Nuclear magnetic resonance sensors and methods for chemical sensing in tissue

Abstract

Rapid, sensitive, and minimally invasive sensing of metabolites, chemicals, and biological molecules within tissue is a largely unsolved problem. Sensing molecular oxygen, pH, and water content is of particular interest as they have been shown to be useful for improving disease diagnosis and treatment monitoring in a diverse range of medical fields including trauma, solid tumor cancers, tissue grafts, wound healing, dehydration, athletic performance, and congestive heart failure. Nuclear magnetic resonance (NMR) offers a non-ionizing, rapid, repeatable, and molecularly sensitive measurement technique for chemical sensing. Existing hardware for highly versatile single sided measurement systems is insufficient for clinical use due to constraints on the size and shape of samples that can be measured, inadequate magnetic field performance, and low sensitivity. This thesis describes the development of a portable, single-sided NMR system for research and clinical use. A magnet assembly based on a linear Halbach array was developed to produce a large, remote, and uniform field. Suitable impedance matching circuitry was designed and constructed to efficiently transmit signals between NMR probes and a radiofrequency spectrometer. This system is suitable for use in NMR measurement within a clinical environment.