Model-Assisted Process Optimization for Trivalent Ligand-siRNA Conjugation via CuAAC Click Chemistry.

Area of Science:

• Biotechnology and Gene Therapy
• Chemical Biology
• Drug Delivery Systems

Background:

• Small interfering RNA (siRNA) is a promising gene therapy agent for genetic disorders and cancers.
• Chemical modifications and ligand conjugation are crucial for enhancing siRNA stability, targeting, and delivery.
• Copper-catalyzed azide-alkyne cycloaddition (CuAAC) is a biocompatible and efficient method for creating RNA conjugates.

Purpose of the Study:

• To systematically optimize CuAAC click chemistry conditions for synthesizing trivalent targeting ligand-RNA conjugates.
• To identify key parameters influencing the efficiency and yield of ligand-RNA conjugation.
• To establish a standardized protocol for large-scale production of multivalent RNA therapeutics.

Main Methods:

• Design of experiments (DOE) screening was employed to identify critical factors for CuAAC optimization.
• Key parameters investigated included azide equivalents, oligonucleotide concentration, reaction pH, and ligand/copper ratio.
• Optimization focused on achieving efficient synthesis of trivalent targeting ligand-RNA conjugates.

Main Results:

• Four critical factors influencing CuAAC efficiency were identified: azide equivalents, oligo concentration, reaction pH, and ligand/Cu ratio.
• Optimal design spaces for these parameters were determined through systematic screening.
• A standardized protocol for large-scale production of multivalent ligand-RNA conjugates was established.

Conclusions:

• The optimized CuAAC click chemistry provides a robust and scalable method for producing targeted RNA therapeutics.
• This advancement facilitates the clinical translation of RNA interference (RNAi) therapies.
• Efficient synthesis of multivalent ligand-RNA conjugates is key to overcoming delivery challenges in gene therapy.