Theoretical exploration of the stabilities and detonation parameters of nitro-substituted 1H-benzotriazole.

CONTEXT: The nitro group was introduced into the nitrogen heterocycle of 1H-benzotriazole to design a total of 31 derivatives. To estimate the thermal stability of these derivatives, the heat of formation (HOF) is calculated based on the isodesmic reaction. The bond dissociation energy (BDE) was also predicted based on the homolytic reaction to further evaluate the dynamic stability. To evaluate the possibility of utilizing as high energy density compounds (HEDCs), the detonation parameters including the detonation pressure (P), detonation velocity (D), and explosive heat (Q) are predicted by taking advantage of the Kamlet-Jacobs empirical equation. To measure the sensitivity to impact, both the characteristic height (H50) and free space in crystal (∆V) are considered in this paper. Based on our calculations, D-series and E are found to be the candidates for HEDCs. METHODS: The Gaussian 09 software package was used in this paper. The B3PW91 hybrid function with the 6-311 + G(d,p) basis set was chosen to perform the structural optimization, frequency analysis, heat of formation, and bond dissociation energy. The detonation parameters were calculated following the Kamlet-Jacobs equation.

Adhesive polydopamine-based photothermal hybrid hydrogel for on-demand lidocaine delivery, effective anti-bacteria, and prolonged local long-lasting analgesia.

Considering the astonishing prevalence of localized pain affecting billions of patients worldwide, the development of advanced analgesic formulations or delivery systems to achieve clinical applicability is of great significance. In this study, an integrated PDA-based LiH@PDA@Ag@PAA@Gelatin system was designed for sustained delivery of lidocaine hydrochloride (LiH). By optimizing the preparation process and formulation of the hydrogel, the hydrogel exhibited superior mechanical properties, reversibility, adhesion strength, and self-healing attributes. Moreover, PDA@Ag nanoparticles were evenly dispersed within the hydrogel, and the optimized PDA@Ag@PAA@Gelatin showed a higher photothermal conversion efficiency than that of pure PDA. Importantly, LiH@PDA@Ag@PAA@Gelatin could effectively capture and eradicate bacteria through the synergistic interaction between near-infrared (NIR), PDA, Ag and LiH. In vitro and in vivo tests demonstrated that LiH@PDA@Ag@PAA@Gelatin exhibited higher drug delivery efficiency compared to commercial lidocaine patches. By evaluating the mechanical pain withdrawal threshold of the spared nerve injury (SNI) model in rats, it was proven that LiH@PDA@Ag@PAA@Gelatin enhanced and prolonged the analgesic effect of LiH. Furthermore, LiH@PDA@Ag@PAA@Gelatin induced by NIR possessed excellent on-demand photothermal analgesic ability. Therefore, this study develops a convenient method for preparing localized analgesic hydrogel patches, providing an important step towards advancing PDA-based on-demand pain relief applications.

Construction and mechanism study of lignin-based polyurethane with high strength and high self-healing properties.

Lignin is a natural polymer with abundant functional groups with great application prospects in lignin-based polyurethane elastomers with self-healing abilities. In this study, a lignin self-healing polyurethane (PUDA-L) was specially designed using lignin as the raw material of polyurethane, combining lignin with Diels-Alder (DA) bond and hydrogen bonds. The experimental results showed that PUDA-L was prepared with good thermal stability, fatigue resistance, shape memory effect, excellent mechanical strength, and self-healing ability by partially replacing the crosslinking agents with bio-based lignin and hydroxylated modified lignin to increase the hydroxyl content. Polyurethane has a tensile strength of up to 29 MPa and an elongation at break of up to 500 %. The excellent self-healing ability of PUDA-L originates from the internal DA bonds and cross-linked hydrogen bonds. After the dumbbell sample was fused and heated at 130 °C for 4 h, the elastomer could be completely healed, the tensile strength was restored to 29 MPa, and the self-healing efficiency was up to 100 %. The developed PUDA-L elastomer has promising applications in sensors and smart skins.

