THE USE OF ELECTROCHEMICAL TRANSDUCTION IN DEVELOPING PSII BASED BIOSENSORS-PRO'S AND CON'S

There is an increasing demand worldwide for low cost, fast, and reliable methods for monitoring chemical species, additives, and xenobiotics in clinical chemistry, environmental sciences, and food related processes. Chemical sensors and biosensors offer all these advantages since they can be easily used in both laboratory and field applications. In developing sensors and biosensors one of the key-issues is related to the capability of designing the perfect match between appropriate transduction (to ensure the signal sensitivity) and biorecognition element functionality (to ensure specific discrimination of the targeted analyte, sensitivity and response stability). The use of signal amplifiers as nanoparticles/nanowires in order to enhance the electrochemical response will be discussed and exemplified for Pt@M bimetallic nanoparticles and Carbon Nanofibres-Gold Nanoparticles. The exploitation of PSII enriched membranes is particularly suitable for the development of electrochemical biosensors as the enzyme is selectively activated by light consequently minimizing the electrochemical interferences1,2. The use of different photosynthetic strains will be discussed and the obtained results will be compared for various electroactive surfaces supports. In order to ensure the biosensor functionality it should be maintained the cell viability which will ensure the proper photosynthetic activity. Consequently, when designing a biosensor one of the critical points is the bio-recognition element immobilization, since the immobilization must preserve, or, if possible improve, the bio-mediator activity. Results obtained by using two immobilization protocols will be presented, influence of material load, temperature, pH variation, etc. being discussed. The results obtained using a new developed PSII-Pt@Au_CSPE amperometric biosensors applied in assessing the urban water contaminants will be presented; the optimum response was characterized by a sensitivity of 15nA/µmolL-1 for TCE/PCE contaminants.