An Albumin-Holliday Junction Biomolecular Modular Design for Programmable Multifunctionality and Prolonged...

Area of Science:

• Biomolecular engineering
• Drug delivery systems
• Nucleic acid nanotechnology

Background:

• Advanced drug delivery requires long circulation and specific cell targeting for efficacy.
• Current systems often lack modularity for multifunctional design.

Purpose of the Study:

• To develop a modular biomolecular assembly for enhanced drug delivery.
• To create a system with extended circulation and programmable targeting capabilities.

Main Methods:

• Covalent conjugation of a four-stranded oligonucleotide Holliday Junction (HJ) motif to recombinant human albumin (rHA).
• Functionalization and purification of modules using HPLC and electrophoretic gel-shift assays.
• Incorporation of an epidermal growth factor receptor (EGFR)-targeting nanobody for specific cell binding.
• Assessment of cellular recycling via albumin-neonatal Fc receptor (FcRn) binding affinity.
• Evaluation of circulatory half-life in humanized FcRn/albumin mice.

Main Results:

• Successful synthesis and assembly of the rHA-HJ construct.
• EGFR-targeting nanobody facilitated ~150-fold increased specific binding to EGFR-expressing cells.
• Retained FcRn binding affinity and FcRn-driven cellular recycling.
• Achieved a 4-fold extension in circulatory half-life (2.2 h vs. 0.55 h) compared to the HJ alone.

Conclusions:

• Introduced a novel albumin-nucleic acid construct with extended half-life and modular multifunctionality.
• Demonstrated the potential of this platform for advanced, programmable drug delivery systems.