纳米科技与纳米木材学的发展方向

纳米科技是21世纪知识创新和技术创新的源泉,纳米木材学是纳米科技与木材科学交叉融合的必然产物.提出了纳米木材学的研究领域和发展方向.     

Chitin Research Revisited

Two centuries after the discovery of chitin, it is widely accepted that this biopolymer is an important biomaterial in many aspects. Numerous studies on chitin have focused on its biomedical applications. In this review, various aspects of chitin research including sources, structure, biosynthesis, chitinolytic enzyme, chitin binding protein, genetic engineering approach to produce chitin, chitin and evolution, and a wide range of applications in bio- and nanotechnology will be dealt with.     

Biogenic Synthesis of Copper Nanoparticles Using Bacterial Strains Isolated from an Antarctic Consortium Associated to a Psychrophilic Marine Ciliate: Characterization and Potential Application as Antimicrobial Agents

In the last decade, metal nanoparticles (NPs) have gained significant interest in the field of biotechnology due to their unique physiochemical properties and potential uses in a wide range of applications. Metal NP synthesis using microorganisms has emerged as an eco-friendly, clean, and viable strategy alternative to chemical and physical approaches. Herein, an original and efficient route for the microbial synthesis of copper NPs using bacterial strains newly isolated from an Antarctic consortium is described. UV-visible spectra of the NPs showed a maximum absorbance in the range of 380–385 nm. Transmission electron microscopy analysis showed that these NPs are all monodispersed, spherical in nature, and well segregated without any agglomeration and with an average size of 30 nm. X-ray powder diffraction showed a polycrystalline nature and face centered cubic lattice and revealed characteristic diffraction peaks indicating the formation of CuONPs. Fourier-transform infrared spectra confirmed the presence of capping proteins on the NP surface that act as stabilizers. All CuONPs manifested antimicrobial activity against various types of Gram-negative; Gram-positive bacteria; and fungi pathogen microorganisms including Escherichia coli, Staphylococcus aureus, and Candida albicans. The cost-effective and eco-friendly biosynthesis of these CuONPs make them particularly attractive in several application from nanotechnology to biomedical science.     

纳米技术在生物医学中的研究进展

20世纪80年代开始研究的纳米技术在90年代获得了突破性进展,它给许多行业带来巨大变化,它对生物医学的渗透与影响是显而易见的.利用纳米技术可将生物降解性和生物相容性的聚合物与药物一起制成纳米药物,作为靶向药物制剂,直接导入病灶部位的器官、组织甚至细胞,达到提高药物疗效,降低毒性的作用;将纳米材料作为药物载体,可增加某些药物的胃肠吸收,提高其生物利用度;将纳米材料作为载体,可用于基因的输送和治疗.文章就纳米技术在生物医学中的研究进展做一综述.     

纳米技术在种子生产、加工与处理中的应用

种子是农业生产的第一要素,优质的种子是农业可持续发展的基础。综述了纳米技术在作物育种和种子加工与处理等方面的应用。纳米技术尚处于发展初期,未来的发展潜力巨大,但也存在一定的不确定性风险,选择安全可靠的纳米技术,对于种业的发展意义重大。     

纳米技术在寄生虫学中的应用

纳米技术是20世纪80年代新兴发展起来的核心信息技术,广泛应用于生命医学、光电化工等领域。纳米技术与寄生虫病的试剂仪器诊断、药物治疗及疫苗防控环节有机结合,全面应用于纳米金标检测试纸条、试剂盒和仪器设备、纳米载体靶向驱虫药物、新型纳米疫苗佐剂的研发制备等方面,深入渗透到医学领域并广泛应用到寄生虫学中。作者着眼于当前纳米技术在寄生虫学中的应用,重点阐述了其在寄生虫病的检测诊断、驱虫药物和疫苗佐剂中的应用情况,包括胶体金标记免疫亲和层析、微粒材料合成、生物传感等纳米技术在寄生虫病检测诊断中的应用,总结了新型纳米驱虫药物脂质载体、化学合成药、草本中药研发的进展,并对疫苗佐剂研发中的热点,如纳米脂质体、聚合物颗粒、细胞因子的相关进展进行了概述。本文旨在为纳米技术在寄生虫学中的深入应用和研究提供参考。     

Novel impacts of nanoparticles on soil properties: tensile strength of aggregates and compression characteristics of soil

