Nanoparticles (NPs) based on the
biodegradable acetalated dextran
polymer (Ac-Dex) were used for near-infrared (NIR) imaging and controlled
delivery of a PtIV prodrug into cancer cells. The Ac-Dex
NPs loaded with the hydrophobic PtIV prodrug 3 (PtIV/Ac-Dex NPs) and with the novel hydrophobic NIR-fluorescent
dye 9 (NIR-dye 9/Ac-Dex NPs), as well as
Ac-Dex NPs coloaded with both compounds (coloaded Ac-Dex NPs), were
assembled using a single oil-in-water nanoemulsion method. Dynamic
light scattering measurements and scanning electron microscopy images
showed that the resulting Ac-Dex NPs are spherical with an average
diameter of 100 nm, which is suitable for accumulation in tumors via
the enhanced permeation and retention effect. The new nanosystems
exhibited high drug-loading capability, high encapsulation efficiency,
high stability in physiological conditions, and pH responsiveness.
Drug-release studies clearly showed that the PtIV prodrug 3 release from Ac-Dex NPs was negligible at pH 7.4, whereas
at pH 5.5, this compound was completely released with a controlled
rate. Confocal laser scanning microscopy unambiguously showed that
the NIR-dye 9/Ac-Dex NPs were efficiently taken up by
MCF-7 cells, and cytotoxicity assays against several cell lines showed
no significant toxicity of blank Ac-Dex NPs up to 1 mg mL–1. The IC50 values obtained for the PtIV prodrug
encapsulated in Ac-Dex NPs were much lower when compared with the
IC50 values obtained for the free PtIV complex
and cisplatin in all cell lines tested. Overall, our results demonstrate,
for the first time, that Ac-Dex NPs constitute a promising drug delivery
platform for cancer therapy.
The
promising field of nanomedicine stimulates a continuous search
for multifunctional nanotheranostic systems for imaging and drug delivery.
Herein, we demonstrate that application of supramolecular chemistry’s
concepts in dendritic assemblies can enable the formation of advanced
dendrimer-based nanotheranostic devices. A dendrimer bearing 81 triazolylferrocenyl
terminal groups adopts a more compact shell-like structure in polar
solvents with the ferrocenyl peripheral groups backfolding toward
the hydrophobic dendrimer interior, while exposing the more polar
triazole moieties as the dendritic shell. Akin to lipids, the compact
dendritic structure self-assembles into uniform nanovesicles that
in turn self-assemble into larger vesosomes in water. The vesosomes
emit green nontraditional intrinsic fluorescence (NTIL), which is
an emerging property as there are no classical fluorophores in the
dendritic macromolecular structure. This work confirms the hypothesis
that the NTIL emission is greatly enhanced by rigidification of the
supramolecular assemblies containing heteroatomic subluminophores
(HASLs) and by the presence of electron rich functional groups on
the periphery of dendrimers. This work is the first one detecting
NTIL in ferrocenyl-terminated dendrimers. Moreover, the vesosomes
are stable in biological medium, are uptaken by cells, and show cytotoxic
activity against cancer cells. Accordingly, the self-organization
of these dendrimers into tertiary structures promotes the emergence
of new properties enabling the same component, in this case, ferrocenyl
group, to function as both antitumoral drug and fluorophore.
The design and development of multifunctional epoxy thermosets have recently stimulated continuous research on new degradable epoxy monomers. Herein, tri-and tetra-epoxidized imidazolium monomers were rationally designed with cleavable ester groups and synthesized on a multigram scale (up to 100 g), yielding room-temperature ionic liquids. These monomers were used as molecular building blocks and cured with three primary amine hardeners having different reactivities, leading to six different network architectures. Overall, the resulting epoxy−amine networks exhibit high thermal stability (>350 °C), excellent mechanical properties combined with a shape memory behavior, glass transition temperatures (T g s) from 55 to 120 °C, and complete degradability under mild conditions. In addition, nonpolarizable, all-atom molecular dynamics simulations were applied in order to investigate the molecular interactions during the polyaddition reaction-based polymerization and then to predict the thermomechanical and mechanical properties of the resulting networks. Thus, this work employs computational chemistry, organic synthesis, and material science to develop high-performance as well as environmentally friendly networks to meet the requirements of the circular economy.
Novel folate γ-ferrocene conjugates were synthesized through a regiospecific route, and showed selectivity and enhanced cytotoxicity against Frα-positive malignant cells.
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