What Is Nanotechnology?
2013; Elsevier BV; Volume: 20; Issue: 6 Linguagem: Inglês
10.1053/j.ackd.2013.08.008
ISSN1548-5609
Autores Tópico(s)Molecular Communication and Nanonetworks
Resumo"There's Plenty of Room at the Bottom."—Richard P. FeynmanNanotechnology is often considered (in retrospect) to have academic and popular culture birthdates: the academic birth when Nobel laureate Richard Feynman delivered his 1959 "There's plenty of room at the bottom" lecture to the American Physical Society, followed 7 years later by Richard Fleischer's popular 1966 science fiction movie Fantastic Voyage, starring Stephen Boyd and Raquel Welch.1Feynman R.P. There's plenty of room at the bottom.Eng Sci. 1960; 23: 22-36Google Scholar, 2Fleischer R. Fantastic Voyage. Twentieth Century Fox Film Corporation, Los Angeles, CA1966Google Scholar In his lecture at Caltech, Feynman reflected on the large difference between length scales appreciable by human eyes and hands (eg, 1 m) and the length scales of fundamental blocks of matter (eg, metal atoms), which are hundreds of picometers (10−12m) in size, and proposed a thought experiment. Similar to the way a pantograph mechanically reproduces an image at a smaller size, Feynman imagined a cascade of machines, each manufacturing and manipulating a smaller version of itself, until finally the smallest machine could manipulate individual atoms. Feynman predicted technologies with the ability to carry vast information in small packages and craft molecular tools that could cure disease in patients who "swallowed the doctor".1Feynman R.P. There's plenty of room at the bottom.Eng Sci. 1960; 23: 22-36Google Scholar In the movie Fantastic Voyage, that exact fantasy of a cell-sized "repair truck" was dramatized in the guise of a miniaturized submarine and crew injected into a patient's bloodstream to remove a cerebral blood clot.Feynman's lecture was delivered only a decade after Shockley's invention of the junction transistor and only a year after Jack Kilby's successful implementation of the first integrated circuit at Texas Instruments; therefore, there was the mood and the means to miniaturize electronic devices. As silicon technology matured, it was appreciated that the same manufacturing processes that were used for integrated circuits could also be used to manufacture mechanical devices. Harvey Nathanson is generally credited with the invention of the first microelectromechanical systems (MEMS) device integrating electrical and mechanical components in 1965.3Nathanson R.A. Wickstrom H.C. A resonant-gate silicon surface transistor with high-Q band-pass properties.Appl Phys Lett. 1965; 7: 84-86Crossref Scopus (104) Google Scholar Thus, the genesis of technologies entering the medical marketplace today, in 2013, occurred fully a half century ago.Atomic-scale nanotechnology remained an underdeveloped niche (the actual role of either the lecture or the movie in catalyzing research is probably smaller than now claimed) until 1981. Gerd Binnig and Heinrich Rohrer, both at IBM's Zurich Research Institute, developed a microscope capable of imaging individual atoms, the scanning tunneling microscope (STM), for which they received the Nobel Prize in Physics in 1986. I had the opportunity to see a very early STM prototype at IBM's Thomas J. Watson Research Center in Yorktown Heights, New York, in 1985. This technology relatively rapidly evolved into tabletop atomic force microscopes, which can deliver spatially and chemically resolved images of surfaces and have the ability to move and manipulate individual atoms.4Browne M.W. 2 Researchers Spell 'I.B.M.,' atom by atom. New York Times, New York1990Google Scholar Since the mid-1980s, MEMS and nanotechnology have entered consumer goods, in products ranging from airbag accelerometers to inkjet printer cartridges to nanoemulsion sunscreens.This issue of Advances in Chronic Kidney Disease introduces MEMS and nanotechnology to the nephrology community. So what is nanotechnology, and what is nanotechnology to the doctor? The broadest descriptive brush stroke is that nanotechnology refers to engineering efforts in a size domain in which surfaces dominate material behavior. What does this mean? There are relatively commonplace kitchen-table examples that can illuminate the concept. Compare plastic cling-film to aluminum foil. Plastic cling-film adheres to kitchenware because of van der Waals or electrostatic forces between its surface and