Measurement of magnetic nanoparticle relaxation time

Brownian magnetic relaxation of water-based cobalt nanoparticle ferrofluids

Following the synthesis of monodispersed 20 nm cobalt nanoparticles via a thermal decomposition method we have successfully transferred these hydrophobic nanoparticles into the water phase using tetramethylamonium hydroxide pentahydrate as phase transfer agent and 12-aminododecanoic acid as a stabilizing agent. Frequency dependent ac susceptibility of water-based cobalt nanoparticle ferrofluids...

Real-time measurement of Brownian relaxation of magnetic nanoparticles by a mixing-frequency method

Design and validation of magnetic particle spectrometer for characterization of magnetic nanoparticle relaxation dynamics

The design and validation of a magnetic particle spectrometer (MPS) system used to study the linear and nonlinear behavior of magnetic nanoparticle suspensions is presented. The MPS characterizes the suspension dynamic response, both due to relaxation and saturation effects, which depends on the magnetic particles and their environment. The system applies sinusoidal excitation magnetic fields v...

Scaling of transverse nuclear magnetic relaxation due to magnetic nanoparticle aggregation.

The aggregation of superparamagnetic iron oxide (SPIO) nanoparticles decreases the transverse nuclear magnetic resonance (NMR) relaxation time T2CP of adjacent water molecules measured by a Carr-Purcell-Meiboom-Gill (CPMG) pulse-echo sequence. This effect is commonly used to measure the concentrations of a variety of small molecules. We perform extensive Monte Carlo simulations of water diffusi...

Characterisation of magnetic nanoparticles by temperature dependent measurement of magnetic relaxation

The utilisation of magnetorelaxometry using labels containing magnetic nanoparticles (MNP) establishes new fields of application in medical in vitro and in vivo diagnostics [1]. An essential prerequisite for the implementation of these diagnostic procedures consists in a noticable improvement of the sensitivity by development of MNP providing a large relaxation signal. We present a new method f...