PlasmoBridge Chip Enables Ultrasensitive and Rapid Monitoring of Methotrexate

Why It Matters

Instant, accurate methotrexate measurement can prevent dose‑related toxicity and improve oncology outcomes, filling a critical gap in therapeutic drug monitoring. Its low‑cost, point‑of‑care design could accelerate precision dosing adoption across hospitals.

Key Takeaways

• PlasmoBridge detects methotrexate down to 4.64×10⁻⁸ M.
• Aptamer‑nanoparticle bridge creates stable SERS hotspots.
• CNN analysis yields R² > 0.99 across 10⁻⁷‑10⁻⁴ M.
• Real‑time monitoring reduced MTX toxicity in mouse model.
• Chip offers rapid, low‑cost alternative to LC‑MS/MS.

Pulse Analysis

Methotrexate remains a cornerstone chemotherapeutic, yet its narrow therapeutic window forces clinicians to rely on periodic lab tests that are expensive, time‑consuming, and often unavailable at the bedside. Conventional LC‑MS/MS platforms deliver high accuracy but require specialized equipment and skilled technicians, while immunoassays suffer from cross‑reactivity and limited sensitivity. This diagnostic bottleneck hampers real‑time dose adjustments, exposing patients to either sub‑therapeutic efficacy or severe organ toxicity.

PlasmoBridge tackles these challenges through an innovative aptamer‑nanoparticle dual‑assembly that forms a plasmonic nanobridge. Silver nanoparticles linked by methotrexate‑specific aptamers generate intense surface‑enhanced Raman scattering (SERS) hotspots, amplifying the molecular signal without sacrificing selectivity. Coupled with a convolutional neural network for spectral deconvolution, the chip delivers a detection limit of 4.64 × 10⁻⁸ M and maintains linearity (R² > 0.99) across three orders of magnitude. The result is a rapid, reproducible assay that can be performed directly on serum samples within minutes.

Beyond analytical performance, the technology signals a shift toward AI‑augmented point‑of‑care therapeutics. In mouse models, real‑time monitoring guided by the CNN model enabled dose titration that preserved antitumor activity while dramatically reducing hepatic, renal, and intestinal injury. Such precision dosing aligns with the broader move toward personalized medicine and could be extended to other narrow‑window drugs. For hospitals, the low‑cost, portable nature of PlasmoBridge promises to democratize therapeutic drug monitoring, potentially reshaping oncology care pathways and opening new revenue streams for diagnostic manufacturers.