Evaporation-Induced Biomolecule Detection on VersatileSuperhydrophilic Patterned Surfaces: Glucose and DNA Assay

摘要

We introduce a droplet-based biomolecular detection platform using robust, versatile, and low-cost superhydrophilic patterned superhydrophobic surfaces. Benefitting from confinement and evaporation-induced shrinkage of droplets on wetted patterns, we show enrichment-based biomolecular detection using very low sample volumes. First, we developed a glucose assay using fluorescent polydopamine (PDA) based on enhancement of PDA emission by hydrogen peroxide (H2O2) produced in enzyme-mediated glucose oxidation reaction. Incubation in evaporating droplets resulted in brighter fluorescence compared to that in bulk solutions. Droplet assay was highly sensitive toward increasing glucose concentration while that in milliliter-volume solutions resulted in no fluorescence enhancement at similar time scales. This is due to droplet evaporation that increased the reaction rate by causing enrichment of PDA and glucose/glucose oxidase as well as increased concentration of H2O2 generated in shrinking droplet. Second, we chemically functionalized wetted patterns with single-strandedDNA and developed fluorescence-based DNA detection to demonstratethe adaptability of the patterned surfaces for a different class ofassay. We achieved detection of glucose and DNA with concentrationdown to 130 μM and 200 fM, respectively. Patterned superhydrophobicsurfaces with their simple production, sensitive response, and versatilitypresent potential for bioanalysis from low sample volumes.