title: Preferential magnetic targeting of carbon nanotubes to cancer sites: noninvasive tracking using MRI in a murine breast cancer model.
abstract: OBJECTIVE
  This study evaluated the improvement in magnetic targeting of single-walled carbon nanotubes (SWCNTs) in a 4T1-induced breast cancer murine model and compared their enhanced delivery with active targeted SWCNTs conjugated with a specific antibody for prospective applications as drug-delivery nanocarriers.
  
  
  METHODS
  Polyvinylpyrrolidone SWCNTs, loaded with iron oxide nanoparticles to improve their magnetic resonance detection and magnet attraction using an optimized flexible magnet positioned over the tumor site were developed. They were equally conjugated with Endoglin/CD105 antibody for SWCNTs active targeting. A noninvasive MRI protocol was then optimized to allow in vivo imaging of tumor site, sensitive detection of SWCNTs and apparent diffusion coefficient measurements. Special focus was devoted to evaluate the biocompatibility of the used SWCNTs.
  
  
  RESULTS
  Iron-tagged SWCNTs exhibited very high magnetic resonance r2* relaxivities allowing their sensitive detection using noninvasive MRI and enhanced targeting using the magnet. Biocompatibility evaluations confirmed their safety for animal administration. Both T2* and apparent diffusion coefficient measurements confirmed their enhanced magnetic targeting starting from 2 h postinjection while a lower, but statistically significant enhanced targeting of antibody-conjugated active targeting was observed starting from 24 h postinjection of iron-tagged SWCNT + CD105 samples.
  
  
  CONCLUSIONS
  These results demonstrate the efficiency of magnetic targeting to specifically deliver higher load of iron-tagged SWCNTs as novel nanocarriers for cancer theranostics and allow their sensitive detection using noninvasive MRI.
authors: Department of Radiological Sciences, Molecular & Cellular Imaging Lab, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
authors: Achraf
authors: A
authors: Al Faraj
authors: Asma Sultana
authors: AS
authors: Shaik
authors: Baraa
authors: B
authors: Al Sayed
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D045744:Cell Line, Tumor; D002470:Cell Survival; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry; D000071063:Endoglin; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007501:Iron / Q000737:chemistry; D008027:Light; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D015674:Mammary Neoplasms, Animal / Q000473:pathology* / Q000628:therapy*; D053768:Metal Nanoparticles / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D050997:Nanomedicine / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009369:Neoplasms / Q000473:pathology / Q000628:therapy*; D011760:Pyrrolidinones / Q000737:chemistry; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D000071063:Endoglin; C502004:Eng protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D037742:Nanotubes, Carbon; D011760:Pyrrolidinones; D007501:Iron
keywords: DDS; MRI; SWCNTs; active and passive targeting; breast cancer; drug delivery systems; magnetic targeting noninvasive imaging; single-walled carbon nanotubes