| Title: |
Tether-Length Dependence of Bias in Equilibrium Free-Energy Estimates for Surface-to-Molecule Unbinding Experiments |
| Authors: |
Ostertag, L.; Utzig, T.; Klinger, C.; Valtiner, M. |
| Source: |
Langmuir |
| Publication Year: |
2018 |
| Collection: |
Max Planck Society: MPG.PuRe |
| Description: |
The capabilities of atomic force microscopes and optical tweezers to probe unfolding or surface-to-molecule bond rupture at a single-molecular level are widely appreciated. These measurements are typically carried out unidirectionally under nonequilibrium conditions. Jarzynski's equality has proven useful to relate the work obtained along these nonequilibrium trajectories to the underlying free energy of the unfolding or unbinding process. Here, we quantify biases that arise from the molecular design of the bond rupture experiment for probing surface-to-molecule bonds. In particular, we probe the well-studied amine/gold bond as a function of the linker's length which is used to anchor the specific amine functionality during a single molecule unbinding experiment. With increasing linker length, we observe a significant increase in the average work spent on polymer stretching and a strongly biased estimated interaction free energy. Our data demonstrate that free energy estimates converge well for linker lengths below 20 nm, where the bias is |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Availability: |
http://hdl.handle.net/21.11116/0000-0001-5D73-6 |
| Accession Number: |
edsbas.77DC7D30 |
| Database: |
BASE |