Co-assembly of Amphiphilic Triblock Copolymers with Nanodrugs and Drug Release Kinetics in Solution

Polymeric vesicles present great potential in disease treatment as they can be featured as a structurally stable and easily functionalized drug carrier that can simultaneously encapsulate multiple drugs and release them on-demand. Based on the dissipative particle dynamics (DPD) simulation, the drug-loaded vesicles were designed by the co-assembly process of linear amphiphilic triblock copolymers and hydrophobic nanodrugs in solvents, and most importantly, the drug release behavior of drug-loaded vesicles were intensively investigated. The drug-loaded aggregates, such as vesicles, spherical micelles, and disk-like micelles, were observed by varying the size and concentration of nanodrugs and the length of the hydrophobic block. The distribution of nanodrugs in the vesicles was intensively analyzed. As the size of the nanodrugs increases, the localization of nanodrugs change from being unable to fully wrap in the vesicle wall to the uniform distribution and finally to the aggregation in the vesicles at the fixed concentration of nanodrugs. The membrane thickness of the drug-loaded polymeric vesicle can be increased, and the nanodrugs localized closer to the center of the vesicle by increasing the length of the hydrophobic block. The nanodrugs will be released from vesicles by varying the interactions between the nanodrug and the solvent or the hydrophobic block and the solvent, respectively. We found that the release kinetics conforms to the first-order kinetic model, which can be used to fit the cumulative release rate of nanodrugs over time. The results showed that increasing the size of nanodrugs, the length of hydrophobic block, and the interaction parameters between the hydrophobic block and the solvent will slow down the release rate of the nanodrug and change the drug release process from monophasic to biphasic release model

Co-assembly of Amphiphilic Triblock Copolymers with Nanodrugs and Drug Release Kinetics in Solution

Polymeric vesicles present great potential in disease treatment as they can be featured as a structurally stable and easily functionalized drug carrier that can simultaneously encapsulate multiple drugs and release them on-demand. Based on the dissipative particle dynamics (DPD) simulation, the drug-loaded vesicles were designed by the co-assembly process of linear amphiphilic triblock copolymers and hydrophobic nanodrugs in solvents, and most importantly, the drug release behavior of drug-loaded vesicles were intensively investigated. The drug-loaded aggregates, such as vesicles, spherical micelles, and disk-like micelles, were observed by varying the size and concentration of nanodrugs and the length of the hydrophobic block. The distribution of nanodrugs in the vesicles was intensively analyzed. As the size of the nanodrugs increases, the localization of nanodrugs change from being unable to fully wrap in the vesicle wall to the uniform distribution and finally to the aggregation in the vesicles at the fixed concentration of nanodrugs. The membrane thickness of the drug-loaded polymeric vesicle can be increased, and the nanodrugs localized closer to the center of the vesicle by increasing the length of the hydrophobic block. The nanodrugs will be released from vesicles by varying the interactions between the nanodrug and the solvent or the hydrophobic block and the solvent, respectively. We found that the release kinetics conforms to the first-order kinetic model, which can be used to fit the cumulative release rate of nanodrugs over time. The results showed that increasing the size of nanodrugs, the length of hydrophobic block, and the interaction parameters between the hydrophobic block and the solvent will slow down the release rate of the nanodrug and change the drug release process from monophasic to biphasic release model

Co-assembly of Amphiphilic Triblock Copolymers with Nanodrugs and Drug Release Kinetics in Solution

Polymeric vesicles present great potential in disease treatment as they can be featured as a structurally stable and easily functionalized drug carrier that can simultaneously encapsulate multiple drugs and release them on-demand. Based on the dissipative particle dynamics (DPD) simulation, the drug-loaded vesicles were designed by the co-assembly process of linear amphiphilic triblock copolymers and hydrophobic nanodrugs in solvents, and most importantly, the drug release behavior of drug-loaded vesicles were intensively investigated. The drug-loaded aggregates, such as vesicles, spherical micelles, and disk-like micelles, were observed by varying the size and concentration of nanodrugs and the length of the hydrophobic block. The distribution of nanodrugs in the vesicles was intensively analyzed. As the size of the nanodrugs increases, the localization of nanodrugs change from being unable to fully wrap in the vesicle wall to the uniform distribution and finally to the aggregation in the vesicles at the fixed concentration of nanodrugs. The membrane thickness of the drug-loaded polymeric vesicle can be increased, and the nanodrugs localized closer to the center of the vesicle by increasing the length of the hydrophobic block. The nanodrugs will be released from vesicles by varying the interactions between the nanodrug and the solvent or the hydrophobic block and the solvent, respectively. We found that the release kinetics conforms to the first-order kinetic model, which can be used to fit the cumulative release rate of nanodrugs over time. The results showed that increasing the size of nanodrugs, the length of hydrophobic block, and the interaction parameters between the hydrophobic block and the solvent will slow down the release rate of the nanodrug and change the drug release process from monophasic to biphasic release model

Designing Multimodal ON–OFF Nanoswitches of DNA-Functionalized Nanoparticles by Stimuli-Responsive Polymers

