scholarly journals Molecular recognition of human islet amyloid polypeptide assembly by selective oligomerization of thioflavin T

2020 ◽  
Vol 6 (32) ◽  
pp. eabc1449
Author(s):  
Lanlan Yu ◽  
Wenbo Zhang ◽  
Wendi Luo ◽  
Robert L. Dupont ◽  
Yang Xu ◽  
...  
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Molecular Probes ◽  
Thioflavin T ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Islet Amyloid ◽  
Theoretical Understanding ◽  
Adhesive Interactions ◽  
Cohesive Interaction

Selective oligomerization is a common phenomenon existing widely in the formation of intricate biological structures in nature. The precise design of drug molecules with an oligomerization state that specifically recognizes its receptor, however, remains substantially challenging. Here, we used scanning tunneling microscopy (STM) to identify the oligomerization states of an amyloid probe thioflavin T (ThT) on hIAPP8–37 assembly to be exclusively even numbers. We demonstrate that both adhesive interactions between ThT and the protein substrate and cohesive interactions among ThT molecules govern the oligomerization state of the bounded ThT. Specifically, the work of the cohesive interaction between two head/tail ThTs is determined to be 6.4 kBT, around 50% larger than that of the cohesive interaction between two side-by-side ThTs (4.2 kBT). Overall, our STM imaging and theoretical understanding at the single-molecule level provide valuable insights into the design of drug compounds using the selective oligomerization of molecular probes to recognize protein self-assembly.

scholarly journals Realizing Two-Dimensional Spin Arrays on Surfaces via Halogen-Bonding Molecular Self-Assembly

2021 ◽  
Author(s):  
Dingguan Wang ◽  
Zishen Wang ◽  
Shaofei Wu ◽  
Arramel Arramel ◽  
Xinmao Yin ◽  
...  
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Halogen Bonding ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Halogen Bonds ◽  
Tunneling Microscopy ◽  
Single Molecule Level ◽  
Magnetic Devices ◽  
Temperature Scanning

Well-ordered spin arrays are highly desirable for next-generation molecule-based magnetic devices, and yet its synthetic method remains a challenging task. Herein, we demonstrate the realization of two-dimensional supramolecular spin arrays on surfaces via halogen-bonding molecular self-assembly. A bromine-terminal perchlorotriphenymethyl radical with net carbon spin was synthesized and deposited on Au(111) to achieve two-dimensional supramolecular spin arrays. By taking advantage of the diversity of halogen bonds, five supramolecular spin arrays are presented with ultrahigh spin densities (up to the value of 3 × 10<sup>13</sup> spins at the size of a flash drive), as probed by low-temperature scanning tunneling microscopy at the single-molecule level. First principle calculations verify that the formation of three distinct types of halogen bonds can be used to tailor supramolecular phases via molecular coverage and annealing temperature. Our work demonstrates supramolecular self-assembly as a promising method to engineering 2D spin arrays for potential application in magnetic devices.

Scanning Tunneling Microscopy Reveals Single-Molecule Insights into the Self-Assembly of Amyloid Fibrils

ACS Nano ◽  
2012 ◽  
Vol 6 (8) ◽  
pp. 6882-6889 ◽  
Author(s):  
Nataliya Kalashnyk ◽  
Jakob T. Nielsen ◽  
Erik H. Nielsen ◽  
Troels Skrydstrup ◽  
Daniel E. Otzen ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Single Molecule ◽  
Self Assembly ◽  
Amyloid Fibrils ◽  
The Self ◽  
Scanning Tunneling ◽  
Tunneling Microscopy

scholarly journals Self-Assembly of Covalently Linked Porphyrin Dimers at the Solid–Liquid Interface

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 3018 ◽  
Author(s):  
Thomas Habets ◽  
Dennis Lensen ◽  
Sylvia Speller ◽  
Johannes A.A.W. Elemans
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Liquid Interface ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Metal Porphyrin ◽  
Metal Centers ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Porphyrin Dimers

