PDMS porous microneedles used as engineered tool in advanced microfluidic devices and their proof-of-concept for biomarker detection

The advancement of organ-on-a-chip (OoC), as end-use preclinical tool, has been slackened with the technological and engineering challenges that in-situ real-time monitoring of physicochemical and biological parameters still represent. In this study, the envisioned solution to surpass this challenge is the integration of a microneedle (MN) patch into a microfluidic device to collect cell culture media directly from the organ chamber and drive it to a module envisioned to contain the biosensing system for real-time monitoring. For that, porous MNs (PMNs) were fabricated using a polydimethylsiloxane (PDMS) bulk material, casted with one of two materials, one organic and one inorganic, which were explored to create micropores after removal processes. The developed PMN arrays were characterized regarding their mechanical, wettability, permeability and porosity properties. Then, the selected PMN patch, with the best combined properties to serve as media collector was integrated into a proof-of-concept microfluidic system and the system validated through albumin optical absorption analysis. The findings of this study highlight the potential to use PMN patches in advanced microfluidic platforms to simplify the integration of biosensor systems, and thus, with high potential of applicability in biomedical research and preclinical diagnostic tools.