Profile

Harold Craighead

Professor of Engineering, Cornell University, Ithaca, New York, USA

Professor Harold Craighead, of Cornell University, has been a pioneer in the fabrication and application of ultra-small structures and devices. In recent years he and his research group have demonstrated several new approaches to molecular sorting and analysis using nanoscale fluid systems and devices for confining optical excitation to extremely small volumes for spectroscopy of small systems, even single molecules. He has also directed research in the creation and utilization of nanomechanical systems. He has been leading efforts to exploit the research and application opportunities at the bio–nano interface. He was the founding director of the multi-institutional Nanobiotechnology Center, proposed to the National Science Foundation in 1999. He is frequently called upon to speak on the future application of nanostructures and devices, particularly for chemical, biological and medical applications.

Educational and Professional Positions
B.S. Physics, with high honors & high honors in Physics, University of Maryland, 1974
Ph.D. Physics, Cornell University, 1980
Member of Technical Staff, Device Physics Research Dept., Bell Laboratories, 1979–1984
Research manager and creator, Quantum Structures Research, Bellcore, 1984–1989
Professor, School of Applied and Engineering Physics, Cornell University, 1989–present
Director, National Nanofabrication Facility, Cornell University, 1989–1995
Director, School of Applied and Engineering Physics, Cornell University, 1998–2000
Founding director, Nanobiotechnology Center, Cornell University, 2000–2001
Interim Dean, College of Engineering, Cornell University, 2001–2002
Co-Director, Nanobiotechnology Center, Cornell University, 2002–present
Charles W. Lake, Jr., Professor of Engineering, 2001–present

Boyhood to Bell Labs to beautiful Ithaca

Craighead was born in Lancaster County PA in 1952, the eldest child of Esta and Moyer Craighead. He was raised in a small town environment, where he was able to build and launch model rockets and collect frogs and turtles as a child and then take college-level science, mathematics and computer courses at Elizabethtown College while attending high school. This early college-level work paved the way for more sophisticated course work once he arrived at the University of Maryland and prepared him for early involvement in university-level research as an undergraduate at Maryland and as a summer researcher at Yale.

Craighead attributes his success as a scientist to his parents who encouraged his scientific curiosity as a child and encouraged him over the long years of formal education. Popular science also played a part. His interest in science was stimulated, for example, by Don Herbert in the “Watch Mr. Wizard” TV show (http://www.museum.tv/archives/etv/W/htmlW/watchmrwiz/watchmrwiz.htm). His general interest in science and math took a turn toward physics in high school, and he continued studying physics as an undergrad at the University of Maryland and as a graduate student at Cornell.

In 1979, Craighead completed his graduate work, started his professional career at Bell Labs in Holmdel, NJ, and married Teresa. The Craigheads have one son, Daniel, who attends middle school in Ithaca. Teresa does part-time project coordination for Cornell Information Technologies. Daniel is interested in running, computer games, basketball, Legos, and manifests the “Craighead curiosity gene.”

Craighead and his family are based in Ithaca, New York, home to Cornell University, where Craighead is a member of the faculty. There are several well-known clichés about Ithaca and they are all true: it is “centrally isolated” in upstate New York—part of its charm for many—and it is “gorgeous.” The local bumper stickers claim “Ithaca is Gorges” a play on words that attributes the natural beauty of the area to the gorges left behind by the glaciers that passed through two million years ago. The population of almost 30 000 increases by more than 25 000 when students are in town, and all 55 000 people complain about the weather although they are secretly proud of their ability to withstand long winters. Come to Ithaca, and you’ll hear a good snow story…or complaints that it wasn’t a “good” winter, meaning not enough snow to satisfy the skiers.

Historical research perspective: Craighead’s research included early focus on nanoscale structures

The formation and exploitation of nanoscale structures and devices has been a theme of Craighead’s scientific career.

Cornell—graduate student years

His thesis work at Cornell involved an experimental study of the formation and optical properties of metal nanoparticles in dielectric media. These films had applications as solar photo-thermal collectors. The spectral dependence of the optical properties of thin films were tailored by the nanoscale structure of the materials.

Bell Labs

He began his professional career at Bell Laboratories, in Holmdel, NJ in the Device Physics Research Department. Research there focused on studies of high-resolution semiconductor fabrication processes, including lithography with high-energy finely-focused electron beams. This work resulted in the creation of the smallest wires and etched structures on GaAs for that time. Craighead also did research on optical data storage media and display devices based on media with dimensions less than optical wavelengths, where the optical properties of the devices were modulated by nanoscale structural changes in the media.

