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Lab‑on‑a‑chip technologies advance Dal's reputation as a leader in marine research
In the Star Trek universe, the legendary tricorder is an advanced device used to diagnose patients or to characterize the environment. No blood tests or invasive procedures are required in the analysis. Characters such as Dr. McCoy simply point the portable gadget at their patients, and instantly receive a diagnosis.
To this day, the multifunctional tool, which was used for data analysis, continues to fascinate scientists around the world, including Dr. Vincent Sieben. In fact, the Dalhousie University Faculty of Engineering professor was so captivated by the concept, he performed research to enable aspects of the device while completing his PhD in Micro-electromechanical systems and Nano systems at the University of Alberta.
From there, the Tricorder inspired Sieben’s pioneering research in the lab-on-a-chip and microfluidics fields.
One may wonder what the two entities have in common. As Sieben describes it, much like the tricorder, a lab-on-a-chip refers to technologies housed inside a portable device that integrate one or several analyses, usually performed in a laboratory, onto a single chip.
Sieben is now bringing his extensive knowledge to Dal’s Ocean’s Engineering Hub and developing sensors to measure marine environments. Although lab-on-a-chip technologies have been around since the 1990s, its use in the deep ocean has only begun to evolve within the last decade.
Hired in March of 2018, the Sexton Chair in Underwater Sensing and an Associate Professor in Electrical Engineering, is developing tiny in-situ microfluidic sensors that will monitor nutrients, metals, hydrocarbons and microbes in the ocean.
In collaboration with other researchers in the Faculty and at Dal, including Dr. Mae Seto who was recently appointed the Irving Shipbuilding Chair in Marine Engineering and Autonomous Systems, and Dr. Douglas Wallace from Dal’s Department of Oceanography, Sieben will integrate his sensors onto underwater vehicles.
The miniature chips are housed on a portable power system and then strapped onto Autonomous Underwater Vehicles (AUV) and deployed into the ocean. The sensors are intended to collect data within environments often too dangerous or too expensive for human exploration.
From there, the chips allow researchers to instantly measure valuable characteristics of the ocean’s chemistry including nitrate, nitrite, ammonium, phosphate, silicate and iron.
Although oceans cover 70 per cent of the planet, they are presently under-sampled both spatially and temporally due to current approaches in data collection. Sieben says one of the main challenges in developing lab-on-chip devices for the deep sea is the design and fabrication of the device on a very small scale. These tools must be both cost efficient and functional, and of course, small enough to fit onto a small robot.
“The focus of our lab-on-a-chip program is to develop sensors that are better suited for long-term deployment at sea without having scientists themselves go out to collect the data,” he says. “So if we have miniature sensors that are small enough to integrate onto these AUVs, and that consume very little power, then we can conceivably collect much more ocean data over space and time.”
A sea of knowledge
Traditionally, advances in lab-on-a-chip technology have focused mainly in the area of healthcare and recently in oil and gas. However, in 2008, a group of scientists at the National Oceanography Center in Southhampton, UK conducted research on the first lab-on-chip nutrient and microbiology sensors for the deep ocean. Their team of talented researchers included Dr. Vince Sieben.
Their chip, powered by a support system roughly the size of a large drinking bottle, was dropped into the ocean at a depth of 1600m and used to measure the temperature and salinity of the water.
“The professors who recruited me at the time had a vision of utilizing microfluidics in harsh environments. When it came to this type of technology, the work was a change in complexity that really excited me,” says Sieben. “The thought of throwing a lab-on-a chip system in the deep blue put butterflies in my stomach. So, I joined their group.”
Sieben says lab-on-a-chip integrates many areas of technology including microfluidics and nanofluidics. The devices incorporate several laboratory functions on a chip that ranges in size from a few millimeters to a few square centimeters. Sample analysis occur on location rather than being transported to a larger laboratory. He says the process, which helps achieve thorough automation, also reduces the risk of human error and interpretation.