The synthesis and surface self-assembly behavior of two types of metal-porphyrin dimers is described. The first dimer type consists of two porphyrins linked via a rigid conjugated spacer, and the second type has an alkyne linker, which allows rotation of the porphyrin moieties with respect to each other. The conjugated dimers were equipped with two copper or two manganese centers, while the flexible dimers allowed a modular built-up that also made the incorporation of two different metal centers possible. The self-assembly of the new porphyrin dimers at a solid–liquid interface was investigated at the single-molecule scale using scanning tunneling microscopy (STM). All dimers formed monolayers, of which the stability and the internal degree of ordering of the molecules depended on the metal centers in the porphyrins. While in all monolayers the dimers were oriented coplanar with respect to the underlying surface (‘face-on’), the flexible dimer containing a manganese and a copper center could be induced, via the application of a voltage pulse in the STM setup, to self-assemble into monolayers in which the porphyrin dimers adopted a non-common perpendicular (‘edge-on’) geometry with respect to the surface.

scholarly journals Realizing Two-Dimensional Spin Arrays on Surfaces via Halogen-Bonding Molecular Self-Assembly

2021 ◽  
Author(s):  
Dingguan Wang ◽  
Zishen Wang ◽  
Shaofei Wu ◽  
Arramel Arramel ◽  
Xinmao Yin ◽  
...  
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Halogen Bonding ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Halogen Bonds ◽  
Tunneling Microscopy ◽  
Single Molecule Level ◽  
Magnetic Devices ◽  
Temperature Scanning

Well-ordered spin arrays are highly desirable for next-generation molecule-based magnetic devices, and yet its synthetic method remains a challenging task. Herein, we demonstrate the realization of two-dimensional supramolecular spin arrays on surfaces via halogen-bonding molecular self-assembly. A bromine-terminal perchlorotriphenymethyl radical with net carbon spin was synthesized and deposited on Au(111) to achieve two-dimensional supramolecular spin arrays. By taking advantage of the diversity of halogen bonds, five supramolecular spin arrays are presented with ultrahigh spin densities (up to the value of 3 × 10<sup>13</sup> spins at the size of a flash drive), as probed by low-temperature scanning tunneling microscopy at the single-molecule level. First principle calculations verify that the formation of three distinct types of halogen bonds can be used to tailor supramolecular phases via molecular coverage and annealing temperature. Our work demonstrates supramolecular self-assembly as a promising method to engineering 2D spin arrays for potential application in magnetic devices.

Charge Transfer Complexation Boosts Molecular Conductance Through Fermi Level Pinning

2018 ◽  
Author(s):  
Kun Wang ◽  
Andrea Vezzoli ◽  
Iain Grace ◽  
Maeve McLaughlin ◽  
Richard Nichols ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Molecule ◽  
Quantum Interference ◽  
Transmission Function ◽  
Scanning Tunneling ◽  
Charge Transfer Complexes ◽  
Tunneling Microscopy ◽  
Quantum Interference Effect ◽  
Single Molecule Junctions ◽  
Charge Transfer Complexation

We have used scanning tunneling microscopy to create and study single molecule junctions with thioether-terminated oligothiophene molecules. We find that the conductance of these junctions increases upon formation of charge transfer complexes of the molecules with tetracyanoethene, and that the extent of the conductance increase is greater the longer is the oligothiophene, i.e. the lower is the conductance of the uncomplexed molecule in the junction. We use non-equilibrium Green's function transport calculations to explore the reasons for this theoretically, and find that new resonances appear in the transmission function, pinned close to the Fermi energy of the contacts, as a consequence of the charge transfer interaction. This is an example of a room temperature quantum interference effect, which in this case boosts junction conductance in contrast to earlier observations of QI that result in diminished conductance.<br>

scholarly journals Mechanical single-molecule potentiometers with large switching factors from ortho-pentaphenylene foldamers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jinshi Li ◽  
Pingchuan Shen ◽  
Shijie Zhen ◽  
Chun Tang ◽  
Yiling Ye ◽  
...  
Keyword(s):  
Charge Transport ◽  
Single Molecule ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Helical Structures ◽  
Anchoring Groups ◽  
Molecular Conductance ◽  
And Control ◽  
Helical Molecules ◽  
Shed Light

AbstractMolecular potentiometers that can indicate displacement-conductance relationship, and predict and control molecular conductance are of significant importance but rarely developed. Herein, single-molecule potentiometers are designed based on ortho-pentaphenylene. The ortho-pentaphenylene derivatives with anchoring groups adopt multiple folded conformers and undergo conformational interconversion in solutions. Solvent-sensitive multiple conductance originating from different conformers is recorded by scanning tunneling microscopy break junction technique. These pseudo-elastic folded molecules can be stretched and compressed by mechanical force along with a variable conductance by up to two orders of magnitude, providing an impressively higher switching factor (114) than the reported values (ca. 1~25). The multichannel conductance governed by through-space and through-bond conducting pathways is rationalized as the charge transport mechanism for the folded ortho-pentaphenylene derivatives. These findings shed light on exploring robust single-molecule potentiometers based on helical structures, and are conducive to fundamental understanding of charge transport in higher-order helical molecules.

