We have rationally designed a new theranostic agent by coating near-infrared (NIR) light-absorbing polypyrrole (PPY) with poly(acrylic acid) (PAA), in which PAA acts as a nanoreactor and template, followed by growing small fluorescent silica nanoparticles (fSiO₂ NPs) inside the PAA networks, resulting in the formation of polypyrrole@polyacrylic acid/fluorescent mesoporous silica (PPY@PAA/fmSiO₂) core–shell NPs. Meanwhile, DOX-loaded PPY@PAA/fmSiO₂ NPs as pH and NIR dual-sensitive drug delivery vehicles were employed for fluorescence imaging and chemo-photothermal synergetic therapy in vitro and in vivo. The results demonstrate that the PPY@PAA/fmSiO₂ NPs show high in vivo tumor uptake by the enhanced permeability and retention (EPR) effect after intravenous injection as revealed by in vivo fluorescence imaging, which is very helpful for visualizing the location of the tumor. Moreover, the obtained NPs inhibit tumor growth (95.6 % of tumors were eliminated) because of the combination of chemo-photothermal therapy, which offers a synergistically improved therapeutic outcome compared with the use of either therapy alone. Therefore, the present study provides new insights into developing NIR and pH-stimuli responsive PPY-based multifunctional platform for cancer theranostics.

Gd³⁺-aggregated gold nanoclusters (AuNCs) encapsulated by silica shell (Gd³⁺-A-AuNCs@SiO₂ NPs) were strategically designed and prepared. The as-prepared nanoparticles exhibit aggregation-enhanced fluorescence (AEF), with an intensity that is up to 3.8 times that of discrete AuNCs. The clusters served as novel nanoprobes for in vitro and in vivo multimodal (fluorescence, magnetic resonance, and computed X-ray tomography) cancer imaging

The selected-control preparation of uniform core–shell and yolk–shell architectures, which combine the multiple functions of a superparamagnetic iron oxide (SPIO) core and europium-doped yttrium oxide (Y₂O₃:Eu) shell in a single material with tunable fluorescence and magnetic properties, has been successfully achieved by controlling the heat-treatment conditions. Furthermore, the shell thickness and interior cavity of SPIO@Y₂O₃:Eu core–shell and yolk–shell nanostructures can be precisely tuned. Importantly, as-prepared SPIO@Y₂O₃:Eu yolk–shell nanocapsules (NCs) modified with amino groups as cancer-cell fluorescence imaging agents are also demonstrated. To the best of our knowledge, this is the first report on the selected-control fabrication of uniform SPIO@Y₂O₃:Eu core–shell nanoparticles and yolk–shell NCs. The combined magnetic manipulation and optical monitoring of magnetic–fluorescent SPIO@Y₂O₃:Eu yolk–shell NCs will open up many exciting opportunities in dual imaging for targeted delivery and thermal therapy.

Hollow mesoporous SiO₂ (mSiO₂) nanostructures with movable nanoparticles (NPs) as cores, so-called yolk-shell nanocapsules (NCs), have attracted great research interest. However, a highly efficient, simple and general way to produce yolk-mSiO₂ shell NCs with tunable functional cores and shell compositions is still a great challenge. A facile, general and reproducible strategy has been developed for fabricating discrete, monodisperse and highly uniform yolk-shell NCs under mild conditions, composed of mSiO₂ shells and diverse functional NP cores with different compositions and shapes. These NPs can be Fe₃O₄ NPs, gold nanorods (GNRs), and rare-earth upconversion NRs, endowing the yolk-mSiO₂ shell NCs with magnetic, plasmonic, and upconversion fluorescent properties. In addition, multifunctional yolk-shell NCs with tunable interior hollow spaces and mSiO₂ shell thickness can be precisely controlled. More importantly, fluorescent-magnetic-biotargeting multifunctional polyethyleneimine (PEI)-modified fluorescent Fe₃O₄@mSiO₂ yolk-shell nanobioprobes as an example for simultaneous targeted fluorescence imaging and magnetically guided drug delivery to liver cancer cells is also demonstrated. This synthetic approach can be easily extended to the fabrication of multifunctional yolk@mSiO₂ shell nanostructures that encapsulate various functional movable NP cores, which construct a potential platform for the simultaneous targeted delivery of drug/gene/DNA/siRNA and bio-imaging.

A method is reported for the first time for the selected-control, large-scale synthesis of monodispersed Fe₃O₄@C core–shell spheres, chains, and rings with tunable magnetic properties based on structural evolution from eccentric Fe₂O₃@poly(acrylic acid) core–shell nanoparticles. The Fe₃O₄@C core–shell spheres, chains, and rings were investigated as anode materials for lithium-ion batteries. Furthermore, a possible formation mechanism of Fe₃O₄@C core–shell chains and rings has also been proposed.