Bell Communications Research

At the break up of AT&T in 1984, Craighead transferred to the newly created Bell Communications Research and became a research manager in the Solid State Science and Technology Laboratory. He formed and headed the Quantum Structures Research Group responsible for advanced lithography, device fabrication and experimental quantum device studies in ultra-small systems. His personal research centered on semiconductor nanofabrication processes and the physical properties of ultra-small structures. He explored ion etching processes in compound semiconductors, with, in several cases, the first published accounts of reactive ion etching processes in several material systems. He also worked on semiconductor quantum dots and wires.

Cornell—professional years

Craighead joined the faculty of Cornell University as a Professor in the School of Applied and Engineering Physics in 1989, teaching at the undergraduate and graduate levels. From 1989 until 1995 he was Director of the National Nanofabrication Facility (NNF) at Cornell University. At that time the NNF was the only national resource for creation of nanostructures in a range of material systems. Overseeing and guiding this activity gave Craighead a perspective for the direction and impact of nanoscale science and technology. During this period he began to put more of his research efforts into the biological applications of nanostructures. He organized several conferences and workshops on the science and application of nanostructures with biology becoming more of a dominant theme. In 1994, for example, along with Professors Jelinski and Hoch of Cornell he organized the international conference on Nanofabrication and Biosystems: Frontiers and Challenges.¹

Craighead continued to maintain a vigorous research program in nanostructures while assuming a variety of administrative positions at Cornell. He was Director of the School of Applied and Engineering Physics from 1998 to 2000 and Interim Dean of Engineering from 2001–2002, in which capacity he helped to guide the area of nanostructure science and engineering as a significant thrust at Cornell.

Expanding on his personal interest and activity in connecting nanoscale research and biology, he led Cornell’s effort that formed, in 2000, the multi-institutional Nanobiotechnology Science Center. He was the founding director and is now co-director for research.

He contributed to the workshops and reports that led to the establishment of the US National Nanotechnogy Initiative, co-authoring one of the initial reports on the application of nanostructure science and technology to biology and medicine.

While not new to the scientific community, the promise of nanotechnology captured the imagination of the business world and the general public in the late 1990s. Forbes magazine devoted its annual “E Gang” issue to nanotechnology in 2001, heralding it as “The Next Big Idea.” Along with the work of peers from throughout the world, Craighead’s research on nanoscale systems was introduced to the business world.

Several of the technologies derived from Craighead’s research have been licensed to start-up companies and he has served on the scientific advisory boards of several nanotechnology-related new companies. Craighead is also a founder, along with his former student Stephen Turner, of Nanofluidics Inc. Nanofluidics is pioneering the integration of microcircuitry, optics, and biochemistry and aims to push out the frontiers of miniaturized fluidics and single-molecule analysis.

Current research

Nanomechanical systems

Professor Craighead’s research group has spent considerable effort on the study of mechanical devices with dimensions as small as a few tens of nanometers.^2–11 Part of the research involves finding new approaches for creating small functional structures. Using electron beam lithography and other high-resolution fabrication processes, various materials from silicon to diamond have been investigated for their mechanical behavior when formed into small objects. These nanoscale systems are particularly interesting for high-frequency resonant operation in conjunction with electronics and for measurement of very small forces and masses. The research group has found interesting optical interactions that can be used to both detect and drive the motion of the small oscillating devices. Functions such as amplification and frequency tuning can also be performed with the electrically or optically activated mechanical resonant devices. A fanciful, guitar shaped device, made with the same silicon-based processes used for high-frequency resonant structures captivated the general community and was displayed in the popular press. It is listed in the Guinness Book of World Records as the world’s smallest guitar. The approaches used to create small moving mechanical devices have been adapted for the handling of fluids in similar ultra-small geometries. This is the enabling technology for work on single molecule analysis and separations.

Single molecule analysis

Professor Craighead is researching the use of nanostructures for the analysis and sorting of individual molecules.^12–19 This includes the use of ultra-small fluidic systems to isolate molecules for optical analysis or analysis by their “mechanical” properties as they distort to move through structures with dimensions comparable to or smaller than their molecular size. These approaches have included the use of nano-constrictions of various shapes that form controllable entropic barriers for separating biopolymers by shape or molecular size. Methods for isolating molecules for individual optical analysis have included squeezing molecules one-at-a-time through narrow tubes and measuring their individual fluorescence. This has been used, for example, to analyze the size of DNA fragments in small fluid channels. Individual active biomolecules can also be isolated in quasi-zero-dimensional metallic structures that isolate optical excitation to volumes on the order of zeptoliters, allowing the real-time investigation of enzymatic activity. A recent example of this approach involved the observation of single nucleotide incorporation in the polymerization of DNA. Related nanofabrication approaches with metallic systems have been used to create sub-wavelength size anisotropic rods for optical observation of the action of rotating molecular motors. The hope is that engineered nano-optical and nanofluidic systems can be used to observe single biomolecule activity and may even be incorporated in highly parallel systems for rapid and ultra-sensitive analytical systems based on single molecule detection and analysis.

