Ion Transport across Biological Membranes by Carborane-Capped Gold Nanoparticles
Grzelczak, Marcin P. (University of Liverpool)
Danks, Stephen P. (University of Liverpool)
Klipp, Robert C. (Portland State University)
Belic, Domagoj (University of Liverpool)
Zaulet, Adnana (Institut de Ciència de Materials de Barcelona)
Kunstmann-Olsen, Casper (University of Liverpool)
Bradley, Dan F. (University of Liverpool)
Tsukuda, Tatsuya (The University of Tokyo)
Viñas, Clara (Institut de Ciència de Materials de Barcelona)
Teixidor, Francesc (Institut de Ciència de Materials de Barcelona)
Abramson, Jonathan J. (Portland State University)
Brust, Mathias (University of Liverpool)
Universitat Autònoma de Barcelona

Data:	2017
Resum:	Carborane-capped gold nanoparticles (Au/carborane NPs, 2-3 nm) can act as artificial ion transporters across biological membranes. The particles themselves are large hydrophobic anions that have the ability to disperse in aqueous media and to partition over both sides of a phospholipid bilayer membrane. Their presence therefore causes a membrane potential that is determined by the relative concentrations of particles on each side of the membrane according to the Nernst equation. The particles tend to adsorb to both sides of the membrane and can flip across if changes in membrane potential require their repartitioning. Such changes can be made either with a potentiostat in an electrochemical cell or by competition with another partitioning ion, for example, potassium in the presence of its specific transporter valinomycin. Carborane-capped gold nanoparticles have a ligand shell full of voids, which stem from the packing of near spherical ligands on a near spherical metal core. These voids are normally filled with sodium or potassium ions, and the charge is overcompensated by excess electrons in the metal core. The anionic particles are therefore able to take up and release a certain payload of cations and to adjust their net charge accordingly. It is demonstrated by potential-dependent fluorescence spectroscopy that polarized phospholipid membranes of vesicles can be depolarized by ion transport mediated by the particles. It is also shown that the particles act as alkali-ion-specific transporters across free-standing membranes under potentiostatic control. Magnesium ions are not transported.
Ajuts:	European Commission 321172
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Artificial ion transporters ; Gold nanoparticles ; Carborane ; Membrane potential ; Fluorescence spectroscopy ; Electrochemistry
Publicat a:	ACS nano, Vol. 11 (november 2017) , p. 12492-12499, ISSN 1936-086X

DOI: 10.1021/acsnano.7b06600
PMID: 29161496

8 p, 2.6 MB

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