Gly-Gly-Mediated Assembly of Higher-Quality Nanoparticle Supercrystals at Room Temperature

DNA-functionalized nanoparticles assemble into ordered colloidal superlattices via programmable DNA hybridization, yet excessively strong interparticle binding frequently results in kinetic trapping, necessitating stringent thermal annealing protocols. Herein, we report a peptide-mediated strategy employing glycylglycine (Gly-Gly) to precisely modulate DNA-DNA interactions, thereby enabling the room-temperature fabrication of high-quality DNA-AuNP superlattices. Gly-Gly moderately destabilizes DNA duplexes by modulating Na⁺ ion exclusion and migration, thereby suppressing the formation of metastable aggregates and facilitating structural reorganization to achieve maximized nearest-neighbor DNA-DNA contacts. Using this strategy, BCC, FCC, and AlB₂-type lattices are successfully fabricated, including architectures that feature the strongest DNA sticky-end interactions reported to date, which remain inaccessible under conventional thermal annealing protocols. This work establishes a robust, operationally simple, and broadly applicable approach to kinetic control of colloidal crystallization, thereby expanding the programmable phase space of DNA-encoded nanoparticle superlattices.