Aptamers enhance flexibility in biosensor design. An aptasensor employs aptamers as a biological recognition element for biosensing. This paper presents design, fabrication, and evaluation of a microcantilever aptasensor. To identify and avoid potential bottlenecks in the aptasensor design, the parameters of the aptasensor are investigated through modelling and simulation. Next, thin SU-8 microcantilevers are fabricated to form the aptasensor. Characterization of the fabricated aptasensor is presented. Next, a plasma-based surface funtionalisation method is used to immobilize aptamers on the aptasensor. Finally, an evaluation of the performance of the aptasensor is performed through detection of thrombin molecules. The evaluation results are presented and discussed.