Bimetallic MnCo oxide nanohybrids prepared from Prussian blue analogue for application as impedimetric aptasensor carrier to detect myoglobin

The accurate detection of myoglobin (Myo) in human serum plays a crucial role in early diagnosis of acute myocardial infarction. This work presents a novel impedimetric aptasensor for sensitive and selective detection of Myo, in which bimetallic MnCo oxide nanohybrids (represented by MnOxCoOy) were used as platforms for anchoring Myo aptamer strands. A series of MnOxCoOy nanohybrids were prepared from bimetallic MnCo-based Prussian blue analogue (PBA) nanocubes via calcination at different temperatures under N2 atmosphere. Basic characterizations revealed that homogeneously-distributed MnOx and CoOy nanoparticles were achieved at 500 °C (MnOxCoOy,500) calcination, which immensely enhanced the electrochemical conductivity in addition to boosting the aptamer immobilization. Compared with the pristine MnCo-PBA-based aptasensor, the MnOxCoOy,500-based aptasensor exhibited higher sensitivity and selectivity for Myo detection, with lower detection limit of 0.56 fg·mL−1 (0.034 fM) in a wide dynamic range of 0.01~2000 pg·mL−1, which is the most sensitive among similar previously reported Myo sensors. Moreover, the constructed MnOxCoOy,500-based aptasensor displayed good stability, excellent reproducibility and acceptable applicability in human serum. The proposed strategy establishes a remarkable platform for the construction of aptasensor that is feasible for the Myo detection in a real human serum sample.