Nanomaterials: An Introduction
01 Jan 2021-Vol. 16, pp 1-27
Abstract: Nanotechnology offers a significant advantage in science, engineering, medicine, medical surgery, foods, packing, clothes, robotics, and computing from the beginning of the twenty-first century. As the potential scientific discovery always contains some good and bad effects on human civilization and the environment, nanotechnology is not an exception. The major drawbacks include economic disruption along with imposing threats to security, privacy, health, and environment. The introduction of the chapter discusses the historical background of nanotechnology. Later it also discusses the advancement of nanotechnology to date with its benefits. Major drawbacks of nanotechnology arise in human health due to the enormous involvement in medicine, food, agriculture, etc. This chapter also deals with environmental nano pollution and its effect on society, highlighting the social-economic disruption due to the rapid use of nanotechnology. Nano pollution affects not only human beings but also other living beings like microorganisms, animals and plants, which are briefly reviewed. This chapter also demonstrates the safety and security of nanotechnological developments, current policy and regulation status, challenges, and future trends. Finally, it is concluded, while nanotechnology offers more efficient power sources, faster and modern computers and technologies, life-saving medical treatments, but due to some negative impacts, it bounds us to think twice before any further advanced technological applications.
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TL;DR: In this article, a nanosecond pulse laser-assisted photoporation using titanium-oxide nanotubes (TNT) for highly efficient intracellular delivery has been established.
10 citations
TL;DR: In this article , the authors present diverse aptamer-functionalized hybrid nanomaterial conjugates designs and their applications for sensing and decontamination, and several isolated aptamer sequences for algal toxins are addressed in this review.
9 citations
TL;DR: In this paper , a D-shaped photonic crystal fiber sensor with 10 layers of graphene on the surface plasmon of gold is proposed for tuning refractive index (RI) sensitivity in the visible and IR regions.
Abstract: A simple design of a D-shaped photonic crystal fiber sensor with 10 layers of graphene on the surface plasmon of gold is proposed for tuning refractive index (RI) sensitivity in the visible and IR regions. The proposed structure has been simulated by optimizing the mesh size and the method of finite-difference eigenmode. By tuning the chemical potential of graphene ( μ c ), we realize tunable and enhanced RI sensing for a wide RI range from 1.35 to 1.42. The maximum wavelength sensitivities of the proposed sensor are 5200 nm/RIU, 6000 nm/RIU, and 7500 nm/RIU for μ c = 0.8 e v , 1.0 ev, and 1.2 ev, respectively. Further, sensor characteristic parameters such as amplitude sensitivity, resolution, and figure of merit have been investigated for different chemical potentials. All dramatic changes in sensor parameters show an advancement plan to control and tune RI-based optical sensors assisted by graphene.
6 citations
01 Jan 2023
TL;DR: In this paper , the authors focused on the collateral effects of the nanoparticles on the human and environmental health and proposed a method to assess and assess NP environmental effect, interactions with live creatures, and their accumulation in ecosystems.
Abstract: The development of nanotechnology in the field of agriculture and environment during recent times has significantly advanced the area and paved the way for future nanotechnologies. Though the substantial effect of the particle size on the material toxicities has been well recognized, however, the effect of the particle size on the nanoparticle behavior and reactivity is not well known. Currently, nanoparticles are used to tackle the environment pollution in terms of removal of toxins from water, soil, sewage, and air. They have also been employed in environmental instrumentation, including sensors, green nanotechnology, and greenhouse gas reduction. However, apart from these, there are some harmful effects of the nanoparticles on the environment. Therefore, using NPs in remediation treatments is not a short-term solution. However, it is critical to study and assess NP environmental effect, interactions with live creatures, and their accumulation in ecosystems. Considering all these factors, the current chapter is focused on the study of the collateral effects of the nanoparticles on the human and environmental health.
1 citations
TL;DR: In this paper , the authors have fabricated cellulose-based films hybridized with chitosan and g-C3N4 for visible light-induced removal of methylene blue and Cr (VI) ions from water.
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TL;DR: Variable degree of cell and protein response have been found based on variable film synthesis parameters but in overall, required biocompatibility has been established for all types of film-coating.
