title: Influence of Temperature on the Colloidal Stability of Polymer-Coated Gold Nanoparticles in Cell Culture Media.
abstract: The temperature-dependence of the hydrodynamic diameter and colloidal stability of gold-polymer core-shell particles with temperature-sensitive (poly(N-isopropylacrylamide)) and temperature-insensitive shells (polyallylaminine hydrochloride/polystyrensulfonate, poly(isobutylene-alt-maleic anhydride)-graft-dodecyl) are investigated in various aqueous media. The data demonstrate that for all nanoparticle agglomeration, i.e., increase in effective nanoparticle size, the presence of salts or proteins in the dispersion media has to be taken into account. Poly(N-isopropylacrylamide) coated nanoparticles show a reversible temperature-dependent increase in size above the volume phase transition of the polymer shell when they are dispersed in phosphate buffered saline or in media containing protein. In contrast, the nanoparticles coated with temperature-insensitive polymers show a time-dependent increase in size in phosphate buffered saline or in medium containing protein. This is due to time-dependent agglomeration, which is particularly strong in phosphate buffered saline, and induces a time-dependent, irreversible increase in the hydrodynamic diameter of the nanoparticles. This demonstrates that one has to distinguish between temperature- and time-induced agglomerations. Since the size of nanoparticles regulates their uptake by cells, temperature-dependent uptake of thermosensitive and non-thermosensitive nanoparticles by cells lines is compared. No temperature-specific difference between both types of nanoparticles could be observed.
authors.affiliation: Fachbereich Physik, Philipps Universität Marburg, Marburg, Germany.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Zyuzin
authors.affiliation: Department of Chemistry, Universität Bayreuth, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Honold
authors.affiliation: Fachbereich Physik, Philipps Universität Marburg, Marburg, Germany.|CIC biomaGUNE, Donostia-San Sebastián, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Carregal-Romero
authors.affiliation: Fachbereich Physik, Philipps Universität Marburg, Marburg, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Kantner
authors.affiliation: Department of Chemistry, Universität Bayreuth, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Karg
authors.affiliation: Fachbereich Physik, Philipps Universität Marburg, Marburg, Germany.|CIC biomaGUNE, Donostia-San Sebastián, Spain.
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Parak
mesh_terms: D002021:Buffers; D003102:Colloids / Q000737:chemistry*; D003470:Culture Media / Q000737:chemistry*; D000067493:Dynamic Light Scattering; D004705:Endocytosis; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057446:Hydrodynamics; D053768:Metal Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D002021:Buffers; D003102:Colloids; D003470:Culture Media; D011108:Polymers; D014867:Water; D006046:Gold
keywords: agglomeration; cellular uptake; colloidal properties; nanoparticles; temperature-responsive materials