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Perovskite manganates (AMnO 3 ) exhibit diverse structural, thermal, electrical, and magnetic properties. Their strong magnetocaloric effect (MCE) near the Curie temperature ( T C ) makes them ideal for magnetic-thermal anti-icing and deicing in power transmission lines. Below T C , ferromagnetic AMnO 3 produces heat through multiple mechanisms, with the changing magnetic field induced by the strong AC current, causing heat through magnetic hysteresis and eddy currents, alongside the direct MCE. Above T C , no heating is generated, as MCE is unfavorable, thus preventing additional energy loss at elevated temperatures. In this work, La 0.7 Ca 0.254 Sr 0.046 MnO 3 with T C close to 0 °C were synthesized by solid-state reaction. It is found that particle size >10 μm is beneficial for a large MCE, based on the results of particle size dependence of MCE. The resulting maximum magnetic entropy change at 277 K is 7.69 J·kg -1 ·K -1 , and an adiabatic temperature change of 3.87 K at 277 K is achieved under 5 T. The prototype cable is fabricated using a well-established wire drawing process. A climate-simulation chamber is employed for the anti-icing and deicing experiments. The prototype cables demonstrated a strong capability for deicing and anti-icing. This simple and cost-effective prototype cable shows significant potential for mitigating the icing problem of overhead high-voltage power transmission lines.

Actuators with fast and precise controllable responses are highly in demand for implementing agilely accurate mechanical movements in smart robots, intelligent sensors, biomimetic devices, and so on. Here, we report a graphene-based moisture actuator with accurately controllable direction and position responses achieved by a fast, controlled, and even programmable one-step laser reduction method. The laser reduction-induced oriented microstructures help to precisely guide the direction and location of the moisture response in graphene-based Janus films. The excellent moisture-mechanical response behaviors in these novel moisture actuators originate from the Janus structures and the periodic microstructures of a line-scanned layer. Our customized complex intelligent devices such as drums, bands, and three-dimensional wave humidity drives can highly match and verify the finite element simulations, which will inspire the creation of further smart robot designs for accurate deformation.

Successful implementation of carbon molecular sieve (CMS) membranes in large scale chemical processes inevitably relies on fabrication of high performance integrally skinned asymmetric or thin-film composite membranes. In principle, to maximize separation efficiency the selective CMS layer should be as thin as possible which requires its lateral confinement to a supporting structure. In this work, we studied pyrolysis-induced structural development as well as ethanol vapor-induced swelling of ultrathin CMS films made from a highly aromatic polyimide of an intrinsic microporosity (PIM-PI) precursor. Utilization of a light polarization-sensitive technique, spectroscopic ellipsometry, allowed for the identification of an internal orientation within the turbostratic amorphous CMS structure driven by the laterally constraining support. Our results indicated a significant thickness dependence both in the extent of pyrolytic collapse and response to organic vapor penetrant. Thinner, substrate-confined films (∼30 nm) collapsed more extensively leading to a reduction of microporosity in comparison to their thicker (∼300 nm) as well as self-supported (∼70 μm) counterparts. The reduced microporosity in the thinner films induced changes in the balance between penetrant-induced dilation (swelling) and filling of micropores. In comparison to thicker films, the initial lower microporosity of the thinner films was accompanied by slightly enhanced organic vapor-induced swelling. The presented results are anticipated to generate the fundamental knowledge necessary to design optimized ultrathin CMS membranes. In particular, our results reinforce previous findings that excessive reduction of the selective layer thickness in amorphous microporous materials (such as PIMs or CMS) beyond several hundred nanometers may not be optimal for maximizing their fluid transport performance.

Ferroelectric polymers are regarded as the preferred material in dielectric energy storage devices because of their high dielectric constant. However, their relatively low breakdown strength and efficiency restrict their practical application. This work combines coaxial spinning and hot pressing to compound the highly insulating linear poly(methyl methacrylate) (PMMA) and ferroelectric poly(vinylidene fluoride) (PVDF) to obtain a PMMA/PVDF all-organic film with a ferroconcrete-like structure. Further, improvements in the energy storage performance over those of the pristine polymer were achieved via modulation of the PMMA to PVDF ratio. The 45% PMMA/PVDF film had an energy storage density of 17.7 J/cm 3 and an energy efficiency of 73% at 640 kV/mm. Moreover, 51% PMMA/PVDF exhibited the best energy storage density ( U = 20.7 J/cm 3 , η = 63% at 630 kV/mm). This work, therefore, provides a new idea for the design of all-organic polymer films for the field of energy storage.

