Anisotropic gold nanoparticles: A survey of recent synthetic methodologies

Anisotropic gold nanoparticles (AuNPs) have very important and unique applications in a wide range of fields, including optical sensing, biomedicine, and chemical catalysis, among others. This has attracted considerable attention of the scientific community in the last two decades. The pursuit of novel synthetic methodologies has become a current trend, in which the reaction parameters and the final AuNPs morphologies (e.g., nanoplates, nanorods, and branched) are constantly being optimized. Anisotropic AuNPs can be produced through two synthetic routes: seed and seedless based methodologies. Both approaches can be subclassified in chemical and green chemical methods. Chemical methods use surfactants or polymers as reducing or stabilizing agents, while green chemical methods use eco-friendly reactants. In this work, a classification scheme is proposed for recently reported synthetic methodologies. Moreover, the most important synthesis mechanisms and key parameters of the methodologies under review are discussed.