Author: Falishia Sloan
Institution: Eastern Virginia Medical School
Date: February 2008
"Research has no end: when you accomplish this, you accomplish one, and you search for the other, and in this way it never ends. That's why we need new researchers to carry it on."
--Dr. Xiaohung Nancy Xu, 2006
Nanoscience. What does this word, not even recognized by standard computer spell-check, mean? Much more important than what it means, however, is what it is,possibly the next frontier in science. Sure, there's big picture (macro) science and there's small scale (micro) science, but, as we are now finding out, when we observe materials at the nano level, there's a whole world of virtually untapped potential that may hold answers to many scientific, biomedical, and technological issues we have today.
Scientists routinely study the functions and properties of atoms and molecules at the macro-scale, meaning that atoms and molecules are studied in large quantities. What happens, however, when we isolate atoms and molecules and study the properties of these components of matter in extremely small quantities?
Nanoscience is the scientific study of materials and events in various interdisciplinary areas of science on the nanometer scale (less than 100 nanometers). It basically deals with the study of the structure and function of scientific particles such as atoms, molecules, macromolecules, various types of bonding, etc., on a nanoscale. It is truly a versatile area of science much like biochemistry; a blanket subject area that combines biology, chemistry, biochemistry, and technology among other things.
Nanoscience is unique in emphasizing the "bottom-up" approach of science,starting from the atomic level and building up,as opposed to the "top-down" approach of starting from something containing many atoms and breaking it down to fewer atoms, though it encompasses both. Nanoscience has very tight correlations with its fellow "nano" disciplines, one of the most notable being nanotechnology, which actually allows us to use technology small enough to practice nanoscience.
What's so special about "nano"?
A single nanometer is one billionth of a meter wide and 1/100,000th of the width of a single human hair. Though that may seem impressive, you may still wonder why the study of a smaller sample of something we've already studied (for example, an element) is really that important,wouldn't it all be the same? The short answer is no.
The extremely interesting thing about elements and science in general is that all substances do not act the same at different concentrations or amounts. Once we start to study matter at the nanometer scale, it begins to exhibit different properties. The ratio of atoms on the surface to the particle volume is much higher for nanoscale than for larger particles. That makes them behave more like single atoms than bulk matter: quantum effects start to come into play. They are unique in nano-sized particles, and do not exist in macro- nor micro-sized particles of the same substances. The study of elements such as gold at the nanolevel has already yielded some interesting results:,while gold in larger quantities is extremely beautiful to look at, at the nanoscale it transforms into a beautifully performing catalyst impregnated with new capabilities at this new level.
Another example of the unique properties of nano-sized particles is that nanodevices have the ability to actually self-assemble, meaning they build themselves up atom by atom. With the capacity of nanodevices to build themselves up and exhibit unique properties, the potential for advanced treatments and technologies utilizing nanoscience is practically endless.
So where did this idea of really small things come from?
Though the realization of the potential in nanoscience may be fairly new, the study of materials at such a small scale is not. The basic discoveries of science procuring our current trend towards nanoscience chiefly came from scientists such as Joseph Proust (who designed the basis for molecular formulas) and Albert Einstein (who, among other things, speculated on the relation of heat, volume, and particle movement). These scientists and scientists like them revolutionized the science world in their era and ours with their contributions. Since the discovery of the atom, smaller units of matter such as the quark had been found, but there had yet to be an area of science dedicated to and realizing the importance of all aspects of science at the nanoscale,that is, until 1959.
Richard Feynman, a Noble-prize winning physicist, was the first to venture into the unknown, smaller world of science by writing about the study of science at the nanoscale in his paper, "There's Plenty of Room at the Bottom," in 1959. In the late 1950s, a mere 50 years ago, the thought of studying anything at the nanoscale was unheard of, and the practice was even rarer. Feynman's paper, which explored the role of physics and nanotechnology in the future, transformed the way scientists everywhere thought about science at an extremely small scale.
The Emergence of nanotechnology
Yes, we had discovered that matter is composed of atoms, but was there a way to manipulate these atoms? Was there a way to study nano-sized materials with nano-sized technology? After Richard Feynman's paper, the next great landmark in the conception of nanoscience came in 1974, when Norio Taniguchi, a professor at Tokyo Science University, first used the term "nanotechnology" in a scientific paper. Once the word "nanotechnology" was introduced to the tongues of scientists everywhere, other words proudly bearing the prefix "nano" emerged (including nanoscience), all describing their subjects at the nanoscale.
