Core-shell assay based aptasensor for sensitive and selective thrombin detection using dark-field microscopy

A robust and ultrasensitive bio-sensor based on the target-aptamer recognition strategy and microscopic enumeration of gold nanoparticles (AuNPs) using dark field microscopy (DFM) was developed. In this assay, upon addition of target molecule, the AuNPs that linearly related to the concentration of target molecules released from the MB were optically counted. The limit of detection was determined to be 2.54 fM using thrombin as a model target.144