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Paper Published - Luis Pantaleone - Exerting pulling forces in fluids by directional disassembly of microcrystalline fibres

  • 29-07-2024

We are happy to report that our groupmember Luis Pantaleone has published an article in Nature Nanotechnology in July 2024 on "Exerting pulling forces in fluids by directional disassembly of microcrystalline fibres".

Abstract

Biomolecular polymerization motors are biochemical systems that use supramolecular (de-)polymerization to convert chemical potential into useful mechanical work. With the intent to explore new chemomechanical transduction strategies, here we show a synthetic molecular system that can generate forces via the controlled disassembly of self-organized molecules in a crystal lattice, as they are freely suspended in a fluid. An amphiphilic monomer self-assembles into rigid, high-aspect-ratio microcrystalline fibres. The assembly process is regulated by a coumarin-based pH switching motif. The microfibre crystal morphology determines the monomer reactivity at the interface, resulting in anisotropic etching. This effect exerts a directional pulling force on microscopic beads adsorbed on the crystal surface through weak multivalent interactions. We use optical-tweezers-based force spectroscopy to extract mechanistic insights into this process, quantifying a stall force of 2.3 pN (±0.1 pN) exerted by the ratcheting mechanism produced by the disassembly of the microfibres.


The article can be found using the following link:

https://www.nature.com/articles/s41565-024-01742-x


a, Amino-functionalized 1 µm polystyrene beads adsorb onto the crystal surface through a multivalent interaction. b, Disassembly of the fibre is controlled by the pH-switchable coumarin motif as part of the aromatic scaffold of the monomer. Under basic pH conditions, the assembled VsA monomer (blue) is hydrolysed into its soluble VsA4− form (red). c, Force spectroscopy measurement with OT. During the anisotropic etching of the microcrystals, the beads move by a biased diffusion mechanism. A pulling force (i) displaces the beads from the centre of the optical trap (ii) to maintain the multivalent interaction with the surface. Monomer hydrolysis occurs predominantly at the fibre edge (iii), directing the disassembly process along the fibre axis (iv).