Electrospun TiO2 nanofiber integrated lab-on-a-disc for ultrasensitive protein detection from whole blood

Abstract

ELISA-based devices are promising tools for the detection of low abundant proteins in biological samples. Reductions of the sample volume and assay time as well as full automation are required for their potential use in point-of-care diagnostic applications. Here, we present a highly efficient lab-on-a-disc composed of a TiO₂ nanofibrous mat for sensitive detection of serum proteins with a broad dynamic range, with only 10 μL of whole blood within 30 min. The TiO₂ nanofibers provide high specific surface area as well as active functional groups to capture large amounts of antibodies on the surface. In addition, the device offers efficient mixing and washing for improving the signal-to-noise ratio, thus enhancing the overall detection sensitivity. We employ the device for the detection of cardiac biomarkers, C-reactive protein (CRP) and cardiac troponin I (cTnI), spiked in phosphate-buffered saline (PBS) as well as in serum or whole blood. The device exhibited a wide dynamic range of six orders of magnitude from 1 pg mL⁻¹ (~8 fM) to 100 ng mL⁻¹ (~0.8 pM) and a low detection limit of 0.8 pg mL⁻¹ (~6 fM) for CRP spiked in CRP-free serum and a dynamic range of 10 pg mL⁻¹ (~0.4 pM) to 100 ng mL⁻¹ (~4 nM) with a detection limit of 37 pg mL⁻¹ (~1.5 pM) for cTnI spiked in whole blood.