“Fastening” Porphyrin in Highly Cross-Linked Polyphosphazene Hybrid Nanoparticles: Powerful Red Fluorescent Probe for Detecting Mercury Ion

It is a significant issue to overcome the concentration-quenching effect of the small fluorescent probes and maintain the high fluorescent efficiency at high concentration for sensitive and selective fluorescent mark or detection. We developed a new strategy to “isolate” and “fasten” porphyrin moieties in a highly cross-linked poly­(tetraphenylporphyrin-<i>co</i>-cyclotriphosphazene) (TPP–PZS) by the polycondensation of hexachlorocyclotriphosphazene (HCCP) and 5,10,15,20-tetrakis­(4-hydroxyphenyl)­porphyrin (TPP-(OH)₄) in a suitable solvent. The resulting TPP–PZS particles were characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), ³¹P nuclear magnetic resonance (NMR), and ultraviolet and visible (UV–vis) absorption spectra. Remarkably, TPP–PZS particles obtained in acetone emitted a bright red fluorescence both in powder state and in solution because the aggregation of porphyrin moieties in “H-type” (face-to-face) and “J-type” (edge-to-edge) was effectively blocked. The fluorescent TPP–PZS particles also showed superior resistance to photobleaching, and had a high sensitivity and selectivity for the detection of Hg²⁺ ions. The TPP–PZS particles were therefore used as an ideal material for preparing test strips to quickly detect/monitor the Hg²⁺ ions in a facile way

Facile Synthesis of Superparamagnetic Fe₃O₄@polyphosphazene@Au Shells for Magnetic Resonance Imaging and Photothermal Therapy

Multifunctional nanoparticles were prepared by directly welding superparamagnetic Fe₃O₄ nanoparticles and Au shells together with highly cross-linked polyphosphazene as “glue” in a facile but effective way. The as-prepared particles can simultaneously take advantages of both magnetization of Fe₃O₄ core for magnetic resonance imaging diagnosis and strong near-infrared absorption of Au nanoshell for photothermal therapy

Highly Cross-Linked and Biocompatible Polyphosphazene-Coated Superparamagnetic Fe₃O₄ Nanoparticles for Magnetic Resonance Imaging

Highly cross-linked and biocompatible poly­(cyclotriphosphazene-<i>co</i>-4,4′-sulfonyldiphenol) (PZS) were used to directly coat hydrophilic superparamagnetic Fe₃O₄ nanoparticles by a facile but effective one-pot polycondensation. The obtained core–shell Fe₃O₄@PZS nanohybrids were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and X-ray diffraction spectra. Interesting, the size and T₂ relaxivity of Fe₃O₄@PZS increased with increasing the mass ratio of Fe₃O₄ to PZS. All these nanohybrids could be internalized by HeLa cells but show negligible cytotoxicity. The PZS layer slowly degraded into less dangerous forms such as 4,4′-sulfonyldiphenol, phosphate and ammonia at neutral or acid atmosphere. Considering their excellent water dispersibility, colloidal and chemical stability, magnetic manipulation, and magnetic resonance imaging (MRI) properties, Fe₃O₄@PZS nanohybrids have great potential in MRI diagnosis of cancer

Facile Preparation of Doxorubicin-Loaded and Folic Acid-Conjugated Carbon Nanotubes@Poly(<i>N</i>‑vinyl pyrrole) for Targeted Synergistic Chemo–Photothermal Cancer Treatment

We developed a bifunctional nanoplatform for targeted synergistic chemo–photothermal cancer treatment. The nanoplatform was constructed through a facile method in which poly­(<i>N</i>-vinyl pyrrole) (PVPy) was coated on cut multiwalled carbon nanotubes (c-MWNTs); FA-PEG-SH was then linked by thiol–ene click reaction to improve the active targeting ability, water dispersibility, and biocompatibility and to extend the circulation time in blood. The PVPy shell not only enhanced the photothermal effect of c-MWNTs significantly but also provided a surface that could tailor targeting molecules and drugs. The resulting MWNT@PVPy-S-PEG-FA possessed high drug-loading ratio as well as pH-sensitive unloading capacity for a broad-spectrum anticancer agent, doxorubicin. Owing to its outstanding efficiency in photothermal conversion and ability in targeted drug delivery, the material could potentially be used as an efficient chemo–photothermal therapeutic nanoagent to treat cancer

Golden Single-Walled Carbon Nanotubes Prepared Using Double Layer Polysaccharides Bridge for Photothermal Therapy

Golden single-walled carbon nanotubes (SWNTs) were prepared by growing gold nanoparticles onto the bilayer polysaccharide functionalized SWNTs. The layer-by-layer self-assembly of sodium alginate and chitosan on SWNTs provided an ideal surface with high density of active metal-binding groups such as amino and carboxylic acid groups, and then an approach of seed growth was adopted to facilitate the formation of gold nanoparticles coated SWNTs. The resulting golden SWNT hybrids have good water dispersibility and biocompatibility and tend to enter cancer cells. Interestingly, they have an enhanced NIR absorption and effectively transfer NIR laser into heat. The material can quickly cause localized hyperthermia, resulting in rapid cell death, and therefore appears to act as a highly effective photothermal converter for cancer ablation

Multifunctional Nanoflowers for Simultaneous Multimodal Imaging and High-Sensitivity Chemo-Photothermal Treatment

