Biosensors and Bioelectronics 26 (2011) 4070–4075 Contents lists available at ScienceDirect Biosensors and Bioelectronics journal homepage: www.elsevier.com/locate/bios Development of a lab-on-a-chip device for diagnosis of plant pathogens Sandra Julich a , Marko Riedel b,1 , Mark Kielpinski a , Matthias Urban a , Robert Kretschmer c,d , Stefan Wagner b , Wolfgang Fritzsche a , Thomas Henkel a , Robert Möller c,e,∗ , Sabine Werres b,∗∗ a Institute of Photonic Technology (IPHT), Nanobiophotonics Department, Albert-Einstein-Str. 9, 07745 Jena, Germany b Julius Kuehn Institute – Federal Research Centre for Cultivated Plants (JKI), Institute for Plant Protection in Horticulture and Forests, Messeweg 11/12, 38104 Braunschweig, Germany c Friedrich-Schiller-University, Institute of Physical Chemistry, Helmholzweg 4, 07743, Jena, Germany d Institute of Photonic Technology (IPHT), Microscopy Department, Albert-Einstein-Str. 9, 07745 Jena, Germany e Institute of Photonic Technology (IPHT), Spectroscopy/Imaging Department, Albert-Einstein-St. 9, 07745 Jena, Germany article info Article history: Received 6 January 2011 Received in revised form 22 March 2011 Accepted 27 March 2011 Available online 2 April 2011 Keywords: Lab-on-a-chip system Microarray PCR Diagnosis Phytophthora Detection abstract A lab-on-a-chip system for rapid nucleic acid-based analysis was developed that can be applied for diagnosis of selected Phytophthora species as a first example for use in plant pathology. All necessary polymerase chain reaction process (PCR) and hybridization steps can be performed consecutively within a single chip consisting of two components, an inflexible and a flexible one, with integrated microchan- nels and microchambers. Data from the microarray is collected from a simple electrical measurement that is based on elementary silver deposition by enzymatical catalyzation. Temperatures in the PCR and in the hybridization zone are managed by two independent Peltier elements. The chip will be integrated in a compact portable system with a pump and power supply for use on site. The specificity of the lab-on- a-chip system could be demonstrated for the tested five Phytophthora species. The two Pythium species gave signals below the threshold. The results of the electrical detection of the microarray correspond to the values obtained with the control method (optical grey scale analysis). © 2011 Elsevier B.V. All rights reserved. 1. Introduction Development of diagnostic methods for pathogens is one of the major scientific tasks in a world with increasing trade and mobility. It is not only human and animal medicine that requires specific and sensitive diagnostic techniques, phytopathologists as well ask for methods to detect infection of officially regulated plant pathogens in plants and plant products. Within the last decade, lab-on-a-chip devices have come more frequently to the attention of diagnosticians (Haeberle and ∗ Corresponding author at: Friedrich-Schiller-University, Institute of Physical Chemistry, Helmholzweg 4, 07743, Jena, Germany. Tel.: +49 3641 206 306; fax: +49 3641 206 399. ∗∗ Corresponding author at: Julius Kühn-Institut (JKI), Messeweg 11/12, 38104 Braunschweig, Germany Tel.: +49 531 299 4407; fax: +49 531 299 3009. E-mail addresses: sandra.julich@ipht-jena.de (S. Julich), Marko.Riedel@LELF.Brandenburg.de (M. Riedel), mark.kielpinski@ipht-jena.de (M. Kielpinski), matthias.urban@ipht-jena.de (M. Urban), robert.kretschmer@ipht- jena.de (R. Kretschmer), stefan.wagner@jki.bund.de (S. Wagner), wolfgang.fritzsche@ipht-jena.de (W. Fritzsche), thomas.henkel@ipht-jena.de (T. Henkel), robert.moeller@ipht-jena.de (R. Möller), sabine.werres@jki.bund.de (S. Werres). 1 Present address: Landesamt für ländliche Entwicklung, Landwirtschaft und Flurneuordnung, Pflanzenschutzdienst, Ref. 34, Steinplatz 1, 15806 Zossen, Germany. Zengerle, 2007; Mark et al., 2010). This new microtechnique offers several advantages such as low energy and reagent consumption and short reaction times. The small size of the lab-on-a-chip designs enables portability and the processing of a high number of samples directly in the field (Figeys and Pinto, 2000; Kricka, 2001). In molecular biology and diagnostics, standard methods like polymerase chain reaction (PCR) (Mullis and Faloona, 1987; Saiki et al., 1986) or hybridization of DNA (desoyxribonucleic acids) (Britten, 1963) have been transferred to chip devices. To date, PCR chips have been constructed in various forms like microchambers (Nagai et al., 2001; Wilding et al., 1994), flow-through thermocy- clers (Felbel et al., 2008; Kopp et al., 1998; Reichert et al., 2008; Schneegaß et al., 2001) and planar chip devices (Guttenberg et al., 2005; Pipper et al., 2007). Different materials like glass (Pjescic et al., 2010; Waters et al., 1998), silicon, or polymers like e.g. poldimethylsiloxane (PDMS) (Cady et al., 2005; Xiang et al., 2007), polycarbonate (Liu et al., 2004), polymethylmethacrylate (Lee et al., 2004; Ueda et al., 2000) or SU-8 (El-Ali et al., 2004; West et al., 2002) were used as substrates. Temperature management is imple- mented either by integrated heaters and temperature sensors using microstructures (Bhattacharya et al., 2007; El-Ali et al., 2004) or the chip devices are placed on external components like Peltier elements (Lund-Olesen et al., 2008; Matsubara et al., 2005). The three techniques mainly used in chip technology to detect DNA are electrophoresis (Takahashi et al., 1969), Real-Time PCR (Heid et al., 0956-5663/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.bios.2011.03.035