Abstract: Diamond-like nanocomposite (DLN) films consist of network structure of amorphous carbon and quartz like silicon. In the present work, DLN films have been synthesized on pyrex glass and subsequently, their biocompatibility have been investigated through primary and secondary cell adhesion, cytotoxicity, protein adsorption and murine peritoneal macrophage activation experiments. Variable degree of cell and protein response have been found based on variable film synthesis parameters but in overall, required biocompatibility has been established for all types of film-coating.
31 citations
TL;DR: In this article, microwave assisted rapid extracellular biosynthesis of silver nanoparticles was carried out by using carom seed (Trachyspermum copticum) extract as the reducing agent.
Abstract: Microwave-assisted rapid extracellular biosynthesis of silver nanoparticles was carried out by using carom seed (Trachyspermum copticum) extract as the reducing agent. The reaction mixture containing AgNO3 and carom seed extract when exposed to microwave irradiation resulted in reducing silver ions to bio-functionalized silver nanoparticles of size 6- 50 nm. The AgNP were characterized by UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Themogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR) are used to understand the possible mechanism of biosynthesis. In this study, we have also investigated the antimicrobial and antioxidant activities of bio-functionalized AgNP. The antibacterial activity is investigated by measuring the zone of inhibition and antioxidant study is done using 1,1-diphenyl-2-picryl hydrazyl (DPPH) method.
29 citations
TL;DR: Structural investigation of fucoidans is of great difficulties because of varieties of monosaccharide compositions, different types of glycosidic linkages, presence of large numbers of non-carbohydrate substituents.
Abstract: Marine algae are ancient photosynthetic organisms that constitute the largest group in the plant kingdom. They are used for functional food, cosmetic additives, supplements productions, and in traditional medicine due to taste, prophylactic, and therapeutic effects. Algae contain microelements and iodine-containing organic compounds, as well as vitamins, mannitol more than terrestrial plants.
Polysaccharides of algae are especially valuable substances. Some of them (for example agarose, carrageenans, and alginates) have found widespread application. Information about them was published a long time ago and described in detail in books. At the moment polysaccharides synthesized by brown algae (laminarans and especially fucoidans) are of greatest interest. A laminarans were found in both marine and terrestrial organisms. It should be noticed that fucoidans are truly marine polysaccharides. The general term “fucoidan” is used to integrate the molecules, differenced in composition, structure, and in degree of sulfation, acetylation, etc. (Berteau and Mulloy, 2003; Kusaykin et al., 2008). Content of fucoidans depends on the species and on the stage of development of algae and may vary from 0.1 to 20% of dry weight of algae (Mabeau et al., 1990; Zvyagintseva et al., 2003). Huge amount of reserves of fucoidans accumulate in brown algae, which grow in the seas at temperate and northern latitudes (Ermakova et al., 2011; Sokolova et al., 2011; Men'shova et al., 2012; Thinh et al., 2013). Analogs of these polysaccharides have not been found on the land till now. Fucoidans long since are attracted attention due to diverse biological activity, low toxicity, and plant origin (Berteau and Mulloy, 2003; Kusaykin et al., 2008). Last is important because of contamination and side effects of the preparation produced from animals (for example, heparin).
A large number of publications are devoted to the study of antitumor, anticoagulant, antimutagenic activities, and immunostimulatory, antiinfective and antioxidant properties of these polysaccharides. However, despite the obvious prospects for exploitation in medicine, none of fucoidan is declared yet as a drug. The reason is that the structural diversity of fucoidans is extremely large. Structural investigation of fucoidans is of great difficulties because of varieties of monosaccharide compositions, different types of glycosidic linkages, presence of large numbers of non-carbohydrate substituents. There are only a small number of fucoidans with established basic elements of the chemical structure (Chizhov et al., 1999; Bilan et al., 2002, 2004, 2008; Zvyagintseva et al., 2003; Shevchenko et al., 2007; Anastyuk et al., 2009, 2010, 2014; Kuznetsova, 2009; Ale et al., 2011; Vishchuk et al., 2011, 2013; Thinh et al., 2013). Unfortunately in the study of biological properties and enzymatic transformations of these molecules, fucoidans with unidentifiable structure are often used, thus reducing the generalization of the results obtained. Over the past 15–20 years there has been an increase in the number of structural studies of fucoidans. It became obvious that the study of their biological action, without regard to the structure does not allow to create drugs based on these polysaccharides.
