Au nanoplates (quasi-two-dimensional single crystals) are most commonly synthesized using a mixture of Au precursors via approaches involving multiple processing steps and the use of seed crystals. Here, we report the synthesis of truncated-hexagonal {111}-oriented micrometer-scale Au nanoplates on graphene multilayers using only potassium tetrabromoaurate (KAuBr) as the precursor. We demonstrate that the nanoplate sizes can be controllably varied from tens of nanometers up to a few micrometers by introducing desired concentrations of chloroauric acid (HAuCl) to KAuBr and their thicknesses from ∼13 to ∼46 nm with the synthesis time. Through a series of experiments carried out as a function of synthesis time and precursor composition [mixtures of HAuCl and KAuBr, KBr, or ionic liquid 1-butyl-3-methylimidazolium bromide ([Bmim]Br)], we identify the optimal HAuCl and KAuBr concentrations and synthesis times that yield the largest and the thinnest size nanoplates. We show that the nanoplates are kinetically limited morphologies resulting from preferential growth of {111} facets facilitated by bromide ions in KAuBr solutions; we suggest that the presence of chloride ions enhances the rate of Au deposition and the relative concentration of chloride and bromide ions determines the shape anisotropy of resulting crystals. Our results provide new insights into the kinetics of nanoplate formation and show that a single precursor containing both Au and Br is sufficient to crystallize nanoplates on graphitic layers, which serve as reducing agent while enabling the nucleation and growth of Au nanoplates. We suggest that a similar approach may be used for the synthesis of nanoplates of other metals on weakly interacting van der Waals layers for, potentially, a variety of new applications.
Ralstonia solanacearum is an important bacterial pathogen that can infect a broad range of plants worldwide. A previous study showed that R. solanacearum could respond to exogenous organic acids or amino acids to modulate cell motility. However, it was unclear whether R. solanacearum uses these compounds to control infection. In this study, we found that R. solanacearum GMI1000 uses host plant metabolites to enhance the biosynthesis of virulence factors. We demonstrated that l ‐glutamic acid from host plants is the key active component associated with increased extracellular polysaccharide production, cellulase activity, swimming motility, and biofilm formation in R. solanacearum GMI1000. In addition, l ‐glutamic acid also promoted colonization of R. solanacearum cells in the roots and stems of tomato plants and accelerated disease incidence. Furthermore, genetic screening and biochemical analysis suggested that RS01577 , a hybrid sensor histidine kinase/response regulator, is involved in l ‐glutamic acid signalling in R. solanacearum . Mutations in RS01577 and exogenous addition of l ‐glutamic acid to the GMI1000 wild‐type strain had overlapping effects on both the transcriptome and biological functions of R. solanacearum , including on motility, biofilm formation, and virulence. Thus, our results have established a new interaction mechanism between R. solanacearum and host plants that highlights the complexity of the virulence regulation mechanism and may provide new insight into disease control.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.