Hyeok Choi - US grants

DESCRIPTION (provided by applicant) The increasing occurrence of harmful algal blooms (HABs) in water resources worldwide is alarming the environmental and health authorities because of their potential to release biological toxins, in particular, microcystins produced from cyanobacterial HABs. Microcystins are among the most powerful natural poisons known. Exposure to microcystins can affect the number and diversity of wild animal populations, cause bioaccumulation of toxins in the tissues of fish and shellfish, and indirectly affect other organisms through the food chain and eventually humans. Methodologies for early detection or in-situ/remote sensing of outbreaks of the toxins would provide a major mechanism for reducing/preventing exposures to the toxins released by HABs. Current monitoring methods employing on-site sampling followed by in-lab analysis of HAB toxins (direct micro-observation) are neither sustainable nor practical to meet the vast spatial and temporal measuring need. Alternatively, remote sensing approaches based on identifying standard color products from satellite images (indirect macro-observation) are useful for monitoring general algal bloom activities. However, such color products are neither specific to HABs nor necessarily indicative of toxin release. As a result, it is important to determine the toxic/non-toxic nature of algal blooms and even the species of HAB toxins in a more sustainable and responsive manner. In the investigators efforts to find a complementary approach to the two different observing methods, they propose to real-time monitor the level of microcystins in-situ using an innovative wireless sensor network. Due to the lack of knowledge regarding assays of microcystins on a microscale sensor suitable for real field applications, there have been few attempts to implement the in-situ sensing idea. As a result, this study provides: 1) novel approaches to monitor toxin release during HAB activities, 2) novel ideas to quantify and qualify various microcystins at trace levels, and 3) integrated ways to realize the sensor network suitable for field applications. The investigators aim at 1) pioneering a microcystin-selective optical sensor to detect multiple microcystins at trace levels, 2) exploring an integrated chip-scale sensing node to automatically execute the sensing protocol, and 3) developing a wireless sensor network to communicate assay data and operation command between sensing nodes and remote authorities. Eventually, they will deploy the wireless sensor network in a potential HAB site in Great Lakes to monitor the spatial and temporal variation of microcystins. Public Health Relevance: The in situ wireless sensing network can monitor various lethal biological toxins, microcystins in water resources sustainably and responsively and communicate the information to remote authorities in real-time for establishing an early warning system to protect public health. Monitoring general algal bloom activities gives an idea on potential hazard while monitoring actual biological toxin release gives an insight on imminent hazard.

The increasing frequency of harmful algal blooms (HABs) in marine and freshwater environments worldwide is a significant public health and environmental science concern because of the potential release of biological toxins -- in particular, microcystins (MCs) produced from cyanobacterial HABs. Current monitoring methods employing on-site sampling followed by in-lab analysis of HAB toxins (direct micro-observation) are neither sustainable nor practical to meet the vast spatial and temporal measuring need. Alternatively, remote sensing approaches based on identifying standard color products from satellite images (indirect macro-observation) are useful for monitoring general algal bloom activities. However, such color products are neither specific to HABs nor necessarily indicative of toxin release. As a result, it is important to determine the toxic/non-toxic nature of algal blooms and even identify the species of HAB toxins in a more effective, sustainable, and responsive manner. In our efforts to find a complementary approach to the two different observing methods, the overall goal of this proposed study is to real-time monitor the level of MCs in situ using an innovative wireless sensor network.

In this project, researchers at the University of Texas at Arlington, New Mexico State University, and Virginia Polytechnic Institute will explore: (1) novel approaches to monitor toxin release during HAB activities, (2) innovative ideas to qualify and quantify various MCs at trace levels, and (3) integrated ways to realize the sensor network suitable for field applications. The proposed sensing system will utilize a surface-customized optical antenna to assay MCs selectively and sensitively. The antenna, consisting of arrays of resonant nanostructures with various transducer layers specific to multiple MCs, detects specific bindings of MCs to the transducer layers by analyzing the spectral characteristics of the subwavelength surface plasmon. A wireless sensing network to communicate assay data and operation command between sensing nodes and remote authorities will be developed. Most of the components necessary for executing the sensing protocol, including array chip, optical sensor, photo-detector array, and circuitries, are incorporated into a chip-size single substrate for system automation.

Broader Impacts: Results of this project are expected to have significant impacts on the design and development of sensor networks and on scientific studies in the area of in situ environmental monitoring. The in situ real-time monitoring approach benefits immediate decision-making and timely response, which are crucial elements for establishing an early warning system as an environmental infrastructure. Educational impacts include students training by participating in the project, research integration with curricula, and hands-on research experience using the in situ sensor network testbed. Software tools and simulators developed during this project will be made available via the internet to research and education communities. Team members will take advantage of the existing organizations and programs in the participating universities to recruit and mentor students from underrepresented groups.

JOINT FUNDING BY NSF AND NIEHS: The original proposal on which this project is based (R01 ES021951-01) was submitted to the National Institutes of Environmental Health Sciences (NIH/NIEHS) in response to Funding Opportunity Announcement RFA-ES-11-013 , "Oceans, Great Lakes and Human Health (R01)", an opportunity jointly sponsored by NSF. This project is cooperatively funded through separate awards from NSF and NIEHS.