Significant progress in PbS quantum dot solar cells has been achieved through designing device architecture, engineering band alignment, and optimizing the surface chemistry of colloidal quantum dots (CQDs). However, developing a highly stable device while maintaining the desirable efficiency is still a challenging issue for these emerging solar cells. In this study, by introducing an ultrathin NiO nanocrystalline interlayer between Au electrodes and the hole-transport layer of the PbS-EDT, the resulting PbS CQD solar cell efficiency is improved from 9.3 to 10.4% because of the improved hole-extraction efficiency. More excitingly, the device stability is significantly enhanced owing to the passivation effect of the robust NiO nanocrystalline interlayer. The solar cells with the NiO nanocrystalline interlayer retain 95 and 97% of the initial efficiency when heated at 80 °C for 120 min and treated with oxygen plasma irradiation for 60 min, respectively. In contrast, the control devices without the NiO nanocrystalline interlayer retain only 75 and 63% of the initial efficiency under the same testing conditions.

Self-healing, adhesive conductive hydrogels are of great significance in wearable electronic devices, flexible printable electronics, and tissue engineering scaffolds. However, designing self-healing hydrogels with multifunctional properties such as high conductivity, excellent mechanical property, and high sensitivity remains a challenge. In this work, the conductive self-healing nanocomposite hydrogels based on nanoclay (laponite), multiwalled carbon nanotubes (CNTs), and N-isopropyl acrylamide are presented. The presented nanocomposite hydrogels displayed good electrical conductivity, rapid self-healing and adhesive properties, flexible and stretchable mechanical properties, and high sensitivity to near-infrared light and temperature. These excellent properties of the hydrogels are demonstrated by the three-dimensional (3D) bulky pressure-dependent device, human activity monitoring device, and 3D printed gridding scaffolds. Good cytocompatibility of the conductive hydrogels was also evaluated with L929 fibroblast cells. These nanocomposite hydrogels have great potential for applications in stimuli-responsive electrical devices, wearable electronics, and so on.

An electrolyte using 2,3,4,5,6-pentafluorophenyl methanesulfonate (PFPMS) as a versatile additive is investigated through calculating the molecular orbital energies of additives and solvents and designing the electrolyte composition, and the comparative performances of LiNi 0.5 Co 0.2 Mn 0.3 O 2 /graphite cells operating in a wide-temperature range are improved. It is revealed that PFPMS can form interfacial films on both the cathode and anode surfaces, resulting in a decrease of the cell impedance and the side reactions between the active materials and electrolyte. Compared to the cells without additive of 74.9% and those with vinylene carbonate (VC) of 76.7%, the cycling retention of the cell with 1.0 wt % PFPMS reaches 91.7% after 400 cycles at room temperature. In particular, for the high-temperature storage at 60 °C for 7 d, the cell containing 1.0 wt % PFPMS exhibits optimal capacity retention of 86.3% and capacity recovery of 90.6%; for the low-temperature discharge capacity retention at -20 °C, the cell with 1.0 wt % PFPMS maintains at 66.3% at 0.5 C, while for the cells without additive and containing 1.0 wt % VC, their retention values are 55.0 and 62.1%, respectively. The excellent cycling, wide-temperature practicability, and rate capability of the cells with PFPMS demonstrate that the electrolyte with PFPMS additive is promising for applications in LiNi 0.5 Co 0.2 Mn 0.3 O 2 /graphite batteries.

Electrohydrodynamic (EHD) printing has been recently investigated as an effective technique to produce high-resolution conductive features. Most of the existing EHD printing studies for conductive features were based on metallic nanoparticle inks in a microdripping mode, which exhibited relatively low efficiency and commonly required high-temperature annealing process to achieve high conductivity. The EHD printing of high-resolution conductive features at a relatively low temperature and in a continuous cone-jetting mode is still challenging because the conductive inks might connect the charged nozzle, and the grounded conductive or semiconductive substrates to cause discharge and terminate the printing process. In this study, the EHD printing process of conductive polymers in a low-temperature cone-jetting mode was explored to fabricate conductive microstructures. The smallest width of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) lines was 27.25 ± 3.76 μm with a nozzle diameter of 100 μm. It was interesting to find that the electrohydrodynamically printed PEDOT:PSS-PEO features exhibited unique thermal properties when a dc voltage was applied. The conductive and thermal properties of the resultant features were highly dependent on the printing layer number. Microscale PEDOT:PSS features were further encapsulated into electrospun nanofibrous mesh to form a flexible sandwich structure. The EHD printing of PEDOT:PSS features with tunable conductive and thermal properties might be useful for the applications of flexible and wearable microdevices.

