A Multi-transducer biosensor in monitoring large classes of pollutants for food quality and safety

Nowadays, there is an increasing demand worldwide for low cost, fast and reliable methods for monitoring chemical species. Biosensors offer all these advantages since they can be easily used both in laboratory and in field applications (1,2). This rapidly expanding field has an annual growth rate of 60 %, with major impetus from the health-care industry (30% of the world's total analytical market) supported with other analytical areas of food & environmental monitoring and security. The world total analytical market is approx 12 billion/year and less than 0.1% of this market is currently using biosensors. One main reason of this reduced growth is that each biomediator requires a specific device and a lot of effort for a small market. The instrument reported in this paper, and developed by the synergy of an R&D institution and a industrial high tech company, intends to contribute to reduce this gap by moving biosensors from the research laboratories to market developing a system that can be used for a large range of applications: agro-food, industry for drinkable products, fermentation industry, waste water management, microbial contamination, security, defence et several al. In particular, we designed and fabricated a new advanced biosensor for the detection of agrofood pollutants by combination of amperometric and optical transducers with microorganisms and enzymes as bioreceptors (1-3). It utilizes as biosensing elements a multi-array of photosynthetic unicellular green alga Chlamydomonas reinhardtii as well as Laccase and Tyrosinase enzymes, immobilised on screen printed electrodes over an area of few millimetres. It was developed for the detection of pesticides present in food owning to large classes of chemical compounds such as triazine, fenylurea, diazine and phenolic pesticides, with very low limits of detection that ranged from 0.9 x 10-11 M to 3.0 x 10-9 M, depending on the biomediator and the herbicide pairing tested (4). Environmental and human health problems related to the use of synthetic pesticides have created an increasing pressure against their use. According to the FAO's dossier issued in Jakarta in May 2001 the human and material costs of the giant pesticides business accounts for 25mln of people poisoned every year and 30bln of annual turnover. The most recent EU directive concerning pesticides (EC Regulation No 149/2008 of 29th January 2008) fixes the maximum residue levels of pesticides in food and feed of plant and animal origin to values between 0.01-0.05 mg/kg depending on the compound. The proposed biosensor aims at providing solutions to these issues by offering low cost easy to use tools for real time monitoring.