Design of a label-free mass sensor based on three-dimensional nanomagnetic bead for ultrasensitive detection of cardiac troponin I

In this research, an innovative and highly sensitive mass sensor was designed for cardiac troponin I (cTnI) detection based on 3D nanomagnetic beads, which do not need to be labelled using signal probes. The proposed sensor was characterized by several technologies, such as transmission electron microscopy (TEM), UV-visible spectrophotometry, atomic force microscopy (AFM), Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), etc. Under optimum conditions, the frequency showed a remarkable linear dependence on cTnI concentration within the interval of 1.0 pg mL -1 to 10.0 ng mL -1 , with a detection limit of 0.2 pg mL -1 . This biosensor showed ultrasensitivity, time-efficiency, and lower costs, and consequently can be expected to be applied in real life.