A Study of the Phosphorylcholine Polymer Coating of a Polymethylpentene Hollow Fiber Membrane.

A phosphorylcholine polymer (poly(MPC-co-BMA-co-TSMA), PMBT) was prepared by free radical polymerization and coated on the surface of the polymethylpentene hollow fiber membrane (PMP-HFM). ATR-FTIR and SEM analyses showed that the PMBT polymer containing phosphorylcholine groups was uniformly coated on the surface of the PMP-HFM. Thermogravimetric analysis showed that the PMBT had the best stability when the molar percentage of MPC monomer in the polymer was 35%. The swelling test and static contact angle test indicated that the coating had excellent hydrophilic properties. The fluorescence test results showed that the coating could resist dissolution with 90% (v/v%) ethanol solution and 1% (w/v%) SDS solution. The PMBT coating was shown to be able to decrease platelet adherence to the surface of the hollow fiber membrane, and lower the risk of blood clotting; it had good blood compatibility in tests of whole blood contact and platelet adhesion. These results show that the PMBT polymer may be coated on the surface of the PMP-HFM, and is helpful for improving the blood compatibility of membrane oxygenation.

Portable Comestible-Liquid Quality Test Enabled by Stretchable and Reusable Ion-Detection Photonic Papers.

Currently, there have been widespread investigation conducted into responsive photonic crystal hydrogels (RPCHs) characterized by high selectivity and sensitivity for colorimetric indicators and physical/chemical sensors. In spite of this, it remains challenging to use RPCHs for sensing due to their limited mechanical property and molding capability. In the present study, a double-network structure is proposed to design highly stretchable, sensitive, and reusable ion-detection photonic papers (IDPPs) for assessing the quality of visual and portable comestible liquids (e.g., soy sauce). It is constructed by integrating polyacrylamide and poly-methacryloxyethyl trimethyl ammonium chloride with highly ordered polystyrene microspheres. The double-network structure improves the mechanical properties of IDPPs with their elongation at break increasing from 110 to 1600%. Meanwhile, the optical properties of photonic crystals are retained. The IDPPs achieve a fast ion response by applying control on the swelling behavior of the hydration radius of the counter ions through ion exchange. Given a certain concentration range (0.01-0.10 M), chloride ions can be detected fast (3-30 s) by exchanging ions with a small hydration radius through an IDPP, which is clearly observable. Due to the improvement of mechanical properties and the reversible exchange of ions derived from IDPPs, their reusability is significantly enhanced (>30 times). Characterized by a simple operation, high durability, and excellent sustainability, these IDPPs are promising for practical application in food security and human health assessment.

Mesoscopic Simulations of Diselenide-Containing Crosslinked Doxorubicin-Loaded Micelles and Their Tumor Microenvironment Responsive Release Behaviors.

There is currently limited research on the structure-property relationship of reduction stimuli-responsive polymeric crosslinked micelles using mesoscopic simulations. Herein, dissipative particle dynamics (DPD) simulations were used to simulate the self-assembly process of the blank non-crosslinked micelle, the structure and doxorubicin (DOX) distribution of diselenide crosslinked micelle with different crosslinker contents (CCs) based on the nearest-neighbor bonding principle. The results revealed that the formation of a three-layer spherical micelle and the loaded DOX mainly distributed in the polycaprolactone (PCL) core and hydroxyethyl methacrylate (HEMA) mesosphere. The larger the dosage of DOX, the more DOX encapsulated, but the encapsulation of DOX in the hydrophobic domain would reach saturation when the dosage increased to 6.0 %. In micelles with lower CCs or crosslinking levels (CLs), DOX entered the middle layer and the inner core faster. Then, based on the nearest media-bead bond breaking principle and subsequently DPD simulation, the effects of different CCs on the micelle structure and DOX release properties were investigated. Low CC could cause fast drug release. With the increase of CCs, the micelle showed a slower DOX release trend. The multilayer crosslinked network system also affected the DOX release rate. Hence, this work can provide some mesoscale guidance for the structural design and structure-property relationship of stimuli-responsive reversible crosslinked micelles for drug delivery.

