SILVER NANOMATERIALS AS ELECTRON MEDIATORS IN A BIO-ELETRONIC TONGUE DEDICATED TO THE ANALYSIS OF MILKS. THE ROLE OF THE ASPECT RATIO OF NANOPARTICLES VS. NANOWIRES

The integration of silver nanomaterials as electron mediators in electrochemical biosensors has proven to be an efficient strategy to promote the electron transfer from the active site of the enzyme to the electrode due to their high surface-to-volume ratio and high conductivity [1]. Silver nanomaterials can be found in a variety of shapes and sizes, and the appropriate selection can be crucial to improve the affinity with biomolecules and the electrochemical response. In this work, two voltametric bioelectronic tongues (bioET) formed by biosensors based on the combination of enzymes with silver nanoparticles (AgNPs) (bioET-1) or silver nanowires (AgNWs) (bioET-2) have been developed and used to analyze milks. Each array was formed by six biosensors formed by enzymes (glucose oxidase, galactose oxidase, lactate dehydrogenase, β-galactosidase, urease and a blank), capable to detect compounds usually found in milks. Principal component analysis (PCA) has revealed the ability of both biosensor systems to discriminate between milk samples with different fat contents, but with some differences, attributed to the structure employed in the detection. The method developed is simple, and the short response time permits its use in assaying milk samples online.