Surface Modification of Coordination Polymers with Biomolecules for Cellular Uptake

Coordination polymers (CPs) or metal-organic frameworks (MOFs) are attractive porous materials because of their potential applications such as molecular storage, separation, heterogeneous catalysis, chemical sensing and others. Recently, nano-sized MOFs have been studied as drug delivery vehicles and biomedical imaging agents. Despite the growing interest on MOFs in the biological field, their instability and poor biocompatibility restrict their application to biomaterials. In order to improve the stability and to provide biocompatibility, surface modification of MOFs has been advanced by using a thin silica shell, hydrophilic organic polymers (PEG and PVP) and biomolecules. In this topic, I focus on the recent researches on the surface modification of MOF nanoparticles with biomolecules such as nucleic acid, lipid bilayer and protein. The MOF nanoparticles covered with biomolecules exhibit increased stability under physiological condition, and enhanced cellular uptake compared with unmodified MOF nanoparticles. These results clearly indicate that biomolecule conjugation to MOFs is a useful strategy for creating novel biomaterials. Fig. 1 (a) Structure of [Zr6(m3-O)4(m3-OH)4(C8H3O4)6] (UiO66)4), (b) Surface modification of UiO-66-N3 nanoparticles dibenzylcyclooctyne (DBCO) functionalized DNA.