Point-of-care testing of methotrexate using a controlled release sensor based on a personal glucose meter

Methotrexate (MTX), a widely administered medication for treating an array of tumors and autoimmune disorders, necessitates stringent monitoring due to the potential for severe adverse effects associated with its high dosage. Nevertheless, the existing methods for monitoring MTX are often intricate, time-consuming and incur significant costs. In this work, we constructed a controlled release sensor, harnessing the versatility of a personal glucose meter (PGM), which had been devised for the swift detection of MTX. This innovative approach employed HP-UiO-66-NH₂ as a nanoscale reservoir for glucose encapsulation, with aptamer-conjugated gold nanoparticles (AuNPs@Apt) serving as molecular gates, sealing the pores of the nano-container. Upon the introduction of MTX into the solution, a specific recognition event occurred between the aptamer and MTX, leading to the formation of a stable AuNPs@Apt-MTX complex. This interaction triggered the release of AuNPs@Apt from the surface of HP-UiO-66-NH₂, allowing glucose to escape, which was then detected by the PGM. This method demonstrated a robust linear response to MTX concentrations spanning from 0.1 μM to 20 μM, with a remarkable detection limit of 0.1 μM. Extensive experiments underscored the platform's exceptional selectivity for MTX detection, coupled with excellent reproducibility and stability, with a detection time of only 30 minutes. Importantly, it had been successfully applied to the analysis of MTX in diluted human serum with satisfactory recoveries. Given its portability and cost-effectiveness, this platform paved a novel avenue for monitoring MTX blood drug levels, offering significant potential for clinical applications and drug monitoring strategies.