Nanoparticles (NPs) affect most soil properties but there have been no assessments of their effects on the compression behavior of soil and the strength of aggregates. Therefore, we assessed the impact of NPs on the bulk density and the confined compression and tensile strength of aggregates of a calcareous loamy soil. Using a factorial design, we assessed the effects of two factors on the soil properties, i.e., NP type (first factor) at two levels comprising Fe nano-oxide (Fe₃O₄, N₁) and Mg nano-oxide (MgO, N₂), and treatment amount (second factor) at four levels with dry mass percentages of 0%, 1%, 3%, and 5%. The soil bulk density increased with the Fe level but decreased with the Mg level in ranges of 0.02–0.04 and 0.02–0.08 g cm^–3, respectively. The compression curve characteristics were not affected by the NPs. Compared with N₁, the N₂ treatment significantly increased the soil void ratio in 86% of the applied stresses. N₁ also significantly enhanced the soil tensile strength at suctions of 30, 100, and 1500 kPa, ranging from 0.5 to 15.3 kPa. The 3% Mg and 1% Fe dosages of nano-oxides had the optimal effects, so they should be considered in future investigations.     

The effect of metal-containing nanoparticles on the health,performance and production of livestock animals and poultry

The application of high doses of mineral feed additives in the form of inorganic salts increases the growth performance of animals, but at the same, due to their low bioavailability, can contaminate the environment. Therefore, there is a need to find a replacement of administering high doses of minerals with an equally effective alternative. The application of lower doses of metal-containing nanoparticles with the same effect on animal production could be a potential solution. In the present review, zinc, silver, copper, gold, selenium, and calcium nanoparticles are discussed as potential feed additives for animals. Production of nanoparticles under laboratory conditions using traditional chemical and physical methods as well as green and sustainable methods – biosynthesis has been described. Special attention has been paid to the biological properties of nanoparticles, as well as their effect on animal health and performance. Nano-minerals supplemented to animal feed (poultry, pigs, ruminants, rabbits) acting as growth-promoting, immune-stimulating and antimicrobial agents have been highlighted. Metal nanoparticles are known to exert a positive effect on animal performance, productivity, carcass traits through blood homeostasis maintenance, intestinal microflora, oxidative damage prevention, enhancement of immune responses, etc. Metal-containing nanoparticles can also be a solution for nutrient deficiencies in animals (higher bioavailability and absorption) and can enrich animal products with microelements like meat, milk, or eggs. Metal-containing nanoparticles are proposed to partially replace inorganic salts as feed additives. However, issues related to their potential toxicity and safety to livestock animals, poultry, humans, and the environment should be carefully investigated.     

Zinc delivery to plants through seed coating with nano-zinc oxide particles

In India, zinc (Zn) has been recognized as the fourth most important yield-limiting nutrient after nitrogen (N), phosphorus (P) and potassium (K). Supplementing the zinc (Zn) requirement of agricultural crops through water soluble zinc sulfate ZnSO₄ fertilizer is a costly management option whereas, utilization of ZnO (water insoluble and a cheaper material) as a source of Zn could be an alternative cost effective option to encourage farmers for wider adoption. In this present investigation, in order to supply the requisite amount of Zn to the plants, a protocol has been developed to coat the seeds of maize (Zea mays L.), soybean (Glycine max L.), pigeon pea (Cajanas cajan L.) and ladies finger (Abelmoschus esculentus L.) with microns scale (<3 µm) and nano-scale (<100 nm) ZnO powder at 25 mg Zn/g seed and at 50 mg Zn/g seed. Different Zn sources, ethyl alcohol, and crude pine oleoresin (POR) were used for coating of seeds. The germination test carried out with coated and uncoated seeds indicated better germination percentage (93–100%) due to ZnO coating as compared to uncoated seeds (80%). Pot culture experiment conducted with coated seeds also revealed that the crop growth with ZnO coated seeds were similar to that observed with soluble Zn treatment applied as zinc sulfate heptahydrate (ZnSO₄·7H₂O) (at 2.5 ppm Zn) which is evident from the periodic SPAD reading taken after 20, 25, 30 and 45 days after sowing. Application of Zn through different sources also enhanced the auxin indole-3-acetic acid (IAA) production in plant roots, which subsequently improved the overall growth. The most important advantage of seed coating with ZnO (both micron/nano-scale) is that it did not exert any osmotic potential at the time of germination of the seed, thus, the total requirement of Zn of the crop can be loaded with the seed effectively through nano-scale ZnO particle.