HPMA-Based Nanoparticles for Fast, Bioorthogonal iEDDA Ligation.

Area of Science:

• Polymer Chemistry
• Nanotechnology
• Biomedical Engineering

Background:

• Fast and bioorthogonal reactions are crucial for advanced biomedical applications, including tumor pretargeting.
• Polymeric nanoparticles offer versatile platforms for drug delivery and imaging.
• Tetrazine (Tz) click chemistry provides rapid and specific conjugation capabilities.

Purpose of the Study:

• To design and synthesize amphiphilic HPMA-based block copolymers functionalized with tetrazine (Tz) click units.
• To prepare and characterize Tz-covered nanoparticles (micelles and colloids) using the developed polymer system.
• To evaluate the bioorthogonal reactivity and conjugation efficiency of these nanoparticles with biomacromolecules.

Main Methods:

• Synthesis of HPMA-based amphiphilic block copolymers with end-chain (Tz-CTA) or statistical tetrazine incorporation.
• Preparation of tetrazine-covered nanoparticles (micelles, colloids) from the functionalized copolymers.
• Assessment of nanoparticle reactivity via inverse electron-demand Diels-Alder (iEDDA) reaction with trans-cyclooctenes (TCO).
• Conjugation studies with antibodies in physiological buffer and human blood plasma using fluorescence correlation spectroscopy (FCS).

Main Results:

• Successfully synthesized HPMA-based polymers with strategically placed tetrazine units.
• Prepared stable Tz-covered nanoparticles with reactivity comparable to low molar mass tetrazines.
• Demonstrated efficient conjugation of core-cross-linked micelles to antibodies at low concentrations in both buffer and plasma.

Conclusions:

• The developed HPMA-based polymer platform enables the creation of highly reactive, bioorthogonal nanoparticles.
• These nanoparticles exhibit efficient conjugation capabilities with large biomacromolecules in complex biological environments.
• The findings support the potential of these tetrazine-functionalized nanoparticles for applications like tumor pretargeting.