High porosities, large surface areas, and tunable functionalities made metal-organic frameworks (MOFs) as effective carriers for drug delivery. One of the most promising MOFs is the zeolitic imidazolate framework (ZIF-8) crystal, an advanced functional material for small-molecule delivery, due to its high loading ability and pH-sensitive degradation. As a novel carrier, ZIF-8 nanoparticles were used in this work to control the release of an autophagy inhibitor, 3-methyladenine (3-MA), and prevent it from dissipating in a large quantity before reaching the target. The cellular uptake in HeLa cells of 3-MA encapsulated in ZIF-8 (3-MA@ZIF-8 NPs) is facilitated through the nanoparticle internalization with reference to TEM observations and the quantitative analyses of zinc by ICP-MS. The autophagy-related proteins and autophagy flux in HeLa cells treated with 3-MA@ZIF-8 NPs show that the autophagosome formation is significantly blocked, which reveals that the pH-sensitive dissociation increases the efficiency of autophagy inhibition at the equivalent concentration of 3-MA. In vivo experiments, when compared to free 3-MA, 3-MA@ZIF-8 NPs show a higher antitumor efficacy and repress the expression of autophagy-related markers, Beclin 1 and LC3. It follows that ZIF-8 is an efficient drug delivery vehicle in antitumor therapy, especially in inhibiting autophagy of cancer cells.

A facile and targeted gene delivery system was prepared by conjugating β-cyclodextrin modified polyethylenimine (PEI-CD) and adamantyl peptide (AdGRGDS) based on host-guest interaction. With the rational design between PEI-CD and AdGRGDS, the PEI-CD/AdGRGDS gene delivery system showed excellent DNA binding capability and exhibited good ability to compact DNA into uniform spherical nanoparticles. In vitro luciferase assay showed that gene expression transfected by PEI-CD/AdGRGDS was stronger than that by PEI-CD in HeLa cells, whereas gene expression transfected by PEI-CD/AdGRGDS and PEI-CD was similar to each other in COS7 cells. Internalization of complexes was qualitatively studied using a confocal laser scanning microscope (CLSM) and quantitatively analyzed by flow cytometry, respectively, and targeting specificity was also evaluated by CLSM. Results of CLSM and flow cytometry indicated that PEI-CD/AdGRGDS had good targeting specificity to tumor cells with integrin αvβ3 overexpression. To further evaluate the targeting specificity and transfection efficiency in vivo, a rat model with murine hepatic carcinoma cell line H22 was used. PEI-CD/AdGRGDS showed stronger gene expression efficiency than PEI-CD via in vivo transfection of pORF-LacZ and pGL-3 plasmids after subcutaneous injection. Interestingly, PEI-CD/AdGRGDS also showed high targeting specificity and transfection distribution to tumor xenograft after tail-vein injection. In vitro and in vivo assays highlighted the importance of GRGDS targeting specificity to tumor cells with integrin αvβ3 overexpression and demonstrated that the PEI-CD/AdGRGDS gene delivery system would have great potential for targeted tumor therapy.

Intracellularly biotriggered decomposition of gene vectors is generally thought to benefit transfection. However, the bioresponsiveness is far from satisfactory, and the exact role of biodecomposition in the transfection process remains unclear to date. To overcome the challenges, highly rapid bioresponse of vectors has to be achieved so as to greatly amplify the intracellular deviation compared with the noncontrolled pattern. To this end, a supramolecular polyrotaxane has been elaborately designed by integrating reversible dynamics of supramolecular assembly and chemically labile bonds, in order to effectively propel intracellular decomposition. Inside tumor cells, the redox-responsive bulk dissociation of the supramolecular vector readily took place and was further accelerated by the lysosomal-acidity-triggered terminal decomposition. Both the in vitro and in vivo experiments have demonstrated that this supramolecule could mediate considerably more rapid gene accumulation in nuclei than the nonresponsive controls including PEI25K, the gold standard of nonviral vectors. Along with the structural decomposition, the supramolecule simultaneously underwent the transition of fluorescence quenching, favoring the evaluation over the bioresponsiveness inside cells. Based on the resulting data, it is suggested that the biotriggered volume expansion of supramolecule/DNA complexes may be the major factor accounting for that dramatically accelerated transnuclear gene transport during cellular mitosis, thus affecting the transfection. This study offers an understanding of the intracellular gene transport from a new viewpoint.

