5 research outputs found
Rapid removal of ultra-high-concentration <i>p</i>-nitrophenol in aqueous solution by microwave-enhanced Fe/Cu bimetallic particle (MW-Fe/Cu) system
<p>Ultra-high-concentration PNP-contained wastewaters are produced sometimes due to the wide application of this nitrophenolic compound in the chemical industry. However, there is a lack of appropriate technologies to rapidly pretreat the ultra-high-concentration wastewater. Therefore, a new microwave-enhanced Fe/Cu bimetallic particles (MW-Fe/Cu) system was developed to rapidly remove ultra-high-concentration PNP. First, the priority of the determinative parameters was obtained by orthogonal experiment. Based on this result, the effects of initial pH, microwave power, Fe/Cu dosage and initial PNP concentration on PNP removal were optimized thoroughly. Under the optimal conditions (i.e. initial pH = 1.0, MW power = 385 W, Fe/Cu dosage = 30 g/L and initial PNP concentration = 4000 mg/L), four control treatment systems (i.e. MW-Fe<sup>0</sup>, heating-Fe/Cu, MW alone and Fe/Cu alone system) were set up to compare with the MW-Fe/Cu system. The results suggest that high PNP removal (more than 99% with 2.5 min, <i>k</i><sub>1</sub>/<i>k</i><sub>2</sub> = 1.18/6.91 min<sup>−1</sup>) and COD removal (26.6% with 5 min treatment) could be obtained by the MW-Fe/Cu system, which were much superior to those obtained using the MW-Fe<sup>0</sup> (<i>k</i><sub>1</sub>/<i>k</i><sub>2</sub> = 0.62/2.21 min<sup>−1</sup>) and the heating-Fe/Cu system (<i>k</i><sub>1</sub>/<i>k</i><sub>2</sub> = 0.53/1.52 min<sup>−1</sup>). Finally, the determination of the intermediates of PNP degradation by HPLC indicated that the MW assistance process did not change the degradation pathway of PNP. This concludes that the new MW-Fe/Cu system was the promising technology for pretreatment of wastewater containing ultra-high-concentration toxic and refractory pollutants at a fairly short treatment time.</p
An Approach for the Sphere-to-Rod Transition of Multiblock Copolymer Micelles
The shape of polymer micelles is important for pharmaceutical
applications
as drug delivery. In this article, an approach inducing sphere-to-rod
transition of multiblock polyurethane micelles has been developed
through introducing a second hydrophilic component phosphatidylcholine
group into the polymer chains. Time-resolved dynamic light scattering
(DLS), combined with transmission electron microscopy (TEM), was employed
to investigate the kinetics of morphology transition. Moreover, a
dissipative particle dynamics (DPD) simulation method was applied
to study the mechanism of sphere-to-rod transition. These experimental
and simulation studies revealed that the hydrophilic phosphatidylcholine
groups can create defects on the surfaces of spherical polyurethane
micelles, thus, making positive contribution to adhesive collisions
and leading to the fusion of spherical micelles into rod-like micelles.
This finding provides new insight into the origins of rod-like polymer
micelles, which is valuable for the design and preparation of novel
polymeric drug carriers with tailored properties
Multifunctional Mixed Micelles Cross-Assembled from Various Polyurethanes for Tumor Therapy
A challenge in the development
of multifunctional drug delivery systems is to establish a reasonable
and effective synthetic route for multifunctional polymer preparation.
Herein, we propose a unique protocol to prepare multifunctional micelles
by a cross-assembly process using three different functional polyurethanes
incorporating acidic sensitive hydrazone, folic acid for active targeting,
and gemini quaternary ammonium (GQA) as efficient cell uptake ligands,
respectively. These multifunctional mixed micelles (GFHPMs) have been
endowed tunable particle sizes and zeta potential and a unique three-order-layer
cross-assemble structure. Their drug-loading contents have been significantly
improved, and drug release profiles displayed controlled release of
their payloads under acid condition. The folate and GQA ligands showed
a synergistic effect to enhance the cell uptake. Biodistribution and
antitumor effect of these micelles were systematically investigated
in vivo, the mixed micelles could penetrate into the depths of tumors,
and drug concentrations in tumors reached the maximum of 6.5% ID/g
at 24 h, resulting in an excellent therapeutic effect that the volumes
of tumors treated with GFHPM are five times smaller than those treated
with blank micelles. Our present work provides an effective approach
to the design of multifunctional nanocarriers for tumor-targeted and
programmed intracellular drug delivery
Surface Distribution and Biophysicochemical Properties of Polymeric Micelles Bearing Gemini Cationic and Hydrophilic Groups
Polymeric
micelles containing cationic gemini quaternary ammonium (GQA) groups
have shown enhanced cellular uptake and efficient drug delivery, while
the incorporation of polyÂ(ethylene glycol) (PEG) corona can potentially
reduce the absorption of cationic carriers by opsonic proteins and
subsequent uptake by mononuclear phagocytic system (MPS). To understand
the interactions of GQA and PEG groups and their effects on the biophysicochemical
characteristics of nanocarriers, a series of polyurethane micelles
containing GQA and different molecular weights of PEG were prepared
and carefully characterized. It was found that the GQA and PEG groups
are unevenly distributed on the micellar surface to form two kinds
of hydrophilic domains. As a result, the particle surface with some
defects cannot be completely shielded by the PEG corona. Despite this,
the longer PEG chains with a brush conformation provide superior stabilization
and steric repulsion against the absorption of proteins and, thus,
can reduce the cytotoxicity, protein absorption, and MPS uptake of
micelles to some extent. This study provides a new understanding on
the interactions between PEG chains and cationic groups and a guideline
for the design and fabrication of safe and effective drug delivery
systems
Additional file 2: of cepip: context-dependent epigenomic weighting for prioritization of regulatory variants and disease-associated genes
Descriptions and abbreviations of the 127 tissues/cell types. (XLSX 14 kb