Fig. 6.

Schematic representation for Multiplexed Ligation Based Electrochemical Biosensor with Nonfouling Surface.

The 3′ end of the gold electrode tethered thiolated capture probes hybridize with their complementary sequences of target DNA. A biotinylated (indicated by letter B) signal probe that is also complementary to other part of the target DNA binds adjacently to thiolated capture probe leaving a nick. This nick is then sealed (indicated by small black box) with DNA ligase. Following denaturation and washing, only ligated products would be tethered to the gold electrode. These ligated products are biotinylated at their 3′ end and therefore can bind to avidin-horseradish peroxidase conjugate (indicated by crescent and star shapes respectively) for generation of amperometric signal