Detection of a single cobalt microparticle with a microfabricated atomic magnetometer

We present magnetic detection of a single, 2 {\mu}m diameter cobalt microparticle using an atomic magnetometer based on a microfabricated vapor cell. These results represent an improvement by a factor of 105 in terms of the detected magnetic moment over previous work using atomic magnetometers to detect magnetic microparticles. The improved sensitivity is due largely to the use of small vapor cells. In an optimized setup, we predict detection limits of 0.17 {\mu}m^3.Comment: 3 pages, 3 figure

Near-zero-field nuclear magnetic resonance

We investigate nuclear magnetic resonance (NMR) in near-zero-field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J-coupling). This is in stark contrast to the high field case, where heteronuclear J-couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with non-trivial spectra.Comment: 5 pages, 5 figure

Applications of Atomic Magnetometry and Hyperpolarized Xenon

Conventional nuclear magnetic resonance techniques have been exploited by scientists for everything from protein structure determination and clinical imaging, to drug synthesis and design. However, there are still several limitations, including portability, expense, and sensitivity. New methods will be described for sensitivity enhancement using xenon hyperpolarization and inexpensive low-field detection of nuclear quadrupole resonance (NQR), J-coupling, and hyperpolarized xenon (hp-Xe). Low-field detection is performed with an alkali vapor atomic magnetometer which is known to be extremely sensitive at earth's magnetic field and lower. This low field sensitivity allows for detection of nucleus interactions that are normally overshadowed by the much stronger Zeeman interactions at low field, such as NQR and J-coupling interactions. Lower magnetic field detection of conventional (Zeeman) NMR interactions are problematic due to the inherent loss of polarization at low fields. Hyperpolarization techniques, such as hp-Xe, allow NMR signal to be independent of the leading field strength. Hp-Xe is explored at high fields for microfluidic rapid screening applications, and at low field to expand the applications of these techniques

Ferrozine Assay for Simple and Cheap Iron Analysis of Silica-Coated Iron Oxide Nanoparticles

The Ferrozinen assay is applied as an accurate and rapid method to quantify the iron content of iron oxide nanoparticles (IONPs) and can be used in biological matrices. The addition of ascorbic aqcid accelerates the digestion process and can penetrate an IONP core within a mesoporous and solid silica shell. This new digestion protocol avoids the need for hydrofluoric acid to digest the surrounding silica shell and provides and accessible alternative to inductively coupled plasma methods. With the updated digestion protocol, the quantitative range of the Ferrozine assay is 1 - 14 ppm. <br /

Ferrozine Assay for Simple and Cheap Iron Analysis of Silica-Coated Iron Oxide Nanoparticles

The Ferrozinen assay is applied as an accurate and rapid method to quantify the iron content of iron oxide nanoparticles (IONPs) and can be used in biological matrices. The addition of ascorbic aqcid accelerates the digestion process and can penetrate an IONP core within a mesoporous and solid silica shell. This new digestion protocol avoids the need for hydrofluoric acid to digest the surrounding silica shell and provides and accessible alternative to inductively coupled plasma methods. With the updated digestion protocol, the quantitative range of the Ferrozine assay is 1 - 14 ppm. <br

Designing Iron Oxide Nanoparticles for Image Guided Thermal Medicine Applications

This work evaluates MRI relaxation and the specific absorption rate properties of iron oxide nanoparticles (IONPs) as a function of diameter (6-32 nm). We conclude that the ideal IONP diameter for image guided heating applications is dependent on the magnetic field strength of the MRI for the intended application. <br /

An optimized microfabricated platform for the optical generation and detection of hyperpolarized 129Xe.

Low thermal-equilibrium nuclear spin polarizations and the need for sophisticated instrumentation render conventional nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) incompatible with small-scale microfluidic devices. Hyperpolarized 129Xe gas has found use in the study of many materials but has required very large and expensive instrumentation. Recently a microfabricated device with modest instrumentation demonstrated all-optical hyperpolarization and detection of 129Xe gas. This device was limited by 129Xe polarizations less than 1%, 129Xe NMR signals smaller than 20 nT, and transport of hyperpolarized 129Xe over millimeter lengths. Higher polarizations, versatile detection schemes, and flow of 129Xe over larger distances are desirable for wider applications. Here we demonstrate an ultra-sensitive microfabricated platform that achieves 129Xe polarizations reaching 7%, NMR signals exceeding 1 μT, lifetimes up to 6 s, and simultaneous two-mode detection, consisting of a high-sensitivity in situ channel with signal-to-noise of 105 and a lower-sensitivity ex situ detection channel which may be useful in a wider variety of conditions. 129Xe is hyperpolarized and detected in locations more than 1 cm apart. Our versatile device is an optimal platform for microfluidic magnetic resonance in particular, but equally attractive for wider nuclear spin applications benefitting from ultra-sensitive detection, long coherences, and simple instrumentation