Portable Detection of Algal Toxins Using a Surface Plasmon Resonance (SPR) Fiber Optic Probe Coated With a Molecular Imptinted Polymer

Algal blooms, caused by cyanobacteria, are increasing in frequency, duration, geographic extent, and severity in the coastal and freshwater ecosystems of the United States and other countries. One-third of the 50 genera of cyanobacteria can produce toxins and approximately 60 percent of these are toxic. Because these toxins represent a significant hazard to humans, livestock, and wildlife, it is essential that their concentrations in raw surface waters and finished waters be routinely quantified. High performance liquid chromatography-based methods for detecting algal toxins generally are complex, expensive, and time consuming because the analyses cannot be done onsite. Although simpler screening methods, such as enzyme-linked immunosorbent assay, sometimes are quite sensitive, they tend to lack specificity. Thus, there is a need for a monitoring system that is field deployable, inexpensive, highly specific to single toxins, and has the capacity for a high throughput of samples. The goal of this Phase I research project is to systematically develop a surface plasmon resonance (SPR) fiber optic probe coated with a molecularly imprinted polymer (MIP) that will provide fast, simple, and sensitive detection of microcystin-LR. Phase I objectives are to: (1) synthesize molecularly imprinted thin films specific to microcystin-LR on gold-coated SPR probes; (2) integrate the SPR probes into an existing fiber optic detection scheme to create a system for the robust measurement of microcystin-LR; and (3) evaluate the specificity and sensitivity of the integrated SPR system for the detection of microcystin-LR in raw, tap, and deionized water at different pH values. The demonstration of this MIP technology in Phase I, combined with the fiber optic detection scheme, will validate a new detection platform for algal toxins. Dual objectives in Phase II then will become possible. These include: (1) development of additional MIP layers measuring a wider class of toxins, and (2) scale up to production for the specific probes and the spectroscopic monitoring systems.