Plasmonic Fiber Optic Sensing Platform for Point-of-Care Pharmacokinetic Monitoring of Platinum Chemotherapeutics: Toward Ultratrace Multi-omics Precision Chemotherapy Management

Precision chemotherapy management requires efficient and ultrasensitive dynamic monitoring of drug pharmacokinetics alongside real-time tracking of critical biomarker responses, yet existing clinical diagnostic systems neither achieve real-time integration of these critical parameters nor provide point-of-care testing (POCT) capabilities within a unified analytical framework. Here, we develop a plasmonic fiber-optic sensing platform based on tilted fiber Bragg grating surface plasmon resonance (TFBG-SPR) for point-of-care pharmacokinetic monitoring of platinum chemotherapeutics. By utilizing programmable DNA-based biosensors, our system achieves femtomolar-level detection limits for platinum drugs in minimal sample volumes (10 μL, 100-fold dilution). The platform's modular design enables rapid adaptation to diverse molecular targets with ultratrace multichannel spectral detection, providing inherent capability for parallelized multiomics monitoring by simultaneously addressing chemotherapeutics, DNA, RNA, and protein targets. In a longitudinal clinical cohort study via our proposed sensing platform, we observed an inverse correlation between platinum drug concentrations and miRNA-21 expression levels in colorectal cancer patients undergoing dose-adjusted chemotherapy, while ovarian cancer patients exhibited dynamic miRNA-21 responses to platinum drug concentration variations. These findings highlight the potential utility of miRNA-21 as a candidate biomarker for further investigation into drug efficacy and tumor progression mechanisms. By integrating ultratrace drug monitoring with targeted multiomics profiling on a unified platform─a critical prerequisite for data standardization in future artificial intelligence-driven analysis, our platform bridges the gap between clinical pharmacokinetics and molecular biomarker analysis, offering a fundamental POCT tool for precision chemotherapy optimization and personalized cancer management.