Analytica Chimica Acta 453 (2002) 165–172 Surface plasmon resonance biosensor for genetically modified organisms detection Elisa Mariotti, Maria Minunni ∗ , Marco Mascini Università degli Studi di Firenze, Dipartimento di Chimica, Via G. Capponi 9, 50121 Firenze, Italy Received 28 June 2001; received in revised form 11 October 2001; accepted 11 October 2001 Abstract The development of a surface plasmon resonance (SPR) affinity biosensor based on DNA hybridisation is described. This biosensor has been applied to genetically modified organisms (GMOs) detection. Single stranded DNA (ssDNA) probes were immobilised on the sensor chip of an SPR device and the hybridisation between the immobilised probe and the complementary sequence (target) was monitored. The probe sequences were internal to the sequence of 35S promoter and NOS terminator which are inserted sequences in the genome of GMO regulating the transgene expression. The system has been optimised using synthetic oligonucleotides, then applied to real samples analysis. Samples, containing the transgenic target sequences, were amplified by polymerase chain reaction (PCR) and then detected with the SPR biosensor. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Surface plasmon resonance; Biosensor; Polymerase chain reaction 1. Introduction 1.1. GMOs characterisation GMOs are referred to as living organisms whom genome has been modified by the introduction of an exogenous gene able to express an additional protein that confers new characteristics. The foreign DNA is usually inserted in a gene “cassette” consisting of an expression promoter (P), a structural gene (“encoding region”) and an expres- sion terminator (T) (Fig. 1). Alternatively physical methods (e.g. particle gun) or chemical methods (e.g. polyethylene glycol or electroporation) may be used [1]. The promoter of the subunit 35S of ribosomal RNA of cauliflower mosaic virus (P35S) and the ter- ∗ Corresponding author. E-mail address: minunni@unifi.it (M. Minunni). minator NOS from Agrobacterium tumefaciens are widely used for the production of many transgenic vegetables, as soy Roundup Ready TM , maize Mais- Gard and the tomato Flavr Savr. At present, many GMOs, included many vegetables, have already been set up. Some genetically engineered plants are waiting for authorisation, whereas others have already been approved by several countries: US, Canada, European Union, Switzerland, Australia, Argentina, Brazil and Japan. Concerning GM plants, new proteins usually con- fer herbicide tolerance [2], fertility/maturation mod- ification or virus, fungi, parasite, drug or insect re- sistance [3]. Many countries have developed laws controlling the marketing of GMOs. In the EU the directive 90/220 regulates the approval and the re- lease of GMOs. Labelling of the genetically modified organism is not mandatory in US, but in Europe the novel food regulation will require the labelling 0003-2670/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S0003-2670(01)01458-1