Genosensors and Aptasensors

The use of streptavidin modified nanoparticles permitted rapid formation of an easily detected conjugate with biotinylated DNA through a streptavidin-biotin interaction, thus avoiding the need of synthesizing DNA modified with nanoparticles, a more time-consuming procedure. The protocol employing a competitive binding assay allowed the detection of unlabeled DNA both completely complementary or with one or two mismatches. In order to visualize the presence and distribution of AuNPs, a silver enhancement 

Electrochemical biosensors based on DNA aptamers (aptasensors) are of growing interest due to their high sensitivity and selectivity. This is particularly due to unique properties of 

DNA or RNA aptamers - the single stranded nucleic acids with high affinity to proteins or to other low and macromolecular compounds, which is comparable with that of antibodies. These special characteristics open new routes in biosensor assembling for further practical applications, such as detection of toxicants in food or environment. 

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