the surface of the vessel. The plastic film, if delivered in a block, would not have the useful properties it delivers as a film. Only as a film do surface effects become much more evident than the bulk properties with which we are familiar, such as density or weight and elasticity. In contrast, aluminum foil clings to a pan because the user deforms the foil to mechanically latch it to the material, as it also does at larger sizes. Nanotechnology is the engineering of particles, devices, and coatings at length scales that exploit forces and effects (eg, electrostatics and surface tension) to deliver a desired effect.It can be argued that nephrologists are already seasoned nanotechnology users because the pore structures of dialysis membranes are tuned at the nanometer scale to produce high- and low-flux membranes for clinical use.5Ronco C. Bowry S. Nanoscale modulation of the pore dimensions, size distribution and structure of a new polysulfone-based high-flux dialysis membrane.Int J Artif Organs. 2001; 24: 726-735PubMed Google Scholar, 6Fissell W.H. Humes H.D. Fleischman A.J. Roy S. Dialysis and nanotechnology: now, 10 years, or never?.Blood Purif. 2007; 25: 7-12Crossref PubMed Scopus (4) Google Scholar Nanotechnology concepts tend to emerge in medicine in 3 broad areas. The first, and possibly the closest to widespread clinical use, is nanoparticles, such as quantum dots and dendrimers. In this issue of Advances in Chronic Kidney Disease, Brede and Labhasetwar introduce nanoparticles and describe the myriad of strategies by which the interactions among particles, plasma, and tissues can be controlled by the "shell" or outer skin of the particle whereas the interior core carries a "payload" of a drug or a contrast agent. Chen and Wickline then advance this idea by describing how magnetic resonance (MR) imaging and nanoparticle contrast agents carrying a particular payload, perfluorocarbons, can provide insight not just into the anatomic structures of the kidney but also into regional oxygenation within the kidney, which has immediate applications to the understanding of acute kidney injury and its imperfect recovery. Charlton, Beeman, and Bennett review approaches to MR assessment of kidney function and then discuss an unanticipated and exciting application of MR and nanoparticles to assess kidney mass, functional reserve, and nephron endowment by counting functional glomeruli. Thurman and Serkova expand further on this concept of using nanoparticles to link spatial localization to tissue pathology in their discussion of agents that image inflammation and diagnosis of glomerular disease. Finally, Zuckerman and Davis expand on the use of nanoparticles, taking us from diagnostic imaging to molecularly targeted therapeutics.The second area in which nanotechnology influences medicine is miniaturization of familiar devices, such as pressure transducers and needles and the formation of nanoporous membranes.7Fissell W.H. Dubnisheva A. Eldridge A.N. Fleischman A.J. Zydney A.L. Roy S. High-performance silicon nanopore hemofiltration membranes.J Memb Sci. 2009; 326: 58-63Crossref PubMed Scopus (138) Google Scholar Moving to the second broad area, miniaturized devices, Kim and Roy, pioneers in biomedical applications of MEMS, describe the technology toolkit underlying MEMS and follow with a comprehensive review of MEMS applications to biomedical devices such as implanted sensors, transducers, and point-of-care testing units. Johnson and colleagues make another connection from the "cleanroom" to nephrology by discussing potential applications of porous silicon films to dialysis, although they acknowledge the technical barriers to implementing a practical device that is based on silicon nanotechnology. The third area in which nanotechnology influences medicine and medical devices is atomic-scale control of surface characteristics through coatings and monolayers. Baoxia Mi introduces us to the molecular control of surfaces. Mi discusses how surface characteristics and chemistry affect membrane fouling and failure, a familiar issue to any nephrologist who has rounded in a dialysis unit.Over a half century has elapsed since Feynman's lecture, and MEMS and nanotechnology are instrumental parts of everyday life. Nanotechnology has not provided the injectable submarines of Fantastic Voyage nor engulfed the planet in a "gray goo" of self-replicating machines.8Drexler K.E. Engines of Creation: The Coming Era of Nanotechnology. Anchor Books, New York, NY1986Google Scholar "There's Plenty of Room at the Bottom."