Cu-MOF-NH2@Au-based ratiometric electrochemical aptasensor for ultrasensitive H1N1-HA protein detection.

This study developed a ratiometric electrochemical aptasensor to detect the H1N1 virus by targeting its hemagglutinin (HA) protein. In the experimental design, a Cu-MOF-NH2@Au nanocomposite was utilized as the sensing platform, where the Cu-MOF provided a stable internal reference signal at approximately − 0.2 V (vs. Ag/AgCl). Simultaneously, the ferrocene-L-cysteine complex (Fc-L-Cys) produced a target response signal at + 0.3 V, and the combination of these two signals enabled a ratiometric output mode. By immobilizing capture aptamers on the Cu-MOF-NH2@Au surface and enabling them to specifically recognize the HA protein in conjunction with Fc-L-Cys-labeled detection aptamers, a “sandwich” detection structure was formed, further enhancing the aptasensor’s specificity and sensitivity. As the HA protein concentration increased, the redox peak of Cu-MOF-NH2@Au decreased while that of Fc increased. Based on this inverse trend, the ratio of the two signals (R = ΔICu / ΔIFc) exhibited a linear relationship with the logarithm of the HA protein concentration. The aptasensor demonstrated an extensive linear detection range from 1 pg/mL to 1 µg/mL, with a low detection limit of 0.56 pg/mL, and a total assay time of approximately 20 min. It also showed excellent repeatability, stability, and anti-interference ability. In spiked saliva samples, recoveries ranged from 93.8% to 107.6%. These findings indicate that the developed aptasensor possesses strong practicality and promising clinical application potential.