Molecular self-assembly of nucleic acids on 2D materials is a rapid, inexpensive and scalable technique towards the formation of highly-ordered hierarchical nanostructures. The self-assembly of biomolecules and DNA/RNA nucleobases into well-defined hierarchical structures has been a topic of recent research interest. The structural organization of DNA nucleobases on 2D material surfaces has facilitated the wide scale applications of functionalized nanomaterials as biosensors in nanoelectronic devices. Molecular self-assembly of noncanonical guanine and cytosine nucleobases on graphene and h-BN monolayers are investigated using DFT and MD methods. The monolayer self-assembly of DNA nucleobases is propagated in presence of material surface. The substrate induced effect in molecular assembly is critical and the nature of self-assembly on graphene regulates the patterned growth and stabilization of the complexes in gas (vacuum) and aqueous phases.

To understand the fundamental mechanisms governing the self-assembly, we further consider the self-assembly of noncanonical DNA nucleobases on h-BN investigating their growth patterns and molecular ordering. The result based on atomistic MD simulation methods find that the molecular assembly on h-BN is driven by the inherent polarity of the bases: guanine into 2D aggregated network and cytosine into 1D linear arrays. The base-base intermolecular interactions are crucial in guiding the self-assembly while the base-surface interactions facilitate surface recognition and monolayer adsorption on h-BN. Thermal annealing at elevated temperatures demonstrate molecular reconstruction in the growth patterns; cytosine disintegrates into distinct 1D chains while guanine forms an extended network with reduced intermolecular H-bonds. The theoretical findings provide a comprehensive yet succinct understanding of the dominant interactions at the bionano- interface thereby realizing fully self-assembled structural motifs for DNA based device fabrication applications.

Selected Publications:

Nabanita Saikia and Ravindra Pandey, J. Phys. Chem. C 2018, 122, 3915–3925.

Nabanita Saikia, Floyd Johnson, Kevin Waters and Ravindra Pandey, Nanotechnology 2018, 29, 195601.

Nabanita Saikia, Kevin Waters, Shashi Karna and Ravindra Pandey, ACS Omega 2017, 2, 3457-3466.

Nabanita Saikia, Shashi Karna and Ravindra Pandey, Phys. Chem. Chem. Phys. 2017, 19, 16819-16830.