Color transformation and fluorescence of Prussian blue-positive cells: implications for histologic verification of cells labeled with superparamagnetic iron oxide nanoparticles.
Superparamagnetic iron oxide (SPIO) nanoparticles, either modified or in combination with other macromolecules, are being used for magnetic labeling of stem cells and other cells to monitor cell trafficking by magnetic resonance imaging (MRI) in experimental models. The correlation of histology to MRI depends on the ability to detect SPIO-labeled cells using Prussian blue (PB) stain and fluorescent tags to cell surface markers. Exposure of PB-positive sections to ultraviolet light at a wavelength of 365 nm commonly used fluorescence microscopy can result in color transformation of PB-positive material from blue to brown. Although the PB color transformation is primarily an artifact that may occur during fluorescence microscopy, the transformation can be manipulated using imaging process software for the detection of low levels of iron labeled cells in tissues samples.
Frank
Joseph A
JA
Experimental Neuroimaging Section, Laboratory of Diagnostic Radiology Research and Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, National Instituets of Health, Bethesda, MD 20892, USA. jafrank@helix.nih.gov
Kalish
Heather
H
Jordan
E Kay
EK
Anderson
Stasia A
SA
Pawelczyk
Edyta
E
Arbab
Ali S
AS
D000818:Animals; D016477:Artifacts; D003116:Color; D004396:Coloring Agents / Q000737:chemistry*; D005295:Ferrocyanides / Q000737:chemistry*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000737:chemistry / Q000166:cytology; D053768:Metal Nanoparticles / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D051381:Rats; D013194:Staining and Labeling / Q000379:methods*; D014466:Ultraviolet Rays
D004396:Coloring Agents; D005295:Ferrocyanides; C000170:ferric ferrocyanide; D052203:Ferrosoferric Oxide