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Home , Calvin Quate, Heinrich Rohrer

Niches and Nanotech The future keeps getting smaller, and potential benefits loom large.

MICHAEL J. FELTON

he chemical enterprise—whether focused can have hundreds of on producing and developing chemicals or millions of transistors, and Tanalytical techniques—is exploring the Texas Instruments and new frontiers of the microscale and nanoscale. Intel have announced Instruments have been getting smaller and detec- that new chips will be tion limits have been lowered. The move to produced with features as interacting with the world at these very small small as 65 nm. dimensions is changing the nature of the modern While engineers and scientists at Intel and laboratory, providing new life to existing tools and other companies were making the “computer on fertile ground for new methods of chemical analy- a chip” trillions of times over, several companies sis and production. were using the same fabrication techniques to produce very different devices. In 1968, H. C. Computer on a Chip Nathanson and colleagues at Westinghouse first The development of microtechnology demonstrated that 3-D structures began with innovation in the elec- could be made out of silicon using tronics industry. In 1947, the first integrated-circuit fabrication tech- transistor was invented, which niques. In 1974, National Semicon- allowed vacuum tubes to be replaced ductor applied the fabrication by a very small piece of germanium techniques to mass-produce strain and, later, silicon. By 1954, the tran- gauges. These developments led to sistor radio was developed, but more- products such as microfabricated complicated electronics were difficult accelerometers, which are used in to make because wiring numerous cars to trigger air bags during a crash. transistors was labor-intensive and Integrated-circuit fabrication Top: Richard E. Smalley (r), prone to errors. In July 1958, Jack techniques were applied to more Luminaries of the Chemical Sciences, Kilby at Texas Instruments decided to try to make than mechanical and electrical systems. One of 2002 an entire electrical circuit, not just the transistor, the first liquid applications of microtechnology was Center: Gyrolab microlaboratory disc, out of silicon, thus reducing the size and making ink-jet printing. The ink-jet concept was proven courtesy of Gyros AB circuits easier to produce. Shortly after, in January in 1878 in England by Lord Rayleigh and was 1959, at Fairchild Semiconductor finally transformed into working technology in independently developed an entire circuit on sili- 1951 by Siemens. However, these early printers con. Both technologies were patented, but interest produced continuous streams of ink, which wasted in the so-called integrated circuits waned. ink. In the late 1970s, several companies Almost a decade later, in 1968, Noyce and were researching drop-on-demand ink-jet fellow engineer Gorden Moore left Fairchild Semi- printing, and in 1979, Canon succeeded, conductor and started Intel Corp. Intel first followed shortly by Hewlett-Packard. The produced silicon-based memory chips, but it was ink-jet printer heads contain etched silicon approached by a Japanese company, Busicom, to wafers with microscopic channels that allow design and build 12 integrated-circuit chips for ink to flow to hundreds of nozzles. incorporation into a handheld calculator. An engineer at Intel, Ted Hoff, suggested designing Lab-on-a-Chip one chip that could perform the function of all 12 Making analytical instruments using integrated- chips. After negotiating with Busicom for the rights circuit fabrication techniques was a conceptual to the design of this first microprocessor, Intel leap. In 1975, researcher S. C. marketed its 4004 integrated circuit as a “computer Terry reported on an idea to make a gas chromato- on a chip.” The 4004 had 2300 transistors and had graph etched in silicon, but little was done about wires as small as 10 µm wide, but by 1982, Intel’s producing one. Much later, Stephen Fodor at Affy- 286 microprocessor had 134,000 transistors with max used a technique similar to photolithography, wires as small as 1.5 µm. Today’s integrated circuits which is used in making integrated circuits, to

