Contents lists available at ScienceDirect Materials Science & Engineering C journal homepage: www.elsevier.com/locate/msec A fluorescence Nano-biosensors immobilization on Iron (MNPs) and gold (AuNPs) nanoparticles for detection of Shigella spp Narges Elahi a,d , Mehdi Kamali a, ⁎ , Mohammad Hadi Baghersad b , Bahram Amini c, ⁎ a Nano biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran b Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran c Department of Biochemistry, Zanjan University of Medical Sciences, Zanjan, Iran d Department of Medical Nanotechnology, Schcool of Advance Medical Scinces and Technologies, Shiraz University of Medical Scinces, Shiraz, Iran. ARTICLE INFO Keywords: Fluorescence biosensor Shigella Spa gene MNPs AuNPs ABSTRACT The highly sensitive and specificity detection are very important in diagnosis of foodborne pathogens and prevention of spread diseases. Therefore, in the present study, a highly sensitive fluorescence Nano-biosensors was designed for detection of Shigella species. For achieved this purpose, DNA probes and gold nanoparticles (AuNPs) were designed and synthesized, respectively. Then, two DNA probes as signal reporter were im- mobilized on surface of AuNPs. On the other hand, Iron nanoparticles (MNPs) were synthesized and modified with SMCC (Sulfosuccinimidyl 4-Nmaleimidomethyl cyclohexane-1- carboxylate). The 3th DNA probe was im- mobilized on surface of MNPs for separation of target DNA. The MNP-DNA probe and DNA probe-AuNP- fluorescence DNA probe were added to target DNA. The MNP- DNA probe-target DNA-DNA probe-AuNP- fluorescence DNA probe complex was isolated by a magnet. The fluorescence DNA probe was released on surface of AuNPs and the fluorescence intensity was read by fluorescence spectrophotometry. Sensitivity and specificity of designed Nano-biosensor was determined. The results showed that the fluorescence intensity was increased with increasing of target DNA concentration. Linear related between target DNA and fluorescence intensity was observed in 2.3 × 10 2 up to 2.3 × 10 7 CFU mL -1 . The linear equation and regression were Y = 1.8 X + 23.4 and R 2 0.9953. Limit of detection (LOD) were determined 90 CFUmL -1 . The specificity of Nano-biosensor in present of other bacteria was confirmed. 1. Introduction According to the World Health Organization (WHO), foodborne diseases are very important in public health and increased in the both developed and developing countries. Salmonella, Shigella, and diarrhea genic E. coli are prevalently cause bacterial diarrhea in children under the age of five. Among these pathogens, the Shigella has very important in inflammatory diarrhea and dysentery. Consequently, it introduces a serious challenge for public health authorities worldwide [1]. Ultra- sensitive, rapid, and reliable analysis as well as the detection of food- borne pathogens at an early stage is an indispensable component of strategies for the prevention of the outbreak of foodborne diseases, which are crucial threats to human health [2,3]. Accessible bacteria detection can be divided into two categories: conventional and modern methods [4,5]. Microbiological plating, mi- croscopic visualization, biochemical tests, nucleic-acid-based methods, and immunologic method are the conventional analytical methods for Shigella detection [4–6]. PCR [7], multiplex PCR [8–10], multiplex real- time PCR [11–14], and Loop-mediated isothermal amplification (LAMP) [15] are the number of the nucleic-acid-based techniques that there are employed for Shigella detection. High cost, need for special tools, the need to preparing samples and expensive are limited of use this methods [16–18]. Therefore, rapid, sensitive, and specific methods for bacteria detection are necessary. Recently, biosensor-based methods, as the modern generation of detection, have progressed to a great extent [19,20]. Some of applied biosensors in the microbial analysis of foodborne pathogens are the optical-based, SPR-based, piezoelectric-based, immune-based, and electrochemical-based-sensors. The superiority of biosensors has nu- merous reasons, but the main reasons are that they enable fast or real- time detection and they provide the specific, sensitive, on-site diagnosis of analyses with minimal samples, while granting portability and multi- pathogen detection for both field and laboratory analyses [4,6]. The applications of biomaterials in biosensors are providing scopes for new https://doi.org/10.1016/j.msec.2019.110113 Received 10 April 2019; Received in revised form 19 August 2019; Accepted 21 August 2019 ⁎ Corresponding authors. E-mail addresses: mehkamali@yahoo.co.uk (M. Kamali), bamini50@yahoo.com (B. Amini). Materials Science & Engineering C 105 (2019) 110113 Available online 22 August 2019 0928-4931/ © 2019 Elsevier B.V. All rights reserved. T