About $20 billion per year of economic productivity is lost in the U.S. alone due to illnesses caused by waterborne pathogens. Pathogen detection in recreational and potable water sources remains a major challenge to date. To prevent human exposure to pathogens, it is crucial to achieve realor near-real time awareness of the microbial contamination status of surface waters, i.e. when and where water is contaminated. To make a qualitative leap in continuous and effective surface-water monitoring, there is urgent need for new rapid laboratory-independent methods for monitoring and detection of waterborne pathogens.
The PI's long-term goal is the development of autonomous hydrogel-based swimming biosensors to provide real- and near-real time information on the microbial contamination status of surface waters. The objective of this particular application, which is the next phase in attaining the PI's long-term goal, is to develop a proof-of-concept device for microbial water quality exploration, capable of swimming in open water and detecting E.Coli, an important microorganism indicative of fecal contamination of surface waters. The rationale for this work is that, once the technological base for aquatic biosensors is developed, the continuous exploration of surface waters and dynamic mapping of various water quality parameters will become possible, which will lead, in turn, to a decrease in human exposure to waterborne pathogens and increase in the security of homeland's water supply.
Aim #1: Demonstrate Hydrogel Locomotion in Unconstrained Aquatic Environment. Cylindrical hydrogels of various diameters and lengths will be synthesized and immersed in water. A laser spotirradiation will be used to induce photo-thermal volume phase transition in the hydrogel, resulting in body shape changes necessary for swimming.
Aim #2: Demonstrate Capture of E.Coli in Unconstrained Aqueous Environment. The hydrogels will be functionalized and exposed to E. Coli in an unconstrained aqueous medium. Attachment of microorganisms to the hydrogels will be confirmed with a microscope.
Aim #3: Incorporate the Signal Transduction Mechanism. The hydrogels will be functionalized to express chromophore that fluoresces in the presence of E.Coli.
The approach taken in this proposal is creative as it espouses state-of-the-art methods from two different fields: Materials Science and Engineering provides methodology for hydrogel synthesis and coupling of biorecognition and signal transduction elements, while device mobility and control are implemented with Robotic Technology. This approach is also original because no aquatic gel-based pathogen biosensors currently exist. Finally, the project's deliverable is poised to transform the way microbial surface water quality is monitored, and paves the way to generating continuous real- or near real time information on microbial surface water contamination. The proposed research is expected to contribute a swimming biosensor for water exploration and microbial detection. This contribution is significant because it will create the technological platform to revolutionize the monitoring and management of surface water sources for recreational and potable use.
Broader Impacts:
Exposure to development of new technologies is vital in shaping future careers of high-school and college students. We propose to engage and educate graduate and undergraduate students, high school students and teachers in the entire duration of the project. A partnership will be formed with two UC programs (REU-Research Experience for Undergraduates, and STEP-Science and Technology Enhancement Program). Through this partnership, 1 UC graduate student (STEP Fellow), 2 undergraduate students and 2 high school students will train and participate in research and product development in the PI lab; and 2 high school teaching units will be developed in collaboration between the PIs, STEP Fellows and high school teachers. These teaching units will be incorporated into the STEM curriculum in at least one high school in Cincinnati with a large underrepresented student body. In addition, STEP Fellows will train as future faculty of STEM disciplines by integrating their education, research, and career development. The schools are emphasizing STEM education, and it is the goal of STEP to encourage and motivate students to pursue higher education. A major long-term benefit to society from this project is the reduction of human exposure to waterborne microbial contaminants, which will increase the quality of life, reduce the economic burden of waterborne disease and increase the security of homeland's water supply.
An earthworm’s mechanism for movement, called peristaltic motion, has been refined by nature over millions of years. A team of University of Cincinnati researchers led by Drs. Yeghiazarian and Nistor used this mechanism to design swimming soft synthetic devices. Isopropylacrilamide hydrogels have the unique capability of shrinking and swelling in response to stimuli such as heat, light, pH change, and electricity, among others. The researchers figured out how to synthesize hydrogels that have the ability to absorb energy from laser irradiation. Then, by selectively heating the hydrogels with lasers, they forced them to undulate like worms in water. This motion actually makes gels "swim", and can be used for exploration of environments that are difficult or not feasible to navigate using conventional devices. The team then proceeded to equip the hydrogels with E. coli-capturing antibodies, and proved the hydrogels’ ability to capture the microbe in water. This is the first step towards developing swimming biosensors that can detect pathogens in water and send that information to water managers and the public. The work at University of Cincinnati sets a new biotechnological platform for conjugating a range of materials such as antibodies, medicine or mechanical cargo like cameras, to the surface of hydrogels. This is likely to significantly expand uses of this versatile soft material. The research team’s novel systems, for which student Jarod Gregory received the top national recognition for undergraduate research – the 2014 Goldwater Award, are detailed in two publications in the Journal of Applied Polymer Science.
