Abstract: In one aspect, the disclosure relates to a universal method for biomarker extraction and detection from clinical samples using magnetic nanoparticles (MNPs) coupled with a locked aptamer-initiator approach. The MNP bound locked aptamer undergoes a conformational change in the presence of the target biomarker and the unfolded initiator triggers a hybridization chain reaction with a structurally stabilized catalytic trimeric triplex DNAzyme hairpin. Amplicons from the hybridization chain reaction can be incubated with hemin to obtain a stable triplex structure that has horseradish peroxidase-like activity in the presence of H2O2 and a substrate molecule. The intensity of the signal is directly proportional to the amount of biomarker present. Binding one or more reagents on a nanoparticle can be coupled with this approach for use in a microfluidic or paper fluidic platform. In any of these aspects, the assay can detect as low as femtogram amounts of biomarker from the clinical sample.

Abstract: In an embodiment, the present disclosure pertains to a microfluidic device composed of a substrate having an inlet region and a first storage region, a fluid transporting channel in fluid communication with the inlet region, an expandable component in fluid communication with the fluid transporting channel and coupled to a movable arm, and a fluid transporting region coupled to the movable arm and operable to be moved in a horizontal direction to the fluid transporting channel to thereby form fluidic contact between the inlet region and the first storage region upon expansion of the expandable component. In an additional embodiment, the present disclosure pertains to a method of fluid flow utilizing a microfluidic device of the present disclosure.