Liver cancer is currently among the most challenging cancers to diagnose and treat. It is of prime importance to minimize the side effects on healthy tissues and reduce drug resistance for precise diagnoses and effective treatment of liver cancer. Herein, we report a facile but high-yield approach to fabricate a multifunctional nanomaterial through the loading of chitosan and metformin on Mn-doped Fe₃O₄@MoS₂ nanoflowers. Mn-doped Fe₃O₄ cores are used as simultaneous <i>T</i>₁/<i>T</i>₂ magnetic resonance imaging (MRI) agents for sensitive and accurate cancer diagnosis, while MoS₂ nanosheets are used as effective near-infrared photothermal conversion agents for potential photothermal therapy. The surface-functionalized chitosan was able not only to improve the dispersibility of Mn-doped Fe₃O₄@MoS₂ nanoflowers in biofluids and increase their biocompatibility, but also to significantly enhance the photothermal effect. Furthermore, metformin loading led to high suppression and eradication of hepatoma cells when photothermally sensitized, but exhibited negligible effects on normal liver cells. Due to its excellent combination of <i>T</i>₁/<i>T</i>₂ MRI properties with sensitive chemotherapeutic and photothermal effects, our study highlights the promise of developing multifunctional nanomaterials for accurate multimodal imaging-guided, and highly sensitive therapy of liver cancer

Fluorescent and Cross-linked Organic–Inorganic Hybrid Nanoshells for Monitoring Drug Delivery

Functionalized and monodisperse nanoshells have attracted significant attention owing to their well-defined structure, unique properties, and wide range of potential applications. Here, the synthesis of cross-linked organic–inorganic hybrid nanoshells with strong fluorescence properties was reported via a facile precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) and fluorescein on silica particles used as templates. The resulting poly­(cyclotriphosphazene-<i>co</i>-fluorescein) (PCTPF) nanoshells were firm cross-linked shells with ∼2.2 nm mesopores that facilitated the transport of drug molecules. The fluorescent nanoshells also exhibited excellent water dispersibility and biocompatibility; thus, they can be considered as ideal drug vehicles with high doxorubicin storage capacity (26.2 wt %) and excellent sustained release (up to 14 days). Compared to doxorubicin (DOX) alone, the PCTPF nanoshells more efficiently delivered DOX into and killed cancer cells. Moreover, the PCTPF nanoshells also exhibited remarkable fluorescent emission properties and improved photobleaching stability in both suspension and solid state owing to the covalent immobilization of fluorescein in the highly cross-linked organic–inorganic hybrids. The exceptional fluorescent properties enabled the release of DOX as well as the distribution of nanoshells and DOX to be monitored

Three new coumarin derivatives from <i>Maytenus hookeri</i>

Three new coumarin derivatives named maytenucoums A-C (1-3), along with six known analogs (4-9), were isolated from the branches of Maytenus hookeri. Their structures were determined by comprehensive spectroscopic data analysis, including NMR and HR-ESIMS. In the preliminary assays, compound 4 showed cytotoxic activity against the A549, SK-Hep1 and HCT116 cells with IC50 values of 29.0, 28.6 and 54.4 μM, respectively.</p

Fluorescent Organic Nanoparticles Constructed by a Facile “Self-Isolation Enhanced Emission” Strategy for Cell Imaging

To achieve the highly emissive features and overcome the troublesome photobleaching for fluorescent organic molecules, a facile and versatile strategy named “self-isolation enhanced emission (SIEE)” was developed to prevent the π–π stacking of organic fluorophores by linking alkyl chains on their conjugated backbones. As a proof-of-concept, one or two octyl groups were grafted onto the backbone of 4,7-di­(thiophen-2-yl)­benzo­[<i>c</i>]­[1,2,5]­thiadiazole (termed as DTBT-0), resulting in two different molecules, termed as DTBT-1 and DTBT-2, respectively. Compared with DTBT-0, DTBT-1 and DTBT-2 exhibited remarkably enhanced fluorescent properties in both aggregated thin films and nanoparticles, demonstrating that the SIEE method could isolate the fluorophores effectively and then prevent their π–π stacking to achieve the impressive fluorescent properties. After proper surface modification, excellent water dispersibility, biocompatibility, and improved resistance to photobleaching were also achieved for highly emissive DTBT-2-based nanoparticles, which were then successfully applied for cellular imaging

NaGdF₄:Yb³⁺/Er³⁺@NaGdF₄:Nd³⁺@Sodium-Gluconate: Multifunctional and Biocompatible Ultrasmall Core–Shell Nanohybrids for UCL/MR/CT Multimodal Imaging

Multimodal bioimaging nanoparticles by integrating diverse imaging ingredients into one system, represent a class of emerging advanced materials that provide more comprehensive and accurate clinical diagnostics than conventional contrast agents. Here monodisperse and biocompatible core–shell nanoparticles, NaGdF₄: Yb³⁺/Er³⁺@NaGdF₄:Nd@sodium-gluconate (termed as GNa-Er@Nd), with about 26 nm in diameter were successfully prepared by a facile two step reactions in high boiling solvents, and followed a ligand exchange process with sodium gluconate. The resulting GNa-Er@Nd nanoparticles were well characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), and zeta potentials. These nanohybrids present brightly dual-wavelength excited upconversion luminescence (UCL) under both 980 and 793 nm laser because of the synergistic effect of Yb³⁺/Er³⁺ and Nd³⁺. They also exhibited excellent relaxivity parameters (<i>r</i>₁) in magnetic resonance imaging (MRI) and Hounsfield units (HU) in X-ray computed tomography (CT) that are comparable to the clinical contrast agents. Therefore, these small and monodisperse nanoparticles provide options to construct a unique platform for potential multimodal UCL/CT/MRI imaging simultaneously