The next great support for nanoscience came from Eric Drexler, the first person ever to obtain a PhD in nanotechnology in 1991,after already obtaining 3 other degrees from Massachusetts Institute of Technology (MIT). Drexler was greatly influenced by the contributions of both Richard Feynman and Norio Taniguchi. After writing three books on the promises of nanotechnology, he gave a presentation on nanotechnology before a congressional committee in 1992. In addition, Drexler opened an institute dedicated to promoting nanotechnology, the Foresight Institute, which continues to function today.
What are we doing with nanoscience now?
Nanoscience today continues in its quest to become a forefront in the interdisciplinary areas of science technology. Nanoscience's growing mark on our society is exemplified by the various new programs and exciting research currently taking place.
To date, nanoscience has already yielded a few well-known advancements, such as mirrors that don't fog and suntan lotion, but we have also gained serious ground in the detailed observation of nanoparticles (clusters of atoms at the nanoscale). As mentioned before, materials such as gold at the nanoscale have proven to be powerful catalysts. This characteristic, known as the "quantum size effect," is unique in nano-sized particles, and does not exist in macro- nor micro-sized particles of the same substances. One method of nanoscience currently under study for use in medicine is that of gold nanoshells,small, golden balls capable of absorbing heat and light. If it were possible to bind these nanoshells to malignant, cancerous cells and radiate them, the nanoshells may absorb the heat from the radiation and destroy only the (bad) cancerous cells, leaving the other cells free of damage. This could eliminate or reduce the side effects of chemotherapy that stem from the damage of healthy cells as well as damaged cells during the treatment.
In addition, techniques such as scanning probe microscopy are utilized to observe, create, and manipulate nanoparticles. Scanning tunneling microscopes and atomic force microscopes are used to observe the surface of these nanoparticles and move them around. Machinery such as these aids the self-assembling process of the nanoparticles. Nanoscience, and, more specifically, nanotechnology, is currently being used to create nanowires, which may one day be able to conduct electrical currents out of extremely small compounds. Nanoscience also carries the torch of methods introduced into the science and technology fields long ago, techniques such as lithography, focused ion beam machining, and atomic and molecular layer deposition.
Spearheaders in Nanoscience at the University level
Today, various colleges and universities are recognizing the emerging importance of nanoscience and nanotechnology by creating programs designed to focus on the current and future uses of nanoscience. One such institute is The Nanoscience and Nanotechnology Institute (NNI) at the University of Iowa.
Vicki Grassian, Director of the Nanoscience and Nanotechnology Institute and Professor of Chemistry at the University of Iowa, described the NNI@UI as a place where the various disciplines represented at the university can come together to study the possibilities in nanoscience and nanotechnology. "NNI@UI focuses on...the fundamental properties of nanomaterials, but will also focus on issues related to applications and implications of nanoscience and nanotechnology in environmental processes and human health," Grassian said. "The mission is to provide a venue where researchers from all disciplines of science and engineering can gather to share ideas and discuss their views and prospects of nanoscience, nanoengineering, nanomedicine, and nanotechnology." Grassian credits the creation of the NNI to the university's realization of the importance of the emerging fields of nanoscience and nanotechnology. "In general," she said, "it was recognized that there were growing strengths on campus in nanoscience and nanotechnology. The goal of the institute is to nurture science and technology at the nanometer scale with a research emphasis not only on the fundamental properties of the materials but on the environmental and human health aspects of nanoscience and nanotechnology." Grassian hopes that the NNI will expand the variety of research currently going on at the University of Iowa.
Funding to the university supporting this new area of research interest currently amounts to about 6 million dollars, which is a testament to its the importance. Grassian stated that the institute is very efficient in gaining interest in nanoscience and nanotechnology on campus. "The institute provides administrative support to the faculty and to joint projects and programs, supports joint research initiatives, sponsors seminars and conferences, encourages entrepreneurialism, encourages collaborations both internally and externally, connects to external organizations, and supports educational initiatives," she said.
According to Grassian, the University of Iowa's plan to use the new Nanoscience and Nanotechnology Institute to fully delve into this field and explore the possibilities within. "NNI@UI will coordinate the ongoing efforts at the University of Iowa to more effectively take advantage of opportunities afforded by the National Nanotechnology Initiative and build on research strengths of the University of Iowa."
In addition, she attested to the importance of nanoscience and nanotechnology research by other researchers and universities. "Nanoscience and nanotechnology can potentially improve our environment, advance research in energy and offer new modes of drug delivery and disease detections," she said. "New technologies involving nanoscience are just being developed in a variety of areas for disease detection and improving human health. I am hoping these can lead to major advances in key areas such as cancer research. I see a very bright future for nanoscience and its potential for the development of new materials with very controlled properties that can be used in a wide range of applications from environmental remediation to drug delivery to energy storage."
