Peptide-Controlled Assembly of Macroscopic Calcium Oxalate Nanosheets

摘要

The fabrication of two-dimensional (2D) biomineral nanosheets is of high interest owing to their promise for applications in electronics, filtration, catalysis, and chemical sensing. Using a facile approach inspired by biomineralization in nature, we fabricate laterally macroscopic calcium oxalate nanosheets using beta-folded peptides. The template peptides are composed of repetitive glutamic acid and leucine amino acids, self organized at the air water interface. Surface-specific sum frequency generation spectroscopy and molecular dynamics simulations reveal that the formation of oxalate nanosheets relies on the peptide Ca2+ ion interaction at the interface, which not only restructures the peptides but also templates Ca2+ ions into a calcium oxalate dihydrate lattice. Combined, this enables the formation of a critical structural intermediate in the assembly pathway toward the oxalate sheet formation. These insights into peptide ion interfacial interaction are important for designing novel inorganic 2D materials.