It is a challenging task to realize highly reversible ON–OFF nanoswitches over a wide range of temperatures, which emerge as a versatile toolbox for use in nanobiotechnology. Herein, nanoparticles (NPs) bifunctionalized by DNA strands and stimuli-responsive polymers are proposed to construct multimodal ON–OFF nanoswitches by the coarse-grained model. The successful achievement of multimodal ON–OFF nanoswitches for bifunctionalized NPs at lower temperatures is attributed to the synergistic effects of the contraction and expansion configurations of stimuli-responsive polymers, combined with the hybridization–dehybridization event of DNA strands. Importantly, our simulations isolate the conditions of programmable self-assembly of bifunctionalized NPs to realize the multimodal ON–OFF nanoswitches by the changes of temperature and chain rigidity. In addition, it is found that the bifunctionalized NPs in the ON state display anisotropic and patchy features due to an introduction of stimuli-responsive polymers. Our simulation results provide fundamental insights on qualitative predictions of ON/OFF states of DNA-based NPs, which can aid in realizing a set of ON–OFF nanoswitches by the rational design of functionalization molecules

Transformation of Chloroform in Model Treatment Wetlands: From Mass Balance to Microbial Analysis

Chloroform is one of the common disinfection byproducts, which is not susceptible to degradation and poses great health concern. In this study, the chloroform removal efficiencies and contributions of sorption, microbial degradation, plant uptake, and volatilization were evaluated in six model constructed wetlands (CWs). The highest chloroform removal efficiency was achieved in litter-added CWs (99%), followed by planted (46–54%) and unplanted CWs (39%). Mass balance study revealed that sorption (73.5–81.2%) and microbial degradation (17.6–26.2%) were the main chloroform removal processes in litter-added CWs, and that sorption (53.6–66.1%) and plant uptake (25.3–36.2%) were the primary contributors to chloroform removal in planted CWs. Around 60% of chloroform got accumulated in the roots after plant uptake, and both transpiration and gas-phase transport were expected to be the drivers for the plant uptake. Sulfate-reducing bacteria and methanogens were found to be the key microorganisms for chloroform biodegradation through cometabolic dechlorination, and positive correlations were observed between functional genes (dsrA, mcrA) and biodegradation rates. Overall, this study suggests that wetland is an efficient ecosystem for sustainable chloroform removal, and that plant and litter can enhance the removal performance through root uptake and microbial degradation stimulation, respectively

Stretchable PEDOT:PSS/Li-TFSI/XSB Composite Films for Electromagnetic Interference Shielding

Electromagnetic interference (EMI) shielding materials with stretchability are important for developing wearable and flexible appliances. Herein, lithium bis­(trifloromethanesulfonyl)­imide (Li-TFSI)-doped poly­(3,4-ethylenedioxythiophene):poly­(styrene sulfonate) (PEDOT:PSS) and carboxylated styrene-butadiene rubber (XSB) latex are used to prepare stretchable EMI shielding composite films of 0.2 mm in thickness. In these films, the doped PEDOT:PSS nanoparticles form tenuous conductive pathways between the hexagonally packed latex particles, resulting in higher EMI shielding efficiency (EMI SE) compared with the films containing traditional dopant ethylene glycol. For the purpose of stretchable EMI shielding, the films containing 6 wt % PEDOT:PSS and 6 wt % Li-TFSI demonstrate EMI SE of 50 and 30 dB (12.4 GHz) at 0 and 100% strains, respectively, being the highest values among the reported shielding composites except for those using liquid metal as the filler. The investigation also provides a simple and environmentally friendly preparation method being highlighted for the development of lightweight stretchable EMI shielding materials for applications in flexible electronics in the near future

Mechanisms and Kinetics Studies of Butylated Hydroxytoluene Degradation to Isobutene

2,6-Di-tert-butyl-hydroxytotulene (BHT) is a widely used antioxidant in various fields. In this study, we explored comprehensively the mechanisms and kinetics of BHT degradation to produce isobutene using the density functional theory method. Furthermore, the intrinsic chemical reactivity of BHT was investigated using the electrostatic potential, average local ionization energy, and Fukui function, and the most likely reaction site with OH radical was predicted. Two initiation pathways of BHT with OH radicals were reported. The OH addition pathways at the C2 site of BHT was found more likely to occur than the pathways of H abstracts from the t-butyl group due to the lower energy barrier. Rate constants of two initiation pathways were calculated by transition state theory, and they were promoted by the temperature rise. Mayer bond order and localized molecular orbitals analysis were conducted to reveal the variation of the chemical bonds in the reaction process. The tertiary butyl radical that had been generated in the OH-addition reaction was more likely to generate isobutene with the participation of oxygen. Overall, this research could help to reveal the transformation mechanism of isobutene produced by BHT degradation

Schematic diagram of truncated 5′- flanking sequences of FHL2 exon 1a.

<p>These truncations were fused to the luciferase reporter gene in the pGL4.10-basic vector. Numbers indicate positions relative to the transcription start site (TSS, +1).</p

Activities of FHL2 1a and 1b 2k-promoters co-transfected with different concentrations of TP53 expression plasmid in HEK293 cells.

<p>Data obtained from three independent experiments, each done in triplicates. Data were normalized by pGL4 and pcDNA3.1 and presented as mean ± SEM. Triple asterisks (***) indicates <i>P</i><0.001, double asterisks (**) indicates <i>P</i><0.01 and single asterisk (*) indicates <i>P</i><0.05 by unpaired t-test.</p

The correlation between the expression levels of FHL2 and TP53.

<p>The real-time PCR results were analysed using SPSS (version 16.0).</p