AuNP decorated-Ni-MOF nanosheet based cDNA sensor for detection of miRNA-128 in Alzheimer's disease.

A cDNA sensor based on gold nanoparticles (Au) supported on nickel metal-organic framework nanosheets (MOF-NS) modified fluorine-tin oxide (FTO) glass electrode for the ultrasensitive and selective detection of miRNA-128 biomarker associated with the progression of Alzheimer's disease (AD) has been reported. The MOF-NS and Au nanoparticles were electrodeposited onto FTO electrode using chronoamperometry to immobilize 5'-biotinylated DNA (btn-cDNA) complementary to miRNA-128 by streptavidin-biotin interaction, generating the modified electrode (btn-cDNA/SV/Au/MOF-NS/FTO). The fabricated electrode was characterized using various surface characterization techniques, including FESEM, XPS, FTIR, and electrochemical methods. The fabricated electrode was then utilized for the selective detection of miRNA-128 using electrochemical impedance spectroscopy. The results indicated a linear response range of 1.0 × 10-1 fM-1.0 × 102 nM with limit of detection of 0.017 fM, and sensitivity of 180.11 Ω fM-1cm-2. Moreover, the cDNA sensor showed satisfactory performance with real serum samples from AD patients and healthy individuals, as validated by real time-PCR technique with area under curve of 0.93 and a sensitivity of 90%, respectively, demonstrating the potential of present cDNA sensing approach in the biomedical field.