title: Phase-resolved magnetomotive OCT for imaging nanomolar concentrations of magnetic nanoparticles in tissues.
abstract: Magnetic nanoparticles (MNPs) are increasingly important in magnetic resonance and biomedical optical imaging. We describe a method for imaging MNPs by detecting nanoscale displacements using a phase-resolved spectral-domain optical coherence tomography (OCT) system. Biological tissues and phantoms are exposed to approximately 800 G magnetic fields modulated at 56 and 100 Hz to mechanically actuate embedded iron oxide MNPs (approximately 20 nm diameter). Sensitivity to 27 microg/g (approximately 2 nM) MNPs within tissue phantoms is achieved by filtering paramagnetic from diamagnetic vibrations. We demonstrate biological feasibility by imaging topically applied MNPs during their diffusion into an excised rat tumor over a 2 hour time period.
authors.affiliation: Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Oldenburg
authors.forename: Vasilica
authors.initials: V
authors.lastname: Crecea
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Rinne
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Boppart
mesh_terms: D000818:Animals; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D005290:Ferric Compounds / Q000032:analysis; D007089:Image Enhancement / Q000379:methods*; D066298:In Vitro Techniques; D008280:Magnetics; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D053758:Nanoparticles / Q000032:analysis / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide