Work

Multivariate quantification of methotrexate in the presence of mercaptopurine on lab-on-disc: double filtration assay

Year: 2026

Type: article

Abstract: Therapeutic drug monitoring (TDM) is crucial for ensuring patient safety and treatment efficacy, particularly for medications with a narrow therapeutic window. Current gold standard techniques, such as HPLC, are highly accurate but limited by high costs, long processing times, and reliance on centralized laboratories and trained personnel for operation. Multiplexing in TDM, lacking in most of the currently used techniques, offers an opportunity to enhance analytical throughput and reduce sample volumes, thereby improving patient comfort and ultimately could also reduce the cost of analysis. Therefore, we are introducing a Surface Enhanced Raman Spectroscopy (SERS)-based centrifugal microfluidic platform enabling simultaneous detection of two drugs from less than 20 μL of patient sample. A key feature of the system is on-disc integration of precipitation and filtration, using regenerated cellulose membrane. This serves as an effective sample pretreatment strategy that enhances reproducibility and spectral quality by reducing biological interference. A second filtration step directly on the SERS substrate embedded in the disc, driven by centrifugal forces, proved to enhance further quantification of drugs from blood samples. The developed platform demonstrated reliable analytical performance for two target analytes, methotrexate (MTX) and mercaptopurine (6-MP), where MTX was successfully validated with patient samples, confirming clinical relevance. An average relative recovery (RR%) of 93% confirmed the clinical feasibility of this approach and its applicability to real-world scenarios. These results highlight that a SERS-based platform with integrated sample cleaning has strong potential for point-of-care TDM.

Source: Chemical Engineering Journal

DOI: 10.1016/j.cej.2026.181185