When Iowa State University established its electrical engineering department in 1909, then-department head Fred A. Fish and his colleagues concentrated their research on areas such as telephone switchboard communications and electric motors. Since then, electrical engineers at Iowa State have expanded their research as they helped build the world’s first electronic digital computer and invented the encoding process used in nearly all fax machines.
Today, as the Department of Electrical and Computer Engineering (ECpE) celebrates its centennial, three young faculty members equipped with a new lab filled with high-powered microscopes and other tools are paving the way for electrical engineers at Iowa State to create biorelated tools and applications for agriculture, medicine, and other fields.
If it seems odd that electrical engineers are studying living organisms using Petri dishes and atomic force microscopes, it’s not so odd to three assistant professors—Santosh Pandey, Liang Dong, and Jaeyoun Kim—who are on the forefront of the rapidly growing bioengineering research area. The professors are addressing three bioengineering problems from different angles and are part of ECpE’s newly created bioengineering research group.
Mining the biological intelligence of parasites
With new equipment that includes an atomic force microscope that can study nanoengineered materials and single molecules, as well as a carbon dioxide incubator for growing biological specimens in the lab, Santosh Pandey recently began a research project to study the behaviors of parasitic nematodes that destroy crops and infect farm animals.
Pandey and his interdisciplinary research team of plant pathologists and biomedical scientists fabricate microscale fluidic devices for experiments to understand the relationship between the nematodes’ behavior and their genetic composition. In addition, they are developing bioassays (i.e., quantitative scientific experiments designed to test a material’s effect on a living organism) to isolate individual behavioral modalities, which eventually can be linked to specific genetic mutations and signal transduction in an organism’s neural network.
“Experimental techniques to observe nematodes’ parasitic behavior are limited,” says Pandey, “and there is an urgency to develop new bioassays that can detect and sense nematode behavior with high precision and specificity.
“The ultimate goal,” he continues, “is to understand how the behavior of this parasitic organism is related to its genetic makeup and its neural network. Eventually, we could use these nematodes as model organisms to understand the fundamentals of parasitism and extrapolate their learning, memory, and aging properties to certain human behavior.”
The team is also conducting tests to learn about the nematodes’ social behavior, migratory and host-invasion patterns, sense of smell and taste, memory and learning abilities, and feeding, mating, and reproductive habits. Once the current research is complete, bioinformatics technology will help the researchers to understand the vast data collected from their experiments and decipher the various gene-regulating circuits that control a nematode’s specific behaviors.
The U.S. Army and Department of Defense are highly interested in this research area, Pandey explains, because the biological intelligence of nematodes could be mimicked in devices such as search and navigation tools that use artificial intelligence.
“Because nematodes have highly sensitive and specialized sensing mechanisms, it is expected that their inherent search and navigation ‘algorithms’ are far more advanced than humans ever imagined,” Pandey says. “Hopefully, knowledge of this biological intelligence could be used to enhance artificial intelligence—the kind that controls robots and other man-made systems.”
The research could help farmers, too. According to a California State University Agricultural Research Initiative report, the U.S. agricultural industry loses more than $10 billion of crop produce each year due to parasitic nematode infestation.
“Understanding why, when, and how nematodes invade a land, migrate to the root system, and infect the plant will enable us to develop better strategies to obstruct their migration, mitigate their parasitic effects, and eventually stop their devastating effects on crops in the least toxic and most sustainable manner,” Pandey says.
A ‘pacemaker’ for the inner ear
More than 90 million Americans will experience balance problems in their lifetimes, according to the National Institutes of Health. Of these, at least two million will suffer chronic impairment, costing more than $1 billion a year to treat.
That’s why Liang Dong is working with two microelectronics scientists from the ECpE department and physicians from the University of Minnesota and the University of Iowa to develop a vestibular prosthesis, an electronic device to replace the inner ear’s vestibular organ, which helps people maintain balance, posture, and their body’s orientation.
“The core of the vestibular prosthesis project is to develop a miniaturized motion sensor,” Dong says. “The device will be made of inexpensive, biocompatible polymers such as polydimethylsiloxane and liquids such as water. This is a distinct feature of the device.”
