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Photothermal therapy (PTT) based on semiconducting polymer nanoparticles (SPNs) is a promising strategy to treat solid tumors, but its ability to combine with chemotherapy for immune remodeling to efficiently suppress metastatic cancers has rarely been studied. Here, we demonstrate that PTT combined with chemotherapy can efficiently elicit immunity to suppress metastatic tumor growth. Specifically, we rationally designed a new SPN (PDPSe NPs) as a photothermal agent for PTT with a large mass extinction coefficient in the near-infrared region (e.g., 44.9 L g -1 cm -1 at 808 nm), high photothermal conversion efficiency (62.5%) and excellent biocompatibility. A hypoxia-activated anti-tumor drug, tirapazamine (TPZ), was selected for chemotherapy. Strikingly, the combination therapy not only induced tumor cell death in the primary tumor, but also effectively suppressed the growth of distant tumors (mimicking metastatic tumors) without PTT. Importantly, the combined therapies exhibit synergistic effects on immune remodeling. Immunofluorescence data suggest that the inhibition of metastatic tumor growth is attributed to the immune remodeling triggered by PTT and chemotherapy. This work demonstrates a new paradigm of utilizing PTT together with hypoxia-activated drugs to effectively retard metastatic tumor growth.

Photoacoustic (PA) imaging in the second near-infrared (NIR-II) window (especially at 1064 nm) has the benefits of low background signal, high spatial resolution and deep tissue penetration. Here we report a semiconducting polymer nanoparticle (PDPPTBZ NP) and demonstrate its potential as a contrast agent for PA imaging of orthotopic brain tumors, using a 1064 nm pulsed laser as a light source. PDPPTBZ NPs have maximum absorption at 1064 nm with a mass extinction coefficient of 43 mL mg-1 cm-1, which is the highest value reported so far in this region. The high photothermal conversion efficiency (67%) and near non-fluorescence impart PDPPTBZ NPs with excellent PA properties. We used PDPPTBZ NP-containing agar gel phantoms even at a low concentration (50 μg mL-1) to successfully image to a depth of 4 cm (of chicken-breast tissue), with an ultralow power fluence (4 mJ cm-2). Furthermore, we could clearly visualize a glioma tumor in a mouse at a depth of 3.8 mm below the skull. This study demonstrates that PDPPTBZ NPs display great potential as a NIR-II PA contrast agent for high quality deep tissue imaging.

Bacterial infections are problematic in many healthcare-associated devices. Antibacterial surfaces integrating the strength of bacteria repellent and bactericidal functions exhibit an encouraging efficacy in tackling this problem. Herein, a hierarchical dual-function antibacterial polymer brush coating that integrates an antifouling bottom layer with a bactericidal top layer is facilely constructed via living photograft polymerization. Excellent resistance to bacterial attachment is correlated with the antifouling components, and good bactericidal activity is afforded by the bactericidal components, and therefore the hierarchical coating shows an excellent long-term antibacterial capability. In addition, due to the presence of the hydrophilic background layer, the hierarchical surface has the greatly improved biocompatibility, as shown by the suppression of platelet adhesion and activation, the inhibition of erythrocyte adhesion and damage, and low toxicity against mammalian cells. The hierarchical polymer brush system provides the basis for the development of long-term antibacterial and biocompatible surfaces., (Copyright © 2016. Published by Elsevier B.V.)

Although polycationic surfaces have high antimicrobial efficacies, they suffer from high toxicity to mammalian cells and severe surface accumulation of dead bacteria. For the first time, we propose a surface-initiated photoiniferter-mediated polymerization (SI-PIMP) strategy of constructing a "cleaning" zwitterionic outer layer on a polycationic bactericidal background layer to physically hinder the availability of polycationic moieties for mammalian cells in aqueous service. In dry conditions, the polycationic layer exerts the contact-active bactericidal property toward the adherent bacteria, as the zwitterionic layer collapses. In aqueous environment, the zwitterionic layer forms a hydration layer to significantly inhibit the attachment of planktonic bacteria and the accumulation of dead bacteria, while the polycationic layer kills bacteria occasionally deposited on the surface, thus preserving the antibacterial capability for a long period. More importantly, the zwitterionic hydrated layer protects the mammalian cells from toxicity induced by the bactericidal background layer, and therefore hierarchical antibacterial surfaces present much better biocompatibility than that of the naked cationic references. The dominant antibacterial mechanism of the hierarchical surfaces can switch from the bactericidal efficacy in dry storage to the bacteria repellent capability in aqueous service, showing great advantages in the infection-resistant applications.