—Richard P. Feynman Nanotechnology is often considered (in retrospect) to have academic and popular culture birthdates: the academic birth when Nobel laureate Richard Feynman delivered his 1959 "There's plenty of room at the bottom" lecture to the American Physical Society, followed 7 years later by Richard Fleischer's popular 1966 science fiction movie Fantastic Voyage, starring Stephen Boyd and Raquel Welch.1Feynman R.P. There's plenty of room at the bottom.Eng Sci. 1960; 23: 22-36Google Scholar, 2Fleischer R. Fantastic Voyage. Twentieth Century Fox Film Corporation, Los Angeles, CA1966Google Scholar In his lecture at Caltech, Feynman reflected on the large difference between length scales appreciable by human eyes and hands (eg, 1 m) and the length scales of fundamental blocks of matter (eg, metal atoms), which are hundreds of picometers (10−12m) in size, and proposed a thought experiment. Similar to the way a pantograph mechanically reproduces an image at a smaller size, Feynman imagined a cascade of machines, each manufacturing and manipulating a smaller version of itself, until finally the smallest machine could manipulate individual atoms. Feynman predicted technologies with the ability to carry vast information in small packages and craft molecular tools that could cure disease in patients who "swallowed the doctor".1Feynman R.P. There's plenty of room at the bottom.Eng Sci. 1960; 23: 22-36Google Scholar In the movie Fantastic Voyage, that exact fantasy of a cell-sized "repair truck" was dramatized in the guise of a miniaturized submarine and crew injected into a patient's bloodstream to remove a cerebral blood clot. Feynman's lecture was delivered only a decade after Shockley's invention of the junction transistor and only a year after Jack Kilby's successful implementation of the first integrated circuit at Texas Instruments; therefore, there was the mood and the means to miniaturize electronic devices. As silicon technology matured, it was appreciated that the same manufacturing processes that were used for integrated circuits could also be used to manufacture mechanical devices. Harvey Nathanson is generally credited with the invention of the first microelectromechanical systems (MEMS) device integrating electrical and mechanical components in 1965.3Nathanson R.A. Wickstrom H.C. A resonant-gate silicon surface transistor with high-Q band-pass properties.Appl Phys Lett. 1965; 7: 84-86Crossref Scopus (104) Google Scholar Thus, the genesis of technologies entering the medical marketplace today, in 2013, occurred fully a half century ago. Atomic-scale nanotechnology remained an underdeveloped niche (the actual role of either the lecture or the movie in catalyzing research is probably smaller than now claimed) until 1981. Gerd Binnig and Heinrich Rohrer, both at IBM's Zurich Research Institute, developed a microscope capable of imaging individual atoms, the scanning tunneling microscope (STM), for which they received the Nobel Prize in Physics in 1986. I had the opportunity to see a very early STM prototype at IBM's Thomas J. Watson Research Center in Yorktown Heights, New York, in 1985. This technology relatively rapidly evolved into tabletop atomic force microscopes, which can deliver spatially and chemically resolved images of surfaces and have the ability to move and manipulate individual atoms.4Browne M.W. 2 Researchers Spell 'I.B.M.,' atom by atom. New York Times, New York1990Google Scholar Since the mid-1980s, MEMS and nanotechnology have entered consumer goods, in products ranging from airbag accelerometers to inkjet printer cartridges to nanoemulsion sunscreens. This issue of Advances in Chronic Kidney Disease introduces MEMS and nanotechnology to the nephrology community. So what is nanotechnology, and what is nanotechnology to the doctor? The broadest descriptive brush stroke is that nanotechnology refers to engineering efforts in a size domain in which surfaces dominate material behavior. What does this mean? There are relatively commonplace kitchen-table examples that can illuminate the concept. Compare plastic cling-film to aluminum foil. Plastic cling-film adheres to kitchenware because of van der Waals or electrostatic forces between its surface and the surface of the vessel. The plastic film, if delivered in a block, would not have the useful properties it delivers