Biocompatibility, Pharmaceutical and Biomedical Applications L. Harivardhan Reddy,†,‡ Jose ́ L. Arias, Julien Nicolas,† and Patrick Couvreur*,† †Laboratoire de Physico-Chimie, Pharmacotechnie et Biopharmacie, Universite ́ Paris-Sud XI, UMR CNRS 8612, Faculte ́ de Pharmacie, IFR 141, 5 rue Jean-Baptiste Cleḿent, F-92296 Chat̂enay-Malabry, France Departamento de Farmacia y Tecnología Farmaceútica, Facultad de Farmacia, Campus Universitario de Cartuja s/n, Universidad de Granada, 18071 Granada, Spain ‡Pharmaceutical Sciences Department, Sanofi, 13 Quai Jules Guesdes, F-94403 Vitry-sur-Seine, France

Magnetic nanoparticles: design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications.

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Superparamagnetic iron oxide nanoparticles (SPIONs): Development, surface modification and applications in chemotherapy

Magnetic sensors can be classified according to whether they measure the total magnetic field or the vector components of the magnetic field. The techniques used to produce both types of magnetic sensors encompass many aspects of physics and electronics. Here, we describe and compare most of the common technologies used for magnetic field sensing. These include search coil, fluxgate, optically pumped, nuclear precession, SQUID, Hall-effect, anisotropic magnetoresistance, giant magnetoresistance, magnetic tunnel junctions, giant magnetoimpedance, magnetostrictive/piezoelectric composites, magnetodiode, magnetotransistor, fiber optic, magnetooptic, and microelectromechanical systems-based magnetic sensors. The usage of these sensors in relation to working with or around Earth's magnetic field is also presented

Magnetic sensors and their applications

Nanostructures have attracted huge interest as a rapidly growing class of materials for many applications. Several techniques have been used to characterize the size, crystal structure, elemental composition and a variety of other physical properties of nanoparticles. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed. In addition, given that the significance of nanoparticles in basic research and applications is constantly increasing, it is necessary that researchers from separate fields overcome the challenges in the reproducible and reliable characterization of nanomaterials, after their synthesis and further process (e.g. annealing) stages. The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles. Different characterization techniques are classified according to the concept/group of the technique used, the information they can provide, or the materials that they are destined for. We describe the main characteristics of the techniques and their operation principles and we give various examples of their use, presenting them in a comparative mode, when possible, in relation to the property studied in each case.

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Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

A targeted drug delivery system is the need of the hour. Guiding magnetic iron oxide nanoparticles with the help of an external magnetic field to its target is the principle behind the development of superparamagnetic iron oxide nanoparticles (SPIONs) as novel drug delivery vehicles. SPIONs are small synthetic γ-Fe2O3 (maghemite) or Fe3O4 (magnetite) particles with a core ranging between 10 nm and 100 nm in diameter. These magnetic particles are coated with certain biocompatible polymers, such as dextran or polyethylene glycol, which provide chemical handles for the conjugation of therapeutic agents and also improve their blood distribution profile. The current research on SPIONs is opening up wide horizons for their use as diagnostic agents in magnetic resonance imaging as well as for drug delivery vehicles. Delivery of anticancer drugs by coupling with functionalized SPIONs to their targeted site is one of the most pursued areas of research in the development of cancer treatment strategies. SPIONs have also demonstrated their efficiency as nonviral gene vectors that facilitate the introduction of plasmids into the nucleus at rates multifold those of routinely available standard technologies. SPION-induced hyperthermia has also been utilized for localized killing of cancerous cells. Despite their potential biomedical application, alteration in gene expression profiles, disturbance in iron homeostasis, oxidative stress, and altered cellular responses are some SPION-related toxicological aspects which require due consideration. This review provides a comprehensive understanding of SPIONs with regard to their method of preparation, their utility as drug delivery vehicles, and some concerns which need to be resolved before they can be moved from bench top to bedside.

