Sometimes we get bombarded with emails from people who are new to the field about certain aspects of nanotechnology - can it cure cancer? Where can I buy nanobots? What is a nanomaterial? Is nanotechnology dangerous? And so forth. You get the idea. The question asked most often is simply this: 'What is nanotechnology?' That's why we have decided to add a new segment to our Nanowerk website that we call 'Ten things you should know about nanotechnology'. What we have been trying to do here is to provide a brief overview of some important aspects and issues and answer some of the basic questions on nanotechnologies. Of course, there is lots of important information that we omitted. But we feel that, if you are new to nanotechnology, this is a good point to start.
Many of the properties of a given nanoparticle not only depend on its chemical composition but also on its size and shape, i.e. its morphology. These morphological factors have significant impact on a nanoparticle's optical and catalytic properties. Accordingly, nanoparticle manufacturers have developed numerous 'recipes' for synthesizing particles with desired size and shape. To facilitate systematic investigation on the morphology-property relationship, it would be highly desirable if one reaction system can be engineered to yield as many different shapes as possible with minimal degree of parameter tuning. To that end, researchers proposed a way to systematically engineer the morphologies of nanoparticles by constructing an evolutionary tree, which consists of several pathways, each showing a 'string' of evolving shapes over the courses of a single reaction. The tree not only displays the relationship between different shapes, but also offers designing principles for producing more complex shapes by crossing over different pathways during nanoparticle growth.
In a recent Nanowerk Spotlight we reported on a single molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots. One of the challenges the researchers in this work had was to measure distances between probes bound to combed DNA with nanometer resolution. Whereas very short distance (below 10 nm) can be assessed by FRET measurements and distances above the Rayleigh criterion can be measured, say, with a standard microscopy picture and a ruler, distances in between need to be addressed differently. This is were a novel approach by scientists at UCLA fills the gap, and, as they claim, better than other techniques do.
A recent study has shown that nineteenth century thermodynamics can still provide useful insights into twenty-first century nanosciences; and all this can be done with pencil and paper rather than an expensive super-computer! When the size of materials approaches the nanoscale, matter begins to behave highly exotically. By shrinking the size of materials, the surface-to-volume ratio increases. Considering this, scientists can study size effects on material properties from macroscopic laws, the so-called top-down approach. In thermodynamics, the Gibb's energy concept is particularly suited to describe the liquid-solid phase transition (what we mortals call the melting temperature).
Not surprisingly, it has been scientists in The Netherlands - a country that has long been conducting large-scale and long-term field studies on the benefits of certain plants to mental and physical health (scientists refer to this effort as the 'great coffee house smoke screen studies') - that have come up with a nanotechnology discovery that could well revolutionize many consumer products from food to toys. In a report released today, April 1, the Dutch scientists report that a nanoparticulate substance found in Cannabis sativa, also know as marijuana, has an amazing ability to kill fat cells in the human body. Hoping to ride an early wave of commercialization, the Dutch research group has already filed for patent protection and registered the trademark 'Royal Spliffmeister Edition' for a range of planned products.
When it comes to nanotechnologies, Americans have a big problem: Nanotechnology and its capacity to alter the fundamentals of nature, it seems, are failing the moral litmus test of religion. Survey results from the United States and Europe reveal a sharp contrast in the perception that nanotechnology is morally acceptable. Those views, according to the report, correlate directly with aggregate levels of religious views in each country surveyed. In the United States and a few European countries where religion plays a larger role in everyday life, notably Italy, Austria and Ireland, nanotechnology and its potential to alter living organisms or even inspire synthetic life is perceived as less morally acceptable. In more secular European societies, such as those in France and Germany, individuals are much less likely to view nanotechnology through the prism of religion and find it ethically suspect.
Scientists are intensely researching how animals like spiders and geckos generate the high adhesion force that allows them to cling to walls and walk on ceilings, feet over their head. While this research so far has focused on novel materials like carbon nanotubes to replicate spider feet and gecko toes, a key challenge for materials engineers is the scaling up of such materials from small animals to, say, spiderman gloves that support a fully grown human. Complementing the ongoing gecko biomimetic materials research, Nicola M. Pugno, an Associate Professor of Structural Mechanics at the Politecnico di Torino in Italy, has developed what he termed Adhesive Optimization Laws.
Titanium dioxide nanoparticles have become a commercially significant nanomaterial and are being used in products around the world - in cosmetics and sunscreen lotions, paint formulations, coatings, self-cleaning additives, even in antibacterial applications. The increased use of nanomaterials such as titania goes hand in hand with a growing number of reports on the risks associated with these materials, which have arisen because insufficient information has been gathered about their reactivity and stability once they leave the laboratory. Unfortunately, pinpointing every conceivable situation that nanoparticles could interact in is an enormous multi-parameter problem and solving this by experimental testing alone is not feasible due to the huge numbers of combinatorial variations. This is where theoretical predictions can help, by rapidly and systematically sampling possibilities, and highlighting where experimentalists should focus their attention.