A Bumb

Publications (2)7.96 Total impact

• Article: Preparation and characterization of a magnetic and optical dual-modality molecular probe.

  A Bumb, C A S Regino, M R Perkins, M Bernardo, M Ogawa, L Fugger, P L Choyke, P J Dobson, M W Brechbiel
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  ABSTRACT: Multi-modality imaging probes combine the advantages of individual imaging techniques to yield highly detailed anatomic and molecular information in living organisms. Herein, we report the synthesis and characterization of a dual-modality nanoprobe that couples the magnetic properties of ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) with the near infrared fluorescence of Cy5.5. The fluorophore is encapsulated in a biocompatible shell of silica surrounding the iron oxide core for a final diameter of approximately 17 nm. This silica-coated iron oxide nanoparticle (SCION) has been analyzed by transmission electron microscopy, dynamic light scattering, and superconducting quantum interference device (SQUID). The particle demonstrates a strong negative surface charge and maintains colloidal stability in the physiological pH range. Magnetic hysteresis analysis confirms superparamagnetic properties that could be manipulated for thermotherapy. The viability of primary human monocytes, T cells, and B cells incubated with the particle has been examined in vitro. In vivo analysis of agent leakage into subcutaneous A431 tumors in mice was also conducted. This particle has been designed for diagnostic application with magnetic resonance and fluorescence imaging, and has future potential to serve as a heat-sensitive targeted drug delivery platform.
  Nanotechnology 04/2010; 21(17):175704. · 3.98 Impact Factor
• Article: Synthesis and characterization of ultra-small superparamagnetic iron oxide nanoparticles thinly coated with silica.

  A Bumb, M W Brechbiel, P L Choyke, L Fugger, A Eggeman, D Prabhakaran, J Hutchinson, P J Dobson
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  ABSTRACT: Ultra-small superparamagnetic iron oxide nanoparticles (SPIOs) were synthesized by co-precipitation of iron chloride salts with ammonia and then encapsulated with thin (~2nm) layers of silica. The particles have been characterized for size, diffraction pattern, surface charge, and magnetic properties. This rapid and economical synthesis has a number of industrial applications; however, the silica-coated particles have been optimized for use in medical applications as MR contrast agents, biosensors, DNA capturing, bioseparation and enzyme immobilization.
  Nanotechnology 09/2008; 19(33):335601. · 3.98 Impact Factor