The GaAs/AlGaAs-Based Extended Gate HEMT Cardiac Troponin-I Biosensor: Design, Mechanism and Clinical Detection

Herein, we designed several structures of GaAs/AlGaAs extended gate high electron mobility transistors (EG-HEMT) for cTnI detection, in order to explore the mechanism of bio-detection, the limit of detection (LOD) as well as the application in clinical detection. The experiment carried out that 50y structure of EG-HEMT biosensor, whose extended electrode is 50 times as large as the gate, has highest biological regulation ability (
$\delta $
). Meanwhile, the concentration range of cTnI detection using 50y EG-HEMT biosensor is about 100 fg ml
⁻¹
to
$10~\mu \text{g}$
ml
⁻¹
, which is much broader than that of Unicel Dxl800 (usually be used in clinical detection). Furthermore, due to the influence of parasitic resistance and other factors,
$\delta $
increases with the increase of y, but the rising rate of
$\delta $
decreases at the same time. By comparing the detecting results of clinical samples, 30y EG-HEMT is the best in the detection of cTnI concentration with a relative error of 6%. In a higher concentration range, it is more accurate than that of the Unicel Dxl800, breaking through its limit.