Corn-inspired high-density plasmonic metal-organic frameworks microneedles for enhanced SERS detection of acetaminophen.

Effective monitoring of acetaminophen (APAP) dosage is crucial for preventing antipyretic abuse, ensuring therapeutic efficacy, and minimizing toxic effects. However, existing self-monitoring methods are limited. In this study, we designed a plasmonic microneedle (MN) sensor for real-time nondestructive monitoring of acetaminophen levels in dermal interstitial fluid (ISF) by employing a handheld Raman spectrometer. The fabricated MN sensor incorporated a high-density plasmonic MOFs known as HDPM, which unique structure of large specific surface area, specific pore structure as well as high density gold nanospheres packing enabled the excellent performance of selective ISF drug enrichment and surface-enhanced Raman scattering (SERS). The maximum electric field enhancement factor of the HDPM nanostructure could be calculated as 5.73 × 107. The developed HDPM@MNs was characterized with a core-shell type "soft on the outside and rigid on the inside" structure, which exhibited sufficient hardness and flexibility to penetrate the dermal tissue with little damage, and robust SERS enhancement effect in APAP detection without any interfering peaks. Through a hydrogel drug simulation experiment, the sensor demonstrated robust capabilities for acetaminophen enrichment and monitoring, exhibiting excellent stability and repeatability. The quantitative detection window spanned from 1 to 100 μM, with a low detection limit reaching 0.45 μM. Furthermore, by monitoring the concentration of acetaminophen in the interstitial fluid of rat skin at different doses and for different administration times, the HDPM@MNs can be used to determine the pharmacokinetics of acetaminophen in rats and the physiological characteristics associated with various dosage regimens. This work not only holds promise for drug monitoring but also provides a novel approach for nondestructive monitoring of other crucial low-abundance physiological markers.