Collision dynamics of single, nucleic acid-tethered nanoparticle

Description:
In this work, we investigate the collision dynamics of a single tethered platinum nanoparticle (PtNP) on a gold electrode surface via a DNA linker. Tethered single collision events were investigated though the use of scanning electrochemical cell microscopy (SECCM), a powerful new technique. Using SECCM, a characterized nanopipette filled with electrolyte solution is brought into contact with the electrode surface that is sparsely decorated with 5 nm PtNPs attached to short, partially hybridized 21 nucleotide DNA. Once contact is made, voltage is applied to a localized, nanoscale area, and the current response is measured. Upon contact with the electrode surface, we see the current response from the hydrogen evolution reaction (HER) when a single tethered PtNP contacts the gold electrode surface. More specifically, the single tethered PtNP is attached by utilizing DNA hybridization. In our work, single citrate-coated Pt nanoparticles are linked to an electrode surface via a thiol terminated nucleic acid strand that is bound to a gold electrode at the 5’ terminus also via thiol chemistry. Interestingly, we find that a single tethered PtNP shows multipeak current response that suggests elastic behavior upon each collision. The collision events are also dependent on the length and structure of DNA tether, giving important insight into how the nucleic acid structure and flexibility impact collisional frequency of the particle to the surface. The observations reported give insight into entity electrochemistry of particles tethered to an electrode surface via a flexible linker and can provide insight into the signaling mechanism of folding based sensors that rely on nucleic acid recognition.

Speaker: Audrey Pumford - University of Cincinnati