Engineering sustainable, safe food from the field to the table

Growing new networks

A team led by Hongwei Zhang, professor of electrical and computer engineering, has developed CyNet, an open-source, wireless networking infrastructure to support data-driven research. CyNet takes on the challenge of quickly and reliably transmitting agricultural measurements from the crop field to plant scientists’ computers – and serves as a prototype for bringing much-needed broadband to rural areas.

Connecting field to cloud

Iowa State predictive phenomic plant scientists gather detailed data from growing crop plants using cameras and other sensors. Before CyNet, a researcher would physically visit an Iowa State research farm to collect and transport data, a slow process with risks for data loss.
So, Zhang’s team combined OpenAirInterface, an open-source software developed to promote new 5G-type cellular applications, with NI Universal Software Radio Peripheral, an inexpensive, flexible technology where functionality is determined by software rather than hardware.

Now cameras transmit photos of growing plants to a base station antenna tower on the farm – and, in real time, connect to Iowa State cloud computing systems.

“CyNet is likely the first cellular network developed purposefully for agricultural research,” said Zhang. “Researchers now reliably get the data they need for analysis in real time, without ever leaving their offices. We hope that speeding up the data transmission process will help speed advances in crop productivity.”

Prototyping rural broadband

Beyond agricultural research, CyNet also has demonstrated applications in collecting sensor data needed for autonomous transportation research, but Zhang sees CyNet as an important first step in a much bigger mission: increasing access to rural broadband.

“With CyNet we’ve created a prototype of a new low-cost way to extend network reach,” said Zhang. “Iowa State has the right strength of expertise, paired with our land-grant mission, to do much more. We can team up with industry partners, rural communities and other stakeholders to lead research in delivering rural broadband.”

Co-principal investigators on the CyNet project include Patrick Schnable, Distinguished Professor of Agronomy and Iowa Corn Promotion Board Endowed Chair in Genetics; Arun Somani, associate dean for research, Anson Marston Distinguished Professor of Engineering and Philip and Virginia Sproul Professor in Electrical and Computer Engineering; Ahmed Kamal, professor of electrical and computer engineering; and Anuj Sharma, associate professor of civil, construction and environmental engineering, along with collaborators at Iowa State’s Research and Demonstration Farms, Research Park and Institute for Transportation.

Sensors for food safety

Food safety testing usually takes place in the lab by highly training technicians, but on-site, real-time, low-cost monitoring is our best tool to stop contaminated food from reaching consumers. Carmen Gomes, associate professor of mechanical engineering, is making key innovations in biosensor fabrication and system design to ensure food safety.

Quickly sensing salmonella

Gomes’ team used laser induction to fabricate highly sensitive graphene-electrode immunosensors that electrochemically quantify salmonella pathogens in chicken.

“Making the sensor technology possible is graphene, a material that’s a carbon honeycomb, only an atom thick and known for its strength, electrical conductivity, surface area and biocompatibility. Making graphene practical on a disposable food-safety sensor is low-cost laser induction that’s a one-step direct-write fabrication process that uses a CO2 laser to create electrodes for electrochemical sensors to detect foodborne pathogens,” said Gomes.

The technique is lower cost than other graphene-based electrodes because it does not require expensive nanomaterials or high-temp, high-pressure fabrication. The sensors showed the kind of quick, highly-sensitive results needed for fast-paced pathogen detection in food processing facilities.

Keeping listeria out of lettuce

Gomes was the first to develop and demonstrate a platinum interdigitated microelectrode biosensor to detect contamination in hydroponic lettuce growing facilities.

“Hydroponic systems present a major challenge to controlling pathogens, like listeria, but we’ve shown we can do real time, on-site sensing to help prevent contaminated lettuce from reaching consumers,” said Gomes.

The sensing system is incorporated into the growing system sediment traps, uses smartphones to read data, features sensors that can be reused several times – all while complying with all regulatory standards.

Flagging high histamine levels

Gomes, collaborating with colleague Jonathan Claussen, associate professor of mechanical engineering, used aerosol jet printing to create graphene electrochemical histamine sensors to detect levels most likely to trigger severe allergic reactions.

“This histamine sensor is not only for fish. Bacteria in food produce histamine. So, it can be a good indicator of the shelf life of food. The high-resolution electrodes produced by aerosol jet printing is necessary for electrochemical sensors to detect small molecules, such as histamine,” Gomes said.

The technique developed by Gomes’ team can also likely be used for a wider range of sensing challenges, from environmental toxins and nutrients in soil, to foodborne pathogens and health monitoring and diagnosis.