“Many of the biogeochemical measurements performed on marine water still rely on wet-chemistry protocols. When scientists perform these finely-tuned and sensitive processes in a laboratory, there can exist slight variations that yield dramatically different results,” he says. “When we string these processes together on-chip, the sample never leaves our closed channels. It is treated the same as the 1000 other samples before it had been. This leads to unprecedented repeatability across a wide-range of users.”
Following his work in Southampton, Sieben was a senior scientist at Schlumberger, the world’s largest oil field service provider. He was the lead scientist on the revolutionary team that delivered the MazeTM SARA analysis, the first commercialisation of a microfluidic sensor in the oil and gas industry. The technology worked by coupling novel microfluidic chip technology and spectroscopy for precise measurements. The technology fully automated a more than 300 step process for testing geographically-diverse oil samples for saturates, aromatics, resins, and asphaltenes (SARA).
While working at Schlumberger, Sieben also had the opportunity to develop expertise in Autonomous Underwater Vehicles and Robotics for inspection and maintenance of subsea energy assets.
“What became apparent to me while working there was the fact there’s a lot of infrastructure that humans have deployed throughout the ocean, but it can be quite costly to continuously monitor those structures,” he says. “Ultimately, both the oil and gas industry and oceanographers are looking to reduce the cost of going out and gathering chemical and biological measurements at sea, and lab-on chip technologies are well suited to address these challenges when coupled with autonomous vehicles.”
A new wave of oceans research
Over the years, Dal has continued to solidify its position as a global leader in oceans research.
In the Spring of 2017, Faculty of Engineering Associate Professor, Dr. Mae Seto, was appointed the Irving Shipbuilding Chair in Marine Engineering and Autonomous Systems. Part of her research focuses on intelligent autonomous systems, and marine robotics, particularly for deployment in difficult environments such as marine and under-ice.
“One of the reason I like working with Dr. Seto is because she always says that her robots are there for a reason, and that reason is for the sensors,” says Sieben. “Whether you’re looking for nutrient trends like we’re doing here at Dal, or monitoring infrastructure as we were doing at Schlumberger, there’s always some type of question you want answered , and those answers require sensors, and those sensors require robots.”
Last summer, Sieben and his team (Andre Hendricks, Cesar Rodriguez, Sean Morgan, Eddy Luy) created and tested Dal’s first lab-on-chip sensor for the deep ocean. Deployment occurred in the heart of Halifax’s Bedford Basin.
The chip, coined by Sieben as “Generation Zero,” was housed in a self-powered system that included all of the off the shelf components required in developing a sensor, including tubing and wires. The box however was the size of a carry-on piece of luggage, and substantially too large to strap onto one of Seto’s small underwater vehicles.
This summer, Sieben has removed all of the original off the shelf components to his model, and engineered a smaller and sleeker sensor that he plans to attach onto a Riptide, a long and narrow AUV, developed in Boston and used by Seto and her team.
“We’ve moved on to what I now call the first generation model which is a sensor that is the size of a 1 litre milk jug,” he says. “I told my students that I want to see the evolution of the chip. I want to go from the big piece of carry-on luggage which we built last year, to the smaller tube we’re creating now. Then I want to create an even smaller sensor hockey puck sized, and finally build something that’s the size of a credit card.”
Sieben says everyone is affected by the ocean, even if you don’t live by the sea. As the world’s population continues to grow, so do factors such as increased greenhouse gases, coastal development and land-use patterns. These leave damaging effects on the marine ecosystem.
Sieben says in better monitoring our oceans, scientists can gather the critical information required in preventing future damage.
“What excites me about applying lab-on-a-chip technologies for ocean monitoring is the cross generational impact that it can have. When I look at my children’s children, I’m hopeful that we will have figured out a way to either measure our impact on the ocean ecosystem or at least be aware on how we’re disturbing them. Our sensors are at the core of that solution.”
This story originally appeared on the cover of the Spring 2019 edition of Engineering magazine. Check out the rest of the issue here! [PDF - 13,100kb].
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