117 research outputs found
Spacer Intercalated Disassembly and Photodynamic Activity of Zinc Phthalocyanine Inside Nanochannels of Mesoporous Silica Nanoparticles
Hydrophobic
photosensitizer zincÂ(II) phthalocyanine (ZnPc) was loaded into adamantane
(Ad) modified nanochannels of mesoporous silica nanoparticles (MSNPs).
The Ad units on the surface of MSNPs were complexed with amino-substituted
ÎČ-cyclodextrin to enhance the solubility of the hybrid in aqueous
solution. The amino groups on ÎČ-cyclodextrin also
provide functional sites for further conjugation with targeting ligands
toward targeted cancer therapy. Since the intercalation of the Ad
spacer isolates loaded ZnPc and prevents its aggregation inside MSNPs,
ZnPc exhibits its monomeric characteristics to effectively generate
cytotoxic singlet oxygen (<sup>1</sup>O<sub>2</sub>) upon light irradiation
(675 nm) in aqueous conditions, leading to efficient photodynamic
activity for successful cancer treatment in vitro. Current research
presents a convenient approach to maintain the monomeric state of
hydrophobic photosensitizer ZnPc by rationally utilizing multifunctional
MSNPs as the carriers. The novel hybrid with targeting capability
achieves active photodynamic property of monomeric ZnPc in aqueous
solution under light irradiation, which may find its way for practical
photodynamic therapy in the future
Targeted Delivery of 5âAminolevulinic Acid by Multifunctional Hollow Mesoporous Silica Nanoparticles for Photodynamic Skin Cancer Therapy
5-Aminolevulinic acid (5-ALA) is
a precursor of a strong photosensitizer, protoporphyrin IX (PphIX),
for photodynamic therapy (PDT). Developing appropriate delivery carriers
that can assist 5-ALA in bypassing the lipophilic barrier to directly
enter into cancer cells is a research focus. The improved delivery
of 5-ALA is even important for skin cancer therapy through PDT process.
In this work, targeting ligand folic acid (FA)-functionalized hollow
mesoporous silica nanoparticles (HMSNPs) were fabricated to deliver
5-ALA for PDT against B16F10 skin cancer cells. The FA targeting ligand
enabled selective endocytosis of 5-ALA loaded HMSNPs into cancer cells.
PphIX formed from delivered 5-ALA exhibited high photocytotoxicity
to the cancer cells in vitro
Anticancer Effect of 뱉Tocopheryl Succinate Delivered by Mitochondria-Targeted Mesoporous Silica Nanoparticles
Mitochondria
targeted mesoporous silica nanoparticles (MSNPs) having
an average diameter of 68 nm were fabricated and then loaded with
hydrophobic anticancer agent α-tocopheryl succinate (α-TOS).
The property of targeting mitochondria was achieved by the surface
functionalization of triphenylphosphonium (TPP) on MSNPs, since TPP
is an effective mitochondria-targeting ligand. Intracellular uptake
and mitochondria targeting of fabricated MSNPs were evaluated in HeLa
and HepG2 cancerous cell lines as well as HEK293 normal cell line.
In addition, various biological assays were conducted with the aim
to investigate the effectiveness of α-TOS delivered by the functional
MSNPs, including studies of cytotoxicity, mitochondria membrane potential,
intracellular adenosine triphosphate (ATP) production, and apoptosis.
