Asymmetric attachment and functionalization of plasmonic nanoparticles on ceramic interfaces

Abstract

The demands for materials that integrate more than one functional imaging or therapeutic unit are of increasing interest for biomedical applications. Here, we present the step-by-step preparation of asymmetric and optically active particles, namely, Gd 2 O 3 @Ag, Gd 2 O 3 @Au, SiO 2 -N 3 @Au, and SiO 2 -SH@Au . Successful attachment of plasmonic nanoparticles to the surface of metal-oxide spheres without necessity of a potentially toxic inter-adhesive layer was proven by optical methods as well as X-ray photoelectron spectroscopy. The combination of optical and magnetic properties as present in Gd 2 O 3 @ Ag and Gd 2 O 3 @Au Janus-type particles leads to dual-imaging probes for optical and magnetic resonance imaging. In addition, functional groups, such as azide groups, were linked to the surface of silica particles previous to Au nanoparticle attachment. Subsequent site-selective click reactions with 5-FAM were successfully performed as demonstrated by UV-Vis measurements. All described systems exhibited excellent long-term stability and can, therefore, be considered as promising candidates for theranostic applications. Graphical abstract

In Situ Green Synthesis of Graphene Oxide-Silver Nanoparticles Composite with Using Gallic Acid

“…Generally, methods such as mechanical grinding, laser ablation, and thermal decomposition are used to reduce the size of bulk silver to obtain AgNPs ( Meyers, et al, 2006 ), and then AgNPs are deposited on the GO sheet through interactions such as physical adsorption or electrostatic bonding ( Karuppiah, et al, 2015 ; Pratheesya, et al, 2019 ; Liu, et al, 2020 ). The step-by-step deposition method has certain advantages in controlling the size and shape of AgNPs, but the operation is complicated, time-consuming, costly and generally requires expensive specialized equipment ( Wang, et al, 2012 ; Stadler, et al, 2018 ).…”

Reagents for labeling with pH-independent fluorescein-based tags

“…There are several conventional reagents for introducing fluorescein moieties into organic molecules: NHSfluorescein and isothiocyanate fluorescein (FITC), 8 5/4'-(aminomethyl)fluoresceins and 5-(aminoacetamido)fluorescein, 9 5-iodoacetamidofluorescein and fluorescein maleimide, 8,10 5carboxyfluorescein, propargylamide (5-FAM Alkyne), 11 6-FAM phosphoramidite. 12 Chemical structures of the mentioned compounds can be find in Supplementary Materials, Scheme 1S.…”