ENTERPRISE OF THE CHEMICAL SCIENCES 125 make a microarray of oligonucleotides. Affymetrix columns, and new companies such as SLS Micro was formed to commercialize the product, which are producing entire instruments consisting of was a dramatic success for biotechnology. Other microscale components. companies developed competing microarray fabri- A new generation of companies, started by cation methods using ink-jet technology. For researchers, is just beginning to introduce and NICHES AND NANOTECH example, Agilent used Hewlett-Packard ink-jet develop products. George Whitesides, the Harvard technology to deliver DNA or proteins for making University professor who invented soft lithography microarrays. that uses poly(dimethylsiloxane), is behind a Mass- During the same period (late 1980s and early achusetts company, Surfacelogix. And Caltech 1990s), Andreas Manz and others used silicon researcher Stephen Quake has started a company fabrication techniques to produce the first liquid called Fluidigm to commercialize his highly paral- pump on a chip, thus starting the field known as lel microfluidic system that resembles computer microfluidics. Manz coined the term µTAS, for microprocessors. micro total analytical system, to describe the goal of making microdevices that would perform analytical functions. Researchers soon replicated The concept of nanotechnology was first succinct- liquid chromatography within a microchannel, ly explained by in a lecture at proving that analytical techniques could be repli- Caltech on December 29, 1959, titled, “There is cated at this scale. Regardless of the terminology, Plenty of Room at the Bottom.” Feynman’s view the description is similar to the products that Intel, was that there was a vast amount of promise in Canon, and Hewlett-Packard had developed to building objects from the bottom up, from individ- Above: Microfluidics channel schematics, Modern Drug make computers and later printers on a chip. ual atoms, rather than the current situation, where Discovery, 2002 New companies such as Aclara Biosciences, technology can handle only millions of atoms at a Caliper Technologies (now Caliper Life Sciences), time. Feynman is cited so often as the father of Orchid Technologies, Gyros, and Cepheid, as well nanotechnology that it is easy to forget simply how as integrated-circuit companies such as Motorola, prophetic he was. He stated, “In the year 2000, began developing “lab-on-a-chip” products. when they look back at this age, they will wonder One of the first microflu- why it was not until the year 1960 that anybody idics products was the LabChip began seriously to move in this direction.” LARRY BOCK system jointly developed by The term nanotechnology was coined in 1974 Beginning with the biotechnology and Internet Caliper Technologies and by Japanese researcher Norio Taniguchi, who was booms in the 1990s, new technology was not Agilent. Caliper, founded in using energy beams to etch nanometer-scale chan- only in the domain of large corporations or uni- 1995, developed a disposable nels at the University of Tokyo. He defined nano- versities—venture capitalism was becoming microfluidic chip that could technology as “production technology to get the commonplace. And one of the most prolific process multiple samples and extra-high accuracy and ultrafine dimensions. . . . and successful venture capitalists is Larry developed a prototype reading The smallest bit size of stock removal, accretion, Bock. Bock began his career at Genentech, instrument to obtain results or flow of materials is probably of one atom or one where he witnessed the biotechnology boom. from reactions on the chip. In molecule, namely 0.1–0.2 nm in length.” But this son of an investment banker and the late 1990s, the company Very little happened with the theory of gourmet chef found starting companies more partnered with Hewlett- nanotechnology until there was a way to see mole- rewarding. Bock founded and was the initial Packard. The partnership cules and atoms at the nanometer level. Feynmen CEO of ARIAD Pharmaceuticals, Neurocrine allowed Hewlett-Packard, foresaw this in 1959 when he said, “For us to make Biosciences, Pharmacopeia, GenPharm which soon changed its labo- more rapid progress is to make the electron micro- International, Argonaut Technologies, Caliper ratory instrument division scope 100 times better.” In 1981, researchers Gerd Technologies, Illumina Technologies, Idun name to Agilent Technolo- Binnig and Heinrich Rohrer at IBM’s Zurich Pharmaceuticals, and Fast Track Systems. He gies, to apply its instrument Research Laboratory invented the scanning tunnel- also cofounded Athena Neurosciences, Vertex expertise toward the refine- ing (STM). The device uses a probe Pharmaceuticals, and Onyx Pharmaceuticals. ment of the analyzing hard- with an extremely precise tip that is held in place Several of these companies have become ware that became the Agilent by piezoelectric disks. The probe travels over a successful, one of which, Caliper Technologies 2100 Bioanalyzer. In 1999, surface and measures the changing current caused (now Caliper Life Sciences), became one of the the Bioanalyzer and Caliper’s by electrons that tunnel across the extremely small major microfluidic instrument makers. Bock is LabChip microfluidic chips distance between the probe and the surface. The now executive chairman of the board of direc- were introduced. Caliper’s result is that atoms can finally be witnessed. Binnig tors of Nanosys, which is working with numer- success raised new interest in and Rohrer won the in for the ous researchers on inorganic semiconductor- microfluidics to replicate or microscope in 1986. based nanotechnology. develop new laboratory The STM could be used only on surfaces and analytics. New companies atoms that were conductors. In 1986, Binnig, such as Nanostream and estab- Christopher Gerber, and at IBM lished makers such as Waters are introducing new developed (AFM). microfluidic-based versions of liquid chromatogra- Instead of using tunneling electrons to look at a phy. The same is true of gas chromatography; surface, the AFM measures the deflection of the Agilent and others are producing microfabricated probe tip as it approaches atoms. Commercializa-

