miRNA203 detection via single-strand DNA hybridization and signal amplification by copper-doped cerium oxide nanoparticles.

Diabetes mellitus is a debilitating disease that can result in the formation of foot ulcers. Healing of these ulcers is additionally impeded, as a consequence of the condition, leading to the persistence of the wounds which can lead to additional ulceration and infection. miRNA203 expression has been correlated with the severity of diabetic wounds and can therefore function as a biomarker for wound health. In the presented study, an electrochemical platform sensor device was produced which allowed the detection of the miRNA203 analyte at concentrations from 1 μM down to 10 fM. The sensor was built using an electrode-bound single-strand DNA species, designed to promote selective hybridization to miRNA203, which was chemically functionalized to a redox-active copper-doped cerium oxide (CuCNP) particle formulation, mediating charge transfer to the electrode substrate. CuCNP synthesis was performed at varying copper contents (0, 5, 8, and 12 mol%) and each formulation was tested to identify an optimal composition for charge transfer in the sensor architecture.