Porous microneedle-based electrochemical aptamer biosensor for the collection and quantitative analysis of dry eye...

Dry eye disease (DED) is a prevalent ocular disorder driven by tear film instability and inflammation. The quantitative measurement of molecular biomarkers in tears can provide reliable and accurate diagnosis and management of DED. This article introduces a porous microneedle-assisted electrochemical aptamer biosensor for the collection and quantitative analysis of DED-associated biomarkers in tears. The porous microneedle component collects tears while the electrochemical aptamer sensor detects interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and matrix metalloproteinase-9 (MMP-9) with the detection limit of 4.46 pg mL^-1, 1.56 pg mL^-1, and 4.97 ng mL^-1, respectively. Clinically, DED is associated with 13 pg mL^-1 of IFN-γ, 4 pg mL^-1 of TNF-α, and MMP-9 concentrations of more than 40 ng mL^-1 in tears, which are above the detection limits of our sensors. By taking MMP-9 as a model biomarker, we demonstrate a complete collection-to-detection workflow using this microneedle-aptamer biosensing device, which would facilitate the realization of point-of-care monitoring of DED.