A MINIATURE SURFACE PLASMON RESONANCE BIOANALYTICAL SYSTEM FOR FIELD DETECTION OF MICROCYSTIN-LR IN SURFACE WATER

Abstract

A miniature surface plasmon resonance (SPR)–based immunoassay system for analyzing microcystin-LR (MC-LR) in surface water has been developed. A Spreeta biosensor was adopted in the SPR flow injection analysis (FIA) system. An optional biofilm immobilization method was exploited using covalent-coupling between a bioconjugate of microcystin-LR and bovine serum albumin [(MC-LR)-BSA] and the golden surface. An acceptable relative standard deviation of repeatability, 1.29% (n = 20), was achieved. An analysis of the calibration curve showed that this method has a detection limit of 0.55 ng/mL, a half-maximal inhibitory concentration (IC₅₀) of 5.6 ng/mL, and a quantitative range of 1.56–25.00 ng/mL. The recovery from water samples containing varying concentrations of MC-LR ranged from 90% to 112%. After samples of tap water and pool water were assayed, it was concluded that tap water did not contain a measurable amount of the analyte, whereas pool water contained 2.39 ng/mL. Compared to other methods of analysis, SPR immunoassay has the advantage of being label-free, rapid, and cost-effective and can easily detect levels of MC-LR within the World Health Organization (WHO) drinking water guidelines. The SPR FIA system with reusable biosensor is compact and convenient for instant in situ determination of MC-LR levels in environmental water.

Keywords:

• free-labeling
• microcystin-LR
• rapid detection
• reusable biosensor
• surface plasmon resonance

ACKNOWLEDGMENTS

This research project was financially supported by the National High Technology Research and Development Program of China (No. 2007AA09Z144, No. 2009AA06Z406) and the Grand Science and Technology Special Project and Priority Theme of Zhejiang Province (No. 2007C13066).