Los Angeles -- A professor of mechanical and aerospace engineering is on a mission from NASA to understand how the workings of biological cells might help inspire the next generation of information-processing systems. For Chih-Ming Ho and his colleagues in varied disciplines, it's all part of a day's work at the University of California at Los Angeles, where engineering research is cutting across traditional boundaries to unite biotechnology, nanotechnology and computer science.
UCLA's Henry Samueli School of Engineering held its first multidisciplinary "research review" this month. The theme of the research review was "Multidisciplinary Engineering for the 21st Century: The Convergence of Bio-Nano-Info Technologies." On display was the latest research in such topics as biometric tissue engineering, networked wireless sensor systems, nanoengineered devices and materials, polymer-based pharmaceuticals, and medical embedded systems.
Speakers emphasized the need to merge biotechnology, nanotechnology and electrical engineering as integrated disciplines. Kang Wang, professor of electrical engineering at UCLA, called for a "heterogenous integration of BNI," or bio-nano-info, into systems that provide low power and high functionality. "The vision is to create robust nanosystems based on multiple technology platforms," he said.
Two professors of computer science discussed wireless sensor work under way through the UCLA-based Center for Embedded Networked Sensing (CENS). Applications range from studying the impact of drugs on the brain to protecting rural communities in Bangladesh from arsenic contamination.
Learning from human cells
Ho outlined his work with the NASA-sponsored Institute for Cell Mimetic Space Exploration (CMISE), which he described as a "world-class systems institute for bio-nano-info fusion." The organization's goal is to mimic the adaptive ability of natural cells to structure themselves into increasingly complex systems, leading to the development and commercialization of technologies for sensing, control and integration of complex natural and artificial systems.
Nature, said Ho, does "a pretty good job" of systems engineering. The "hardware" of a cell consists of millions of nanoscale molecules; the "software" is composed of complex regulatory networks. Like electronic devices, Ho noted, cells have inputs, outputs and control algorithms that operate on data. They have a hierarchical structure and include components analogous to sensors and actuators.
To study the workings of cells, CMISE researchers have developed an "optical nanoscope" that permits the observation of living cells, "optoelectronic tweezers" that can manipulate living cells without damage, and a "nano stethoscope" that can hear sounds from cells. What's needed now, Ho said, is a "smart Petri dish" that can integrate all these technologies and provide real-time stimulus and analysis.
UCLA's Wang discussed his work with the center on Functional Engineered Nano Architectonics (FENA), part of the multi- university Microelectronics Advanced Re- search Corp. FENA is looking to create the next generation of nanoscale technology as CMOS scaling reaches its end. Wang also directs the Western Institute of Nanoelectronics (WIN).
Wang outlined the challenges of shrinking IC process nodes, including power dissipation, variability, small current drive and increasing interconnects. It's not clear how CMOS will scale past 10 nanometers, he said, but "other kinds of devices" might emerge to "rescue us, so we can have another wave of success."
Those new devices may include molecular switches, in which "off" is the ground state and "on" is the metastable state. Research at FENA and WIN employs a bottom polysilicon electrode and a top titanium/aluminum electrode. Another area of research is spintronics, which uses the "spin" of a particle as a state variable. Here, researchers have designed a carrier-mediated spin FET.
The challenge, Wang said, is integrating nanocomponents into large, heterogeneous "nanosystems" that are robust, manufacturable and affordable.
The UCLA computer scientists involved with CENS may find themselves out in the field with ecologists, environmental engineers and marine biologists, noted CS professor Deborah Estrin. "By embedding sensors in the physical environment, we can observe things with [a level of] spatial resolution that was previously unattainable," she said.
Researchers have learned a lot about wireless sensor networks, observed Edward Kohler, professor of computer science at UCLA. At first, he said, researchers thought they would build an application and deploy a network. That, he said, was a "recipe for disaster. The technologists were too busy solving problems for the scientists to solve theirs."
The concept now is to build networks rapidly but be able to change them rapidly in response to what's observed in the field. That has led to the development of an architecture for sensor networks that makes it possible to adapt dynamically to user requests and sampling conditions.
CENS students deployed a sensor network in Bangladesh to check groundwater for arsenic contamination. It uses soil pylons and ion-selective electrode sensors to pinpoint arsenic in flooded rice paddies. Kohler noted that many sensors broke or had to be recalibrated. From this experience, he said, students are developing ways to detect and react to faults as they occur in the field.
Governments are taking note of multidisciplinary engineering, said Eric Werwa, senior legislative assistant to Rep. Mike Honda, D-Calif. "Overlaps in bio, nano and information technologies offer a tremendous opportunity but also pose challenges for policymakers," he said.
For example, there's concern in Congress about the possible dangers of nanotechnology, Werwa said. "People could inhale [nano]particles. Do we know enough about the science of how nanoparticles interact with the human body?"
Ethics is another issue. "Sensor networks can be everywhere and can detect a threat or find a lost child, but they also have great privacy implications," Werwa said. "Where do we want to draw the line? Policymakers see promise, but they want to head off unintended consequences."