Automated online optical biosensing system for continuous real-time determination of microcystin-LR with high sensitivity and specificity: early warning for cyanotoxin risk in drinking water sources.

The accelerated eutrophication of surface water sources and climate change have led to an annual occurrence of cyanobacterial blooms in many drinking water resources. To minimize the health risks to the public, cyanotoxin detection methods that are rapid, sensitive, real time, and high frequency must be established. In this study, an innovative automated online optical biosensing system (AOBS) was developed for the rapid detection and early warning of microcystin-LR (MC-LR), one of the most toxic cyanotoxins and most frequently detected in environmental water. In this system, the capturing molecular MC-LR-ovalbumin (MC-LR-OVA) was covalently immobilized onto a biochip surface. By an indirect competitive detection mode, samples containing different concentrations of MC-LR were premixed with a certain concentration of fluorescence-labeled anti-MC-LR-mAb, which binds to MC-LR with high specificity. Then, the sample mixture was pumped onto the biochip surface, and a higher concentration of MC-LR led to less fluorescence-labeled antibody bound onto the biochip surface and thus to lower fluorescence signal. The quantification of MC-LR ranges from 0.2 to 4 μg/L, with a detection limit determined as 0.09 μg/L. The high specificity and selectivity of the sensor were evaluated in terms of its response to a number of potentially interfering cyanotoxins. Potential interference of the environmental sample matrix was assessed by spiked samples, and the recovery of MC-LR ranged from 90 to 120% with relative standard deviation values <8%. The immunoassay performance of the AOBS was validated with respect to that of conventional high-performance liquid chromatography, and the correlation between methods agreed well (R(2) = 0.9762). This system has successfully been applied to long-term, continuous determination and early warning for MC-LR in Lake Tai from June 2011 to May 2012. Thus, the AOBS paves the way for a vital routine online analysis that satisfies the high demand for ensuring the safety of drinking water sources. The AOBS can also serve as early warning system for accidental or intentional water pollution.

[1]  J. Homola.  Present and future of surface plasmon resonance biosensors , 2003, Analytical and bioanalytical chemistry.

[2]  Volker Schurig,et al.  Chiral discrimination using an immunosensor , 1999, Nature Biotechnology.

[3]  M. Hennion,et al.  Hepatotoxin Production Kinetics of the Cyanobacterium Microcystis aeruginosa PCC 7820, as Determined by HPLC−Mass Spectrometry and Protein Phosphatase Bioassay , 2000 .

[4]  W. Ye,et al.  Diversity and dynamics of microcystin―Producing cyanobacteria in China's third largest lake, Lake Taihu , 2009 .

[5]  J M Calvert,et al.  Use of thiol-terminal silanes and heterobifunctional crosslinkers for immobilization of antibodies on silica surfaces. , 1989, Analytical biochemistry.

[6]  Lirong Song,et al.  Detection of microcystins in environmental samples using surface plasmon resonance biosensor. , 2009, Talanta.

[7]  Y. Ouahid,et al.  Identification of microcystins from three collection strains of Microcystis aeruginosa. , 2010, Environmental pollution.

[8]  Günter Gauglitz,et al.  Surface plasmon resonance sensors: review , 1999 .

[9]  Wei Chen,et al.  Rapid and sensitive detection of microcystin by immunosensor based on nuclear magnetic resonance. , 2009, Biosensors & bioelectronics.

[10]  A. Ballesteros-Gómez,et al.  Recent advances in environmental analysis. , 2011, Analytical chemistry.

[11]  M. He,et al.  Portable optical immunosensor for highly sensitive detection of microcystin-LR in water samples. , 2009, Biosensors & bioelectronics.

[12]  V. Shanov,et al.  A Multiwalled‐Carbon‐Nanotube‐Based Biosensor for Monitoring Microcystin‐LR in Sources of Drinking Water Supplies , 2013 .

[13]  Jean-Louis Marty,et al.  Highly sensitive amperometric immunosensors for microcystin detection in algae. , 2007, Biosensors & bioelectronics.

[14]  M. Dokulil,et al.  Anthropogenic impacts to large lakes in China: the Tai Hu example , 2000 .

[15]  Hans Wolf,et al.  Development of a highly sensitive inhibition immunoassay for microcystin-LR , 2004 .

[16]  Hye-Weon Yu,et al.  Bead-based competitive fluorescence immunoassay for sensitive and rapid diagnosis of cyanotoxin risk in drinking water. , 2011, Environmental science & technology.

[17]  A. Waggoner,et al.  Cyanine-labeling reagents: sulfobenzindocyanine succinimidyl esters. , 1996, Bioconjugate chemistry.

[18]  Booncharoen Wongkittisuksa,et al.  Label-free capacitive immunosensors for ultra-trace detection based on the increase of immobilized antibodies on silver nanoparticles. , 2011, Analytica chimica acta.

[19]  C. MacKintosh,et al.  Purification of type 1 protein (serine/threonine) phosphatases by microcystin‐Sepharose affinity chromatography , 1994, FEBS letters.

[20]  Jiří Homola,et al.  An SPR biosensor for the detection of microcystins in drinking water , 2010, Analytical and bioanalytical chemistry.

[21]  M. Hennion,et al.  Determination of some physicochemical parameters of microcystins (cyanobacterial toxins) and trace level analysis in environmental samples using liquid chromatography. , 1998, Journal of chromatography. A.

[22]  S Herranz,et al.  Automated portable array biosensor for multisample microcystin analysis in freshwater samples. , 2012, Biosensors & bioelectronics.

[23]  Miao He,et al.  A comprehensive immunoassay for the detection of microcystins in waters based on polyclonal antibodies. , 2006, Analytica chimica acta.

[24]  M. Gerpe,et al.  Microcystin–LR, –RR, –YR and –LA in water samples and fishes from a shallow lake in Argentina , 2010 .