Functionalization of iron oxide nanoparticles with a versatile epoxy amine linker

Area of Science:

• Bioconjugation Chemistry
• Nanomedicine
• Molecular Imaging

Background:

• Iron nanoparticles (INPs) are promising for diagnostics and therapy.
• Surface functionalization is crucial for targeted delivery and imaging.
• Developing versatile linkers is key for efficient nanoparticle modification.

Purpose of the Study:

• To synthesize and characterize a novel bifunctional linker molecule.
• To demonstrate the linker's efficacy in functionalizing dextran-coated INPs.
• To evaluate the targeted delivery and imaging capabilities of functionalized INPs.

Main Methods:

• Synthesis of a linker with terminal epoxide and amine groups.
• Conjugation of the linker to dextran-coated INPs.
• Functionalization of INPs with folic acid and fluorescein isothiocyanate.
• Cellular uptake studies using folate receptor-positive and negative cell lines.
• In vitro MRI and fluorescence imaging to assess nanoparticle accumulation.

Main Results:

• The linker molecule exhibited high reactivity towards INP surface alcohols.
• Efficient functionalization of INPs with folic acid (20 molecules/NP) and fluorescein (3 molecules/NP).
• Preferential accumulation of functionalized INPs in folate receptor-positive cells.
• MRI confirmed nanoparticle presence in targeted cells, correlating with fluorescence data.

Conclusions:

• The synthesized linker enables effective surface modification of iron nanoparticles.
• Targeted functionalization with folic acid facilitates receptor-mediated cellular uptake.
• The dual-modality imaging (fluorescence and MRI) validates targeted delivery.
• This linker platform holds potential for developing advanced in vivo diagnostic and therapeutic agents.