A5065730519- Characterization and Applications of Magnetic Nanoparticles
- Advanced MRI Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Micro and Nano Robotics
- Microfluidic and Bio-sensing Technologies
- Nanoparticle-Based Drug Delivery
- Lanthanide and Transition Metal Complexes
- Quantum Information and Cryptography
- MRI in cancer diagnosis
- Microfluidic and Capillary Electrophoresis Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Mechanical and Optical Resonators
- Atomic and Subatomic Physics Research
- Magnetic properties of thin films
- Advanced Sensor and Energy Harvesting Materials
- Hydrogels: synthesis, properties, applications
- Advanced biosensing and bioanalysis techniques
- Electrowetting and Microfluidic Technologies
- Innovative Microfluidic and Catalytic Techniques Innovation
- Quantum, superfluid, helium dynamics
- Photoacoustic and Ultrasonic Imaging
- Quantum Dots Synthesis And Properties
- Orbital Angular Momentum in Optics
- Molecular Communication and Nanonetworks
- Pickering emulsions and particle stabilization
National Institute of Standards and Technology
2013-2024
National Institute of Standards
2020-2023
National Institute of Neurological Disorders and Stroke
2008-2015
National Institutes of Health
2008-2015
Physical Measurement Laboratory
2014-2015
Harvard University
1998-2004
MIT-Harvard Center for Ultracold Atoms
2004
Harvard University Press
2003
We have investigated the efficacy of superparamagnetic iron oxide nanoparticles (SPIONs) as positive T1 contrast agents for low-field magnetic resonance imaging (MRI) at 64 millitesla (mT). Iron oxide-based agents, such FDA-approved ferumoxytol, were measured using a variety techniques to evaluate mT. Additionally, we characterized monodispersed carboxylic acid-coated SPIONs with range diameters (4.9-15.7 nm) in order understand size-dependent properties low-field. MRI mT MRI, magnetometry,...
Current-carrying microcircuits can generate strong magnetic-field gradients; these gradients, in turn, control the position of magnetic microbeads aqueous suspension. Micromagnetic systems were prepared using two representative soft lithography techniques—micromolding capillaries and microtransfer molding—combined with electrodeposition. They capture from solution, hold them a fixed position, move along complex paths. Simply changing current flowing dynamically reconfigure The manipulation...
From microcircuits to metamaterials, the micropatterning of surfaces adds valuable functionality. For nonplanar surfaces, incompatibility with conventional microlithography requires transfer originally planar micropatterns onto those surfaces; however, existing approaches accommodate only limited curvatures. A microtransfer approach was developed using reflowable materials that transform between solid and liquid on demand, freely stretching yield transfers naturally conform down nanoscale...
Superparamagnetic iron oxide nanoparticles (SPIONs) are widely investigated and utilized as magnetic resonance imaging (MRI) contrast therapy agents due to their large moments. Local field inhomogeneities caused by these high moments used generate T2 in clinical high-field MRI, resulting signal loss (darker contrast). Here we present strong T1 enhancement (brighter contrast) from SPIONs (diameters 11 nm 22 nm) observed the ultra-low (ULF) MRI at 0.13 mT. We have achieved a longitudinal...
Abstract Smartphone ubiquity has led to rapid developments in portable diagnostics. While successful, such platforms are predominantly optics-based, using the smartphone camera as sensing interface. By contrast, magnetics-based modalities exploiting compass (magnetometer) remain unexplored, despite inherent advantages optically opaque, scattering or auto-fluorescing samples. Here we report analyte utilizing built-in magnetometer for signal transduction via analyte-responsive...
Inspired by magnetic bubble memory technology, we demonstrate the temporal and spatial manipulation of superparamagnetic beads guided soft patterns in a rotating field. Soft structures allow complex repetitive tasks to be performed. As demonstration, show cyclic capture release antibodies from different microfluidic streams.
A new form of tunable magnetic resonance imaging agent based on precisely dimensioned cylindrical nanoshells is introduced. Using top-down prepatterned substrates, the are fabricated by exploiting what usually regarded as a detrimental processing side-effect, namely redeposition material back-sputtered during ion-milling. The well-resolved nuclear peaks resulting nanostructures attest to nanoscale fabrication control and general feasibility such sputter for variety self-supporting, highly...
We have deflected a beam of metastable helium atoms using the inhomogeneous magnetic field above microfabricated electromagnet mirror. The mirror consisted single current-carrying wire in periodic serpentine pattern on planar sapphire substrate. A time-dependent current (and field) synchronized with pulsed thermal atomic was used to compensate for chromaticity deflection. freedom fabricate wide variety geometries and employ fields make microelectromagnets promising new tools atom manipulation.
Abstract While chemically synthesized superparamagnetic microparticles have enabled much new research based on MRI tracking of magnetically labeled cells, signal‐to‐noise levels still limit the potential range applications. Here it is shown how, through top‐down microfabrication, contrast agent relaxivity can be increased several‐fold, which should extend sensitivity such cell‐tracking studies. Microfabricated agents benefit from both higher magnetic moments and uniformity than their...
This paper describes the fabrication details of magnetic nano- and microstructures that enable a new class multispectral resonance imaging agents. Magnetic field associated geometrical constraints particular to these contrast agents are described, schemes based on both electrochemical deposition thermal evaporation presented. Relative advantages disadvantages top-down microfabrication approaches versus traditional bottom-up chemical synthesis routes discussed with focus trade-offs between...
A simple new approach for transforming micro- and nanoscale spheres into eccentric ellipsoids generating hollow ellipsoidal shell particles is demonstrated based on a rotating, angled, evaporative deposition process. The resulting shells possess unique electromagnetic field properties that enable form of multispectral labeling agent magnetic resonance imaging applications. As service to our authors readers, this journal provides supporting information supplied by the authors. Such materials...
We present a generic fabrication scheme to produce polymer microparticles with engineerable, complex shapes. The particles are made from polyethylene glycol based hydrogels using poly(dimethylsiloxane) (PDMS) molding technique. A simple surface treatment is used pattern the energy of PDMS molds, engendering recessed wells in molds higher than that surface. contrast causes hydrogel precursor wet only inside creating isolated after curing UV light. This eliminates formation an interconnecting...
We show that magnetic resonance imaging (MRI) can be used to visualize the spatiotemporal dynamics of iron oxide nanoparticle growth within a hydrogel network during in situ coprecipitation. The synthesis creates loaded polymer gel, or magnetogel. During coprecipitation, nanoparticles nucleate and grow due diffusion precipitating agent throughout an precursor network. creation particles changes properties allowing monitored via measurements. Formation generates dark, hypointense, contrast...
Cryogenically cooled microelectromagnet mirrors were used to reflect a cloud of free-falling laser-cooled 85Rb atoms at normal incidence. The consisted microfabricated current-carrying Au wires in periodic serpentine pattern on sapphire substrate. fluorescence from the atomic was imaged after it had bounced off mirror. transverse width reached local minimum an optimal current corresponding mirror roughness. A distinct increase roughness found for configurations with even versus odd number...
As fluid channel sizes are reduced, nonspecific binding to walls and particle clogging of microchannels present key obstacles thus far limiting the application microfluidic lab-on-a-chip technologies. Here we show how combining applied electric or magnetic fields with increasing surface tension effects inherent in miniaturization can guide flow prevent adhesion walls. We demonstrate effective two-dimensional focusing within arbitrary geometries that prevents adhesion, allowing accurate...
Guided systems for coherent matter waves are expected to offer substantial improvements over unguided systems, but adiabatic coupler proposals have proven difficult realize. We outline instead considerations a coherence-preserving diabatic approach enabling filters, couplers, and interferometers that can accept multimode guide inputs of up magneto-optical-trap temperatures.
High fat diet (HFD) causes chronic low-grade inflammation and is associated with an increased risk of cerebrovascular pathology neurodegenerative disorders. Hypothalamus can sense peripheral signals has been the major focus HFD induced neuroinflammation. This work aims to study activation BBB endothelial cells, immune cell infiltration, brain in whole real time caused by short-term HFD. Molecular MRI, using a new ultrahigh moment microfabricated gold-iron micro-disc, provides non-invasive...
We have measured the magnitude and roughness of reflecting potential produced by a current-carrying magnetic mirror from which cold rubidium atoms been bounced at normal incidence. By varying current in mirror, study barrier different substates bounce has made. A combination time-of-flight imaging techniques allowed us to potential. demonstrated that observed can be reduced additional wires compensate for finite-size effects, careful control direction bias field.