Disposable electrochemical biosensors for Brettanomyces bruxellensis and total yeast content in wine based on core-shell magnetic nanoparticles

Two different disposable amperometric biosensors for the rapid detection and quantification of Brettanomyces bruxellensis (Brett) and total yeast content in wine were constructed. The biosensing approach implied the use of magnetic capturing elements based on core-shell Fe3O4@SiO2 superparamagnetic nanoparticles (NanoCaptors) functionalized with specific bioreceptors: Concanavalin A (Con A) for total yeast analysis, and anti-Brett polyclonal antibodies for Brett. A Con A-peroxidase conjugate and carbon screen printed electrodes were used as signaling element and sensing interfaces, respectively. The biosensor based on antibody-modified magnetic nanoparticles allowed the amperometric detection of B. bruxellensis in buffer solution and red wine samples in the range of 10 - 10(6) CFU/mL, with low detection limits of 6 CFU/mL and 8 CFU/mL, respectively. In addition, the use of Con A-linked magnetic nanoparticles as capturing elements allowed determination of total yeast content in buffer solution and red wine in the range of 10 - 10(6) CFU/mL, with detection limit of 5 CFU/mL. These electrochemical biosensors also exhibited high reproducibility, selectivity and storage stability.