-based and graphene-based nanomaterials has drawn the attention of scientific investigators on various desalination technologies. These nanomaterials indeed offer advantageous structure, size, shape, porosity and mass transport behavior for membrane separation process. This article  reviews theoretical and experimental investigations of carbon nanotube- and graphene-based composite materials for desalination. Special attention is given to the simulation of molecular transport through these materials. Further, recent advances in the application of functionalization of carbon nanotube- and graphene-based materials for salt rejection and hydraulic permeation properties are discussed.     

Interaction of carbonaceous nanomaterials with wastewater biomass

Increasing production and use of carbonaceous nanomaterials (NMs) will increase their release to the sewer system and to municipal wastewater treatment plants. There is little quantitative knowledge on the removal of multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), or few-layer graphene (FLG) from wastewater into the wastewater biomass. As such, we investigated the quantification of GO and MWCNTs by UV-Vis spectrophotometry, and FLG using programmable thermal analysis (PTA), respectively. We further explored the removal of pristine and oxidized MWCNTs (O-MWCNTs), GO, and FLG in a biomass suspension. At least 96% of pristine and O-MWCNTs were removed from the water phase through aggregation and 30-min settling in presence or absence of biomass with an initial MWCNT concentration of 25 mg·L⁻¹. Only 65% of GO was removed with biomass concentration at or above 1,000 mg·L⁻¹ as total suspended solids (TSS) with the initial GO concentration of 25 mg·L⁻¹. As UV-Vis spectrophotometry does not work well on quantification of FLG, we studied the removal of FLG at a lower biomass concentration (50 mg TSS·L⁻¹) using PTA, which showed a 16% removal of FLG with an initial concentration of 1 mg·L⁻¹. The removal data for GO and FLG were fitted using the Freundlich equation (R² = 0.55, 0.94, respectively). The data presented in this study for carbonaceous NM removal from wastewater provides quantitative information for environmental exposure modeling and life cycle assessment.     

Ammonia adsorption on graphene and graphene oxide: a first-principles study

Motivated by the recent realization of graphene sensor to detect gas molecules that are harmful to the environment, the ammonia adsorption on graphene or graphene oxide (GO) was investigated using first-principles calculation. The optimal adsorption and orientation of the NH₃ molecules on the graphene surfaces were determined, and the adsorption energies (E _b) as well as the Mulliken charge transfers of NH₃ were calculated. The E _b for the graphene are small and seem to be independent of the sites and orientations. The surface epoxy or hydroxyl groups can promote the adsorption of NH₃ on the GO; the enhancement of the E _b for the hydroxyl groups is greater than that for the epoxy groups on the surface. The charge transfers from the molecule to the surfaces also exhibit the same trend. The Brönsted acid sites and Lewis acid sites could stably exist on the GO with surface hydroxyl groups and on the basal, respectively.     

石墨烯与抑癌基因p53 DNA片段相互作用的分子模拟与光谱学验证

石墨烯(graphene,G)及其衍生物由于具有独特的理化性质,被广泛应用于能源、生物医学等领域,但尚缺乏其对生物体和环境潜在危害的研究。采用分子动力学模拟并结合光谱学方法(紫外可见吸收光谱、紫外变温实验及荧光光谱),分析了石墨烯与抑癌基因p53启动子区DNA片段(p53-DNA)间的相互作用,并探讨了相关作用机制。石墨烯的部分芳香环与p53-DNA碱基的芳香环之间存在π-π堆积作用,两者可以通过嵌插作用进行结合,同时还通过沟槽作用进一步结合。光谱实验进一步证实,在石墨烯作用下,p53-DNA的熔点(Tm)值升高,EB-DNA体系发生静态荧光淬灭,说明石墨烯能与p53-DNA结合;同时,p53-DNA与石墨烯结合后在260 nm处的吸光度升高,说明石墨烯对p53-DNA的双螺旋结构具有一定的破坏作用。上述研究结果从分子水平上分析了石墨烯与p53-DNA间的相互作用机制,有助于进一步阐明石墨烯的毒性作用机理。