纳米材料导论课程教学设计和教学方法探索

纳米材料导论为材料化学的专业课,讲解的是纳米材料的性质、制备、表征和应用,本课程的教学目标是使学生了解纳米材料和纳米科技的发展方向。本文结合课程和学生自身的特点及授课经验,对纳米材料导论课程的教学改革方向和措施进行初步探讨,以达到良好的授课效果,培养学生的学习热情和创新能力。     

《纳米材料》教学研究

纳米材料是纳米科技的核心和基础,在大学阶段开设纳米材料课程是培养材料科学类综合、创新性人才的必然要求。通过对《纳米材料》课程教学内容的选择、教学方法和教学手段的创新、理论教学和实践教学相结合、成绩考核方式的改革等方面进行了探索,初步建立了较完善的教学体系。这些教学研究的目的是提高教学质量,拓宽学生的知识面,增加学生的实践能力和创新能力。     

全国第二届纳米材料和技术应用会议在杭州召开

为推动我国纳米材料和技术的应用，加强从事纳米材料科技工作者和企业家之间的联系，促进纳米材料新兴产业的形成，中国材料研究学会于 ５月 ２１日～２４日在杭州市召开全国第二届纳米材料和技术应用会议，内容包括：纳米材料和技术在２１世纪的战略地位及国内外发展概述、纳米材料的应用机遇和纳米材料产业化趋势、特种纳米粉体材料的研究和应用、纳米复合材料和抗菌材料的应用等，并对产业化中的纳米粉碎分散技术、低成本技术、纳米添加技术、纳米陶瓷的高致密化技术、纳米涂层技术等关健技术问题进行了研讨。全国第二届纳米材料和技术应…     

纳米材料及其在工程塑料改性中的应用

简述纳米材料的特性，以及纳米粘土，刚性纳米粒子，碳纳米管和金属纳米粉等纳米材料在聚酰胺，聚甲醛，热塑性聚酯，聚四氟乙烯，聚酰亚胺，聚醚醚酮等通用工程塑料和特种工程塑料改性方面的研究和应用情况，着重分析了工程塑料与各种纳米材料复合的结合点，展望了工程塑料／纳米粒子复合材料的发展前景。     

以纳米二氧化钛为例浅谈纳米材料的教学

随着现代科学技术的快速发展,纳米材料不断被开发并应用于与人类生活息息相关的领域。在精细化工课程纳米材料的教学中,教师也应该与时俱进,将理论联系实际,可以纳米二氧化钛为例阐述其制各方法与应用研究,使学生深刻理解纳米技术的先进性与优越性。     

纳米材料及其技术在涂料中的应用

简介了纳米材料的基本概念和纳米复合涂料的分类，着重叙述了纳米材料在几种功能涂料中的应用情况，并提出了我国纳米复合涂料发展中现存的一些问题。     

金属表面纳米粒子/聚合物复合防腐涂层的研究进展

纳米材料（NMs）具有独特的性能，由其构成的纳米粒子/聚合物复合涂层在金属表面防腐蚀方面是非常经济有效的。本文总结了氧化物基和碳基两种不同纳米材料对纳米粒子/聚合物涂层性能的影响，概述了典型纳米粒子/聚合物复合防腐涂层防腐机理，表明碳基纳米材料可以作为提高防腐涂层阻隔性能的较有前途的纳米填料。最后展望了将纳米粒子/聚合物材料有效应用到金属表面防腐涂层中所面临的挑战和未来发展前景。     

纳米材料改性酚醛树脂研究进展

综述了近年来纳米材料改性酚醛树脂(PF)的研究现状。介绍了不同纳米材料(包括碳纳米管、纳米炭黑、纳米碳纤维、纳米金属粒子、纳米弹性粒子、纳米黏土、纳米SiO2和纳米TiO2等)对PF复合材料性能的影响。探讨了纳米材料在改性PF过程中存在的问题,并对纳米材料改性PF的发展趋势作出了展望。     

纳米材料

纳米材料是一种超细金属铁粉，作为涂料徐于飞机表面具有吸波功能，这就是隐身技术中的雷达波隐身技术。纳米材料分为纳米微粒和纳米固体两类，纳米微粒属于原子簇与宏观物体之间的过渡物质，它既不是宏观系统也不是微观系统，因而具有一定的优异特点。纳米材料自身具备的许多新奇物理和化学性质，使得它在当今与未来科学技术中将发挥重要作用，因而纳米材料有21世纪材料的美誉。纳米材料     

