Biofunctionalization of Metal–Organic Framework Nanoparticles via Combined Nitroxide‐Mediated Polymerization and Nitroxide Exchange Reaction

Abstract

Abstract Surface engineering of metal–organic framework nanoparticles (MOF NPs), and enabling their post‐synthetic modulation that facilitates the formation of bio‐interfaces has tremendous potential for diverse applications including therapeutics, imaging, biosensing, and drug‐delivery systems. Despite the progress in MOF NPs synthesis, colloidal stability and homogeneous dispersity—a desirable property for biotechnological applications, stands as a critical obstacle and remains a challenging task. In this report, dynamic surfaces modification of MOF NPs with polyethylene glycol (PEG) polymer is described using grafting‐from PEGylation by employing nitroxide‐mediated polymerization (NMP) and inserting arginylglycylaspartic acid (RGD) peptides on the surface via a nitroxide exchange reaction (NER). The dynamic modification strategy enables tailoring PEG‐grafted MOF NPs of the type UiO‐66‐NH2 with improved colloidal stability, and high dispersity, while the morphology and lattice crystallinity are strictly preserved. The interaction of PEG‐grafted MOF NPs with human serum albumin (HSA) protein under physiological conditions is studied. The PEG‐grafted colloidal MOF NPs adsorb less HSA protein than the uncoated ones. Therefore, the described approach increases the scope of bio‐relevant applications of colloidal MOF NPs by reducing nonspecific interactions using NMP based PEGylation, while preserving the possibility to introduce targeting moieties via NER for specific interactions.

Keywords

• MOF nanoparticles
• nitroxide exchange reaction
• nitroxide‐mediated polymerization
• post‐synthetic modification
• surface functionalization