Sensors and Actuators B 123 (2007) 204–210 Direct detection of Yersinia pestis from the infected animal specimens by a fiber optic biosensor Hua Wei a,1 , Yongkai Zhao b,1 , Yujing Bi a , Haihong Liu a , Zhaobiao Guo a , Yajun Song a , Junhui Zhai a , Huijie Huang b , Ruifu Yang a,∗ a Laboratory of Analytical Microbiology, State Key Laboratory of Pathogen and Biosecurity, National Center for Biomedical Analysis, Army Center for Microbial Detection and Research, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), No. 20, Dongdajie, Fengtai District, Beijing 100071, China b Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China Received 18 February 2006; received in revised form 4 July 2006; accepted 14 August 2006 Available online 14 September 2006 Abstract The FOB-3, a new type fiber optic biosensor, is designed to rapidly detect a variety of biological agents or analytes with better stability, sensitivity and specificity. In order to detect Y. pestis, a sandwich immunoassay was developed by using the purified antibody against antigen FI immobilized on polystyrene probes as the capture antibody and the monoclonal antibody-Cy5 conjugate as the detector. After a series of optimization for the stability, sensitivity and specificity of the FOB-3, 50–1000 ng/ml of antigen FI and 6 × 10 1 –6 × 10 7 CFU/ml Y. pestis could be detected constantly in about 20 min, and Y. pestis could be detected specifically from Y. pseudotuberculosis, Y. enterocolitica, B. anthracis and E. coli. Then, 39 blind samples, including 27 tissues of mice infected with Y. pestis and 12 tissues of healthy mice as negative control, were detected with the FOB-3. 92.6% infected tissues were identified from the tissues of healthy mice and the tissues containing more than 100 CFU/ml bacteria could be detected by the biosensor. The results demonstrated the feasibility of the FOB-3 as an effective method to detect Y. pestis rapidly and directly from the infected animal specimens with the advantage of portability, simple-operation as well as high sensitivity and specificity. © 2006 Elsevier B.V. All rights reserved. Keywords: Fiber optic biosensor; Sandwich immunoassay; Y. pestis 1. Introduction Yersinia pestis is the etiological agent of plague, which was redefined in 1980s by the World Health Organization (WHO) as a reemerging infectious disease [15]. Moreover, concerns about using Y. pestis as bioterrorism agent are increased after the anthrax spore attack in U.S. in 2001 [10]. Therefore, it is necessary to develop a rapid, precise and convenient method for detecting this condemned bacterium in the field. Comparing with traditional methods to detect Y. pestis such as ELISA [9,18] and passive haemagglutination assay (PHA) [19], a fiber optic biosensor has the advantage of simple-operation, portability and rapid detection on site [2,4,11] ∗ Corresponding author. Tel.: +86 10 66948595; fax: +86 10 83820748. E-mail address: yangrf@nic.bmi.ac.cn (R. Yang). 1 Contributed equally to this work. Biosensors are defined as optic/electronic detection devices that use biological molecules for the detection and quantification of the interested targets [16]. A fiber optic biosensor as one type of biosensors plays an important role in optical elements because of its advantages, which range from anti-electromagnetic radi- ation and electronic frequency to anti-erosion. Miniaturization of devices [22], which is important for the field detection, can be realized in a fiber optic biosensor. In addition, a fiber optic biosensor has the advantage of long-distance transmission of sig- nals (10–1000 m), which is necessary for the remote-controlled detection in dangerous areas. There are several immunoassay formats used in a fiber optic biosensor: direct, displacement, competitive and sandwich assay, among which sandwich assay is commonly used due to its higher sensitivity and convenience for operation on site [2–4,11]. Fiber optic biosensors have been described for its utilization in detection of pathogenic bacteria. Rowe-Taitt et al. detected B. anthracis, F. tularensis, B. abortus with NRL array biosensor 0925-4005/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.snb.2006.08.010 CORE Metadata, citation and similar papers at core.ac.uk Provided by Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences