Magnetic Particles, Sensors, and MRI Contrast Agents
TEM images of sodium alginate and poly-L-lysine coated, silica coated iron nanoeyes
Multifunctional Magnetic Nanoparticles
Multifunctional fluorescent and magnetic nanomaterials have broad application utility for bioimaging, magnetic resonance imaging (MRI), magnetic hyperthermia, and drug delivery. An external magnetic field can be used to heat, guide, orient, and image magnetic particles. Particle fluorescence is useful for sensitive target labeling and subsequent imaging. However, fluorescence measurements are difficult to obtain through deep tissue samples due to scattering, attenuation, and autofluorescence background. Both radioluminescent and rare earth doped upconversion materials are suitable alternatives because X-Ray and near-infrared (NIR) deeply penetrate tissue with minimal background. Radioluminescent materials, such as Gd2O2S:Eu, emit highly penetrating red light when excited by blue light, X-Ray, or alpha/beta radiation. Rare earth doped upconversion materials, such as β-NaGdF4:Yb/Er, emit red/NIR light when excited by NIR light. For this reason, our group develops highly stable, iron oxide core radioluminescent and upconversion particles as multimodal MRI and luminescent contrast agents. Targeted drug delivery, with an understanding of release kinetics and in vivo localization, are also explored for further particle functionalization.Magnetic Sensors
Our group uses magnetically-modulated optical nanoprobes (MagMOONs) in order to study various biophysical processes in vitro and in vivo. Optically tracking magnetically modulated particles through tissue is a challenge for three reasons: first, tissue attenuates both excitation and probe fluorescence light; second, tissue scatters light which causes image blurring; third, tissue autofluorescence obscures fluorescent probe signal. These limitations can be overcome using MagMOONs. MagMOONs are silica particles containing a fluorescent dye and magnetic material. A metal, such as aluminum, is vapor deposited onto one hemisphere of the fluorescent particles in order to generate an orientation dependent fluorescence response. Free MagMOONs in an oscillating magnetic field will blink as they flip between bright and dim orientations, as the metal coated and un-coated hemispheres alternately face the objective during particle rotation. Our group has used MagMOONs to study the enzyme-catalyzed de-gelation of alginate, a material used for both drug delivery and implanted medical devices. Alginate cleavage was indicated by MagMOON blinking after release from the gel. This concept will be applied to detect biofilm growth on biomedical implants, or de-gelation based drug release.
MagMOONs will also be used to track intracellular transport and associated cytotoxicity. With the increasing application of nanoparticles for chemical sensors, chemotherapy and photodynamic therapy delivery agents, as well as viral and non-viral transfection vectors, there is a need to study how nanoparticles are transported through cells and tissues. In addition, micro- and nanoparticle transport plays an important role in toxicity and accumulation of nanoparticles from smoking, environmental inhalation, and particles produced in prosthetic joints.
- Nguyen K.V.T, Anker J.N.: “Monitoring through Tissue the De-gelation of Alginate Gels by Different De-gelling Agents.” IFMBE Proceedings, 46, 62-66 (2014).
- Nguyen K.H.V. and Anker J.N.: “Detecting de-gelation through tissue using magnetically modulated optical nanoprobes (MagMOONs).” Sensors and Actuators B: Chemical. 15, 313-321 (2014).
- Anker J.N., Koo Y.E.L., and Kopelman R.: “Magnetically Guiding and Orienting Integrated Chemical Sensors.” Journal of Magnetism and Magnetic Materials. DOI: 10.1016/j.jmmm.2014.02.089i. (2014).
- Chen H., Moore T., Qi B., Wang F., Colvin D.C., Sanjeewa D., Gore J.C., Mefford O.T., Hwu S.-J., Alexis F., and Anker J.N.: “Multifunctional yolk-in-shell nanoparticles for pH-triggered drug release and imaging.” Small 10, 3364-3370 (2014). DOI: 10.1002/smll.201303769.
- Chen H., Sulejmanovic D., Moore T., Colvin D.C., Qi B., Mefford O.T., Gore J.C., Alexis F., Hwu S-J., and Anker J.N.: “Iron-loaded magnetic nanoparticles for pH-triggered drug release and MRI imaging.” Chemistry of Materials. 26, 2105-2112 (2014). DOI: 10.1021/cm404168a. Selected as an ACS Editor’s Choice.
- Chen H., Qi B., Moore T., Colvin D.C., Crawford T., Gore J.C., Alexis F., Mefford O.T., and Anker J.N.: "Synthesis of bright PEGylated luminescent magnetic up-conversion nanophosphors for dual MRI and deep tissue imaging." Small, 10, 160-168 (2014).
- Chen H., Moore T., Qi B., Colvin D.C., Jelen E.K. Hitchcock D., He J., Mefford O.T., Alexis F., Gore J.C., and Anker J.N.: “Monitoring pH-triggered Drug Release from Radioluminescent Nanocapsules with X-ray Excited Optical Luminescence.” ACS Nano, 7, 1178-1187 (2013). Selected as the article of the month for the ACS Nano Podcast.
- Chen H., Colvin D.C., Qi B., Moore T., He J., Mefford O.T., Alexis F., Gore J.C., and Anker J.N.: “Magnetic and optical properties of multifunctional core-shell radioluminescence nanoparticles.” Journal of Materials Chemistry 22, 12802-12809, (2012).
- Chen H., Patrick, A.L., Yang, Z., VanDerveer D., and Anker J.N.: “High-resolution chemical imaging through tissue with an X-ray scintillator sensor.” Analytical Chemistry, 83, 5045-5049, (2011).
- Chen H., Longfield D.E., Varahagiri V.S., Nguyen K.V.T, Patrick A.L., Qiana H., VanDerveer D.G., and Anker J.N.: “Optical imaging in tissue with X-ray excited luminescent sensors.” Analyst 136, 3438-3445 (2011). (Invited Paper, Special Edition on Emerging Investigators; Tagged as a hot article in the Analyst blog).
- Anker J.N., Koo Y.E., and Kopelman R.: “Magnetically Controlled Sensor Swarms.” Sensors and Actuators B, 25th Anniversary Jubilee Issue, 121, 83-92, (2007). Invited Paper.
- Huang H., Anker J.N., Wang K., and Kopelman R.: “Magnetically Assisted and Accelerated Non-Planar Self-assembly into Strawberry-like Nano/Microparticles.” Journal of Physical Chemistry B, Festschrift in Honor of Charles Harris, 110, 19929-19934, (2006). Invited paper. (16 citations)
- McNaughton B.H., Kehbein K., Anker J.N., and Kopelman R.: “A Sudden Breakdown in Linear Response of a Rotationally Driven Magnetic Microparticle and Application to Physical and Chemical Microsensing.” Journal of Physical Chemistry B., Festschrift in Honor of Robert Sibley, 110, 18958-18964, (2006). Invited paper.
- Anker J.N., Behrend C.J., Huang H., and Kopelman R.: “Magnetically Modulated Optical Nanoprobes (MagMOONs) and Systems.” Journal of Magnetism and Magnetic Materials, 293, 655-662, (2005). (45 citations).
- Behrend C.J., Anker J.N., McNaughton B.H., and Kopelman R.: “Microrheology with Modulated Optical Nanoprobes (MOONs).” Journal of Magnetism and Magnetic Materials, 293, 663-670, (2005).
- McNaughton B.H., Anker J.N., and Kopelman R.: “Magnetic Microdrill as a Modulated Fluorescent pH Sensor.” Journal of Magnetism and Magnetic Materials, 293, 696-701, (2005).
- Roberts T.G., Anker J.N., and Kopelman R.: “Magnetically Modulated Optical Nanoprobes (MagMOONS) for Detection and Quantification of Biologically Important Ions against the Natural Background Fluorescence of Intracellular Environments.” Journal of Magnetism and Magnetic Materials, 293, 715-724, (2005).
- Behrend C.J., Anker J.N., McNaughton B.H., Roberts T.G., Brasuel M., Philbert M.A., and Kopelman R.: “Metal-Capped Brownain and Magnetically Modulated Optical Nanoprobes (MOONs): Micromechanics in Chemical and Biological Microenvironments.” Journal of Physical Chemistry B, Festschrift in honor of Gerald Small, 108, 10408-10414, (2004). Invited paper.
- Behrend C.J., Anker J.N., and Kopelman, R.: “Brownian Modulated Optical Nanoprobes.” Applied Physics Letters, 84, 154-156, (2004). (Article reviewed in Laser Focus World).
- Yan F., Xu H., Anker J.N., Kopelman R., Ross B., Rehemtulla A., and Reddy R.: “Synthesis and Characterization of Silica-Embedded Iron Oxide Nanoparticles for Magnetic Resonance Imaging.” Journal of Nanoscience and Nanotechnology, 4, 72-76, (2004).
- Anker J.N. and Kopelman R.: “Magnetically Modulated Optical Nanoprobes.” Applied Physics Letters, 82, 1102-1104, (2003). (Article reviewed in Biophotonics International).
- Anker J.N., Behrend C.J., and Kopelman R.: "Aspherical Magnetically Modulated Optical Nanoprobes.” Journal of Applied Physics, 93, 6698-6700, (2003).
- Anker J.N., Horvath T. D., and Kopelman R.: “Cooking With Nanoparticles: A Simple Method of Forming Pancake, Roll, and Breaded Polystyrene Microparticles.” European Cells and Materials, 3, 95-97, (2002).