Aptamer-decorated porous microneedles arrays for extraction and detection of skin interstitial fluid biomarkers

The detection of biomarkers in body fluids plays a great role in the diagnosis, treatment, and prognosis of diseases. Here, we present novel aptamer-decorated porous microneedles (MNs) arrays to realize the extraction and detection of biomarkers in skin interstitial fluid (ISF) in situ. The porous MNs arrays are fabricated by replicating the negative molds comprising glass microspheres with a UV-curable ethoxylated trimethylolpropane triacrylate (ETPTA). As the MNs arrays combine the superiorities of porous structure and aptamers, their specific surface area increased significantly to 6.694 m2/g, thus vast of stable aptamer probes with a concentration of 0.9459 μM could be immobilized. In addition, the MNs arrays could extract skin ISF into their porous structure on the basis of the capillarity principle, and subsequently capture and detect skin ISF biomarkers without sample post-process. Taking advantage of these features, we further demonstrated a highly sensitive and rapid detection of ISF endotoxin in the concentration ranges of 0.0342 EU/mL to 8.2082 EU/mL from rats model injected with endotoxin via tail vein by using such aptamer-decorated porous MNs arrays, with the limit of detection (LOD) of 0.0064 EU/mL. These results indicated that the aptamer-decorated porous MNs arrays possess great potential for non-invasive extraction and detection of biomarkers in clinical applications.