Microanalytical systems and biosensors

Recent research has involved miniaturization of chemical separation and analytical methods and the integration of optical and mass spectroscopic techniques with microfluidics.^20–26 Microfluidic approaches allow for parallelism in analysis, analogous to what we find in microelectronics, for higher throughput possibilities. Optical approaches include the incorporation of metallic films or narrow optical gaps in fluidic systems for surface plasmon resonance or photon tunnelling methods for detecting refractive index change of bound materials. Electrically driven separations such as chip-based capillary electrophoretic separations have been investigated in channels of various material composition and the flow and separation possibilities examined. Electrospray sources connected to microfluidic systems allow for simpler integration of mass spectrometry with microfluidics. The Craighead research group is also studying approaches for exploring the activity or character of individual living cells.

Fluid channels integrated with planar waveguide optics.

Nanoscale materials patterning

The high resolution patterning that has been used for creating nanomechanical devices in inorganic systems has been adapted to modify a range of materials from biologically sensitive layers to polymeric systems and optical materials,^27–36 allowing for the creation of ultra-small fluid channels in a range of systems. Non-lithographic processes include the oriented electrospray deposition of polymeric nanofibers as active materials or as templates for nanostructure fabrication in other materials.

The issue of cell interaction with surfaces is important for many biological systems and devices such as medical implants. Aspects of Professor Craighead’s research activity utilize chemically and topographically modified surfaces to test cell-surface interactions.^37–43 With these new approaches the same capabilities that are available to create devices in inorganic materials can be brought to hybrid organic/inorganic systems and utilized for interrogating biological systems.

Oriented polyethylene oxide nanofibers diameters of ~100 nm deposited in an array by a scanning electrodeposition process fluorescently labeled with Rhodamine B and Fluorescine. Conducting polymers of other composition are being studied in the Craighead labs as sensors and electronic devices. (See ref. 36).

Patents and papers

Professor Craighead’s research has resulted in ten issued patents with titles such as: Multiple Optical Channels for Chemical Analysis, Unitary Microcapilliary and Waveguide Structure and Method of Fabrication, Light-Absorbing Materials, Mechanically Resonant Nanostructures and Optical Information Storage and Retrieval. Other patents on chemical and biological applications of micro and nanostructures are pending.

Professor Craighead has published over 240 journal articles and book chapters. He continues to contribute to long-established journals that cover areas of nanoscale physical properties, materials, devices and processing such as Applied Physics Letters, Physical Review Letters, Science, and the Journal of Vacuum Science and Technology. With growing activity in the chemical and biological arenas, recent publications include Analytical Chemistry, Biophysical Journal, Langmuir and a variety of biological journals. Recently created journals that deal with new applications of nanostructures and device miniaturization include Nanotechnology, IEEE Transactions on Nanobioscience and Biomedical Microdevices. Craighead contributes to each of these and serves on their editorial boards.

Craighead had the following comments in response to Lab on a Chip interview questions:

Q: What is the most important aspect/value of micro/nanotechnology?

That is a very open ended question that I do not think I can address completely in a short answer. Many areas of technology, but most notably electronics, and the related display and data storage applications have made great advances in function and availability because of miniaturization. Optical and mechanical systems also have enjoyed similar advances through miniaturization. At this time the technologies are being utilized to provide new research tools and methodologies for understanding chemical and biological systems.

Q: What are the major problems/bottlenecks in miniaturization at present?

The scientific discoveries and engineering advances are exciting and opening up new opportunities. Except for silicon microelectronics, as I mentioned, there are at present few very large-scale applications or markets that can drive major development and complex system integration. Many new applications are emerging, in analytical and lab on a chip areas for example, but these each tend to be in varying architectures, material systems, and areas of use. It requires a “critical mass” of activity to push major new technologies forward, and that takes some time to build.

Q: Are you concerned that there may be too much “hype” with nanotechnology?

I am glad that interest in “nanotechnology” has stimulated general interest in science and engineering. I am afraid, however, that much of this interest may be based on a science fiction version of nanotechnology that involves nanobots and nearly magical materials assembled by nanotechnology. The science fiction version has very little to do with what serious scientists and engineers are actually doing and this causes some confusion when discussing research and technologies. There is probably a bit of irrational exuberance associated with the prefix nano-.

