Two-Dimensional Nucleic Acid Brushes on Colloidal MXene Sheets

DNA immobilization on nanoparticle surfaces enables programmable assembly, gene sensing, and intracellular delivery. However, dense, direct functionalization of atomically thin two-dimensional (2D) materials remains challenging due to their inert basal planes. In contrast, 2D transition metal carbides (MXenes) possess highly polar, chemically active surfaces terminated with -OH, -O-, and -F groups, offering a unique platform for biofunctionalization. Herein, we exploit MXene's surface chemistry for robust DNA grafting via designing a bifunctional catechol- and azide-terminated ligand. The catechol moiety anchors strongly to the MXene surface, while the azide group enables strain-promoted cycloaddition with dibenzocyclooctyne-terminated DNA. The resulting 2D DNA brush exhibits a high grafting density, evidenced by sequence-controlled self-assembly of MXene flakes and heteroassembly with complementary Au nanoparticles. This work presents a simple, effective strategy for producing colloidal two-dimensional nucleic acid brushes, establishing a versatile platform for further exploration of such bioactive nanobrush structures in the fields of nanoscience and biotechnology.