title: Hantzsch dihydropyridines: Privileged structures for the formation of well-defined gold nanostars.
abstract: Anisotropic and branched gold nanoparticles have great potential in optical, chemical and biomedical applications. However their syntheses involve multi-step protocols and the use of cytotoxic agents. Here, we report a novel one-step method for the preparation of gold nanostructures using only Hantzsch 1,4-dihydropyridines as mild reducing agents. The substituent pattern of the dihydropyridine nucleus was closely related to the ease of formation, morphology and stability of the nanoparticles. We observed nanostructures such as spheres, rods, triangles, pentagons, hexagons, flowers, stars and amorphous. We focused mainly on the synthesis and characterization of well-defined gold nanostars, which were produced quickly at room temperature (25°C) in high yield and homogeneity. These nanostars presented an average size of 68 nm with mostly four or six tips. Based on our findings, we propose that the growth of the nanostars occurs in the (111) lattice plane due to a preferential deposition of the gold atoms in the early stages of particle formation. Furthermore, the nanostars were easily modified with peptides remaining stable for more than six months in their colloidal state and showing a better stability than unmodified nanostars in different conditions. We report a new approach using dihydropyridines for the straightforward synthesis of gold nanostructures with controlled shape, feasible for use in future applications.
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile.
authors.forename: Claudio
authors.initials: C
authors.lastname: Zapata-Urzúa
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Pérez-Ortiz
authors.affiliation: Institute for Research in Biomedicine and CIBER-BBN, Barcelona Science Park, Baldiri Reixac 10, 08028 Barcelona, Spain.
authors.forename: Gerardo A
authors.initials: GA
authors.lastname: Acosta
authors.affiliation: Scientific and Technological Centres, University of Barcelona, Lluís Solé I Sabarís 1, 08028 Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Mendoza
authors.affiliation: Scientific and Technological Centres, University of Barcelona, Lluís Solé I Sabarís 1, 08028 Barcelona, Spain.
authors.forename: Lluis
authors.initials: L
authors.lastname: Yedra
authors.affiliation: Scientific and Technological Centres, University of Barcelona, Lluís Solé I Sabarís 1, 08028 Barcelona, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Estradé
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Álvarez-Lueje
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile.
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Núñez-Vergara
authors.affiliation: Institute for Research in Biomedicine and CIBER-BBN, Barcelona Science Park, Baldiri Reixac 10, 08028 Barcelona, Spain; Department of Organic Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Yachay Tech School of Chemistry and Chemical Engineering Yachay City of Knowledge Urcuqui-100199, Ecuador; School of Chemistry and Physics, University of KwaZulu-Natal, 4001 Durban, South Africa. Electronic address: albericio@irbbarcelona.org.
authors.forename: Fernando
authors.initials: F
authors.lastname: Albericio
authors.affiliation: Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, Avda Joan XXII s/n, 08028 Barcelona, Spain. Electronic address: rlavilla@pcb.ub.es.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Lavilla
authors.affiliation: Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Sergio Livingstone 1007, Independencia, Santiago, Chile; Advanced Center for Chronic Diseases (ACCDiS), Chile. Electronic address: mkogan@ciq.uchile.cl.
authors.forename: Marcelo J
authors.initials: MJ
authors.lastname: Kogan
mesh_terms: D004095:Dihydropyridines / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D019163:Reducing Agents / Q000737:chemistry*
chemical_list: D004095:Dihydropyridines; D019163:Reducing Agents; D006046:Gold; C038806:1,4-dihydropyridine
keywords: Dihydropyridines; Electron microscopy; Gold nanostructures; Nanoparticle synthesis; Nanostars