Photoreversible Bond-Based Shape Memory Polyurethanes with Light-Induced Self-Healing, Recyclability, and 3D Fluorescence Encryption.

Developing a shape memory polyurethane with high mechanical properties, excellent self-healing has become a huge challenge for the development of smart materials. Herein, we report the design and fabrication of a shape memory polyurethane network terminated with coumarin units (HEOMC-PU) to address this conundrum. The synthesized HEOMC-PU exhibits exceptional mechanical performance with a breaking elongation of 746% and toughness of 55.5 MJ·m-3. By utilizing the dynamically reversible behavior of coumarin units to repair the damaged network, the efficient self-healing performance (99.2%) of HEOMC-PU is obtained. In addition, the prepared network and light-induced dynamic reversibility endow the HEOMC-PU with both liquid-state remoldability and solid-state plasticity, respectively, enabling polyurethane to be recycled and processed multiple times. Furthermore, based on the fluorescence responsive characteristic of coumarin, HEOMC-PU with a fluorescent pattern can be deformed into specific three-dimensional configurations by combining photolithography, self-healing, and the shape memory effect. Such a multilevel and multidimensional anti-counterfeiting platform with rewritable fluorescent patterns and reconfigurable shapes can open up a new encryption approach for future intelligent anti-counterfeiting.

Unclonable Photonic Crystal Hydrogels with Controllable Encoding Capacity for Anticounterfeiting.

Inspired by the formation of random sparkling microcrystallines in naturally precious opals, we develop a new strategy to produce a class of unclonable photonic crystal hydrogels (UPCHs) induced by the electrostatic interaction effect, which further achieve unclonable encoding/decoding and random high-encrypted patterns along with an ultrahigh and controllable encoding capacity up to ca. 2 × 10166055. Owing to the randomness of colloidal crystals in the self-assembly process, UPCHs with randomly distributed sparkling spots are endowed with unpredictable/unrepeatable characteristics. This, coupled with the water response of UPCHs with angle dependence and robustness, can upgrade the encryption level and address some limitations of easy fading, limited durability, and high cost in practical uses of existing unclonable materials. Interestingly, UPCHs can be readily patterned to exhibit reliable and rapid authentication by utilizing artificial intelligence (AI) deep learning, which can find broad applications in developing unbreakable and portable information storage/steganography systems not limited to anticounterfeiting.

Fabrication of Au Nanoparticle Arrays on Flexible Substrate for Tunable Localized Surface Plasmon Resonance.

In this work, Au nanoparticle (AuNP) arrays on shape memory polyurethane (SMPU) substrates serve as flexible materials for tunable localized surface plasmon resonance (LSPR). AuNP arrays prepared by diblock copolymer self-assembly are transferred from rigid silicon wafers onto flexible SMPU substrates with ultrasonic treatment rather than peeling off directly. The resultant AuNP array SMPU films have excellent mechanical properties and stable thermodynamic properties. The LSPR arising from AuNP arrays is increased by negative bending on SMPU substrates, whereas the LSPR is decreased by positive bending. Besides, upon uniaxial tension, the vertical LSPR is increased first then decreased, whereas the parallel LSPR is similar, resulting in the overall LSPR of AuNP arrays being increased first and then decreased with the mechanical uniaxial tension of SMPU. Moreover, the resultant AuNP array SMPU films exhibit excellent flexibility, stability, and homogeneity in practical surface-enhanced Raman scattering (SERS) application. This approach of incorporating AuNP arrays on SMPU substrates for tuning plasmonic properties have great potential applications in SERS, fluorescence enhancement, and newly optoelectronic materials.

pH/Reduction Dual-Stimuli-Responsive Cross-Linked Micelles Based on Multi-Functional Amphiphilic Star Copolymer: Synthesis and Controlled Anti-Cancer Drug Release.

