1 research outputs found
Polymer-Mediated Formation and Assembly of Silver Nanoparticles on Silica Nanospheres for Sensitive Surface-Enhanced Raman Scattering Detection
To impart a desired optical property
to metal nanoparticles (NPs) suitable for surface-enhanced Raman scattering
(SERS) applications, it is crucial to assemble them in two or three
dimensions in addition to controlling their size and shape. Herein,
we report a new strategy for the synthesis and direct assembly of
Ag NPs on silica nanospheres (AgNPs-SiNS) in the presence of polyÂ(ethylene
glycol) (PEG) derivatives such as PEG-OH, bisÂ(amino)-PEGs (DA-PEGs),
and <i>O</i>,<i>O</i>′-bisÂ(2-aminopropyl)ÂPEG
(DAP-PEG). They exhibited different effects on the formation of Ag
NPs with variable sizes (10–40 nm) and density on the silica
surface. As the molecular weight (MW) of DA-PEGs increased, the number
of Ag NPs on the silica surface increased. In addition, DAP-PEG (MW
of 2000), which has a 2-aminopropyl moiety at both ends, promoted
the most effective formation and assembly of uniform-sized Ag NPs
on a silica surface, as compared to the other PEG derivatives with
the same molecular weight. Finally, we demonstrated that AgNPs-SiNS
bearing 4-fluorobenzenethiol on its surface induced the strong SERS
signal at the single-particle level, indicating that each hybrid particle
has internal hot spots. This shows the potential of AgNPs-SiNS for
SERS-based sensitive detection of target molecules