The effects of tightening a molecular knot.
image: Depiction of the interfacing of the molecular knot between the AFM tip and the substrate.
The knot (in blue) conformation is maintained by coordination to a Lu3+ ion (in green).
Two poly(ethylene glycol) chains are used as tethers for the trapping of the knot between the tip and the substrate.
The mechanical tightening of the knot is associated with an incremental distance of 1.1 nm.
more view.
A study conducted by Anne-Sophie Duwez and Damien Sluysmans from the NANOCHEM group at the University of Liège (Belgium) has made it possible to decode the mechanical response of small-molecule synthetic overhand knots by single-molecule pulling experiments, Nature and highlighted in Chem.
The results, published in the journal have relevance for the design of extended knotted and molecularly woven materials.
To stay up to date with latest top stories, make sure to subscribe to this YouTube channel by clicking the button above this video!
Foreign [Music] The effects of tightening a molecular Knot image depiction of the interfacing Of the molecular not between the AFM tip And the substrate the knot in blue Conformation is maintained by Coordination to lu3 plus ion in green 2 Polyethylene glycol chains are used as Tethers for the trapping of the knot Between the tip and the substrate the Mechanical tightening of the knot is Associated with an incremental distance Of 1.1 NM more view a study conducted by Anne Sophie duas and Damien sleismans From the nanochem group at the University of liege Belgium has made it Possible to decode the mechanical Response of small molecule synthetic Overhand knots by single molecule Pulling experiments nature and Highlighted in sham the results Published in the journal have relevance For the design of extended knotted and Molecularly woven materials to stay up To date with latest top stories make Sure to subscribe to this YouTube Channel by clicking the button above This video knots are fundamental Elements of structure and are found Everywhere either incidentally like Tangled computer cables or for a very Specific function like shoelaces or the Dozens of elaborate knots used by
Sailors at the scientific level knotted Structures exist in various Fields as Diverse as colloids a mixture in which One or more microscopic substance is Dispersed in another substance usually Liquid liquid crystals Optical beams Soap films superfluids and to explain The origins of the early Universe Molecular level knots also occur in DNA RNA proteins and Polymers of sufficient Length and flexibility in the field of Chemistry knots remain a curiosity that Few chemists have heard of even if Organic chemists are now able to Synthesize different types of artificial Knots in small molecules the most famous Of Witcher trefoils pentafoils and Figure eight knots explains and Sophie Duas professor of chemistry and head of The nanicham group at uliage last year a Tree foil of trefoils a triskelion Containing 12 alternating Crossings has Been synthesized these are extremely Sophisticated templated syntheses based On the controlled folding of portions of Molecules around metal ions these Artificial knots have shown promising Properties for anion negative ion Binding membrane transport catalysis Materials Nano Therapeutics and the Kinetic stabilization of supramolecular Structures while such entanglements are Known to affect molecular size and Shaped stability resistance to
Mechanical stress and behavior under Spatial confinement much of the Understanding as to how and why remains Unclear quantifying the response of Knots to external stress is Central to Both their usefulness and limitations in A study published in the scientific Journal gem the uliage researchers Report on the force response of Synthetic small molecule overhand open Treefoils knots synthesized by the group Of Prof David a Lee University of Manchester UK and East China Normal University in Shanghai upon tightening We employed single molecule Force Spectroscopy using an AFM type Microscope explains Damian Lecturer and researcher in the nanochem Group a state-of-the-art technique Pioneered by our group for its Developments on synthetic small Molecules to obtain unprecedented Information on the mechanism of Tightening we have shown that this Mechanism is associated with a high Resisting force and relative rigidity Compared to that for larger biological Knots and can be modulated by the Chemical environment with the support of Quantum chemical calculations carried Out by the group of Prof Francesco Zerbeto University of Bologna Italy they Could demonstrate that the central metal Coordination atom plays a crucial role
In the tightening process and in the Reverse process that recovers the Initial nodded conformation due to the Compact structure the complete recovery Of confirmation after mechanical Perturbation is very fast the tightening Is also found to play an important role In accommodating mechanical stress it Provides a reserve of extensibility the Extra energy that the knotted strand can Absorb in comparison with an unknotted Strand is about 13 kilocalories per all Continues and Sophie duiz these results Illustrate the relative stiffness of These small molecule synthetic knots as Well as their high resistance to External mechanical loads compared to Biological knots the higher Extensibility of the knotted molecule And the extra energy that it can Accommodate in response to Mechanical Perturbations in comparison with an Unknotted one should be relevant for the Design of extended knotted and woven 2D In 3D materials Foreign [Music]
