Single-coil, multisample, proton relaxation method for magnetic relaxation switch assays.

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Medical Diagnostics

Background:

• Nanoparticle-based magnetic relaxation switch (MRSw) biosensors are promising for magnetic resonance (MR) based in vitro diagnostics.
• Point-of-care (POC) diagnostics require simple instrumentation and ease of use.

Purpose of the Study:

• To develop a method for calibrating and expanding the dynamic range of MRSw biosensors in a single step.
• To demonstrate the feasibility of an easy-to-use MRSw-based diagnostic system.

Main Methods:

• High-resolution biexponential analysis was employed to enable measurement and assignment of two samples using a single radio frequency detection coil.
• The method was integrated with a disposable plastic cartridge and dried MRSw reagents.

Main Results:

• A single-step calibration and dynamic range expansion for MRSw biosensors was achieved.
• A two-step (mix and read) process was demonstrated for obtaining a calibrated reading using the integrated system.
• The developed approach significantly simplifies the measurement process for MRSw biosensors.

Conclusions:

• The study demonstrates the feasibility of developing highly user-friendly, MR-based in vitro diagnostic devices.
• The combination of advanced analysis and simplified reagent/cartridge design addresses key requirements for POC diagnostics.
• This work paves the way for accessible and efficient magnetic resonance diagnostics.