Activatable photosensitizers (aPSs) have emerged as promising photodynamic therapy (PDT) agents for simultaneous imaging and selective ablation of cancer. However, traditional synthetic aPSs are limited by complex design and tedious synthesis. Here, aPS regulated by cucurbit[8]uril (CB[8]) for targeted cancer imaging and PDT is reported. This system is based on the host-guest interaction between biotinylated toluidine blue (TB-B) and CB[8] to form 2TB-B@CB[8]. Moreover, a facile strategy to turn off/on the fluorescence and photodynamic activity of TB-B is developed through the reversible assembly/disassembly of 2TB-B@CB[8]. This established system can achieve selective accumulation in tumor, light-up cancer imaging, and enhanced anticancer behavior. Therefore, this work provides a novel and promising strategy for the aPS build via simple and facile regulation of supramolecular chemistry.

Vasoactive intestinal peptide (VIP) was reported to promote angiogenesis. Electrospun nanofibers lead to idea wound dressing substrates. Here we report a convenient and novel method to produce VIP loaded microspheres in polycaprolactone (PCL) nanofibrous membrane without complicated processes. We first coated mussel-inspired dopamine (DA) to nanofibers, then used strong adhesive DA to absorb the functional peptide. PCL membrane was then immersed into acetone to generate microspheres with VIP loading. We employed high pressure liquid chromatography to record encapsulation efficiency of (31.8 ± 2.2)% and loading capacity of (1.71 ± 0.16)%. The release profile of VIP from nanosheets showed a prolonged release. The results of laser scanning confocal microscope, scanning electron microscope and cell counting kit-8 proliferation assays showed that cell adhesion and proliferation were promoted. In order to verify the efficacy on wound healing, in vivo implantation was applied in the full-thickness defect wounds of BALB/c mice. Results showed that the wound healing was significantly promoted via favoring the growth of granulation tissue and angiogenesis. However, we found wound re-epithelialization was not significantly improved. The resulting VIP-DA-coated PCL (PCL-DA-VIP) nanosheets with spatiotemporal delivery of VIP could be a potential application in wound treatment and vascular tissue engineering.

Titanium dioxide and Nb-doped titanium dioxide microspheres with the same size were fabricated by a simple sol-gel method, and the formation mechanism of Nb-doped titanium dioxide microspheres was proposed. Titanium dioxide and Nb-doped titanium dioxide microspheres were adopted as dispersed materials for electrorheological (ER) fluids to investigate the influence of the charge increase introduced by Nb doping on the ER activity. The results showed that Nb doping could effectively enhance the ER performance. Combining with the analysis of dielectric spectroscopy, it was found that the interface polarization of Nb-doped TiO2 ER fluid was larger than that of TiO2 ER fluid, which might be caused by more surface charges in Nb-TiO2 microspheres due to Nb(5+) doping and resulting in enhancement of electric field force and strengthening of fibrous structure. In addition, by comparing and analyzing the permittivity curves of Nb-TiO2/LDPE solid composite and Nb-TiO2/silicone-oil fluid composite, it could be concluded that the enhancement of permittivity at low frequency resulted from the increase of the order degree of dispersed particles in ER fluid rather than from the quasi-dc (QDC) behavior. Moreover, the absolute value of slope of permittivity curves (K) at 0.01 Hz could be utilized as the standard for judging the ability to maintain the chainlike structure. The relationships between polarizability of dispersed particles, dielectric spectrum, parameter K, and ER properties were discussed in detail.

