Optimizing Labeling of Adipose-Derived Mesenchymal Stem/Stromal Cells with Promag Superparamagnetic Iron Oxide Nanoparticles for Clinically Translatable Magnetic Particle Imaging

Objective: This study evaluated the labeling efficiency of human adipose-derived mesenchymal stem/stromal cells (MSCs) with ProMag superparamagnetic iron oxide nanoparticles (SPIONs) under adherent and suspension conditions, aiming to define practical parameters for translational use.

Methods: The MSCs were labeled with 3 ProMag SPION concentrations (10-40 µg/mL) under adherent culture. Labeling efficiency and viability were assessed by Prussian blue staining and an adenosine triphosphate–based viability assay. The MSC identity (CD44, CD90) and hematopoietic markers (CD34, CD45) were analyzed by flow cytometry. Nanoparticle uptake mechanisms were probed using a low-temperature endocytosis inhibition assay. Comparative experiments examined labeling efficiency between adherent cultures and suspension protocols using Eppendorf tubes and Petri dishes.

Results: A concentration of 20 µg/mL achieved an optimal balance between labeling efficiency (79%) and viability (73%) and was used in subsequent assays. The MSC identity was preserved, with >95% CD44/ CD90 expression, though slight increases in CD34 (4.10%) and CD45 (8.55%) were observed after labeling. Uptake occurred predominantly via active endocytosis. Adherent conditions yielded significantly higher labeling efficiency than suspension in Eppendorf tubes (P = .002). Suspension in Petri dishes showed moderately improved uptake but did not reach significance (P = .062).

Conclusion: ProMag SPIONs effectively label adipose-derived MSCs, though efficiency is strongly influenced by the suspension environment. Optimized suspension-based strategies, considering vessel geometry and defined concentration parameters, may enable rapid labeling approaches suitable for real-time magnetic particle imaging in regenerative therapies.

Cite this article as: Özkan S, Trot C, Murray P. Optimizing labeling of adipose-derived mesenchymal stem/stromal cells with promag superparamagnetic iron oxide nanoparticles for clinically translatable magnetic particle imaging. Cerrahpaşa Med J 2025, 49, 0067, doi:10.5152/cjm.2025.25067.