On the basis of these experiments, high anticancer efficiency of α-TOS
delivered by mitochondria targeted MSNPs was demonstrated, indicating
a promising application potential of MSNP-based platform in mitochondria
targeted delivery of anticancer agents
Reduction-Responsive Carbon Dots for Real-Time Ratiometric Monitoring of Anticancer Prodrug Activation in Living Cells
Anticancer
prodrugs have been extensively investigated to lower
toxic side effects of common chemotherapeutic agents in biomedical
fields. To illustrate the activation mechanism of anticancer prodrugs,
fluorescent dyes or single-emission intensity alteration-based approaches
have been widely used. However, fluorescent dyes often suffer from
poor photostability and chemical stability, and single-emission intensity
alteration-based methods cannot avoid the influence from uncontrolled
microenvironment changes in living samples. To overcome these obstacles,
herein, a fluorescence resonance energy transfer (FRET)-based ratiometric
approach was successfully developed for real-time monitoring of anticancer
prodrug activation. Excitation-wavelength-dependent and full-color-emissive
carbon dots (CDs) were used as drug nanocarriers and FRET donor, and
a cisplatinÂ(IV) prodrug was selected as the model drug and the linker
to load the Dabsyl quencher on the surface of CDs. Owing to the FRET
effect, the blue fluorescence of CDs was effectively quenched by the
Dabsyl unit. Under reductive conditions in solution or in living cells
for the reduction of cisplatinÂ(IV) prodrug to PtÂ(II) species, the
blue fluorescence of CDs increased over time, without apparent intensity
change for green or red fluorescence. Thus, the gradually enhanced
intensity ratio of blue-to-green or blue-to-red fluorescence could
be indicative of the real-time reduction of the cisplatinÂ(IV) prodrug
to cytotoxic PtÂ(II) species. This ratiometric method could exclude
the influence from complex biological microenvironments by using green
or red fluorescence of CDs as an internal reference, which provides
new insights into the activation of the cisplatinÂ(IV) prodrug and
offers a great opportunity to design safe and effective anticancer
therapeutics
Dual-Responsive Carbon Dots for Tumor Extracellular Microenvironment Triggered Targeting and Enhanced Anticancer Drug Delivery
In this work, pH/redox dual-responsive
carbon dots (CDs-RGD-PtÂ(IV)-PEG) were fabricated for tumor extracellular
microenvironment triggered targeting and enhanced anticancer drug
delivery. The system consists of fluorescent carbon dots as imaging-guided
drug nanocarriers, cisplatinÂ(IV) as prodrug, and RGD peptide as active
targeting ligand, which is covered by monomethoxypolyethylene glycol
(mPEG) through tumor extracellular pH (6.5â6.8) responsive
benzoic-imine bond. The drug nanocarriers could be tracked by multicolor
fluorescence of carbon dots. After the hydrolysis of benzoic-imine
bond at the tumor extracellular pH to expose the inner targeting RGD
peptide, the drug nanocarriers showed effective uptake by cancer cells
through RGD-integrin α<sub><i>v</i></sub>ÎČ<sub>3</sub> (ligandâreceptor) interaction. Upon the internalization,
the loaded cisplatinÂ(IV) prodrug was reduced to cytotoxic cisplatin
in reductive cytosol of cancer cells to exhibit therapeutic effects.
Confocal imaging, flow cytometry, and cell viability assays using
CDs-RGD-PtÂ(IV)-PEG were performed to reveal the enhanced uptake and
better therapeutic efficiency to cancer cells with high integrin α<sub><i>v</i></sub>ÎČ<sub>3</sub> expression at tumor extracellular
pH than that in physiological condition. The developed CDs-RGD-PtÂ(IV)-PEG
offers a new strategy to provide safe and effective therapeutic agents
based on carbon dots for promising cancer therapy
One-Pot Synthesis of Antitumor Agent PMX 610 by a Copper(II)-Incorporated Mesoporous Catalyst
PMX 610 ((2-(3,4-dimethoxyphenyl)-5-fluorobenzothiazole)
is a benzothiazole
derivative, which shows potent antitumor properties. In this study,
copperÂ(II)-chelated pyrazole functionalized SBA-15 mesoporous silica
(Cu-Py-SBA-15) as a heterogeneous green catalyst was developed for
the synthesis of substituted benzothiazole derivatives including PMX
610. The preparation of pyrazole functionalized SBA-15 (Py-SBA-15)
was achieved by postsynthetic modification of mesoporous silica SBA-15
with 3-aminopropyltriethoxy-silane followed by the Schiff-base condensation
with 1-phenyl-3-(2âČ-hydroxyphenyl)-4-formyl pyrazole. The reaction
of Py-SBA-15 with CuCl<sub>2</sub>·2H<sub>2</sub>O in absolute
ethanol afforded the Cu-Py-SBA-15 catalyst. The as-synthesized catalyst
was fully characterized by several techniques including powder X-ray
diffraction, high-resolution transmission electron microscopy, electron
paramagnetic resonance spectroscopy, X-ray photoelectron spectroscopy, <sup>13</sup>C cross-polarization magic angle spinning NMR, Fourier transform
infrared spectroscopy, field emission scanning electron microscopy,
and N<sub>2</sub> adsorption/desorption measurements. A one-pot-three-component
approach in aqueous medium using the Cu-Py-SBA-15 catalyst was exploited
for direct synthesis of PMX 610. The novel heterogeneous green catalyst
offers high catalytic recyclability without considerable loss of catalytic
activity. The present synthetic strategy is valuable in the preparation
of PMX 610 on account of the use of readily available and inexpensive
starting materials, excellent recyclability of the catalyst, and sustainable
catalytic protocol
Light-Controllable Cucurbit[7]uril-Based Molecular Shuttle
The design and construction of novel artificial molecular
machines can be categorized as a currently important field of modern
chemistry. In the present work, a novel photoresponsive [3]Ârotaxane
containing two cucurbit[7]Âuril (CB[7]) rings and a dumbbell component
consisting of one <i>trans</i>-azobenzene unit along with
two viologen units was developed. Each viologen group was encircled
by a CB[7] ring with a rapid shuttling equilibration distribution
extended to the <i>trans</i>-azobenzene unit located in
the middle of the dumbbell component. Upon the <i>trans</i>-to-<i>cis</i> photoisomerization of the azobenzene unit
under UV light irradiation, a shuttling restriction of the CB[7] rings
along the dumbbell component was observed. The equilibration distribution
of the macrocycles on the dumbbell component can be recovered by the <i>cis</i>-to-<i>trans</i> photoisomerization of the
azobenzene unit under visible light irradiation. Such a controllable
shuttling process was fully characterized by <sup>1</sup>H NMR spectroscopy
and was easily indicated by fluorescent changes of the [3]Ârotaxane
Biocompatible Pillararene-Assembly-Based Carriers for Dual Bioimaging
Present research provides a successful example to use biocompatible pillararene-based assemblies for delivering mixed dyes in dual bioimaging. A series of tadpole-like and bola amphiphilic pillararenes <b>1</b>â<b>4</b> were synthesized by selectively employing water-soluble ethylene glycols and hydrophobic alkyl units as the starting materials. In comparison with their monomers, these amphiphilic pillararenes not only show improved biocompatibility to cells but also could form homogeneous supramolecular self-assemblies. Interestingly, different types of amphiphilic pillararene-based assemblies exhibit various performances on the delivery of dyes with different aqueous solubility. All assemblies can deliver water-soluble rhodamine B to cells, while only tadpole-like amphiphilic pillararene-based assemblies performed better on delivering hydrophobic fluorescein isothiocyanate for imaging. In addition, pillararene derivatives <b>1</b>, <b>3</b>, and <b>4</b> could complex with a viologen guest, further forming stable assemblies for bioimaging. In such cases, the assembly formed from the complex of tadpole-like amphiphile pillararene <b>1</b> with the viologen guest performed better in delivering mixed dyes. Finally, an anticancer drug, doxorubicin, was successfully delivered to cells by using the pillararene-based assemblies. The current research has determined the capacities of pillararene-based assemblies to deliver different dyes for bioimaging and paves the way for using these biocompatible carriers toward combined cancer therapy
Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water
Heavy
metal contamination in water is a serious risk to the public
health and other life forms on earth. Current research in nanotechnology
is developing new nanosystems and nanomaterials for the fast and efficient
removal of pollutants and heavy metals from water. Here, we report
graphene oxide-based microbots (GOx-microbots) as active self-propelled
systems for the capture, transfer, and removal of a heavy metal (i.e.,
lead) and its subsequent recovery for recycling purposes. Microbotsâ
structure consists of nanosized multilayers of graphene oxide, nickel,
and platinum, providing different functionalities. The outer layer
of graphene oxide captures lead on the surface, and the inner layer
of platinum functions as the engine decomposing hydrogen peroxide
fuel for self-propulsion, while the middle layer of nickel enables
external magnetic control of the microbots. Mobile GOx-microbots remove
lead 10 times more efficiently than nonmotile GOx-microbots, cleaning
water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after
chemical detachment of lead from the surface of GOx-microbots, the
microbots can be reused. Finally, we demonstrate the magnetic control
of the GOx-microbots inside a microfluidic system as a proof-of-concept
for automatic microbots-based system to remove and recover heavy metals
Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water
Heavy
metal contamination in water is a serious risk to the public
health and other life forms on earth. Current research in nanotechnology
is developing new nanosystems and nanomaterials for the fast and efficient
removal of pollutants and heavy metals from water. Here, we report
graphene oxide-based microbots (GOx-microbots) as active self-propelled
systems for the capture, transfer, and removal of a heavy metal (i.e.,
lead) and its subsequent recovery for recycling purposes. Microbotsâ
structure consists of nanosized multilayers of graphene oxide, nickel,
and platinum, providing different functionalities. The outer layer
of graphene oxide captures lead on the surface, and the inner layer
of platinum functions as the engine decomposing hydrogen peroxide
fuel for self-propulsion, while the middle layer of nickel enables
external magnetic control of the microbots. Mobile GOx-microbots remove
lead 10 times more efficiently than nonmotile GOx-microbots, cleaning
water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after
chemical detachment of lead from the surface of GOx-microbots, the
microbots can be reused. Finally, we demonstrate the magnetic control
of the GOx-microbots inside a microfluidic system as a proof-of-concept
for automatic microbots-based system to remove and recover heavy metals
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