Another great example of the growth of nanoscience is the nanoscience research conducted by Dr. Chris Sorensen, professor of physics and adjunct professor of chemistry at Kansas State University. Sorensen's work is an excellent example of how properties of a material at the nanometer scale are different than those of the same material at the macroscale. Motivated by a core component of research,curiosity,Sorensen and his team have developed a way to make nano-sized particles that exhibit this very property, noting, for example, that a nanoparticle of gold is actually purple in color and looks very different than gold in larger quantities. They have also found that nanoparticles behave much like molecules: they are soluble in some liquids and insoluble in others, their solubility is temperature dependent, and they often
form a crystalline arrangement of particles (a superlattice) when they precipitate from solution.
A nanoparticle superlattice from the lab of Dr. Chris Sorensen.
Signifying the importance of their research, Sorensen and his research group were awarded a 1.2 million grant from the National Science Foundation's Nanoscale Interdisciplinary Research Team Award program. Sorensen and his team of distinguished scientists, which includes Amit Chakrabarti, Bruce Law, Ken Klabunde, Christer Aakeroy, and Xiaomin Lin, will use the grant to explore how much the nanoparticles behave like their larger counterparts,to further investigate the properties of nanoparticles and their relation to atoms and molecules of the same substance. "Our new grant will explore the physical chemistry of these stoichiometric particle compounds' and their solutions," he said.
"It is neat when different things have a common bond," he said. "Suspensions of particles are different than solutions of molecules, yet we seem to have suspensions that act like solutions. How much further does the similarity between solutions and suspensions, molecules, and particles go?" Sorensen explained that what he hopes to gain from his nanoscience research is a deeper understanding of nature, particularly the behavior and potential of nanoparticles and the relation between their size and their function.
Sorensen is a firm believer in the notion that nanoparticles are the basic units of the future; where we have before based science on atoms and molecules, we will soon base it on nanoparticles. "I have a dream that we can create a whole new chemistry and a whole new materials science based not on atoms and molecules, as we have done so well in the past, but rather based on uniformly sized nanoparticles," he said. Chris Sorensen, like Vicki Grassian, believes that nanoscience truly has a future in and perhaps is the future of science. "Nanoscience will continue to grow and yield significant results of both practical importance and scientific beauty," he said.
1,293 miles away on the East Coast, a professor at North Carolina State University is conducting his own research in nanoscience. Dr. Orlin Velev, associate professor in the Department of Chemical Engineering at North Carolina State University, together with his doctoral students Brian Prevo and Ketan Bhatt,invented a device that will allow for the microscopic study of chemical reactions with a special "factory" that makes and separates individual molecules. This device lends a new mechanism by which scientists can study chemical reactions. Electricity is run through the device, a microfluidic chip, to make cells and suspensions "hover" in the liquid of the chip, allowing them to change within by sorting, combining, encapsulating, or creating new materials.
Illustration of the microfluidic device developed by Dr. Velev and his team.
"I was very interested in the microfluidics area," Velev explained, "but did not want to follow other people's track (who were using permanent microchannels). We had experience in manipulating particles by electric fields and we applied it to the manipulation of droplets, which was a very new area at that time. Thus, we developed an alternative microfluidic technique." Velev and his students believe that their research is a grand example of nanoscience's ability to span the lines of various scientific disciplines in a quest to pursue a common goal. ."It includes elements from nanoscience, microfluidics, materials science, colloidal science,.and electronics. This is what makes it interesting for me and my students, and of course, challenging in many aspects," explained Velev.
Velev believes that, in the future, this technology could have various medical and research advantages such as better detection of disease and toxins in humans. "We have developed a new tool to manipulate droplets and particles and also demonstrated new types of anisotropic spheres, and new microbioassays on this tool." Microbioassays are methods scientists use with liquid samples to detect the existence of specific immunoprotein, virus or bacteria. Such progress could allow for the better detection of dangerous substances in the environment and specific diseases in humans. We are glad to see other scientists using similar methods and furthering the research area," he said. "We hope to be able to deliver practical applications of the technique, and transfer it to companies and organizations that can commercialize it. I think nanoscience is a very large area, and we are exploring a small part of it at present.
Images of silver nanoparticles both outside (A) and inside (B) living cells, courtesy Xiaohung Nancy Xu of Old Dominion University.
Yet another scientist pursuing nanoscience is Dr. Xiaohung Nancy Xu of Old Dominion University (ODU) in Norfolk, Virginia. Dr. Xu has received simultaneous awards from the National Science Foundation and the National Institute of Health, a feat she is nearly unique in accomplishing, for research in the field of nanoscience. Xu and her research team at ODU, are the creators of revolutionary silver nanoparticles that are capable of entering a cell and lighting up the interior. Xu's nanoparticles are unique in a few ways that make them far better than nanoparticles already in use. "These particles are very bright," Xu explained, "and therefore you can see them easily with the eye. They also don't photodecompose, and we can use them to.trace what cells do and where they go. They are also color-size dependent,each size has its own color."