纳米材料改性酚醛树脂研究进展

分析了纳米材料的结构及其特点,综述了碳纳米管、纳米SiO2、纳米铜、纳米TiO2、纳米蒙脱土和纳米分子筛等纳米材料改性酚醛树脂(PF)的研究现状,探讨了纳米材料改性PF存在的问题及今后的研究方向。     

Fabrication and characterization of 1D brushite nanomaterials via sucrose ester reverse microemulsion

In the present study, 1-dimensional (1D) brushite nanomaterials were fabricated through sucrose ester based reverse microemulsion for the first time. X-ray diffraction patterns revealed that the nanomaterials possessed brushite crystal phase with trace amount of hydroxyapatite. The size and morphology of brushite crystals were governed by the changes in the aqueous-to-sucrose ester weight ratio at low initial reactant concentration, giving rise to rod-like and fibre-like 1D nanomaterials. Brushite nanorods and nanofibres with average diameters of 25.53 ± 4.60 nm (aspect ratio  6) and 76.18 ± 19.74 nm (aspect ratio  40), respectively, had been synthesized. As the reactant concentration increased, it became the key factor in controlling nucleation and crystal growth, rendering the aqueous-to-sucrose ester ratio unimportant. Formation mechanism of various morphologies of brushite crystals is postulated.     

Fluorescent Magnetic Nanoparticles for Bioimaging through Biomimetic Surface Modification

Nanostructured materials and systems find various applications in biomedical fields. Hybrid organo–inorganic nanomaterials are intensively studied in a wide range of areas, from visualization to drug delivery or tissue engineering. One of the recent trends in material science is biomimetic approaches toward the synthesis or modification of functional nanosystems. Here, we describe an approach toward multifunctional nanomaterials through the biomimetic polymerization of dopamine derivatives. Magnetite nanoparticles were modified with a combination of dopamine conjugates to give multifunctional magneto-fluorescent nanocomposites in one synthetic step. The obtained material showed excellent biocompatibility at concentrations up to 200 μg/mL and an in vivo biodistribution profile typical for nanosized formulations. The synthesized systems were conjugated with antibodies against HER2 to improve their selectivity toward HER2-positive cancer cells. The produced material can be used for dual magneto-optical in vivo studies or targeted drug delivery. The applied synthetic strategy can be used for the creation of various multifunctional hybrid nanomaterials in mild conditions.     

Metabolomic effects of CeO<Subscript>2</Subscript>, SiO<Subscript>2</Subscript> and CuO metal oxide nanomaterials on HepG2 cells

Background

To better assess potential hepatotoxicity of nanomaterials, human liver HepG2 cells were exposed for 3 days to five different CeO₂ (either 30 or 100 μg/ml), 3 SiO₂ based (30 μg/ml) or 1 CuO (3 μg/ml) nanomaterials with dry primary particle sizes ranging from 15 to 213 nm. Metabolomic assessment of exposed cells was then performed using four mass spectroscopy dependent platforms (LC and GC), finding 344 biochemicals.

Results

Four CeO₂, 1 SiO₂ and 1 CuO nanomaterials increased hepatocyte concentrations of many lipids, particularly free fatty acids and monoacylglycerols but only CuO elevated lysolipids and sphingolipids. In respect to structure-activity, we now know that five out of six tested CeO₂, and both SiO₂ and CuO, but zero out of four TiO₂ nanomaterials have caused this elevated lipids effect in HepG2 cells. Observed decreases in UDP-glucuronate (by CeO₂) and S-adenosylmethionine (by CeO₂ and CuO) and increased S-adenosylhomocysteine (by CuO and some CeO₂) suggest that a nanomaterial exposure increases transmethylation reactions and depletes hepatic methylation and glucuronidation capacity. Our metabolomics data suggests increased free radical attack on nucleotides. There was a clear pattern of nanomaterial-induced decreased nucleotide concentrations coupled with increased concentrations of nucleic acid degradation products. Purine and pyrimidine alterations included concentration increases for hypoxanthine, xanthine, allantoin, urate, inosine, adenosine 3′,5′-diphosphate, cytidine and thymidine while decreases were seen for uridine 5′-diphosphate, UDP-glucuronate, uridine 5′-monophosphate, adenosine 5′-diphosphate, adenosine 5′-monophophate, cytidine 5′-monophosphate and cytidine 3′-monophosphate. Observed depletions of both 6-phosphogluconate, NADPH and NADH (all by CeO₂) suggest that the HepG2 cells may be deficient in reducing equivalents and thus in a state of oxidative stress.

