A light‐activated hypoxia‐responsive drug‐delivery vehicle is described by Q.‐D. Shen, Z. Gu, and co‐workers on page 3313. This conjugated‐polymer‐based nanocarrier can be activated by ...photoirradiation, producing singlet oxygen (1O2) and inducing hypoxia to promote release of its cargo inside tumor cells for enhanced anticancer efficacy.
A multifunctional nanocarrier for encapsulation and delivery of short interfering RNA (siRNA) has been realized using cationic fluorescent polymer core-shell nanoparticles. The nanocarrier has good ...biocompatibility and high transfection efficiency over the most popular transfection reagent, Lipofectamine 2000. Fluorescence resonance energy transfer within the nanocarrier provides a non-invasive and label-free method to track the intracellular release of siRNA.
Nanocarriers with core-shell structure for delivery and non-invasively tracking the intracellular release of siRNA are developed.
The electrocaloric effect (ECE) is enhanced in ferroelectric relaxor terpolymer poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (P(VDF–TrFE–CFE))/ZrO2 nanocomposites. It was observed ...that the interface effects between the polymer matrix and nano-fillers enhance the polarization response and provide additional electrocaloric entropy changes. As a consequence, the nanocomposites exhibit a larger ECE than that of the neat terpolymer, i.e., the adiabatic temperature change of the nanocomposite with 3 volume percent of nano-fillers is 120% of that of the neat terpolymer. The results, for the first time, demonstrate that ECE can be tailored and enhanced through nanocomposite approach in the ferroelectric polymers.
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Flow behavior of solid phases is simulated by means of DEM-CFD in a liquid–solid fluidized bed with magnetization of preliminarily fluidized bed mode (LAST) along a transverse uniform magnetic field. ...By changing the magnetic field strength, the distribution of particles is studied within the bed. The distributions of velocity and volume fraction of particles are analyzed at the different magnetic field intensities. When the magnetic field strength is increased to a value at which the fluidization of strings starts, the particles are found to form straight-chain aggregates along the direction of the magnetic field. At very high magnetic field strengths, the densification of particles is observed, and the liquid channels are forming between the magnetic chains. Simulations indicate that the granular temperature of particles decreases with the increase of magnetic-flux density. The drag force is determined at each particle at the low magnetic field. With an increase of magnetic field strength, magnetic force becomes main force among particles.
It is demonstrated that the magnetic particles and non-magnetic particles having the same density and diameter are fluidized in the bed without the assistance of magnetic field. When the transverse magnetic field is imposed, the magnetic chains of magnetic particles are formed, and non-magnetic particles are fluidized in the bed.
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•Flow behavior of solid phases is simulated by means of DEM-CFD.•By changing the magnetic field strength, the distribution of particles is studied.•The particles form straight-chain aggregates at high magnetic field strengths.•At very high magnetic field strengths, the densification of particles is observed.•Magnetic force becomes main force at very high magnetic field strengths.
The present study describes a flexible nanoplatform based on electrostatic assembly of conjugated polyelectrolytes (CPEs) and carboxylated multi-walled carbon nanotubes (cMWNTs). It is demonstrated ...that the obtained nanocomposites inherit intrinsic optical properties of CPEs and characteristic Raman vibration modes of MWNTs, providing a fluorescence-Raman dual-imaging method for intracellular tracking and locating of MWNTs. We suggest that the cellular internalization of the CPE-cMWNT nanocomposites is a surface charge-dependent process. The strengths of this nanoplatform include satisfying biocompatibility, enhanced protein-repellent property, and ease of implementation, making it available for both in vitro and in vivo applications.
Chemically modified copper phthalocyanine (CuPc) oligomer with active vinyl groups was successfully bonded to poly(vinylidene fluoride-trifluoroethylene) (P(VDF−TrFE)) backbone via free radical graft ...reaction in solution. Improvement of the dispersibility of CuPc oligomer in polymer matrix was confirmed by TEM-observed morphologies. The size of CuPc particulates in the polymer matrix is in the range of 60−120 nm. This nanocomposite (with 25 wt % CuPc) is very flexible with an elastic modulus of 912 MPa, which is nearly the same as that of the polymer matrix, and presents a breakdown field of 37.7 V/μm, while for the blend of P(VDF−TrFE) and CuPc oligomer, it is 29.7 V/μm. The dielectric constant reaches about 100 at 100 Hz and room temperature, representing a more than 6 times increase compared with the matrix. The grafted nanocomposite exhibits a weaker dielectric dispersion in comparison with the blend of P(VDF−TrFE) and CuPc oligomer, particularly at low-frequency range. The low-frequency dielectric dispersion can be attributed to the Maxwell−Wagner−Sillars polarization mechanism.
To fabricate ferroelectric ultrathin polymer films with large dielectric constants for potential all‐organic electronic devices, ferroelectric polymer nanotubes and a composite of the nanotubes with ...a dispersed organic semiconductor have been fabricated by template‐assisted methods. The ferroelectricity drops markedly in spin‐coated ultrathin films less than 100 nm thick, whereas P(VDF‐TrFE) nanotubes with a wall thickness of a few ten nm sustain ferroelectricity. The composite nanotubes exhibit a giant dielectric constant as a result of significantly enhanced interface polarization between the nanosized fillers and the polymer matrix. They could be of practical use in supercapacitors, optoelectronic devices, and sensors.
Increasing needs for whole-body and in vivocellular imaging brings about high requirements for diversity and stability of fluorescence probes. We prepared red, yellow, and blue emissive conjugated ...polymers with good optical properties, excellent photostability, and low cytotoxicity that allowed the colour-coding of liver cancer cells (Bel-7402).
A new class of nanocomposites in which the high dielectric constant copper phthalocyanine oligomer (o-CuPc) was partially grafted to the poly(vinylidene ...fluoride−trifluoroethylene−chlorofluoroethylene) (P(VDF−TrFE−CFE)), a relaxor ferroelectric polymer, was developed. The new approach developed allowed for higher degree of grafting of o-CuPc to the polymer backbone and resulted in a nanocomposite P(VDF−TrFE−CFE)-g-CuPc/CuPc with o-CuPc inclusion size at about 60−100 nm. Compared with simple blend of the terpolymer and o-CuPc, a lower dielectric loss and higher breakdown field were achieved in the grafted nanocomposite which can be attributed to a more uniform distribution of o-CuPc particles in the polymer matrix as well as much reduced inclusion size. Moreover, the dielectric constant of the grafted nanocomposite at frequencies above 1 kHz is much higher than that of the simple blend, indicating an increased interface effect such as the exchange coupling which can enhance the dielectric response, as suggested recently by Li. It is also interesting to note that at high frequencies (∼1 MHz), in addition to the improved dielectric constant, the grafted nanocomposite also exhibits a much lower dielectric loss than the matrix.
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