Graphene: Safe or Toxic? The Two Faces of the Medal

Graphene is considered the future revolutionary material. For its development, it is of fundamental importance to evaluate the safety profile and the impact on health. Graphene is part of a bigger family which has been identified as the graphene family nanomaterials (GFNs). Clarifying the existence of multiple graphene forms allows better understanding the differences between the components and eventually correlating their biological effects to the physicochemical characteristics of each structure. Some in vitro and in vivo studies clearly showed no particular risks, while others have indicated that GFNs might become health hazards. This Minireview critically discusses the recent studies on the toxicity of GFNs to provide some perspective on the possible risks to their future development in materials and biomedical sciences.     

无机纳米晶-生物界面作用的分子机制

无机纳米晶材料以其独特的光、电、磁、力学性质,成为疾病诊断与治疗功能的关键材料.本文总结了无机纳米晶的表面化学活性、离子释放性、晶相结构、晶格缺陷、表面吸附和表面修饰等与尺寸相关的理化性质与生物效应之间的关系.综述了无机纳米晶与蛋白质、磷脂生物膜间的界面相互作用,探讨了纳米晶-生物界面作用的分子机理.这有助于理解无机纳米晶的生物行为和毒理性质,指导设计安全、高效的纳米晶生物医学材料.     

Cytotoxicity Induction by the Oxidative Reactivity of Nanoparticles Revealed by a Combinatorial GNP Library with Diverse Redox Properties

It is crucial to establish relationship between nanoparticle structures (or properties) and nanotoxicity. Previous investigations have shown that a nanoparticle’s size, shape, surface and core materials all impact its toxicity. However, the relationship between the redox property of nanoparticles and their toxicity has not been established when all other nanoparticle properties are identical. Here, by synthesizing an 80-membered combinatorial gold nanoparticle (GNP) library with diverse redox properties, we systematically explored this causal relationship. The compelling results revealed that the oxidative reactivity of GNPs, rather than their other physicochemical properties, directly caused cytotoxicity via induction of cellular oxidative stress. Our results show that the redox diversity of nanoparticles is regulated by GNPs modified with redox reactive ligands.     

Detection of Oxidative Stress Induced by Nanomaterials in Cells—The Roles of Reactive Oxygen Species and Glutathione

The potential of nanomaterials use is huge, especially in fields such as medicine or industry. Due to widespread use of nanomaterials, their cytotoxicity and involvement in cellular pathways ought to be evaluated in detail. Nanomaterials can induce the production of a number of substances in cells, including reactive oxygen species (ROS), participating in physiological and pathological cellular processes. These highly reactive substances include: superoxide, singlet oxygen, hydroxyl radical, and hydrogen peroxide. For overall assessment, there are a number of fluorescent probes in particular that are very specific and selective for given ROS. In addition, due to the involvement of ROS in a number of cellular signaling pathways, understanding the principle of ROS production induced by nanomaterials is very important. For defense, the cells have a number of reparative and especially antioxidant mechanisms. One of the most potent antioxidants is a tripeptide glutathione. Thus, the glutathione depletion can be a characteristic manifestation of harmful effects caused by the prooxidative-acting of nanomaterials in cells. For these reasons, here we would like to provide a review on the current knowledge of ROS-mediated cellular nanotoxicity manifesting as glutathione depletion, including an overview of approaches for the detection of ROS levels in cells.     

Toxicity of superparamagnetic iron oxide nanoparticles: Research strategies and implications for nanomedicine

Superparamagnetic iron oxide nanoparticles （SPIONs） are one of the most versatile and safe nanoparticles in a wide variety of biomedical applications. In the past decades, considerable efforts have been made to investigate the potential adverse biological effects and safety issues associated with SPIONs, which is essential for the development of next-generation SPIONs and for continued progress in translational research. In this mini review, we summarize recent developments in toxicity studies on SPIONs, focusing on the relationship between the physicochemical properties of SPIONs and their induced toxic biological responses for a better toxicological understanding of SPIONs.     