Recently, self‐healing polymers have been one of the most intriguing academic fields due to the fact that they can increase their service lives and reduce the amount of waste. Here we designed and synthesized a novel telechelic polyurethane with dopamine (DA) end groups that are coordinated with Ca2+ to form dynamic non‐covalent bonds. The tensile stress of the designed polyurethanes increases with increase in the amount of metal cation added, while the strain at break slightly decreases. Rheological tests show that the ionic coordination between Ca2+ and catechol can dynamically break and recombine under the stimulation of seawater, endowing the polymer with superior self‐healing properties (up to 84% based on toughness). Therefore, the seawater‐triggered self‐healable, super tough polyurethane presented here is very intriguing as it has many potential applications especially in the marine environment. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Polyurethane elastomers (PUEs) based on 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO) and two kinds of aliphatic polycaprolactone (PCL) diols with molecular weight of 1000 Da and 2000 Da have been synthesized and melt-blended with polycarbonate (PC). The compatibility of PC and PUEs was investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The results indicated that the glass transition temperature ( T g) of PC decreased by 0-40°C when 0-10 wt % of PUEs incorporated into the PC matrix. Phase separation in the blends was not detected by means of DSC characterization, but measurements of DMA and SEM indicated that phase separation existed in the blends of PC and PUEs synthesized with 1000 Da PCL-diol. As for PUEs/PC blend in which 2000 Da PCL-diol as PUEs' soft segments, it turned from completely compatible to partially when the NCO/OH ratio for the PUEs prepolymer was increased from 2 : 1 to 4 : 1. The compatibilities of PC and PUEs were greatly influenced by the molecular weight of polyols and the ratio of NCO/OH in the PUE prepolymer, higher molecular weight of polyols and lower NCO/OH ratio resulted in better compatibility. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

The article presents a study on the crystallization behavior and mechanical properties of the crosslinked plasticized poly(L-lactic acid) or PLLA. The study used differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM) and tensile tests. Results indicated that the crystallization behaviors of both poly(ethylene glycol) or PEG and PLLA in the blends were restrained after irradiation.

We developed a polyurethane material has an excellent self-healing ability as well as mechanical strength. This system was achieved based on dual-crosslinked Diels-Alder (DA) covalent bonding reaction. The first cross-linking point is realized by the DA bonding of polyurethane chain. Because of grafted maleimide group, the maleimide functionalized GO (mGO) sheets can be regarded as analogous cross-linker and provide the second cross-linking point in the system. We investigated and compared the effects of as-produced GO and mGO loading and maleimide functionalization on the mechanical properties and healing efficiency of composites. As a result, compared with those of the pure polyurethane and composites filled with the GO, such maleimide functionalization is found to effectively improve the compatibility between mGO and polymer matrix, increasing mechanical properties and healing efficiency of polyurethane composites. The mechanical properties and healing efficiency of polyurethane can be tuned readily by varying mGO concentration. The healing efficiencies were up to 99% for the nanocomposite containing mGO. These results confirm maleimide functionalization improved dispersion and interfacial interaction between the fillers and the polyurethane matrix. [ABSTRACT FROM AUTHOR]

Abstract: We firstly synthesized and characterized a series of functional carboxylated polyvinylidene fluoride (PVDF-g-AAc). Then the temporal change of the complex viscosity (η*) of the two plates consisting of the graft polymer PVDF-g-AAc and polyamide 6 (PA6) was measured by a rotational rheometer. There were two distinct stages for the change of the complex viscosity (η*) with time: (i) stage I, where η* increased rapidly at short times, a reaction-controlled kinetics was induced; (ii) stage II, where η* increased slowly at a long time, however, a diffusion-controlled kinetics was obtained. Despite whether the kinetics are reaction-controlled or diffusion-controlled, the reaction could be predicted by pseudo-first-order kinetics. Meanwhile, the reaction temperature had an effect on the interfacial width and roughness. The value of the interfacial root-mean-square (rms) roughness obtained from AFM was consistent with that of the interfacial width from ellipsometer at different temperatures. [Copyright &y& Elsevier]

We report a simple method to directly pattern polymer-based photo luminescent material, i.e. a prepatterned mask is placed a close distance above it. The final structure is a positive replica of the lateral structures in the mask with submicrometer resolution. The comparison of luminescence efficiency before and after patterning indicates almost no degradation in optical property of the material during the experiments. The mechanism of pattern formation is also discussed. [Copyright &y& Elsevier]

Regular micrometer-size porous polystyrene film is prepared by water droplet templating, i.e. breath figures are stabilized by the polymer in solution and thermocapillary flow arranges them into ordered packing. The influences of polystyrene molecular weight, solvent properties, and the relative humidity of atmosphere on the pattern formation and hole sizes are investigated. Two different kinds of hole packing fashion are also observed and their formation mechanisms are discussed. [Copyright &y& Elsevier]

This paper presents a straightforward method for patterning thin films of polymers, i.e. a prepatterned mask is used to induce self-assembly of polymers and the resulting pattern is the same as the lateral structures in the mask on a submicrometre length scale. The patterns can be formed at above Tg+30 °C in a short time and the external electric field is not crucial. Electrostatic force is assumed to be the driving force for the pattern transfer. Viscous fingering and novel stress-relief lateral morphology induced under the featureless mask are also observed and the formation mechanisms are discussed. [Copyright &y& Elsevier]

Highly ordered honeycomb-like macroporous films were obtained via self-assembly of a two-armed polymer with a crown ether core under controlled conditions. A possible mechanism is speculated, primarily based on the strong affinity between the crown ether cores. The pore size and arrangement are sensitive to the solvent evaporation rate and the solution concentration. Upon spontaneous drying, the pore diameter (D) depends on the concentration (c) by a relation of D=518c-0.610. [Copyright &y& Elsevier]