Structure-Controlled Molecular Recognition and Charge Transport in Metallized DNA Nanosheets

The integration of molecular recognition and electronic charge transport within a single-material system is central to the development of bioelectronic interfaces. However, in hybrid bioelectronic systems, these functionalities are often governed by poorly defined structural features, making it difficult to establish clear structure-function relationships. Here, we develop a growth-regulated metallization strategy based on self-assembled DNA nanosheets, enabling the formation of ultrathin, laterally extended metal-nucleic acid hybrid structures. By introducing surface-extending DNA brushes, nanosheet growth is sterically regulated and kinetically controlled, with DNA brush spacing governing nanosheet evolution by modulating the competition between lateral expansion and vertical thickening, thereby defining a kinetically stabilized ultrathin regime. This growth mechanism yields ultrathin, laterally extended amorphous nanosheets across multiple metal surfaces. Within this growth-defined system, structural parameters including brush spacing and metal layer thickness can be systematically tuned to regulate molecular recognition and charge transport. For molecular recognition, probe spacing (i.e., DNA brush spacing) and nanosheet thickness jointly determine hybridization performance by regulating steric hindrance and interfacial accessibility, defining an optimal structural window. For charge transport, nanosheet thickness and compositional matching govern transport behavior: increasing thickness enhances electronic coupling and reduces activation barriers, consistent with hopping-dominated transport, while compositionally matched nanosheet/electrode systems exhibit the most efficient interfacial charge transfer. This combination of enhanced hybridization and efficient charge transport enables high-performance electrochemical biosensing. More broadly, this work establishes a growth-controlled strategy for defining structure-function relationships in metal-nucleic acid hybrid systems.