Cardiac arrests are one of the major health problems in present days. Cardiac Troponin-I (cTnI) is one of the important enzymes that causes cardiac arrest. Early diagnosis and proper medication of this saves human life. One of the prominent devices to diagnose troponin I is FET based bio-sensor. Normally, for these sensors’ higher sensitivities will be obtained as these biosensors structure consists of nanowire FETs. Proper selection of materials, dimensions, and doping concentrations of nanowire FET imply the perfection of a nanowire FET-based biosensor. In this work, Silicon Nanowire (SiNW) FET sensor is designed and simulated using COMSOL Multiphysics. Through this design, Identified the presence of different concentrations of cTnI present in human blood. The presence of different enzymes like cTnT, cTnI etc., bring changes in characteristics of SiNW FET sensor. With these changes in characteristics, we can identify the presence of these enzymes of a lower concentration also. The lower concentrations of these biomarkers will bring notable changes in the drain current. The characteristics were analysed with the SiNW FET which is equipped with immobilized antibodies on it. The considerable changes observed in these characteristics of FET sensor identifies the presence of cTnI biomarker and are attached to the monoclonal Antibodies (mAb). Our observations shown that the properties of designed SiNW FET changes with presence of these bio marker materials and a limit of detection is obtained the order of 2pg/mL. with further the design bio sensor with SiNW FET can be used for microfluidic and Lab-on-Chip applications also.