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A6-OP: DEVELOPMENT OF PIEZOELECTRIC BIOSENSOR
FOR THE DETECTION OF PROBIOTIC BACTERIA
H. Szalontai (1), N. Adányi (2), A. Kiss (1)
1 Eszterházy Károly College, Egerfood Regional Knowledge Centre, Eger, Hungary
2 Central Food Research Institute, Budapest, Hungary
(
h.szalontai@ektf.hu)
Due to the stricter food safety regulations there has been a growing demand towards simple, cost-effective and rapid examination methods in the dairy industry. The development of rapid, on the spot measurements in this monitoring procedure has also become essential. For this reason, the use of biosensors has come to the front in the identification of food components and contaminants as alternatives to classical, instrumental analytical and microbiological methods.
Our main task was the elaboration of the basic and applied scientific background of a quartz crystal microbalance based immunosensor examination method for the identification and quantification of Lactobacillus and Bifidobacterium strains used for different dairy products.
In order to achieve the best reproducibility the molecule immobilization and surface regeneration method have to be studied. These fundamental issues had to be examined for the repeated investigation of numerous samples. To optimize the immunosensor system model measurements were applied with bovine serum albumin (BSA) and anti-BSA antibody in flow-through system. We compared two immobilisation methods: self-assembled monolayers (SAM) were created with MHDA (16-mercapto-hexadecanoic acid) and with sulfo-LC-SPDP (sulfosuccinimidyl 6-[3’-(pyridyldithio) propionamido] hexanoate) cross-linking agents [1,2]. The effect of the concentration of immobilized antibody was studied in two type of experimental set-up, batch method and flow injection analysis. We also examined the possibility of crystal reusing. The immobilization of the antibody of probiotic bacteria (Lactobacillus, Bifidobacterium sp.) was followed by the investigation of the proper measuring parameters (flow rate, loop volume, pH and ionic strength of buffer). After the optimization steps probiotic bacteria was identified from pure cultures and the cell number was determined.
The quartz crystal microbalance based immunosensor technique provides rapid, label-free, one step carry out measuring tool for the determination of bacterial cells. Based on the results the QCM technique may become an efficient tool for food safety examinations.
References
- X.-L. Su, Y. Li, Biosensors and Bioelectronics, 2004, 19, 563-574.
- N. Adányi, M. Váradi, N. Kim, I. Szendrő, Current Applied Physics, 2005, 6, 279-286.