Q: As an academic do you have sufficient time for research?

Teaching undergraduates, advising, and participating in institutional service, clearly compete for the time of faculty staff at research universities. Faculty staff who want to maintain high standards in all areas, including leading research efforts in highly competitive areas, tend to work pretty hard, with long days.

Q: What sorts of courses do you teach?

I have taught a range of courses from an introductory laser lab course for freshmen, Electricity and Magnetism for juniors and graduate courses in Micro- and Nano-fabrication. This semester I am teaching an introductory course in nanostructure science and technology for freshman engineers. I am looking forward to working on this new class that includes hands-on labs with some sophisticated equipment such as atomic force microscopes and scanning tunnelling microscopes.

Q: What is the situation with students; is it becoming easier or more difficult to find doctoral and post docs with relevant backgrounds?

The area of nanostructure science and technology is attractive to students, and I have no trouble finding good ones. We are now educating the next generation of students with greater interdisciplinary breadth and abilities to work in diverse research teams. It seems, in general, that fewer American students are interested in careers in science and engineering.

Q: Do you have any overall comments on your career experiences and the future of your field or your personal research directions?

I have found that education and research is an intellectually stimulating and rewarding career. I have been very fortunate to work with outstanding students and researchers at institutions that have been supportive of research and technology development. Over the duration of my career I have seen significant advances in the technologies used to image, manipulate and utilize nanoscale structures and devices. It has been an exciting period that I do not see ending soon. I see my research moving forward in the areas of nanofabrication and single molecule analysis. I believe there is new science to be seen and applications to explore.