as a film. Only as a film do surface effects become much more evident than the bulk properties with which we are familiar, such as density or weight and elasticity. In contrast, aluminum foil clings to a pan because the user deforms the foil to mechanically latch it to the material, as it also does at larger sizes. Nanotechnology is the engineering of particles, devices, and coatings at length scales that exploit forces and effects (eg, electrostatics and surface tension) to deliver a desired effect. It can be argued that nephrologists are already seasoned nanotechnology users because the pore structures of dialysis membranes are tuned at the nanometer scale to produce high- and low-flux membranes for clinical use.5Ronco C. Bowry S. Nanoscale modulation of the pore dimensions, size distribution and structure of a new polysulfone-based high-flux dialysis membrane.Int J Artif Organs. 2001; 24: 726-735PubMed Google Scholar, 6Fissell W.H. Humes H.D. Fleischman A.J. Roy S. Dialysis and nanotechnology: now, 10 years, or never?.Blood Purif. 2007; 25: 7-12Crossref PubMed Scopus (4) Google Scholar Nanotechnology concepts tend to emerge in medicine in 3 broad areas. The first, and possibly the closest to widespread clinical use, is nanoparticles, such as quantum dots and dendrimers. In this issue of Advances in Chronic Kidney Disease, Brede and Labhasetwar introduce nanoparticles and describe the myriad of strategies by which the interactions among particles, plasma, and tissues can be controlled by the "shell" or outer skin of the particle whereas the interior core carries a "payload" of a drug or a contrast agent. Chen and Wickline then advance this idea by describing how magnetic resonance (MR) imaging and nanoparticle contrast agents carrying a particular payload, perfluorocarbons, can provide insight not just into the anatomic structures of the kidney but also into regional oxygenation within the kidney, which has immediate applications to the understanding of acute kidney injury and its imperfect recovery. Charlton, Beeman, and Bennett review approaches to MR assessment of kidney function and then discuss an unanticipated and exciting application of MR and nanoparticles to assess kidney mass, functional reserve, and nephron endowment by counting functional glomeruli. Thurman and Serkova expand further on this concept of using nanoparticles to link spatial localization to tissue pathology in their discussion of agents that image inflammation and diagnosis of glomerular disease. Finally, Zuckerman and Davis expand on the use of nanoparticles, taking us from diagnostic imaging to molecularly targeted therapeutics. The second area in which nanotechnology influences medicine is miniaturization of familiar devices, such as pressure transducers and needles and the formation of nanoporous membranes.7Fissell W.H. Dubnisheva A. Eldridge A.N. Fleischman A.J. Zydney A.L. Roy S. High-performance silicon nanopore hemofiltration membranes.J Memb Sci. 2009; 326: 58-63Crossref PubMed Scopus (138) Google Scholar Moving to the second broad area, miniaturized devices, Kim and Roy, pioneers in biomedical applications of MEMS, describe the technology toolkit underlying MEMS and follow with a comprehensive review of MEMS applications to biomedical devices such as implanted sensors, transducers, and point-of-care testing units. Johnson and colleagues make another connection from the "cleanroom" to nephrology by discussing potential applications of porous silicon films to dialysis, although they acknowledge the technical barriers to implementing a practical device that is based on silicon nanotechnology. The third area in which nanotechnology influences medicine and medical devices is atomic-scale control of surface characteristics through coatings and monolayers. Baoxia Mi introduces us to the molecular control of surfaces. Mi discusses how surface characteristics and chemistry affect membrane fouling and failure, a familiar issue to any nephrologist who has rounded in a dialysis unit. Over a half century has elapsed since Feynman's lecture, and MEMS and nanotechnology are instrumental parts of everyday life. Nanotechnology has not provided the injectable submarines of Fantastic Voyage nor engulfed the planet in a "gray goo" of self-replicating machines.8Drexler K.E. Engines of Creation: The Coming Era of Nanotechnology. Anchor Books, New York, NY1986Google Scholar
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