3 research outputs found
Sub-100 nm Gold Nanoparticle Vesicles as a Drug Delivery Carrier enabling Rapid Drug Release upon Light Irradiation
Previously,
we reported gold nanoparticles coated with semifluorinated ligands
self-assembled into gold nanoparticle vesicles (AuNVs) with a sub-100
nm diameter in tetrahydrofuran (THF). Although
this size is potentially useful for in vivo use, the biomedical applications
of AuNVs were limited, as the vesicular structure collapsed in water.
In this paper, we demonstrate that the AuNVs can be dispersed in water
by cross-linking each gold nanoparticle with thiol-terminated PEG
so that the cross-linked vesicles can work as a drug delivery carrier
enabling light-triggered release. Rhodamine dyes or anticancer drugs
were encapsulated within the cross-linked vesicles by heating to 62.5
°C. At this temperature, the gaps between nanoparticles open,
as confirmed by a blue shift in the plasmon peak and the more efficient
encapsulation than that observed at room temperature. The cross-linked
AuNVs released encapsulated drugs upon short-term laser irradiation
(5 min, 532 nm) by again opening the nanogaps between each nanoparticle
in the vesicle. On the contrary, when heating the solution to 70 °C,
the release speed of encapsulated dyes was much lower (more than 2
h) than that triggered by laser irradiation, indicating that cross-linked
AuNVs are highly responsive to light. The vesicles were efficiently
internalized into cells compared to discrete gold nanoparticles and
released anticancer drugs upon laser irradiation in cells. These results
indicate that cross-linked AuNVs, sub-100 nm in size, could be a new
type of light-responsive drug delivery carrier applicable to the biomedical
field
Gold Nanoparticles Coated with Semi-Fluorinated Oligo(ethylene glycol) Produce Sub-100 nm Nanoparticle Vesicles without Templates
Gold nanoparticles (NPs) with diameters of 5, 10, and
20 nm coated
with semifluorinated oligoÂ(ethylene glycol) ligands were formed into
sub-100 nm hollow NP assemblies (NP vesicles) in THF without the use
of a template. The NP vesicles maintained their structure even after
the solvent was changed from THF to other solvents such as butanol
or CH<sub>2</sub>Cl<sub>2</sub>. NMR analyses indicated that the fluorinated
ligands are bundled on the NPs and that the solvophobic feature of
the fluorinated bundles is the driving force for NP assembly. The
formed NP vesicles were surface-enhanced Raman scattering-active capsules
pH-Dependent Network Formation of Quantum Dots and Fluorescent Quenching by Au Nanoparticle Embedding
A simple approach to the creation of colloidal assemblies is in high demand for the development of functional devices. Here, we present the preparation of CdTe-QD (quantum dot) networks in as little as 1 day simply by pH modification without the use of oxidants. The QD network was tractable in water and casting from a droplet produced a porous networked film on both hydrophobic and hydrophilic solid substrates. Further, we found that citrate-protected gold nanoparticles (AuNPs, <i>d</i> = 5 nm) could be incorporated into the QD networks to afford a QD/Au composite network, and that the fluorescence from the QDs was largely decreased by the addition of a small proportion of AuNPs (QD:AuNP = 99.4:0.6), probably due to the efficient charge transfer through the network. These data indicate that our method is suitable for application to the creation of metal/QD hybrid materials that can be integrated into wet-based processes