Gradient-free microfluidic flow labeling using thin magnetic films and remotely detected MRI

Area of Science:

• Physics
• Engineering
• Chemistry

Background:

• Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) offer noninvasive insights into microscale flows.
• Combining magnetic resonance with microfluidics is challenging due to low sensitivity and complex gradient field generation.

Purpose of the Study:

• To demonstrate a novel method for applying magnetic resonance to microfluidic systems.
• To overcome limitations of traditional magnetic resonance techniques in microscale flow analysis.

Main Methods:

• Utilized remotely-detected MRI (RD-MRI) with static magnetic field gradients.
• Employed thin magnetic films for gradient generation.
• Applied synchronized, frequency-selective pulses for flow path and history selection.

Main Results:

• Successfully encoded microfluidic flow using RD-MRI.
• Demonstrated selection of flow path and history via thin film labels and selective pulses.
• Eliminated the need for high electric currents for pulsed magnetic field gradients.

Conclusions:

• RD-MRI with static magnetic field gradients is a viable method for microfluidic analysis.
• This approach enhances the applicability of NMR and MRI experiments in microscale devices.
• Offers a simplified and more sensitive alternative for studying microscale flows.