11 research outputs found
āFasteningā 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 āisolateā
and āfastenā porphyrin moieties in a highly cross-linked
polyĀ(tetraphenylporphyrin-<i>co</i>-cyclotriphosphazene)
(TPPāPZS) by the polycondensation of hexachlorocyclotriphosphazene
(HCCP) and 5,10,15,20-tetrakisĀ(4-hydroxyphenyl)Āporphyrin (TPP-(OH)<sub>4</sub>) in a suitable solvent. The resulting TPPāPZS particles
were characterized with transmission electron microscopy (TEM), scanning
electron microscopy (SEM), Fourier transform infrared (FTIR), <sup>31</sup>P nuclear magnetic resonance (NMR), and ultraviolet and visible
(UVāvis) absorption spectra. Remarkably, TPPāPZS particles
obtained in acetone emitted a bright red fluorescence both in powder
state and in solution because the aggregation of porphyrin moieties
in āH-typeā (face-to-face) and āJ-typeā
(edge-to-edge) was effectively blocked. The fluorescent TPPāPZS
particles also showed superior resistance to photobleaching, and had
a high sensitivity and selectivity for the detection of Hg<sup>2+</sup> ions. The TPPāPZS particles were therefore used as an ideal
material for preparing test strips to quickly detect/monitor the Hg<sup>2+</sup> ions in a facile way
Facile Synthesis of Superparamagnetic Fe<sub>3</sub>O<sub>4</sub>@polyphosphazene@Au Shells for Magnetic Resonance Imaging and Photothermal Therapy
Multifunctional nanoparticles were
prepared by directly welding superparamagnetic Fe<sub>3</sub>O<sub>4</sub> nanoparticles and Au shells together with highly cross-linked
polyphosphazene as āglueā in a facile but effective
way. The as-prepared particles can simultaneously take advantages
of both magnetization of Fe<sub>3</sub>O<sub>4</sub> 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 Fe<sub>3</sub>O<sub>4</sub> Nanoparticles for Magnetic Resonance Imaging
Highly
cross-linked and biocompatible polyĀ(cyclotriphosphazene-<i>co</i>-4,4ā²-sulfonyldiphenol) (PZS) were used to directly
coat hydrophilic superparamagnetic Fe<sub>3</sub>O<sub>4</sub> nanoparticles
by a facile but effective one-pot polycondensation. The obtained coreāshell
Fe<sub>3</sub>O<sub>4</sub>@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 T<sub>2</sub> relaxivity of Fe<sub>3</sub>O<sub>4</sub>@PZS increased with increasing the mass ratio of Fe<sub>3</sub>O<sub>4</sub> 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 4,4ā²-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,
Fe<sub>3</sub>O<sub>4</sub>@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>āvinyl pyrrole) for Targeted Synergistic ChemoāPhotothermal Cancer Treatment
We
developed a bifunctional nanoplatform for targeted synergistic
chemoāphotothermal cancer treatment. The nanoplatform was constructed
through a facile method in which polyĀ(<i>N</i>-vinyl pyrrole)
(PVPy) was coated on cut multiwalled carbon nanotubes (c-MWNTs); FA-PEG-SH
was then linked by thiolāene 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 chemoāphotothermal 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 Fe<sub>3</sub>O<sub>4</sub>@MoS<sub>2</sub> nanoflowers. Mn-doped Fe<sub>3</sub>O<sub>4</sub> cores are used as simultaneous <i>T</i><sub>1</sub>/<i>T</i><sub>2</sub> magnetic resonance imaging
(MRI) agents for sensitive and accurate cancer diagnosis, while MoS<sub>2</sub> 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
Fe<sub>3</sub>O<sub>4</sub>@MoS<sub>2</sub> 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><sub>1</sub>/<i>T</i><sub>2</sub> 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 OrganicāInorganic 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
organicāinorganic 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 polyĀ(cyclotriphosphazene-<i>co</i>-fluorescein) (PCTPF) nanoshells were firm cross-linked
shells with ā¼2.2 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
organicāinorganic 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 54.4āĪ¼M, respectively.</p
Fluorescent Organic Nanoparticles Constructed by a Facile āSelf-Isolation Enhanced Emissionā 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 āself-isolation enhanced emission (SIEE)ā
was developed to prevent the ĻāĻ 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-diĀ(thiophen-2-yl)ĀbenzoĀ[<i>c</i>]Ā[1,2,5]Āthiadiazole
(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 ĻāĻ 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
NaGdF<sub>4</sub>:Yb<sup>3+</sup>/Er<sup>3+</sup>@NaGdF<sub>4</sub>:Nd<sup>3+</sup>@Sodium-Gluconate: Multifunctional and Biocompatible Ultrasmall CoreāShell 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 coreāshell nanoparticles,
NaGdF<sub>4</sub>: Yb<sup>3+</sup>/Er<sup>3+</sup>@NaGdF<sub>4</sub>: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 Yb<sup>3+</sup>/Er<sup>3+</sup> and Nd<sup>3+</sup>. They also exhibited excellent relaxivity parameters (<i>r</i><sub>1</sub>) 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