A Bioorthogonal Small Molecule Selective Polymeric "Clickase".

Area of Science:

• Polymer Chemistry
• Catalysis
• Nanotechnology

Background:

• Synthetic polymer scaffolds can control molecular interactions.
• Copper-catalyzed alkyne-azide cycloaddition (CuAAC) is a key bioorthogonal reaction.
• Developing selective catalysts is crucial for precise chemical manipulations.

Purpose of the Study:

• To engineer a single-chain nanoparticle (SCNP) catalyst with gating properties for selective small molecule activation.
• To investigate the catalyst's ability to perform extracellular click chemistry.
• To demonstrate applications in ligand screening and in situ drug synthesis.

Main Methods:

• Synthesis of a copper-containing SCNP with polyethylene glycol (PEG) groups.
• Comparison of SCNP catalyst activity with an analogous catalyst bearing ammonium groups.
• Evaluation of SCNP catalyst's cell permeability and extracellular activity.
• Demonstration of SCNP-catalyzed screening of protein-binding ligands and PROTAC-like molecules.
• Application of SCNP for extracellular anticancer drug synthesis and screening.

Main Results:

• The PEG-grafted SCNP catalyst selectively reacted with small molecules, unlike the ammonium-functionalized catalyst which reacted with both proteins and small molecules.
• The SCNP catalyst demonstrated resistance to cellular uptake, enabling extracellular catalysis.
• Proof-of-principle applications successfully showed SCNP's utility in ligand screening and extracellular drug synthesis.
• The SCNP catalyst facilitated in situ anticancer drug synthesis and screening extracellularly.

Conclusions:

• Gating in SCNPs can confer selectivity for small molecule bioorthogonal reactions.
• The developed SCNP catalyst enables controlled extracellular click chemistry.
• This SCNP catalyst offers a versatile platform for applications in drug discovery and development, including ligand screening and targeted drug synthesis.