Talanta 80 (2009) 407–410 Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Short communication Detection of microcystins in environmental samples using surface plasmon resonance biosensor Chenlin Hu a,b , Nanqin Gan a , Yuanyuan Chen c , Lijun Bi c , Xianen Zhang c , Lirong Song a,∗ a State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Donghu Nanlu 7, Wuchang, Wuhan 430072, PR China b Graduate School of Chinese Academy of Sciences, Beijing 100049, PR China c Analytical Biotechnology of State Key Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China article info Article history: Received 19 January 2009 Received in revised form 19 June 2009 Accepted 19 June 2009 Available online 27 June 2009 Keywords: Microcystins Surface plasmon resonance (SPR) Biosensor ELISA abstract An indirect inhibitive surface plasmon resonance (SPR) immunoassay was developed for the microcystins (MCs) detection. The bioconjugate of MC-LR and bovine serum albumin (BSA) was immobilized on a CM5 sensor chip. A serial premixture of MC-LR standards (or samples) and monoclonal antibody (mAb) were injected over the functional sensor surface, and the subsequent specific immunoreaction was moni- tored on the BIAcore 3000 biosensor and generated a signal with an increasing intensity in response to the decreasing MCs concentration. The developed SPR immunoassay has a wide quantitative range in 1–100 gL -1 . Although not as sensitive as conventional enzyme-linked immunosorbent assay (ELISA), the SPR biosensor offered unique advantages: (1) the sensor chip could be reusable without any significant loss in its binding activity after 50 assay-regeneration cycles, (2) one single assay could be accomplished in 50min (including 30-min preincubation and 20-min BIAcore analysis), and (3) this method did not require multiple steps. The SPR biosensor was also used to detect MCs in environmental samples, and the results compared well with those obtained by ELISA. We conclude that the SPR biosensor offers out- standing advantages for the MCs detection and may be further developed as a field-portable sensor for real-time monitoring of MCs on site in the near future. © 2009 Published by Elsevier B.V. 1. Introduction Microcystins (MCs) are a family of cyclic heptapeptides produced mainly by some freshwater cyanobacteria such as Micro- cystis, and are hazardous to humans and animals due to their hepatotoxicity and tumor-promoting activity [1,2]. Among the MCs variants, MC-LR is the most common and well investigated. To reduce the adverse effects on humans and animals, World Health Organization (WHO) has established a maximum permis- sible concentration of 1 gL -1 of MC-LR in drinking water [3]. It is therefore necessary to develop a rapid and reliable method for MCs detection in environmental monitoring. Recently, a series of bio- chemical and physicochemical methods have been developed for MCs detection such as protein phosphatase inhibition assay (PPiA), enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC) and liquid chromatography with mass spectrometry (LC/MS) [4]. However, these methods require either complex operation or expensive materials and devices. To ∗ Corresponding author. Tel.: +86 27 68780806 fax: +86 27 68780871. E-mail address: lrsong@ihb.ac.cn (L. Song). circumvent these drawbacks, several research groups have made the attempts to develop biosensors for MCs detection, such as molecularly imprinted polymer (MIP)-based sensor [5], electro- chemical immunosensors [6–9], and evanescent wave all-fiber immunosensors [10,11]. There have been the reports that described the application of test strips for rapid MCs analysis in situ [12,13]; however, it is still challenging to develop a simple, rapid, and sen- sitive method for MCs analysis. Recently, the optical biosensor based on the surface plasmon resonance (SPR) has received more and more attention because of its own outstanding advantages: allowing rapid and real-time anal- ysis, owning reusable sensor chip, and requiring low amounts of reagents without chemical labels. And it has been successfully and widely employed to detect small molecules of biomedical, food and environmental interest [14]. In this paper, we developed an indi- rect inhibitive SPR immunoassay for the MCs detection. The sensor chip was firstly functionalized by the amine-coupling method, and then the MCs detection was performed with indirectly measuring the inhibition by MCs in samples. The regeneration of the sensor chip was investigated. Moreover, the SPR biosensor was also used to detect MCs in environmental samples, the results were discussed and compared with the conventional ELISA. 0039-9140/$ – see front matter © 2009 Published by Elsevier B.V. doi:10.1016/j.talanta.2009.06.044