Article
Chemistry, Multidisciplinary
Dingxin Fan, James R. Chelikowsky
Summary: Significant progress has been made in increasing the resolution of scanning probe microscopy, with noncontact atomic force microscopy now able to characterize and visualize single molecules with subatomic resolution. Real-space pseudopotentials constructed within density functional theory are used to accurately simulate nc-AFM images of molecules containing heteroatoms, enabling the easy identification of S and I atoms and proposing a method to discriminate N atoms from C atoms using tip functionalization.
Article
Chemistry, Multidisciplinary
Hai Lei, Quan Ma, Zhangxia Wang, Di Zhang, Xiaoyu Huang, Meng Qin, Haibo Ma, Wei Wang, Yi Cao
Summary: This study developed a single-molecule assay to investigate the force-dependent ester hydrolysis. The results showed that the ester hydrolysis rate is surprisingly insensitive to forces. The study revealed that the rate-limiting step for the formation of intermediate states is not affected by applied forces.
Article
Chemistry, Multidisciplinary
Qigang Zhong, Alexander Ihle, Sebastian Ahles, Hermann A. Wegner, Andre Schirmeisen, Daniel Ebeling
Summary: Constructing low-dimensional covalent assemblies with tailored size and connectivity is challenging but important in molecular electronics for tuning the properties of quantum materials. A versatile approach has been developed for building such structures block by block on a surface through highly selective tip-induced intermolecular reactions.
Article
Chemistry, Multidisciplinary
Byung I. Kim, Ryan D. Boehm, Harrison Agrusa
Summary: This study analyzed ten downward portions in the large oscillatory force-distance curve to understand the behavior of a nanoscale water meniscus confined between a sharp probe and a flat substrate in air. The analysis revealed that each downward portion occurs due to a coil-to-bridge transition of self-assembled water chains. These findings provide new insights into the unique properties of water.
Article
Chemistry, Multidisciplinary
Nicolas Neel, Joerg Kroeger
Summary: The study revealed that the formation of a chemical bond between a CO molecule and a Cu(111) surface is accompanied by bending of the molecular probe due to van der Waals attraction and Pauli repulsion, resulting in characteristic changes in the vertical force between CO and Cu(111) as a function of molecule-surface distance. Experimental data were successfully reproduced by model calculations, shedding new light on vertical-force extrema in scanning probe experiments.
Article
Chemistry, Physical
Denis Scaini, Fabio Biscarini, Loredana Casalis, Cristiano Albonetti
Summary: Adjacent patches of alkanethiol molecules with chain lengths ranging from 11 to 15 carbon atoms were fabricated using nanografting within a Self-Assembled Monolayer matrix. The structural and electronic properties of these molecules were investigated using Atomic Force Microscopy and Electrostatic Force Microscopy, highlighting the significant influence of substrate roughness. The results revealed an odd-even dependence of local stiffness on alkyl chain length based on topographic phase signal, and an asymmetric parabolic trend of conformational order versus the alkyl chain length induced by substrate roughness based on electrostatic force signal.
CHEMICAL PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Weijie Zhao, Mats Gothelid, Saman Hosseinpour, Malin B. Johansson, Gen Li, Christofer Leygraf, C. Magnus Johnson
Summary: The adsorption of octadecylphosphonic acid (ODPA) on copper substrates was studied, showing that a multilayer film was formed with increasing deposition time. The robustness of the film was attributed to the formation of Cu-ODPA complexes. Preadsorbing a monolayer of octadecylthiol (ODT) prevented the adsorption of ODPA by abolishing the release of Cu(I) ions.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Eugene Jia Hao Soh, Hippolyte P. A. G. Astier, Dan Daniel, Jia Qing Isaiah Chua, Ali Miserez, Zian Jia, Ling Li, Sean J. O'Shea, Harish Bhaskaran, Nikodem Tomczak, Christian A. Nijhuis
Summary: In this study, we demonstrate the direct manipulation and control of liquid metal droplets using an atomic force microscope, achieving repeated contact and separation with self-assembled monolayers in different environments. We successfully create well-defined contact areas of liquid droplets on alkanethiolate SAMs in ethanol, and achieve smaller geometric contact areas in air compared to previous studies.
Article
Multidisciplinary Sciences
Devin T. Edwards, Marc-Andre Leblanc, Thomas T. Perkins
Summary: Single-molecule force spectroscopy was used to study protein folding dynamics, revealing intrinsic changes in protein folding dynamics and transition state height under different pH conditions. Despite differences in destabilization mechanisms, constant-force landscapes showed minimal differences in transition state height, while force-dependent rates increased as pH decreased. This study provides insights for future AFM-based studies of mechanoresponsive proteins.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Biochemistry & Molecular Biology
Carlos Marcuello, Rocio de Miguel, Anabel Lostao
Summary: Intermittent jumping force is an atomic force microscopy mode that provides simultaneous topography and maximum-adhesion images based on force spectroscopy. By scanning in a repulsive regime and applying very low forces, unspecific tip-sample forces can be avoided. This mode allows for qualitative and quantitative molecular recognition maps obtained at reasonably fast rates, which is advantageous for discriminating between similar protein molecules.
Article
Chemistry, Physical
Joshua J. Buzolic, Hua Li, Zachary M. Aman, Gregory G. Warr, Rob Atkin
Summary: This study demonstrates experimentally that the introduction of an amphiphilic hydrogen bond donor (HBD) in popular deep eutectic solvents (DESs) can induce nanostructure formation, and the nanostructure becomes better defined with an increase in HBD chain length.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Haipei Liu, Zhaowei Liu, Mariana Sa Santos, Michael A. A. Nash
Summary: Single-molecule force spectroscopy (SMFS) is a powerful tool for studying protein folding and mechanical properties. However, the traditional method of immobilization using lysine residues results in a heterogeneous distribution of tether positions. In this study, we compared lysine-based immobilization to site-specific immobilization using genetically encoded peptide tags (ybbR). Our results showed that lysine-based immobilization led to signal deterioration and incorrect classification of unfolding pathways. We also developed a mixed immobilization approach that partially recovered specific signals.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Zhaowei Liu, Rodrigo A. Moreira, Ana Dujmovic, Haipei Liu, Byeongseon Yang, Adolfo B. Poma, Michael A. Nash
Summary: Using single-molecule AFM force spectroscopy in combination with click chemistry, the mechanical interactions between anticalin and its target CTLA-4 were studied. Results showed that pulling from different anchor residues significantly affected rupture forces and dissociation rates. Molecular dynamics simulations revealed a geometric dependency of mechanostability.
Article
Polymer Science
Xiaoye Zhang, Dandan Li, Yu Song, Wenke Zhang
Summary: In this study, the mechanical stability and melting pathway of highly stereoregular syndiotactic polypropylene (s-PP) were investigated using atomic force microscopy (AFM)-based single molecule force spectroscopy (SMFS). It was found that crystal thickness and structure have significant impacts on mechanical stability and melting pathway.
Article
Chemistry, Multidisciplinary
Hai Lei, Junsheng Zhang, Ying Li, Xin Wang, Meng Qin, Wei Wang, Yi Cao
Summary: In this study, a histidine-specific phosphorylation strategy was developed to covalently anchor proteins to an atomic force microscopy. This method improved the data quality of single-molecule force spectroscopy experiments and was successfully applied to investigate the mechanical stability and unfolding process of proteins.