Color correlation to size of nanoparticles. Image courtesy Xiaohung Nancy Xu of Old Dominion University
The novel properties of these silver nanoparticles allow scientists to watch the various biological processes in living cells without disturbing the cell's intrinsic functions. Such advancement in nanoscience may one day lead to advanced detection and treatment of cancer as scientists will be able to observe the changes malignant cells undergo and perform cancer tests on single cells.
Xu will use her grants to apply nanoscience to the treatment of cancer by developing nanoparticle probes capable of studying the way molecular transporters resist the multiple drugs administered in cancer therapy. She will also study the possibility of using nanoparticles themselves to deliver drugs to diseased cells. The molecular transporters she wishes to explore, ATP-binding cassette (ABC) transporters, act as security guards for cells that allow certain substances to enter and deny entrance to others. Such transporters are important in biomedical study, as they recognize and expel certain helpful substances, such as antibiotics, nanoparticle probes, and cancer-fighting medicine, from cells. Such a function of the cell is normal in protecting the cell, but in the case of cancer, it hurts the individual by preventing the destruction of malignant cells.
With continued study, nanoscience may provide a route through which to specifically target malignant cells and destroy them, rather than the current method that destroys not only malignant but also healthy cells in an attempt to eradicate the individual of cancer. Her goal at Old Dominion University is to further the understanding of cellular biological functions using nanoscience. "I think our long-term goal is to make a bio-inspired nanodevice to understand biological functions."
Xu, like the previous researchers, is a firm believer in not only the future of nanoscience and nanotechnology, but also the present applications of the field. She is a very strong advocate for the implementation of nanoscience programs around the country, especially at her home institution of Old Dominion University. Of the future of nanoscience at ODU, she said, "I hope it will be bright, but our university has to invest. I want to emphasize that nanoscience is not a luxurious thing; it is a necessary thing. Nanoscience is much like the computer,it used to be that it was thought of as a luxury, now it is a necessity. It is really in all corners of engineering and medicine. Students need to be educated and prepared for nanoscience. It is a big decision. I don't think a university's research can survive without it 10-20 years from now."
All of the scientists mentioned are forerunners in field of nanoscience simply because they are involved in the field of nanoscience. They all have recognized and acted upon the recognition of nanoscience as an important and integral part of science in the very near future. Hopefully, their contributions and dedication to nanoscience will spearhead a revolution in realizing the importance of this science in the future.
What does the future hold for nanoscience, or rather, what does nanoscience hold for the future?
Considering the ways nanoscience has impacted our world today, nanoscience's mark on the future may be nearly impossible to predict. One thing is certain about nanoscience in the future,nanoscience will be in the future. With continued support and growth, nanoscience may enhance our understanding of materials at the macro level by studying them at the nano level. With this new knowledge, we may be able to help the environment and provide a new approach to the treatments of various diseases on the nanometer scale. The fact that human cells and other nanoparticles self-replicate suggests that further study of materials at this level may yield great discoveries.
In light of all the advantages, some think there is another side to nanoscience. The use of nanoparticles in the human body, for instance, presents a few concerns, as the activity of nanoparticles and their properties is not yet fully understood. Particles of such small proportions may produce unforeseen effects, such as passing through the blood-brain barrier. Realizing these issues, scientists now know that they must first fully understand nanoparticles, their properties, and the way they work before employing them in treating humans. This proves even more the importance of continuing research and study in nanoscience. There are also extreme fears concerning nanobiotechnology, such as the emergence of the "grey goo" theory in which self-replicating nano-sized robots pulverize surface objects on earth. Despite these concerns, the normal scientific and technological application of nanoscience and nanotechnology can initiate great advances in technology and biomedicine in the future.
Nanoscience is a new frontier that the scientific community has only brushed up against before,we've been kissing the edge between micro and nano science for a long time, and it's time we fully explore all that nanoscience has to offer. Every method in science and technology was new at one time, and, just as Dr. Xu of ODU said, even the computer was at one time a figment of somebody's imagination. The development of new methods is natural in science and technology over time. Isn't it a grand example of how thinking grows and changes over time that today we judge the acceptance of a new word by whether or not it is recognized by spell-check rather than whether or not its in the dictionary? With the contributions of nanoscience to biomedicine and technology in the future, the spell-check will surely recognize it in the very near future. Nanotechnology is there, however, and that's a start.
Written by Falishia Sloan
Reviewed by Antje Heidemann
Published by Pooja Ghatalia.