A pressure-assistive microneedles module for interstitial fluid extraction and In situ detection of biomarkers.

Interstitial skin fluid (ISF) is recognized as a promising source of biomarkers, yet point-of-care testing (POCT) based on ISF remains hindered by multiple challenges. To address these issues, specifically improving ISF extraction efficiency and enabling practical POCT analysis, this study developed a painless hollow microneedles (MNs) module. The module connects to a syringe via a flexible tube to generate negative pressure, with the syringe scale directly determining the pressure magnitude applied for ISF extraction. Additionally, grooves at the bottom of the MNs module can accommodate diverse test strips, facilitating the detection of multiple biomarkers. This design features simplicity and ease of operation. It was validated through both in vitro and in vivo experiments: in vitro detection of glucose, pH, and alcohol within 3 min; and in vivo extraction of 10.2 (±1.9) mg of ISF. Notably, this module design eliminates the need for ISF recovery steps or specialized equipment for subsequent analysis. These results demonstrate the design's potential for applications in POCT and personalized medicine.