scholarly journals Strain-Relief Patterns and Kagome Lattice in Self-Assembled C60 Thin Films Grown on Cd(0001)

2021 ◽  
Vol 22 (13) ◽  
pp. 6880
Author(s):  
Zilong Wang ◽  
Minlong Tao ◽  
Daxiao Yang ◽  
Zuo Li ◽  
Mingxia Shi ◽  
...  
Keyword(s):  
Thin Films ◽  
Self Assembly ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Kagome Lattice ◽  
Tunneling Microscopy ◽  
Kagomé Lattice ◽  
Temperature Scanning ◽  
C60 Films

We report an ultra-high vacuum low-temperature scanning tunneling microscopy (STM) study of the C60 monolayer grown on Cd(0001). Individual C60 molecules adsorbed on Cd(0001) may exhibit a bright or dim contrast in STM images. When deposited at low temperatures close to 100 K, C60 thin films present a curved structure to release strain due to dominant molecule–substrate interactions. Moreover, edge dislocation appears when two different wavy structures encounter each other, which has seldomly been observed in molecular self-assembly. When growth temperature rose, we found two forms of symmetric kagome lattice superstructures, 2 × 2 and 4 × 4, at room temperature (RT) and 310 K, respectively. The results provide new insight into the growth behavior of C60 films.

scholarly journals Au(100) as a Template for Pentacene Monolayer

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2393
Author(s):  
Artur Trembułowicz ◽  
Agata Sabik ◽  
Miłosz Grodzicki
Keyword(s):  
Self Assembly ◽  
Molecular Layer ◽  
High Vacuum ◽  
Gold Surface ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Height Difference ◽  
Characteristic Features ◽  
Reconstructed Surface

The surface of quasi-hexagonal reconstructed Au(100) is used as the template for monolayer pentacene (PEN) self-assembly. The system is characterized by means of scanning tunneling microscopy at room temperature and under an ultra-high vacuum. A new modulated pattern of molecules with long molecular axes (MA) arranged along hex stripes is found. The characteristic features of the hex reconstruction are preserved herein. The assembly with MA across the hex rows leads to an unmodulated structure, where the molecular layer does not recreate the buckled hex phase. The presence of the molecules partly lifts the reconstruction—i.e., the gold hex phase is transformed into a (1×1) phase. The arrangement of PEN on the gold (1×1) structure is the same as that of the surrounding molecular domain on the reconstructed surface. The apparent height difference between phases allows for the distinction of the state of the underlying gold surface.

scholarly journals Self-assembly of N-heterocyclic carbenes on Au(111)

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alex Inayeh ◽  
Ryan R. K. Groome ◽  
Ishwar Singh ◽  
Alex J. Veinot ◽  
Felipe Crasto de Lima ◽  
...  
Keyword(s):  
Self Assembly ◽  
Density Functional ◽  
Surface Coverage ◽  
High Mobility ◽  
Heterocyclic Carbenes ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Surface Geometry ◽  
Functional Theory ◽  
Interesting Alternative

AbstractAlthough the self-assembly of organic ligands on gold has been dominated by sulfur-based ligands for decades, a new ligand class, N-heterocyclic carbenes (NHCs), has appeared as an interesting alternative. However, fundamental questions surrounding self-assembly of this new ligand remain unanswered. Herein, we describe the effect of NHC structure, surface coverage, and substrate temperature on mobility, thermal stability, NHC surface geometry, and self-assembly. Analysis of NHC adsorption and self-assembly by scanning tunneling microscopy and density functional theory have revealed the importance of NHC-surface interactions and attractive NHC-NHC interactions on NHC monolayer structures. A remarkable way these interactions manifest is the need for a threshold NHC surface coverage to produce upright, adatom-mediated adsorption motifs with low surface diffusion. NHC wingtip structure is also critical, with primary substituents leading to the formation of flat-lying NHC2Au complexes, which have high mobility when isolated, but self-assemble into stable ordered lattices at higher surface concentrations. These and other studies of NHC surface chemistry will be crucial for the success of these next-generation monolayers.

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