Optimization of Multimodal Nanoparticles Internalization Process in Mesenchymal Stem Cells for Cell Therapy Studies

Area of Science:

• Biomedical Engineering
• Stem Cell Therapy
• Nanotechnology

Background:

• Labeling stem cells with multifunctional nanoparticles (MFNP) presents challenges for in vivo monitoring.
• Human bone marrow mesenchymal stem cells (hBM-MSC) are promising for regenerative medicine but require effective tracking methods.

Purpose of the Study:

• To determine optimal conditions for direct labeling of hBM-MSC using MFNP for in vivo cell tracking.
• To maintain cell viability and homing ability after labeling for subsequent in vivo experiments.

Main Methods:

• Assessed MFNP concentrations (10-50 µg Fe/mL) and incubation periods (4-24 h) with/without magnetic fields.
• Utilized optical microscopy, near-infrared fluorescence (NIRF), and ICP-MS to evaluate cell labeling.
• Applied optimized labeled cells in a stroke model to assess in vivo homing and NIRF signal detection.

Main Results:

• Magnetic field application and maximal MFNP concentration (50 µg Fe/mL) increased iron load fourfold.
• Optimal incubation time of 9 h yielded high cell viability (>98%) and efficient iron uptake (25.4 pg Fe/cell).
• Optimized labeling increased NIRF signal by over 200% at 1 and 7 hours post-labeling.

Conclusions:

• Optimized MFNP labeling using magnetic fields improves hBM-MSC detection via NIRF in vivo.
• The optimized protocol achieves efficient iron loading and maintains cell viability and homing capacity.
• This method offers enhanced non-invasive monitoring of stem cells in preclinical models.