Yuhua Shen

At present, it is still a challenge to prepare multifunctional composite nanomaterials with simple composition and favorable structure. Here, multifunctional Fe₃O₄@nitrogen-doped carbon (N-C) nanocomposites with hollow porous core-shell structure and significant electrochemical, adsorption and sensing performances were successfully synthesized through the hydrothermal method, polymer coating, then thermal annealing process in nitrogen (N₂) and lastly etching in hydrochloric acid (HCl). The morphologies and properties of the as-obtained Fe₃O₄@N-C nanocomposites were markedly affected by the etching time of HCl. When the Fe₃O₄@N-C nanocomposites after etching for 30 min (Fe₃O₄@N-C-3) were applied as the anodes for lithium-ion batteries (LIBs), the invertible capacity could reach 1772 mA h g⁻¹ after 100 cycles at the current density of 0.2 A g⁻¹, which is much better than that of Fe₃O₄@N-C nanocomposites etched, respectively, for 15 min and 45 min (948 mA h g⁻¹ and 1127 mA h g⁻¹). Additionally, the hollow porous Fe₃O₄@N-C-3 nanocomposites also exhibited superior rate capacity (950 mA h g⁻¹ at 0.6 A g⁻¹). The excellent electrochemical properties of Fe₃O₄@N-C nanocomposites are attributed to their distinctive hollow porous core-shell structure and appropriate N-doped carbon coating, which could provide high-efficiency transmission channels for ions/electrons, improve the structural stability and accommodate the volume variation in the repeated Li insertion/extraction procedure. In addition, the Fe₃O₄@N-C nanocomposites etched by HCl for different lengths of time, especially Fe₃O₄@N-C-3 nanocomposites, also show good performance as adsorbents for the removal of the organic dye (methyl orange, MO) and surface-enhanced Raman scattering (SERS) substrates for the determination of a pesticide (thiram). This work provides reference for the design and preparation of multifunctional materials with peculiar pore structure and uncomplicated composition.

The complex physiological environment and inherent self-healing function of tumors make it difficult to eliminate malignant tumors by single therapy. In order to enhance the efficacy of antitumor therapy, it is significant and challenging to realize multi-mode combination therapy by utilizing/improving the adverse factors of the tumor microenvironment (TME). In this study, a novel Fe₃O₄@Au/PPy nanoplatform loaded with a chemotherapy drug (DOX) and responsive to TME, near-infrared (NIR) laser and magnetic field was designed for the combination enhancement of eliminating the tumor. The Fe²⁺ released at the low pH in TME can react with endogenous H₂O₂ to induce toxic hydroxyl radicals (·OH) for chemodynamic therapy (CDT). At the same time, the generated Fe³⁺ could deplete overexpressed glutathione (GSH) at the tumor site to prevent reactive oxygen species (ROS) from being restored while producing Fe²⁺ for CDT. The designed Fe₃O₄@Au/PPy nanoplatform had high photothermal (PT) conversion efficiency and photodynamic therapy (PDT) performance under NIR light excitation, which can promote CDT efficiency and produce more toxic ROS. To maximize the cancer-killing efficiency, the nanoplatform can be successfully loaded with the chemotherapeutic drug DOX, which can be efficiently released under NIR excitation and induction of slight acidity at the tumor site. In addition, the nanoplatform also possessed high saturation magnetization (20 emu/g), indicating a potential magnetic targeting function. In vivo and in vitro results identified that the Fe₃O₄@Au/PPy-DOX nanoplatform had good biocompatibility and magnetic-targeted synergetic CDT/PDT/PTT/chemotherapy antitumor effects, which were much better than those of the corresponding mono/bi/tri-therapies. This work provides a new approach for designing intelligent TME-mediated nanoplatforms for synergistically enhancing tumor therapy.

The Au NCs@PMLE/Ca²⁺ hydrogel possessed PT imaging-guided NIR laser/TME-responsive synergetic cancer PTT/O₂-enhanced PDT as well as remarkable locoregional antitumor effect for cancer therapy.

A cancer theranostic nanoplatform was successfully assembled by liposome co-loaded with oil-soluble Au₄Cu₄ and water-soluble Au₂₅ nanoclusters, which presenting excellent performances with multi-imaging/phototherapy effects.

Cancer is still a major threat to human health at present. Developing new types of integrated nanoplatforms for the accurate diagnosis and effective treatment of cancer is very significant. Herein, an intelligent dual-stage core–shell cancer theranostic nanoplatform (Fe³⁺@Au1Ag24@PbP) with NIR laser/tumor-microenvironment (TME) co-responsiveness and multi-modal imaging-therapy was successfully prepared, which was composed of the precisely structured oil-soluble Au1Ag24 nanoclusters (NCs) and Fe³⁺ ions easily assembled within the oil and aqueous phases of the polyethylene glycol (PEG) block grafted polyketal (PK) copolymer (PK-b-PEG, PbP) vesicles, respectively. In this system, we were delighted to find that the prepared Au1Ag24 NCs possess multi-photoresponsive properties, endowing the nanoplatform with photoacoustic (PA)/photothermal (PT) imaging and synergetic photothermal therapy (PTT)/photodynamic therapy (PDT) for cancer under near-infrared (NIR) laser irradiation. On the other hand, Fe³⁺ ions exhibit multi-TME response and regulation behaviors, including as catalysts for the decomposition of endogenous hydrogen peroxide (H₂O₂) in the solid tumor to produce O₂ and as the oxidizing agent for the consumption of the intracellular GSH to avoid the reduction of the generated ¹O₂; therefore, the synchronously formed Fe²⁺ ions from the redox of Fe³⁺ with GSH could further react with H₂O₂ to produce hydroxyl radical (˙OH), which induced ferroptosis-based cancer treatment. The PbP shell possesses TME/pH sensitivity for controlled drug release and passive targeting, causing a large increase in Au1Ag24/Fe³⁺ accumulation within the weakly acidic tumor region and reducing the side effects on normal tissues. Both in vitro and in vivo experiments demonstrate that the Fe³⁺@Au1Ag24@PbP nanoplatform presented excellent PA/PT imaging-guided synergetic PTT/PDT/ferroptosis effects toward tumor cells and tumors. This integrating multi-responsive and multi-modal theranostic nanoplatform paves a new way for effective cancer therapy.