Nanotechnology Perceptions 

About: Nanotechnology Perceptions is an academic journal published by Collegium Basilea. The journal publishes majorly in the area(s): Diamond & Materials science. It has an ISSN identifier of 1660-6795. It is also open access. Over the lifetime, 106 publications have been published receiving 915 citations.

What is Nanotechnology

Abstract: This introductory chapter defines nanotechnology and introduces the rudiments of a concept system (ontology) for it. The history of nanotechnology is outlined, and the way in which the discoveries of molecular biology have made biology into a paradigm for nanotechnology is explained. The convergence of nanotechnology, biotechnology, information technology and the cognitive sciences is discussed. Finally, the principal motivations for nanotechnology are outlined.

Carbon Nanotube Synthesis and Growth Mechanism

Abstract: A carbon nanotube (CNT) is a tubular structure made of carbon atoms, having diameter of nanometer order but length in micrometers. Right from its discovery, we have been listening exciting quotations about CNT, viz. “CNT is 100 times stronger than stainless steel and six times lighter...” “CNT is as hard as diamond and its thermal capacity is twice that of pure diamond...” “CNT’s current-carrying capacity is 1000 times higher than that of copper...” “CNT is thermally stable up to 4000K...” “CNT can be metallic or semiconducting, depending on their diameter and chirality...” However, it is important to note that all those superlative properties were predicted for an atomically-perfect ideal CNT which is far from the CNTs we are practically producing today. Despite a huge progress in CNT research over the years, we are still unable to produce CNTs of well-defined properties in large quantities by a cost-effective technique. The root of this problem is the lack of proper understanding of the CNT growth mechanism. There are several questions at the growth level awaiting concrete answer. Till date no CNT growth model could be robustly established. Hence this chapter is devoted to review the present state of CNT synthesis and growth mechanism. There are three commonly-used methods of CNT synthesis. Arc-discharge method, in which the first CNT was discovered, employs evaporation of graphite electrodes in electric arcs that involve very high (~4000°C) temperatures (Iijima, 1991). Although arc-grown CNTs are well crystallized, they are highly impure; about 60–70% of the arc-grown product contains metal particles and amorphous carbon. Laser-vaporization technique employs evaporation of high-purity graphite target by high-power lasers in conjunction with high-temperature furnaces (Thess et al., 1996). Although laser-grown CNTs are of high purity, their production yield is very low (in milli gram order). Thus, it is obvious that these two methods score too low on account of efficient use of energy and resources. Chemical vapor deposition (CVD), incorporating catalyst-assisted thermal decomposition of hydrocarbons, is the most popular method of producing CNTs; and it is truly a low-cost and scalable technique for mass production of CNTs (Cassell et al., 1999). That is why CVD is the most popular method of producing CNTs nowadays. Here we will review the materials aspects of CNT synthesis by CVD and discuss the CNT growth mechanism in the light of latest progresses in the field.

Ferritin protein nanocages-the story.

Abstract: Ferritins are a family of large (10-12 nm diameter), self-assembled, protein cages that reversibly synthesize Fe2O3•H2O with up to 4500 iron atoms in a central cavity, 65 or 270 nm3; the protein cages without mineral are sometimes called apoferritin. Fe2O3•H2O synthesis depends on controlled Fe2+ entry though four or eight ion channels, directed transport to multiple Fe2+/O oxidoreductase ("ferroxidase") sites and, in the case of eukaryotic ferritins, guided nucleation and extrusion through channels connecting the active sites to the mineral growth cavity; passage of the diferric oxo catalytic products through the nucleation/extrusion channels allows the eukaryotic ferritin protein cage to influence order in the bulk mineral. Ferritin Fe2+ion channels also control reduction, dissolution, and exit of Fe2+ from the mineral with gated pores on the cytoplasmic surface of ferritin cages. Found in anaerobic and aerobic organisms, from archaea and bacteria to higher plants and animals, ferritins are required for life. They provide metabolic iron concentrates for protein cofactor synthesis, and antioxidant activity after stress. Current applications of ferritin nanocages include clinical measurements of trace amounts released into serum, nutritional sources of concentrated iron, nanomaterial templates, biological delivery of nanosensors, and nanocatalysts. Future applications can exploit the nucleation/ extrusion channels and other metal-protein sites in ferritins.

Nanotechnology - should we be worried

Abstract: From the development of the earliest stone tools to the most sophisticated microprocessor, man has increasingly, and sometimes unwittingly, shaped the world around him through the use of his technologies. These technologies impact upon all aspects of our lives. We depend upon them for the food we eat, our transport and our communications. We rely on them for clean water and an increasingly sophisticated level of healthcare. Whole periods of human history are labelled by reference to the dominant technology of the time—the stone age, the bronze age, the iron age, the industrial age, the computer age. We are all familiar with these terms and use them without thinking about the profound effect that each of the technologies had—both upon the societies that created them and on the planet itself. Frequently, we are not aware of the impacts the older technologies have had on the world in which we now live—for example, stone axes were used to fell the ancient forests that once covered the UK and created the downs and pasture that we now recognize as our “green and pleasant land”. This paper will look at one new area of technology—nanotechnology—and attempt to answer the question “Should we be worried—either about what it is doing now or where it is taking us?” I wonder whether a Neolithic farmer stopped to ask himself the same question while he was felling the trees to create a new stretch of farm land for himself and his family. Before discussing the issue of where nanotechnology is taking us, and whether we should be worried about it, we must try to understand what it is. So, the first question that I would like to address is: “What is nanotechnology?” This is not as easy to answer as one might think, because the term encompasses a huge range of activities. Some people think it is not a single type of activity at all, while others think it is just a term that has been invented to allow researchers to extract large amounts of research funds from government