Other components of the apparatus, which will effectively act like a “pacemaker” for the ear, include three angular accelerometers for rotary movements, three linear accelerometers for straightforward movements, and a series of microelectrodes.
According to Dong, in nature the vestibular system has three semicircular canals filled with fluid that flows when an angular acceleration is experienced by the head. The movement of fluid in the canal is sensed by hair cells growing on the canal walls. Nerves connected to the hair cells send a train of neural signals to the brain, which integrates that information with visual signals and other cues to maintain balance and stabilize vision.
To make an artificial system to match Mother Nature’s intricate natural system, one of Dong’s biggest challenges will be to make the motion sensors small enough to fit inside the device, which will be only one millimeter long (about the size of a pinhead), but also sensitive enough to decipher even the slightest movement of fluid in the ear canal.
Dong’s research team is addressing this challenge by using microfluidics technology to develop biomimetic angular and linear accelerometers that use the fluid’s inertia to efficiently achieve high-acceleration sensitivity in a small package. Also, in order to develop multidirectional sensing abilities for the device, they are creating a new self-assembling technology that can accurately assemble multiple components within a liquid environment.
“If we’re successful, we will be the first to develop an all-polymer, implantable vestibular prosthetic device,” Dong says. “It will be much safer, cheaper, and more bio-friendly than current nonimplantable devices available.”
Tortoise meets hare at the nanoscale
Jaeyoun Kim is working to develop very small plasmonic elements that can control the flow of optical waves at the nanoscale for applications in biosensing. Essentially, he is creating a new plasmonic element with two functions: nanoscale sensing and integration with integrated optics.
“Plasmonic elements are excellent in sensing, but interfacing them with optical components is often cumbersome, unstable, and expensive,” Kim says. “We want to do it with pre-aligned, robust optical waveguides. This is not necessarily a new idea, but there are fundamental differences between the two technologies that currently baffle researchers.”
“Plasmonic sensing” includes any sensing technique that uses a surface plasmon—i.e., a lab-generated hybrid of light and electron density fluctuation—to sense phenomena occurring across a range of 200 nanometers or less. Plasmons are used particularly in biomolecular sensing to monitor the interactions between molecules, DNA, and proteins.
To grasp the size of the objects Kim works with, consider this analogy other scientists have made: a nanometer is to a meter what a marble is to Earth. Kim, who works with objects only a couple hundred nanometers in size, says that plasmonic sensing is an extremely sensitive scheme. And while individuals with large laboratories can easily use plasmonic sensing, the technology is expensive and not portable.
“Our research will enable the much-needed miniaturization and integration,” Kim says, “which will bring plasmonic sensing to on-site uses.”
One such use involves going to farms to test and diagnose farm animals for possibly contagious diseases, a process that currently takes days because farmers have to take samples and mail them to Iowa State University labs. By miniaturizing the technology, testing and diagnosis could be done on site at the farm, allowing farmers to get test results much faster.
As his research progresses, Kim plans to collaborate with professors from Iowa State’s College of Veterinary Medicine to investigate this specific application of his plasmonic devices. But miniaturizing the technology won’t be easy, he says, as his research requires him to work against the physics of plasmons.
“In setups configured for sensing,” Kim observes, “the surface plasmon-politron—the ‘ammunition’ of plasmonics—is inherently faster than optical waves. That’s physics.
“We are trying to couple the two,” Kim continues. “It’s like coupling a hare and a tortoise. We overcome the difficulty by forcefully slowing down the surface plasmon-politron and syncing it with the optical wave.”
Kim isn’t the first researcher to address this speed mismatch of the surface plasmon-politron and optical waves. However, conventional methods have largely been confined to doing something to the waveguide, often leading to highly complicated structures. Kim, on the other hand, plans to design a new plasmon-supporting structure with which he can modify the characteristics of surface plasmons, simplifying the coupling greatly.
“As an engineer,” Kim says, “it is always exciting to find one element capable of doing more than one thing.”