It is now considered that fucoidans are species-specific polysaccharides. This means that each alga synthesizes fucoidan or set of fucoidans characteristic only for it. In monosaccharide composition of fucoidans necessarily there are sulfated residues of fucose and often galactose. As minor components residues of mannose, glucuronic acid, xylose, and other more rare monosaccharides, are present (Kusaykin et al., 2008).
1,3-α-L-Fucans are most often found in algae (Zvyagintseva et al., 2003; Anastyuk et al., 2010). α-1,4-Glycosidic linkage between L-fucose residues is less common and is present mainly as a 1,3;1,4-α-L-fucans. Brown algae also often synthesize galactofucans. The position and content of galactose residues in various galactofucans depend on the type of algae; content is frequently comparable to the that of fucose (Shevchenko et al., 2007; Anastyuk et al., 2009; Thinh et al., 2013). This is the most structurally diverse group of fucoidans. A smallest group of fucoidans is represented by fucomannuronans (Imbs et al., 2011). Furthermore, there are fucoidans, containing more heterogeneous monosaccharide composition.
In order to establish the structure of polysaccharides the most promising approach is based on the use of enzymes. Enzymatic transformation of polysaccharides can be extremely useful not only for the establishment of structural features, but also for the access to biologically active fragments (Silchenko et al., 2013; Menshova et al., 2014; Trincone, 2014). Reports about producers and properties of the enzymes (fucoidanases) are rare despite the growing interest in the fucoidans (Kusaykin et al., 2008). No more than 20 producers of fucoidanases are known, mainly isolated from marine fungi and bacteria (Sakai et al., 2003; Descamps et al., 2006; Rodriguez-Jasso et al., 2010; Silchenko et al., 2013, 2014). This rareness is due to the absence of quantitative simple methods for determination of the activity of fucoidanases. Precise assessment of enzymatic features is also hampered by the use of structurally uncharacterized substrates. So, in their transformation enzymes with different specificities should be involved.
Few sources of fucoidanases were found among marine invertebrates (Kitamura et al., 1992; Giordano et al., 2006; Silchenko et al., 2014). Fucoidanase in Patinopecten yessoensis was discovered in 1992 by the action on fucoidan from Nemacystus decipiens (Kitamura et al., 1992). Information about the structure of substrate reported in the article, consisting of L-fucose residues and small amounts of D-galactose residues, is quite scarce. Data about the type of glycosidic linkages are absent (Tako et al., 1999). High molecular weight products (about 50 kDa) formed sufficiently under the action of fucoidanase from P. yessoensis. Information about their structures is not available.
We found new sources of fucoidanases: the vietnamese mollusk Lambis sp. and the marine bacteria Formosa algae KMM 3553 (Khanh et al., 2011; Silchenko et al., 2014). Analysis of the hydrolysis products of fucoidans with established structure from collection of our laboratory, showed that both fucoidanases are endo-enzymes hydrolyzing α-1,4-glycosidic linkages in fucans (Silchenko et al., 2014).
Purification grade of fucoidans is also important for the investigation of biological properties. Unfortunately, uncharacterized crude preparations are often used even in scientific research. Methods for isolation and purification of fucoidan may be different. The most universal scheme includes preprocessing of algae by organic solvents extracting most secondary metabolites, such as polyphenols and other UV absorbing compounds (Shevchenko et al., 2005). These substances, usually powerful antioxidants, often are strongly associated with fucoidans and removal of them entails great difficulties. We show that the purification of fucoidans from impurities results in a loss of antioxidant activity (Imbs et al., 2015). Not only antioxidant, but also antibacterial activity of fucoidans can be completely or partially due to impurities. Separation of fucoidans from them is not always possible, as polysaccharides often form strong complexes with polyphenols, which cannot be destroyed without affecting the integrity of the fucoidan molecules. Nevertheless the evidence of antioxidant activity due to impurities of fucoidans were studied quite intensively (Wang et al., 2008; Hu et al., 2010; Costa et al., 2011). However the data on the purity of fucoidans is often absent.
