Chemical Modulation of Bioengineered Exosomes for Tissue-Specific Biodistribution

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Drug Delivery

Background:

• Physicochemical properties of nanomaterials are crucial for tissue targeting, biodistribution, and clearance.
• Surface chemistry significantly impacts the targeting, stability, and toxicity of exosome conjugates.
• Exosomes are bioinert nanoparticles with potential for therapeutic applications.

Purpose of the Study:

• To design charge-variable exosomes by conjugating surface proteins with near-infrared fluorophores.
• To investigate the effect of surface charge modulation on exosome biodistribution and clearance in vivo.
• To establish a foundation for developing tissue-specific exosome-based therapeutics.

Main Methods:

• Chemical conjugation of near-infrared fluorophores to exosome surface proteins.
• In vivo administration of modified exosomes (zwitterionic and anionic).
• Monitoring of exosome biodistribution, pharmacokinetics, and clearance routes using fluorescence imaging.
• Assessment of exosome behavior in the lymphatic system after intradermal administration.

Main Results:

• Zwitterionic fluorophore-labeled exosomes exhibited rapid renal clearance with minimal nonspecific tissue uptake.
• Anionic exosomes were cleared via the hepatobiliary route, showing high liver uptake.
• Biodistribution and pharmacokinetics of exosome conjugates mirrored their free fluorophores, indicating surface characteristics govern in vivo fate.
• Chemically modulated exosomes demonstrated distinct kinetic profiles in secondary lymphoid tissues after intradermal administration.

Conclusions:

• Surface charge modulation of exosomes using fluorophore conjugation effectively controls their in vivo fate.
• Zwitterionic and anionic exosomes display distinct biodistribution and clearance pathways.
• These findings support the development of exosome-based therapeutics with tailored tissue specificity and predictable in vivo behavior.