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Superparamagnetic iron oxide nanoparticles: magnetic nanoplatforms as drug carriers

A linear amplifier using a flux-flow phenomenon in a long Josephson junction has been designed and tested by connecting a load resistance. The present experiment has demonstrated that a current gain of 500/Ws (1/µm) is obtained for the load resistance of 9 mΩ when an input signal is applied with a control line of width Ws (µm). An equivalent circuit of the amplifier has also been presented, which shows that the device is most suitable for current amplification with large gain in low impedance circuits.

Flux-Flow-Type Josephson Linear Amplifier with Large Gain and Wide Linear Range

We estimated the effective magnetic anisotropy constant K of magnetic nanoparticles (MNPs) from the temperature dependence of the coercive field Hc of the M–H curve for use in biosensing applications. For this purpose, a previous analytical expression for Hc was extended so that it can be applied to nanoparticles with a size distribution. Using the extended expression for Hc, we estimated the K value of multi-core based MNP sample that consists of crystalline aggregates of elementary particles. We prepared three MNP samples. One is Resovist, in which elementary particles and aggregates are mixed. The Resovist sample was magnetically divided into two fractions called MS1 and MS3, which included mainly aggregates and elementary particles, respectively. We discuss the K value of elementary particles and aggregates from the comparison among the three samples. It is suggested that the K value of the aggregates is much smaller than that of the elementary particles. The temperature dependence of K of the aggregates is also discussed.

Estimation of the effective magnetic anisotropy constant of multi-core based magnetic nanoparticles from the temperature dependence of the coercive field

Three-dimensional magnetic nanoparticle imaging using small field gradient and multiple pickup coils

The evaluation of opposite-side defects in thick ferromagnetic objects (for example, steel plates) is essential for safety maintenance. Eddy-current testing (ECT) can detect defects in metallic specimens; however, owing to the skin effect, its use is limited to the evaluation of surface or subsurface defects. Therefore, in this paper, we propose a non-contacting inspection system that consists of two excitation coils and a detection coil to detect slit defects on the backside of a steel plate using low-frequency ECT (LF-ECT). Using the proposed system, we examine whether LF-ECT mainly detects the leakage or the flux induced by the eddy current, and also examine which direction of the excitation currents in the two excitation coils is suitable for detecting slit defects. The results suggest that the method to drive the current in the same direction and to detect the imaginary part of the magnetic flux density, which corresponds to the flux induced by the eddy current, is suitable for detecting slit defects. Subsequently, we examine the detection limit of the height of the slit defect when the thickness of the steel plate is 10 mm and the width and length of the slit defect are constant, at 50 and 1 mm, respectively. The results demonstrate that the slit defect can be detected by using the proposed system when the height is greater than or equal to 4 mm. Therefore, the proposed system is a promising tool to detect critical defects on the backside of steel plates.

Detection of Slit Defects on Backside of Steel Plate Using Low-Frequency Eddy-Current Testing

AC susceptibility measurement of magnetic markers in solution was applied to biological immunoassays. In this method, the markers that bound to biological target can be detected in the presence of unbound markers. The bound markers were distinguished from the unbound ones by using their different frequency dependence of susceptibility. We detected biotin-conjugated polymer beads with avidin-coated Fe3O4 markers. Changes of the susceptibility caused by the binding reaction between them were shown. Good relationship was obtained between the decrease of susceptibility and the number of polymer beads. Sensitivity of the system was estimated as 3×10-16 mol/ml in terms of molecular-number concentration.

https://iopscience.iop.org/article/10.1143/APEX.2.037001/pdf

Keiji Enpuku

Papers

Flux-Flow-Type Josephson Linear Amplifier with Large Gain and Wide Linear Range

Estimation of the effective magnetic anisotropy constant of multi-core based magnetic nanoparticles from the temperature dependence of the coercive field

Three-dimensional magnetic nanoparticle imaging using small field gradient and multiple pickup coils

Detection of Slit Defects on Backside of Steel Plate Using Low-Frequency Eddy-Current Testing

Liquid Phase Immunoassay Using AC Susceptibility Measurement of Magnetic Markers