Conclusions

Metal oxide nanomaterial exposure may compromise the methylation, glucuronidation and reduced glutathione conjugation systems; thus Phase II conjugational capacity of hepatocytes may be decreased. This metabolomics study of the effects of nine different nanomaterials has not only confirmed some observations of the prior 2014 study (lipid elevations caused by one CeO₂ nanomaterial) but also found some entirely new effects (both SiO₂ and CuO nanomaterials also increased the concentrations of several lipid classes, nanomaterial induced decreases in S-adenosylmethionine, UDP-glucuronate, dipeptides, 6-phosphogluconate, NADPH and NADH).

     

Cytotoxicity screening of 23 engineered nanomaterials using a test matrix of ten cell lines and three different assays

Background

The most common causes of granulomatous inflammation are persistent pathogens and poorly-degradable irritating materials. A characteristic pathological reaction to intratracheal instillation, pharyngeal aspiration, or inhalation of carbon nanotubes is formation of epithelioid granulomas accompanied by interstitial fibrosis in the lungs. In the mesothelium, a similar response is induced by high aspect ratio nanomaterials, including asbestos fibers, following intraperitoneal injection. This asbestos-like behaviour of some engineered nanomaterials is a concern for their potential adverse health effects in the lungs and mesothelium. We hypothesize that high aspect ratio nanomaterials will induce epithelioid granulomas in nonadherent macrophages in 3D cultures.

Results

Carbon black particles (Printex 90) and crocidolite asbestos fibers were used as well-characterized reference materials and compared with three commercial samples of multiwalled carbon nanotubes (MWCNTs). Doses were identified in 2D and 3D cultures in order to minimize acute toxicity and to reflect realistic occupational exposures in humans and in previous inhalation studies in rodents. Under serum-free conditions, exposure of nonadherent primary murine bone marrow-derived macrophages to 0.5 μg/ml (0.38 μg/cm²) of crocidolite asbestos fibers or MWCNTs, but not carbon black, induced macrophage differentiation into epithelioid cells and formation of stable aggregates with the characteristic morphology of granulomas. Formation of multinucleated giant cells was also induced by asbestos fibers or MWCNTs in this 3D in vitro model. After 7-14 days, macrophages exposed to high aspect ratio nanomaterials co-expressed proinflammatory (M1) as well as profibrotic (M2) phenotypic markers.

Conclusions

Induction of epithelioid granulomas appears to correlate with high aspect ratio and complex 3D structure of carbon nanotubes, not with their iron content or surface area. This model offers a time- and cost-effective platform to evaluate the potential of engineered high aspect ratio nanomaterials, including carbon nanotubes, nanofibers, nanorods and metallic nanowires, to induce granulomas following inhalation.     

Ingested engineered nanomaterials: state of science in nanotoxicity testing and future research needs

Background

Engineered nanomaterials (ENM) are used extensively in food products to fulfill a number of roles, including enhancement of color and texture, for nutritional fortification, enhanced bioavailability, improved barrier properties of packaging, and enhanced food preservation. Safety assessment of ingested engineered nanomaterials (iENM) has gained interest in the nanotoxicology community in recent years. A variety of test systems and approaches have been used for such evaluations, with in vitro monoculture cell models being the most common test systems, owing to their low cost and ease-of-use. The goal of this review is to systematically assess the current state of science in toxicological testing of iENM, with particular emphasis on model test systems, their physiological relevance, methodological strengths and challenges, realistic doses (ranges and rates), and then to identify future research needs and priorities based on these assessments.

Methods

Extensive searches were conducted in Google Scholar, PubMed and Web of Science to identify peer-reviewed literature on safety assessment of iENM over the last decade, using keywords such as “nanoparticle”, “food”, “toxicity”, and combinations thereof. Relevant literature was assessed based on a set of criteria that included the relevance of nanomaterials tested; ENM physicochemical and morphological characterization; dispersion and dosimetry in an in vitro system; dose ranges employed, the rationale and dose realism; dissolution behavior of iENM; endpoints tested, and the main findings of each study. Observations were entered into an excel spreadsheet, transferred to Origin, from where summary statistics were calculated to assess patterns, trends, and research gaps.

Results

A total of 650 peer-reviewed publications were identified from 2007 to 2017, of which 39 were deemed relevant. Only 21% of the studies used food grade nanomaterials for testing; adequate physicochemical and morphological characterization was performed in 53% of the studies. All in vitro studies lacked dosimetry and 60% of them did not provide a rationale for the doses tested and their relevance. Only 12% of the studies attempted to consider the dissolution kinetics of nanomaterials. Moreover, only 1 study attempted to prepare and characterize standardized nanoparticle dispersions.

