Atomically precise binding conformations of adenine and its variants on gold using single molecule conductance signatures
Abstract
We demonstrate single molecule conductance as a sensitive and atomically precise probe of binding configurations of adenine and its biologically relevant variants on gold. By combining experimental measurements and density functional theory (DFT) calculations of single molecule–metal junction structures in aqueous conditions, we determine for the first time that robust binding of adenine occurs in neutral or basic pH when the molecule is deprotonated at the imidazole moiety. The molecule binds through the donation of the electron lone pairs from the imidazole nitrogen atoms, N7 and N9, to the gold electrodes. In addition, the pyrimidine ring nitrogen, N3, can bind concurrently and strengthen the overall metal–molecule interaction. The amine does not participate in binding to gold in contrast to most other amine-terminated molecular wires due to the planar geometry of the nucleobase. DFT calculations reveal the importance of interface charge transfer in stabilizing the experimentally observed binding configurations. We demonstrate that biologically relevant variants of adenine, 6-methyladenine and 2′-deoxyadenosine, have distinct conductance signatures. These results lay the foundation for biosensing on gold using single molecule conductance readout.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 15, 2022
- Source ID
- 10.1063/5.0103642
Entities
People
- Amber Chow
- Cheng Qian
- Lu Wang
- Maria Kamenetska
- Xiaoyun Pan
Organizations
- Air Force Office of Scientific Research
- Boston University
- Rutgers University