1. Introduction 20642. Synthesis of Magnetic Nanoparticles 20662.1. Classical Synthesis by Coprecipitation 20662.2. Reactions in Constrained Environments 20682.3. Hydrothermal and High-TemperatureReactions20692.4. Sol-Gel Reactions 20702.5. Polyol Methods 20712.6. Flow Injection Syntheses 20712.7. Electrochemical Methods 20712.8. Aerosol/Vapor Methods 20712.9. Sonolysis 20723. Stabilization of Magnetic Particles 20723.1. Monomeric Stabilizers 20723.1.1. Carboxylates 20733.1.2. Phosphates 20733.2. Inorganic Materials 20733.2.1. Silica 20733.2.2. Gold 20743.3. Polymer Stabilizers 20743.3.1. Dextran 20743.3.2. Polyethylene Glycol (PEG) 20753.3.3. Polyvinyl Alcohol (PVA) 20753.3.4. Alginate 20753.3.5. Chitosan 20753.3.6. Other Polymers 20753.4. Other Strategies for Stabilization 20764. Methods of Vectorization of the Particles 20765. Structural and Physicochemical Characterization 20785.1. Size, Polydispersity, Shape, and SurfaceCharacterization20795.2. Structure of Ferro- or FerrimagneticNanoparticles20805.2.1. Ferro- and Ferrimagnetic Nanoparticles 20805.3. Use of Nanoparticles as Contrast Agents forMRI20825.3.1. High Anisotropy Model 20845.3.2. Small Crystal and Low Anisotropy EnergyLimit20855.3.3. Practical Interests of Magnetic NuclearRelaxation for the Characterization ofSuperparamagnetic Colloid20855.3.4. Relaxation of Agglomerated Systems 20856. Applications 20866.1. MRI: Cellular Labeling, Molecular Imaging(Inﬂammation, Apoptose, etc.)20866.2.

Magnetic Iron Oxide Nanoparticles: Synthesis, Stabilization, Vectorization, Physicochemical Characterizations, and Biological Applications

An analyte monitor includes a sensor, a sensor control unit, and a display unit. The sensor has, for example, a substrate, a recessed channel formed in the substrate, and conductive material disposed in the recessed channel to form a working electrode. The sensor control unit typically has a housing adapted for placement on skin and is adapted to receive a portion of an electrochemical sensor. The sensor control unit also includes two or more conductive contacts disposed on the housing and configured for coupling to two or more contact pads on the sensor. A transmitter is disposed in the housing and coupled to the plurality of conductive contacts for transmitting data obtained using the sensor. The display unit has a receiver for receiving data transmitted by the transmitter of the sensor control unit and a display coupled to the receiver for displaying an indication of a level of an analyte. The analyte monitor may also be part of a drug delivery system to alter the level of the analyte based on the data obtained using the sensor.

Analyte Monitoring Device And Methods Of Use

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.

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 small diameter flexible electrode designed for subcutaneous in vivo amperometric monitoring of glucose is described. The electrode is designed to allow “one-point” in vivo calibration, i.e., to have zero output current at zero glucose concentration, even in the presence of other electroreactive species of serum or blood. The electrode is preferably three or four-layered, with the layers serially deposited within a recess upon the tip of a polyamide insulated gold wire. A first glucose concentration-to-current transducing layer is overcoated with an electrically insulating and glucose flux limiting layer (second layer) on which, optionally, an immobilized interference-eliminating horseradish peroxidase based film is deposited (third layer). An outer (fourth) layer is biocompatible.

Subcutaneous glucose electrode

Disclosed is a transcutaneous coupling apparatus comprising a first member subcutaneously positioned in a user of the invention and also comprising a second member positioned supercutaneously, or outside the skin of the user. Rare-earth magnets are associated with the first and second members to magnetically secure the second member with the first member without significantly adversely affecting the user's skin intervening between the first and second members.

Magnetic transcutaneous mount for external device of an associated implant

An implantable electromagnetic middle-ear bone conduction hearing aid device is disclosed which provides variability to meet a variety of pathological entities of the hearing impaired user. The device utilizes a sound processing component for converting sound into an analog electromagnetic signal and has an output transmitter adapted to be placed supercutaneously on the skull of the user for transmitting the electromagnetic signal transcutaneously. A signal receiving and transmitting component is adapted to be implanted subcutaneously in the bone of the user outside of the middle ear for receiving the transcutaneous electromagnetic signal from the sound processing component and for transmitting the electromagnetic signal subcutaneously into the middle-ear of the user. A vibration generating component is adapted to be implanted in any of the small bones of the ossicular chain in the middle-ear for receiving the subcutaneous electromagnetic signal from the signal receiving and transmitting component and for vibrating the ossicular chain in response to such electromagnetic signal to stimulate normal functioning of the inner ear to create the perception of sound in the hearing impaired user.

Implantable electromagnetic middle-ear bone-conduction hearing aid device

The objective of this study was to produce an improved finite element (FE) model of the human middle ear and to compare the model with human data. We began with a systematic and accurate geometric modeling technique for reconstructing the middle ear from serial sections of a freshly frozen temporal bone. A geometric model of a human middle ear was constructed in a computer-aided design (CAD) environment with particular attention to geometry and microanatomy. Using the geometric model, a working FE model of the human middle ear was created using previously published material properties of middle ear components. This working FE model was finalized by a cross-calibration technique, comparing its predicted stapes footplate displacements with laser Doppler interferometry measurements from fresh temporal bones. The final FE model was shown to be reasonable in predicting the ossicular mechanics of the human middle ear.

Computer-integrated finite element modeling of human middle ear.

A floating mass transducer for assisting hearing in a person is provided Inertial vibration in the floating mass transducer (100) produces vibrations in the inner ear In an exemplary embodiment, the floating mass transducer comprises a magnet assembly (12) and a coil (14) secured inside a housing (10) which is attached to bone within the middle ear The coil is more rigidly secured to the housing than the magnet The magnet assembly and coil are configured such that conducting alternating electrical current through the coil results in vibration of the magnet assembly and coil relative to one another The vibration is caused by the interaction of the magnetic fields of the magnet assembly and coil Because the coil is more rigidly secured to the housing than the magnet assembly, the vibrations of the coil cause the housing to vibrate The floating mass transducer may generate vibrations in the inner ear by being attached to the skull or through a mouthpiece

Bone conducting floating mass transducers

HypothesisThis study investigated whether combined technologies of finite element (FE) analysis and three-dimensional reconstruction of human temporal bones could be used to construct a computational model, useful in describing normal and pathologic middle ear sound conduction.BackgroundFE models fo

Kenneth J. Dormer

Papers

Magnetic transcutaneous mount for external device of an associated implant

Implantable electromagnetic middle-ear bone-conduction hearing aid device

Computer-integrated finite element modeling of human middle ear.

Bone conducting floating mass transducers

Three-dimensional modeling of middle ear biomechanics and its applications.