126 ENTERPRISE OF THE CHEMICAL SCIENCES tion of STM and AFM, commonly lumped togeth- ty of California. In 2000, Evident Technologies er as scanning probe microscopy (SPM), was led was founded by colleagues who were working at by Digital Instruments. In 1986, the company was Lockheed Martin’s Advanced Concepts Research formed and offered its Nanoscope STM, which Division. Many other companies are interested sold for almost $100,000. Many other companies in this area, with production technology being NICHES AND NANOTECH followed, such as Molecular Imaging, Omicron licensed from companies such as IBM as well as Nanotechnology, RHK Technology, Nanofactory, quantum-dot makers partnering with manufactur- Asylum Research, JEOL, Leica, and Veeco (which ers such as Matsushita. is composed of former SPM companies Thermo- The other high-profile material of the nano- , Digital Instruments, TopoMatrix, technology field is carbon. In 1985, Robert Curl, and Park Scientific). Harold Kroto, and Richard Smalley discovered a IBM also found a new use for STM. In 1990, new form of carbon with 60 atoms and shaped D. M. Eigler and E. K. Schweizer published an exactly like a soccer ball. This “buckminsterfuller- STM image of the letters I, B, and M spelled with ene”, as it was called, was very stable, and the 35 individual xenon atoms that were picked up researchers were even able to place metal atoms and moved by STM. Being able to examine, and within the balls of carbon.

even move, atoms has brought about a revolution Production of C60 became commercially useful in material science and chemistry. as research with it became increasingly widespread. For example, some fullerene-based can super- Nanoproducts conduct at reasonably high temperatures (20–40 The new analytical technology has allowed new K), and companies such as C Sixty are examining products to be developed. Micro- and nanoscale ways to use them as antioxidants and mitochon- metal particles have been found to have either drial protectants. In 2002, Frontier Carbon Corp., enhanced or completely unique properties partially owned by Mitsubishi Chemical Corp., compared with larger particles. For instance, opened the first fullerene plant in the world in

microparticles of TiO2 absorb or reflect UV radia- Kitakyushu, Japan, to make 400 kg per year of tion in new sunscreens, but they do not appear fullerenes.

white like bulk TiO2. Many companies are While investigating ways to make fullerenes, involved in developing new particles in a wide , a spectroscopist at NEC Japan, range of fields. One firm, Mach I, produced discovered what are known today as carbon nanoscale magnetic and nonmagnetic iron parti- nanotubes. Nanotubes exhibit unique properties cles for use as catalysts—the smaller particles have such as either conducting electrons or behaving a much higher surface area than the traditional as a semiconductor, depending on their internal larger particles. structure. Because of these properties, they have Some of the most promising new materials found use in many products, from preventing static appear to be new forms of carbon, like buckyballs, buildup in plastic bags used for sensitive electronics carbon nanotubes, and nanoscale semiconductors, to adding strength to plastics and concrete. New such as CdSe quantum dots. The road to the devel- uses are being developed almost every day. In opment of quantum dots, like integrated circuits, September 2003, NEC announced that it could dates back to the late 1950s, when Herbert Kroe- reliably fabricate carbon nanotube transistors, mer at RCA theorized the possibility of a hetero- which could revolutionize the electronics industry. transistor, in which positive and negative charges Carbon nanotubes are already being produced would move in a 2-D plane where two different commercially by more than 16 companies, about semiconductors meet. In the 1970s, Kroemer and half of them in the ; and new facto- Zhores I. Alferov at the A. F. Ioffe Physico-Techni- ries are being built in Japan, Korea, China, and cal Institute in Russia independently developed a France. Current worldwide production in 2002 was heterostructure laser, for which they were awarded more than 2.5 metric tons per day, a staggering the 2000 . Research into the amount considering each tube is mere femtograms. quantum effects of semiconductors continued, and in 1980, Alexander Ekimov and Alexei Efros at Small problems the Ioffe Institute observed quantum confinement Microtechnology and nanotechnology have in zero dimensions, which was also discovered by changed our world. And, although there may be researchers led by L. Brus and R. Rossetti of Bell problems down the road—for example, recent Labs. In the early 1990s, several papers discussed studies indicate that carbon nanotubes may cause possible uses for the zero-dimensional quantum damage to the lungs of rats, and cadmium-based dots, which was borne out by research in communi- quantum dots have been shown to kill rat liver cations technology and biology. cells when cadmium leaches from the dot—few are Several companies are now commercially calling for the end to nanotechnology research. In producing quantum dots for biological use. The fact, many countries are increasing their funding, first entrant was QuantumDot, which was formed including the United States through the U.S. in 1998 on the basis of work done at the Massa- National Nanotechnology Initiative. The trend is Above: MEMS-GC illustration, Today’s Chemist at Work, 2002 chusetts Institute of Technology and the Universi- clear: The future is small. ◆

128 ENTERPRISE OF THE CHEMICAL SCIENCES