Single-Cell Imaging Using Radioluminescence Microscopy Reveals Unexpected Binding Target for [18F]HFB.

Area of Science:

• Biomedical Imaging
• Cellular Biology
• Radiochemistry

Background:

• Cell-based therapies offer promise but tracking infused cells is challenging.
• Positron emission tomography (PET) and positron emission particle tracking (PEPT) are used for cell tracking.
• [18F]HFB is a radiolabel candidate for PEPT due to its labeling capabilities.

Purpose of the Study:

• To characterize the in vitro single-cell labeling efficiency of [18F]HFB.
• To compare [18F]HFB labeling with [18F]FDG at the single-cell level.
• To evaluate the suitability of [18F]HFB for cell tracking applications.

Main Methods:

• In vitro cell labeling with [18F]HFB and [18F]FDG.
• Bulk cell gamma counting for overall binding.
• Single-cell analysis using radioluminescence microscopy (RLM).
• Correlation of radiolabel binding with fluorescent dyes.

Main Results:

• Bulk gamma counting showed higher [18F]HFB binding than [18F]FDG.
• RLM revealed [18F]HFB accumulation in live cells was not significantly higher than background.
• [18F]HFB uptake in live cells was lower than [18F]FDG.
• [18F]HFB preferentially bound to fragmented membranes of dead cells.

Conclusions:

• Bulk analysis of radiolabeling efficiency can be inaccurate.
• Single-cell analysis using RLM is crucial for identifying labeling heterogeneity.
• [18F]HFB may not be suitable for tracking live cells in vivo.
• Further investigation into [18F]HFB's binding to dead cells is warranted.