On the basis of host-guest interactions, this study reported a kind of linear-hyperbranched supramolecular amphiphile and its assembled vesicles for the combined achievement of drug encapsulation and DNA delivery. Amine-attached β-cyclodextrin-centered hyperbranched polyglycerol and linear adamantane-terminated octadecane were arranged to spontaneously interlink together and then self-assemble into nanoscale vesicles. As the model of a hydrophilic agent, DOX·HCl was demonstrated to be readily loaded into the hollow cavity of the vesicles. The drug release pattern could be controlled by adjusting the environmental acidity, favoring the intracellularly fast drug liberation in response to the cellular lysosomal microenvironment. The nanovesicles displayed superior serum-tolerant transgene ability and significantly lower cytotoxicity compared to those of PEI25K, the gold standard of gene delivery vectors. The drug-loaded nanovesicle can co-deliver DNA payloads into cells and allow the preferable accumulation of two payloads in nuclei. The drug encapsulation was found to have little influence on the transfection. This co-delivery vehicle presents a good example of rational design of cationic supramolecular vesicles for stimulus-responsive drug/DNA transport.

A versatile gold nanoparticle-based multifunctional nanocomposite AuNP@CD-AD-DOX/RGD was constructed flexibly via host-guest interaction for targeted cancer chemotherapy. The pH-sensitive anticancer prodrug AD-Hyd-DOX and the cancer-targeted peptide AD-PEG8-GRGDS were modified on the surface of AuNP@CD simultaneously, which endowed the resultant nanocomposite with the capability to selectively eliminate cancer cells. In vitro studies indicated that the AuNP@CD-AD-DOX/RGD nanocomposite was preferentially uptaken by cancer cells via receptor-mediated endocytosis. Subsequently, anticancer drug DOX was released rapidly upon the intracellular trigger of the acid microenvirenment of endo/lysosomes, inducing apoptosis in cancer cells. As the ideal drug nanocarrier, the multifunctional gold nanoparticles with the active targeting and controllable intracellular release ability hold the great potential in cancer therapy.

In this paper, an activable cell-penetrating peptide (CR8G3PK6, ACPP) with a shielding group of 2,3-dimethylmaleic anhydride (DMA) was conjugated with antitumor drug doxorubicin (DOX) to construct a novel prodrug (DOX-ACPP-DMA) for tumor targeted drug delivery. The shielding group of DMA linked to the primary amines of K6 through the amide bond was used to block the cell-penetrating function of the polycationic CPP (R8) through intramolecular electrostatic attraction at physiological pH 7.4. At tumor extracellular pH 6.8, the hydrolysis of DMA led to charge reversal, activating the pristine function of CPP for improved cellular uptake by tumor cells. Confocal laser scanning microscopy (CLSM) and flow cytometry studies revealed that the cellular uptake of DOX-ACPP-DMA was significantly enhanced after acid-triggered activation in both HeLa and COS7 cells. After cell internalization, the overexpressed intracellular proteases would further trigger drug release in cells. Both in vitro and in vivo investigations showed that the peptidic prodrug exhibited significant tumor growth inhibition and demonstrated great potential for tumor therapy.

In this paper, a novel stepwise-acid-active multifunctional mesoporous silica nanoparticle (MSN-(SA)TAT&(DMA)K11) was developed as a drug carrier. The MSN-(SA)TAT&(DMA)K11 is able to reverse its surface charge from negative to positive in the mildly acidic tumor extracellular environment. Then, the fast endo/lysosomal escape and subsequent nucleus targeting as well as intranuclear drug release can be realized after cellular internalization. Because of the difference in acidity between the tumor extracellular environment and that of endo/lysosomes, this multifunctional MSN-(SA)TAT&(DMA)K11 exhibits a stepwise-acid-active drug delivery with a tumor-specific nucleus-targeted property.

Supramolecular microcapsules (SMCs) with the drug-loaded wall layers for pH-controlled drug delivery were designed and prepared. By using layer-by-layer (LbL) technique, the SMCs were constructed based on the self-assembly between polyaldenhyde dextran-graft-adamantane (PAD-g-AD) and carboxymethyl dextran-graft-β-CD (CMD-g-β-CD) on CaCO(3) particles via host-guest interaction. Simultaneously, adamantine-modified doxorubicin (AD-Dox) was also loaded on the LbL wall via host-guest interaction. The in vitro drug release study was carried out at different pHs. Because the AD groups were linked with PAD (PAD-g-AD) or Dox (AD-Dox) by pH-cleavable hydrazone bonds, AD moieties can be removed under the weak acidic condition, leading to destruction of SMCs and release of Dox. The pH-controlled drug release can enhance the uptake by tumor cells and thus achieve improved cancer therapy efficiency.