Detection of magnetic nanoparticles with a large scale AC superconducting susceptometer

Hincapie Ladino, Eduard Alexis; Zufelato, Nícholas; Bakuzis, Andris Figueiroa; Carneiro, Antonio Adilton Oliveira; Covas, Dimas Tadeu; Baffa Filho, Oswaldo

Detection of magnetic nanoparticles with a large scale AC superconducting susceptometer

Data

2017

Autores

Hincapie Ladino, Eduard Alexis

Zufelato, Nícholas

Bakuzis, Andris Figueiroa

Carneiro, Antonio Adilton Oliveira

Covas, Dimas Tadeu

Baffa Filho, Oswaldo

Resumo

Magnetic nanoparticles (MNPs) are being used in several applications in medicine such as hyperthermia, magnetic particle imaging, in vitro and in vivo bioassay, and still there are many other possibilities for use of these particles to come as research progress in this field. One crucial step of its use is the detection of these particles when present in a certain tissue. For in vitro bioassay, the sample can be harvested and placed inside the detector in optimal conditions to favor sensitivity. However, for in vivo human measurements the system must be noninvasive and conform to the anatomic restrictions requiring sensitive detectors and dedicated setups. In this study, we detect nanoparticles with an AC biosusceptometer having an excitation homogeneous magnetic field with 145 μT, provided by a set of rectangular large Rubens coils driven at 10 Hz. The magnetization induced in the sample was detected by a second-order axial gradiometer (20 mm in diameter and 40 mm of baseline) coupled to an RF Superconducting Quantum Interference Device (SQUID) model 330X (BTi). The MNPs used were manganese ferrite-based surface-coated with citric acid (MnFe O Citrate , 2 4 - ) dissolved in water at various concentrations. The colloid is stable at physiological conditions. X-ray diffraction confirmed the spinel structure and using Scherrer’s relation revealed a particle size of 17.3 nm. The magnetization curve showed a typical superparamagnetic behavior with a specific saturation magnetization of 51.2 emu g−1 . The stock solution of nanoparticles had a concentration of 23.17 mg ml−1 , corresponding to 1.7 × 1015 NPs ml−1 . Measurements were made in a volume of 30 ml with 20 × 103 –100 × 103 dilutions of the stock solution of nanoparticles and performed at distances of 1.1, 1.5 and 2.5 cm from the top of the sample vial to the closest coil of the gradiometer. The limits of detection were 8.1 × 109 NP ml−1 , 9.5 × 109 NP ml−1 and 11.0 × 109 NP ml−1 for the distances above. These values suggest that the technique might have interesting applications in the real-time in vivo detection of nanoparticles after systemic injections. The present setup can be improved by using more sensitive SQUID sensors and less noisy cryostats.

Palavras-chave

SQUID, SPION, Magnetic nanoparticle, Susceptibility

Citação

LADINO, E. A. Hincapie et al. Detection of magnetic nanoparticles with a large scale AC superconducting susceptometer. Superconductor Science & Technology, Bristol, v. 30, n. 8, e084007, 2017. DOI: 10.1088/1361-6668/aa7666. Disponível em: https://iopscience.iop.org/article/10.1088/1361-6668/aa7666. Acesso em: 12 set. 2023.