Conclusion

We identified 5 clusters of factors deemed relevant to nanotoxicology of food-grade iENM: (i) using food-grade nanomaterials for toxicity testing; (ii) performing comprehensive physicochemical and morphological characterization of iENM in the dry state, (iii) establishing standard NP dispersions and their characterization in cell culture medium, (iv) employing realistic dose ranges and standardized in vitro dosimetry models, and (v) investigating dissolution kinetics and biotransformation behavior of iENM in synthetic media representative of the gastrointestinal (GI) tract fluids, including analyses in a fasted state and in the presence of a food matrix. We discussed how these factors, when not considered thoughtfully, could influence the results and generalizability of in vitro and in vivo testing. We conclude with a set of recommendations to guide future iENM toxicity studies and to develop/adopt more relevant in vitro model systems representative of in vivo animal and human iENM exposure scenarios.

     

纳米复合涂层的制备和性能研究进展

综述了纳米复合涂层的制备工艺，包括热喷涂、纳米复合镀、纳米粘结粘涂技术、纳米复合涂料技术等；介绍了纳米复合涂层在提高材料力学性能、耐腐蚀性、光学、电学、磁学等方面的性能研究，展望了纳米复合涂层的发展。     

Nanostructure-based thermoelectric conversion: an insight into the feasibility and sustainability for large-scale deployment

Significant scientific progress has been achieved using nanostructured materials for thermoelectric energy harvesting and solid-state cooling through the conversion of waste heat into electricity and vice versa. However, the connection between the small-scale proof-of concept results achieved in research labs and real industrial scale manufacture is still missing. Herein we develop an analysis to determine the appropriate thermoelectric nanomaterials for the large-scale manufacture and deployment in the near future. We cover key parameters such as ZT value, cost, abundance, and toxicity. Maximum ZT values are considered at three temperature ranges. Material cost and abundance are visually demonstrated to improve ease of interpretation. Toxicity is also evaluated to minimize the environmental impact during manufacture and recycling. Lastly, a parameter termed "efficiency ratio" is calculated to give a better qualitative understanding of the feasibility and sustainability of these nanomaterials.     

纳米材料改性水性聚氨酯研究进展

综述了近几年纳米材料对水性聚氨酯的改性研究,包括天然高分子纳米材料改性、黏土矿石类纳米材料改性、纳米碳素材料改性、金属与金属氧化物纳米材料改性。化学改性能提高纳米材料与聚合物基质间的相容性,有利于得到稳定的复合乳液。物理共混改性能更好地将纳米材料的优异特性赋予复合材料。在水性聚氨酯中均匀分散的纳米粒子可以显著提高复合材料的热稳定性与力学性能。开发高效实用的纳米材料有机化改性技术和优化复合材料的制备工艺将是未来制备高性能水性聚氨酯纳米复合材料的发展趋势。     

可控式citZ基因纳米盒的设计与研究

DNA分子具有自我识别的特殊能力，DNA折纸术就是利用这一特性进行核酸纳米材料精准设计和组装的一种新技术。研究者可以利用与DNA脚手架链互补的订书钉链，将长链核酸折叠成与预设模型一致的纳米结构。DNA折纸术最早是2006年由Rothemund提出，一直以来，人们利用M13mp18单链线性DNA进行各种纳米图形的自组装。为了寻找更多的核酸材料进行DNA折纸研究，本文以枯草芽孢杆菌（Bacillus. subtilis 168）citZ基因序列为研究对象，采用改进的DAEDALUS软件，引入“锁钥”结构设计，利用“从下向上”的方法使DNA分子进行自组装，设计出三维体积为50.71nm×50.71nm×50.71nm的citZ基因纳米盒，只有遇到可识别的基因和匹配的“钥匙”时，才可能打开盖子，释放盒中的内容物。这种核酸纳米材料还可以通过调节DNA序列长度调节盒子的内部空间，有望成为一种新型的靶向药物运送载体。     

纳米材料在润滑技术中的应用

本文从微观结构、特性及应用等方面简单介绍了纳米材料，详细阐述了纳米材料作为新型润滑材料的可能性，探讨了纳米材料产生润滑作用的机理，认为纳米材料作为新型润滑材料在理论研究及应用领域都具有广阔的发展前景。