Biosensors for Life Sciences

The biosensors offer the possibility to toxicological investigations from different matrices: water, biological liquids, foods, detecting specific and with very good sensitivities low concentrations of organophosphorus and carbamates pesticides. The applicability of the method is also in environmental protection (Coman et al., 2000), but also in analysis with medical interest (Nivolini et al., 1995; Akyilmaz et al., 2006). The biosensors obtained and characterised have been used PVA-SbQ and sol-gel immobilisation method. Sol-gel method was optimised for immobilisation of different kind of acetylcholinesterase to be able to be use in sensitive detection of some organophosphorus pesticides (methyl paraoxon, clorpyrifos methyl oxon, diazinon) from synthetic samples. The methods were also applied for real sample testing (water, baby food, juice), testing different extraction methods from initial matrices. The extracts were tested also using HPLC-UV, for method validation and for the explanation of the phenomenon that appear during the extraction step. It was concluded that biosensors might be used successfully for rapid, sensitive and specific determination of the organophosphorus and carbamates pesticides and some times mycotoxins (still in work for optimisation procedures) from different media. An important area of research in ChE biosensors is directed toward the development of automated and continuous systems for measuring ChE inhibitors in flow conditions. The automation can be obtained by a computer controlled-programmable valve system which allows reproducible pumping of different reagents including buffers, substrate and inhibitor solutions, reactivating agents and real samples. Further improvement in sensitivity and selectivity can be obtained with the use of sensitive multienzymes which also allow discrimination between the insecticides and other interferences. In the future, compact and portable devices specifically designed for in-field analysis and development of arrays of multiple sensors will constitute another area of intensive research for ChE biosensors. A ChE biosensor array could be designed with each sensor containing a different immobilized enzyme (wild type and mutants ChEs extracted from different sources). This could allow sensitive detection and differentiation of multianalyte mixtures. Considerable progress is expected in genetic engineering for the production of more selective and sensitive ChEs. The future work would like to make the integration of a fully autonomous electrochemical biosensor with pattern recognition techniques for the detection and monitorize the pollutants level in different matrices. The system will provide a continuous, real-time monitoring of immobilized enzymes activities upon exposure to pollutants compounds (Karasinski et al, 2005). Our research group have also in work some animal studies, testing the modification of some enzymes activity after the aflatoxin and ochratoxin innoculation, intending in future to use also cell models.