title: Silicification of peptide-coated silver nanoparticles--A Biomimetic soft chemistry approach toward chiral hybrid core-shell materials.
abstract: Silica and silver nanoparticles are relevant materials for new applications in optics, medicine, and analytical chemistry. We have previously reported the synthesis of pH responsive, peptide-templated, chiral silver nanoparticles. The current report shows that peptide-stabilized nanoparticles can easily be coated with a silica shell by exploiting the ability of the peptide coating to hydrolyze silica precursors such as TEOS or TMOS. The resulting silica layer protects the nanoparticles from chemical etching, allows their inclusion in other materials, and renders them biocompatible. Using electron and atomic force microscopy, we show that the silica shell thickness and the particle aggregation can be controlled simply by the reaction time. Small-angle X ray scattering confirms the Ag/peptide@silica core-shell structure. UV-vis and circular dichroism spectroscopy prove the conservation of the silver nanoparticle chirality upon silicification. Biological tests show that the biocompatibility in simple bacterial systems is significantly improved once a silica layer is deposited on the silver particles.
authors.affiliation: Department of Chemistry, Klingelbergstrasse 80, University of Basel, CH-4056 Basel, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Graf
authors.forename: Alexandre
authors.initials: A
authors.lastname: Mantion
authors.forename: Andrea
authors.initials: A
authors.lastname: Haase
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Thünemann
authors.forename: Admir
authors.initials: A
authors.lastname: Masić
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Meier
authors.forename: Andreas
authors.initials: A
authors.lastname: Luch
authors.forename: Andreas
authors.initials: A
authors.lastname: Taubert
mesh_terms: D032701:Biomimetics / Q000379:methods*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D048168:Escherichia coli K12 / Q000187:drug effects; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry* / Q000494:pharmacology / Q000633:toxicity; D013057:Spectrum Analysis; D013237:Stereoisomerism; D013499:Surface Properties
chemical_list: D010455:Peptides; D012834:Silver; D012822:Silicon Dioxide