NMRn

NMRn is a term used to describe a family of nuclear magnetic resonance techniques adapted for nanoscale systems. It combines conventional NMR spectroscopy with advances in nanofabricated detectors and on-chip sensors to measure nuclei in samples with extremely small volumes or at interfaces. The goal is to obtain chemical, structural, or dynamical information from nanoscale materials that are impractical for traditional, bulk NMR.

Principles in NMRn rely on localized detection to overcome sensitivity limits inherent to small samples. Approaches include microfabricated radiofrequency coils or nanoscale resonators positioned in close proximity to the sample, and detection schemes based on quantum sensors such as nitrogen-vacancy centers in diamond or other solid-state devices. In some implementations, hyperpolarization methods can enhance signal. Measurements can target liquids, solids, or interfacial environments and may utilize pulsed or steady-state techniques.

Instrumentation for NMRn typically combines microcoils or nano-resonators with high-field magnets, often within on-chip or compact probe configurations. Sensor integration may require microfabrication and clean-room processing, and in quantum-sensor-based approaches it may involve optical readout and microwave control. Temperature and environmental conditions are chosen to optimize sensor performance and sample integrity.

Applications of NMRn include studies of nanoparticles, porous materials, thin films, nanowires, and biomolecular assemblies at surfaces or confined volumes. It supports diffusion measurements, relaxation studies, and chemical-shift mapping at the nanoscale, contributing to insights in catalysis, material interfaces, drug delivery systems, and nanostructured materials.

Challenges include limited spectral resolution for certain systems, longer acquisition times, and technical complexity. Ongoing work aims to improve sensitivity, spectral bandwidth, and accessibility, with the goal of broadening adoption in materials science and nanotechnology.