References

1. Nanofabrication and biosystems, ed. H. G. Hoch, L. W. Jelinski and H. G. Craighead, Cambridge University Press, 1996.
2. H. G. Craighead, Science, 2000, 290, 1532–1535.
3. S. Evoy, A. Olkhovets, L. Sekaric, J. M. Parpia, H. G. Craighead and D. W. Carr, Appl. Phys. Lett., 2000, 77, 2397–2399.
4. L. Sekaric, D. W. Carr, S. Evoy, J. Parpia and H. G. Craighead, Sens. Actuators A, 2002, 101, 215–219.
5. L. Sekaric, J. M. Parpia, H. G. Craighead, T. Feygelson, B. H. Houston and J. E. Butler, Appl. Phys. Lett., 2002, 81, 4455–4457.
6. B. Ilic, D. Czaplewcki, M. Zalalutdinov, H. G. Craighead, C. Campagnolo and C. Batt, J. Vacuum Sci. Technol., 2001, 19, 2825–2828.
7. L. Sekaric, M. Zalalutdinov, R. B. Bhiladvala, A. Zehnder, J. Parpia and Harold Craighead, Appl. Phys. Lett., 2002, 81, 2641–2643.
8. L. Sekaric, M. Zalalutdinov, S. Turner, A. Zehnder, J. Parpia and H. G. Craighead, Appl. Phys. Lett., 2002, 80, 3617–3619.
9. M. Zalalutdinov, A. Zehnder, A. Olkhovest, S. Turner, L. Sekaric, B. Ilic, D. Czaplewski, J. M. Parpa and H. G. Craighead, Appl. Phys. Lett., 2001, 79, 695–697.
10. M. Zalalutdinov, A. Olkhovets, A. Zehnder, B. Ilic, D. Czaplewski, H. G. Craighead and J. M. Parpia, Appl. Phys. Lett., 2001, 78, 3142–3144.
11. M. Sato, B. E. Hubbard, A. J. Sievers, B. Ilic, D. A. Czaplewski and H. G. Craighead, Phys. Rev. Lett., 2003, 90, 44102-1–44102-4.
12. J. Han, S. W. Turner and H. G. Craighead, Phys. Rev. Lett., 1999, 83, 1688–1691.
13. J. Han and H. G. Craighead, Science, 2000, 288, 1026–1029.
14. J. Han and H. G. Craighead, Anal. Chem., 2002, 74, 394–401.
15. M. Foquet, J. Korlach, W. Zipfel, W. W. Webb and H. G. Craighead, Anal. Chem., 2002, 74, 1415–1422.
16. S. Turner, M. Cabodi and H. G. Craighead, Phys. Rev. Lett., 2002, 88, 128103-1–128103-4.
17. Mario Cabodi, Stephen W. P. Turner and Harold G. Craighead, Anal. Chem., 2002, 74, 5169–5174.
18. M. J. Levine, J. Korlach, S. W. Turner, M. Foquet, H. G. Craighead and W. W. Webb, Science, 2003, 299, 682–686.
19. R. K. Soong, G. D. Bachand, H. P. Neves, A. G. Olkhovets, H. G. Craighead and C. D. Montemagno, Science, 2000, 290, 1555–1558.
20. M. Furuki, J. Kameoka, H. G. Craighead and M. Isaacson, Sens. Actuators B, 2001, 79, 63–69.
21. J. Kameoka and H. G. Craighead, Sens. Actuators B, 2001, 77, 632–637.
22. J. Kameoka, H. G. Craighead, H. W. Zhang and J. Henion, Anal. Chem., 2001, 73, 1935–1941.
23. Jun Kameoka, Reid Orth, Bojan Ilic, David Czaplewski, Tim Wachs and H. G. Craighead, Anal. Chem., 2002, 74, 5897–5901.
24. J. Gaudioso and H. G. Craighead, J. Chromatogr., A, 2002, 971, 249–253.
25. A. Dias, G. Dernick, V. Valero, M. G. Yong, C. James, H. Craighead and M. Lindau, Nanotechnology, 2002, 13, 285–289.
26. B. Ilic, D. Czaplewski, H. G. Craighead, P. Neuzil, C. Campagnolo and C. Batt, Appl. Phys. Lett., 2000, 77, 450–452.
27. C. K. Harnett, K. M. Satyalakshmi and H. G. Craighead, Appl. Phys. Lett., 2000, 76, 2466–2468.
28. B. Ilic and H. G. Craighead, Biomed. Microdevices, 2000, 2, 317–322.
29. C. K. Harnett, A. Lopez, K. M. Satyalakshmi, Y. F. Chen and H. G. Craighead, Proc. Mater. Res. Soc., 2001, 638, F10.1.1–F10.1.6.
30. A. G. Lopez and H. G. Craighead, Appl. Opt., 2001, 40, 2068–2075.
31. A. Peter Russo, Dace Apoga, Natalie Dowell, William Shain, Andrea M. P. Turner, Harold G. Craighead, A. J. Spence, S. T. Retterer, M. Isaacson, Harvey C. Hoch and James N. Turner, Biomed. Microdevices, 2002, 4(4), 277–283.
32. B. Ilic, D. Czaplewcki, M. Zalalutdinov, B. Schmidt and H. G. Craighead, J. Vacuum Sci. Technol. B, 2002, 20, 2459–2465.
33. C. K. Harnett, K. M. Satyalakshmi and H. G. Craighead, Langmuir, 2001, 17, 178–182.
34. C. K. Harnett, K. M. Satyalakshmi, G. W. Coates and H. G. Craighead, J. Photopolymer Sci. Technol., 2002, 15, 493–496.
35. C. K. Harnett, G. W. Coates and H. G. Craighead, J. Vacuum Sci. Technol., 2001, 19, 2842–2845.
36. Jun Kameoka and H. G. Craighead, Appl. Phys. Lett., 2003, 83, 371–373.
37. D. R. Jung, R. Kapur, T. Adams, K. A. Giuliano, M. Mrksich, H. G. Craighead and D. L. Taylor, Crit. Rev. Biotechnol., 2001, 21, 111–154.
38. C. D. James, R. Davis, M. Meyer, A. Turner, S. Turner, G. Withers, L. Kam, G. Banker, H. G. Craighead, M. Isaacson, J. N. Turner and W. Shain, IEEE Trans. Biomed. Eng., 2000, 47, 17–21.
39. N. Dowell, A. M. P. Turner, H. Hong, S. Rajan, H. G. Craighead, J. N. Turner and W. Shain, Mol. Biol. Cell, 2000, 11, 2831.
40. A. M. P. Turner, N. Dowell, S. W. P. Turner, L. Kam, M. Isaacson, J. N. Turner, H. G. Craighead and W. Shain, J. Biomed. Mater. Res., 2000, 51, 430–441.
41. H. G. Craighead, C. James and A. M. P. Turner, Curr. Opin. Solid State Mater. Sci., 2001, 5, 177–184.
42. Reid N. Orth, Min Wu, David A. Holowka, Harold G. Craighead and Barbara A. Baird, Langmuir, 2003, 19, 1599–1605.
43. B. Ilic, D. Czaplewcki, M. Zalalutdinov, H. G. Craighead, C. Campagnolo and C. Batt, J. Vacuum Sci. Technol., 2001, 19, 2825–2828.

---