Methotrexate Detection in Serum at Clinically Relevant Levels with Electrochemically Assisted SERS on a Benchtop, Custom Built Raman Spectrometer

Abstract

Therapeutic drug monitoring (TDM) is an essential clinical practice for optimizing drug dosing, thereby preventing adverse effects of drugs with a narrow therapeutic window, slow clearance, or high interperson pharmacokinetic variability. Monitoring methotrexate (MTX) during high-dose MTX (HD-MTX) therapy is necessary to avoid potentially fatal side effects caused by delayed elimination. Despite the efficacy of HD-MTX treatment, its clinical application in resource-limited settings is constrained due to the relatively high cost and time of analysis with conventional analysis methods. In this work, we developed (i) an electrochemically assisted surface-enhanced Raman spectroscopy (SERS) method for detecting MTX in human serum at a clinically relevant concentration range and (ii) a benchtop, Raman detection system with an integrated potentiostat, software, and data analysis unit that enables mapping of small areas of SERS substrates and quantitative SERS-based analysis. In the assay, by promoting electrostatic attraction between gold-coated nanopillar SERS substrates and MTX molecules in aqueous samples, a detection limit of 0.13 μM with a linear range of 0.43−2 μM was achieved in PBS. The implemented sample cleanup through gel filtration proved to be highly effective, resulting in a similar detection limit (0.55 μM) and linear range (1.81−5 μM) for both PBS and serum. The developed and optimized assay could also be used on the in-house built, Raman device. We showed that MTX detection can be carried out in less than 30 min with the Raman device, paving the way toward the TDM of MTX at the pointof-need and in resource-limited environments.

Recent Research Progress of Surface‐Enhanced Raman Scattering Dominated Analysis Strategies in Early Diagnosis of Diseases

“…monitoring methotrexate during the drug treatment [234]. A meaningful breakthrough has been appeared in the SERS field.…”

Functional Group-Assisted Fluorescence Sensing Platform for Nanomolar-Level Detection of an Antineoplastic Drug and a Neurotransmitter from Environmental Water and Human Biofluids

“…6−20 Inspired by the recent trend of detection of drugs and biomolecules, we have put forward our contribution for the selective and targeted sensing of two very important analytes, i.e., adrenaline and methotrexate. There are a few probes reported for the sensing of adrenaline and methotrexate by surface plasmon Raman spectroscopy, 21 electrophoresis, 22 liquid chromatography, 23 colorimetry, 24 the electrochemical method, 25 and fluorescence-based techniques. 26 Among the various methods mentioned above, the fluorescence-based approach has the advantages of low cost, easy handling, and simple preparation processes.…”

“…There are a few probes reported for the sensing of adrenaline and methotrexate by surface plasmon Raman spectroscopy, electrophoresis, liquid chromatography, colorimetry, the electrochemical method, and fluorescence-based techniques . Among the various methods mentioned above, the fluorescence-based approach has the advantages of low cost, easy handling, and simple preparation processes .…”

An optical sensing platform for the detection of anti-cancer drugs and their cytotoxicity screening using a highly selective phosphorene-based composite

“…There are several analytical methods for detecting MTX, such as surface plasmon resonance, surface-enhanced Raman scattering, high-performance liquid chromatography, electrolysis, immunoassays, radioimmunoassay, enzyme-multiplied immunoassay, protein binding, enzyme inhibition, microbiological assays, and electrochemical assays. 1,3,[7][8][9][10] In general, the high-pressure liquid chromatography (HPLC) method has been used to measure MTX in blood samples. The main disadvantage of these techniques is they are very complex and costly.…”

“…2 For the treatment of various carcinomas, such as breast, gastric, head, and neck cancers; acute lymphoblastic leukaemia (ALL); osteosarcoma; and choriocarcinoma, body surface area-based doses higher than 500 mg m −2 of MTX (denoted as HD-MTX) are given intravenously. 3 It takes 1–2 hours to be absorbed inside the body once administered. Since MTX is highly toxic, it can prevent the growth of healthy cells, which limits its clinical recommendations.…”