With the growing number of new biomarkers discovered for clinic diagnosis, there is an emerging need for the development of biosensing device. One important application of the biosensor in disease diagnosis is to detect biomarkers and the biosensor should be sensitive enough to measure the small variation in biomarker concentration. Besides, to support the point-of-care diagnostics that can facilitate emergency diagnosis and disease screening, it is important that the sensing device needs to be portable, user-friendly, and support the rapid biomarker detection. In this work, we propose a rapid portable sensing device by utilizing dielectrophoresis force to accelerate the centralization of the biomarkers and the comparator-based operational amplifier to enlarge small signal response. Furthermore, the testing results demonstrate the proposed biosensor can detect subtle admittance variation corresponding to the concentration change of the biomarkers in short assay time. The sensing device is able to detect cardiac troponins level with the limit of detection at 0.1 ng mL(-1), that can satisfy the actual requirements for diagnosis of cardiovascular disease. The proposed biosensor can provide an easy-to-use, cost-effective, and rapid biomarker detection that can be applied to clinical applications to support point-of-care diagnostics.