Nanoantioxidants: Pioneer Types,Advantages, Limitations,and Future Insights

Free radicals are generated as byproducts of normal metabolic processes as well as due to exposure to several environmental pollutants. They are highly reactive species, causing cellular damage and are associated with a plethora of oxidative stress-related diseases and disorders. Antioxidants can control autoxidation by interfering with free radical propagation or inhibiting free radical formation, reducing oxidative stress, improving immune function, and increasing health longevity. Antioxidant functionalized metal nanoparticles, transition metal oxides, and nanocomposites have been identified as potent nanoantioxidants. They can be formulated in monometallic, bimetallic, and multi-metallic combinations via chemical and green synthesis techniques. The intrinsic antioxidant properties of nanomaterials are dependent on their tunable configuration, physico-chemical properties, crystallinity, surface charge, particle size, surface-to-volume ratio, and surface coating. Nanoantioxidants have several advantages over conventional antioxidants, involving increased bioavailability, controlled release, and targeted delivery to the site of action. This review emphasizes the most pioneering types of nanoantioxidants such as nanoceria, silica nanoparticles, polydopamine nanoparticles, and nanocomposite-, polysaccharide-, and protein-based nanoantioxidants. This review overviews the antioxidant potential of biologically synthesized nanomaterials, which have emerged as significant alternatives due to their biocompatibility and high stability. The promising nanoencapsulation nanosystems such as solid lipid nanoparticles, nanostructured lipid carriers, and liposome nanoparticles are highlighted. The advantages, limitations, and future insights of nanoantioxidant applications are discussed.     

环境中典型人工纳米颗粒物毒性效应

随着纳米技术和纳米材料在工业和生活中的大规模应用,大量的人工纳米颗粒物将不可避免地释放到环境介质(如水体、土壤、沉积物等)中。纳米颗粒物所具有的独特性质已引发人们对它们可能造成的健康风险和环境危害的关注和讨论。本文对目前环境中存在的几种主要典型人工纳米颗粒物的性质、来源、纳米毒性及影响纳米毒性的因素进行详细介绍,阐述了纳米颗粒物对生物的可能致毒机理。在分析纳米颗粒物毒性影响因素过程中,提出了纳米材料在环境中相关毒性研究展望。最后文中总结目前纳米材料在环境中的行为和毒性研究中所存在和面临的问题,并在此基础上提出将来纳米材料毒性的研究方向(如纳米材料的定量结构-活性关系,纳米材料表征技术及慢性毒性研究等)及需要改进的相关建议。     

Non-invasive Monitoring of Biochemical Response of Wheat Seedlings Toward Titanium Dioxide Nanoparticles Treatment Using Attenuated Total Reflectance Fourier Transform Infrared and Laser Induced Fluorescence Spectroscopy

Widespread commercial application of titanium dioxide nanoparticles leads to their dispersion in the environment and inevitable interaction with living organisms. Their presence necessitates the monitoring of nanoparticle interactions with plants using advanced techniques that are capable of noninvasively and sensitively estimating the changes involved in the biochemical profile. The current study aims to investigate the effects of titanium dioxide nanoparticles on biochemicals of wheat leaves using label free, nondestructive, rapid, sensitive, and advanced spectroscopic probes: laser induced fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy coupled with multivariate analysis. The fluorescence and infrared spectra of control and titanium dioxide nanoparticle treated wheat leaves were acquired in the region from 400 to 800?nm and 4000 to 485?cm^?1. The treatment of titanium dioxide nanoparticles decreases the chlorophyll content and the concentrations of cellulose, hemicellulose, xyloglucans, pectin, and lignin indicating interferences in the biosynthesis and structure of cell walls of the wheat leaves. The level of amide I, carbonyl, and methylene groups also increases following the treatment of titanium dioxide nanoparticles indicating lipid and protein peroxidation and the accumulation of carbonyl compounds. The changes in the integrated area ratios of the amide II/amide I, carbonyl/methyl, and methylene/amide II bands demonstrate disorder in the membrane integrity. This study establishes the efficiency of noninvasive, label-free, and rapid protocols based on attenuated total reflectance Fourier transform infrared and laser induced fluorescence to monitor the interactions of nanoparticles with plants at early stage of plant growth before visual signs of toxicity appear.