It is interesting to note that specific biological activities of fucoidans are associated with their structures. So, the formation and growth of the colony of breast cancer cells are suppressed by galactofucans from Saccharina japonica and Undaria pinnatifida. Human colon cancer cells are more sensitive to fucoidan from Saccharina cichorioides (consisted of (1→3)-α-L-fucose residues), human melanoma cells—to fucoidan from Fucus evanescens (Moon et al., 2009; Vishchuk et al., 2011, 2013).
Thus, the intensification of structural studies of fucoidans and the use of highly purified preparations will help to dispel some myths about the effect of fucoidans on organisms and to outline the range of biological properties only related to polysaccharides. The first is immunomodulatory (Khil'chenko et al., 2011), antibacterial, antiviral (Prokofjeva et al., 2013), and antitumor activities (Ermakova et al., 2011; Vishchuk et al., 2011, 2013).
In Russia in 2006 the suplement “Fucolam®” (No 77.99.23.3.y.739.1.06, Russia), based on structurally characterized fucoidan from the brown alga Fucus evanescens, synthesizing from 12 to 15% of the polysaccharide, was registered. The biological effects of the “Fucolam®” are studied in detail. It was established that the “Fucolam®” in addition to the immunomodulatory, antibacterial, antiviral, and antitumoral activities has probiotic, hepatoprotective, glucose, and cholesterol lowering effects (Drozd et al., 2006, 2011; Kuznetsova, 2009; Khil'chenko et al., 2011; Lapikova et al., 2012; Besednova et al., 2014, 2015; Zaporozhets et al., 2014). It is a prominent representative of multifunctional agent and can serve as the base for drug development.
According to known data from the studies above mentioned, the spectrum of biological properties of fucoidans is wide enough. These natural substances are outstanding representatives of multifunctional compounds, and this is not a myth but a reality.
29 citations
15 Jul 2015
TL;DR: In this article, the toxicity of nanomaterials, including dendrimers, silver nanoparticles, gold nanoparticles and carbon nanotubes, has been evaluated in vitro and in vivo.
Abstract: The concern regarding the safety of nanomaterials for the human body is constantly raising. On one hand, there is an increase in the production of nanomaterials for technological applications, which raises the risk of accidental exposure of the workers during the technological manipulation. On the other hand, nanomaterials can be designed for medical applications and their faith in the human body, along with their interactions with different tissues, becomes of vital importance. The mechanisms involved in nanomaterials toxicity are discussed, including oxidative stress and inflammation. In vivo toxicity evaluation includes different routes of administration or interaction between the nanomaterial and the organism, as well as a short-term or a long-term exposure or evaluation. Also, the characteristics of nanomaterials, including size, shape, impurities, function, surface coating in relation to their toxicity, were discussed. A particular attention has been given to the evalua‐ tion of the toxicity of dendrimers, silver nanoparticles, gold nanoparticles and carbon nanotubes.
29 citations
Journal Article•
TL;DR: The sponge-microbial association is a potential chemical, ecological phenomenon, which provides sustainable source of supply for developing novel pharmaceutical leads, and counts of actinomycetes were found maximum in sponges during south west monsoon season.
Abstract: The sponge-microbial association is a potential chemical, ecological phenomenon, which provides sustainable source of supply for developing novel pharmaceutical leads. The present study was carried out to investigate the in vitro antimicrobial activity of sponge associated actinomycetes and actinomycetes isolated from marine soil. Sixty three marine actinomycetes strains were isolated from the sponge and soil samples collected from two different stations from Arabian sea, south west coast of India. The counts of actinomycetes were found maximum in sponges during south west monsoon season. The antimicrobial screening showed that, five Streptomyces sp. exhibited antimicrobial activity against eye pathogens, antibiotic sensitive and resistant bacterial pathogens.
28 citations