Novel approach has been constructed for preparing the amphiphilic star copolymer pH/reduction stimuli-responsive cross-linked micelles (SCMs) as a smart drug delivery system for the well-controlled anti-tumor drug doxorubicin (DOX) release. The SCMs had a low CMC value of 5.3 mg/L. The blank and DOX-loaded SCMs both had a spherical shape with sizes around 100-180 nm. In addition, the good stability and well pH/reduction-sensitivity of the SCMs were determined by dynamic light scattering (DLS) as well. The SCMs owned a low release of DOX in bloodstream and normal tissues while it had a fast release in tumor higher glutathione (GSH) concentration and/or lower pH value conditions, which demonstrates their pH/reduction dual-responsiveness. Furthermore, we conducted the thermodynamic analysis to study the interactions between the DOX and polymer micelles in the DOX release process. The values of the thermodynamic parameters at pH 7.4 and at pH 5.0 conditions indicated that the DOX release was endothermic and controlled mainly by the forces of an electrostatic interaction. At pH 5.0 with 10 mM GSH condition, electrostatic interaction, chemical bond, and hydrophobic interactions contributed together on DOX release. With the low cytotoxicity of blank SCMs and well cytotoxicity of DOX-loaded SCMs, the results indicated that the SCMs could form a smart cancer microenvironment-responsive drug delivery system. The release kinetic and thermodynamic analysis offer a theoretical foundation for the interaction between drug molecules and polymer matrices, which helps provide a roadmap for the oriented design and control of anti-cancer drug release for cancer therapy.

Flexible and Superhydrophobic Silver Nanoparticles Decorated Aligned Silver Nanowires Films as Surface-Enhanced Raman Scattering Substrates.

Flexible and superhydrophobic silver nanoparticles decorated aligned silver nanowires (AgNWs@AgNPs) films were employed as efficient surface-enhanced Raman scattering (SERS) substrates to investigate the SERS properties of the Rhodamine B (RB). Aligned silver nanowires were fabricated via interface self-assembly technique and incorporated into shape memory polyurethane (SMPU) by hot-press method, which not only endow the composites with ordered array characteristics but also flexibility due to the presence of polymer. After an electrochemical deposition combined with a galvanic reaction, AgNWs@AgNPs was obtained. At last, the substrate was functioned with perfluorodecanethiol (PFDT), and the target flexible and superhydrophobic silver nanoparticles decorated aligned silver nanowires substrate was obtained. The substrate confines water droplet in a small area, and the analytes were enriched owing to the concentrating effect. The SERS assay using the as-synthesized flexible and superhydrophobic silver films as substrates can detect Rhodamine B as low as10-10 M. The mechanism is thought to relate to the formation of robust superhydrophobic film, which is based on micro- and nanoscaled hierarchical structure provided by the AgNWs@AgNPs layer, strong adhesion between the SMPU film and the AgNWs@AgNPs layer, and the low surface energy molecule adsorption on the silver surface. The combined superhydrophobic and flexible properties endow the SERS substrate with improved detection limit for practical SERS applications.

Facile In Situ Preparation and In Vitro Antibacterial Activity of PDMAEMA-Based Silver-Bearing Copolymer Micelles.

Well-defined polymer micelles with core-shell structure are good delivery platform for stabilizing silver nanoparticles (AgNPs) in the field of antimicrobials targeting diseases. The rational construction of the polymer structure, an efficient, facile, and green preparation approach, and comprehensive exploration of the derived AgNPs are necessary, such as size, particle stability, antibacterial activity, and other properties. Herein, we designed and assessed the in vitro antimicrobial activity of AgNPs-decorated copolymer micelles with different copolymer topologies. First, linear or four-arm star triblock copolymers with the similar molecular weight and degree of polymerization were obtained, which consisted of DMAEMA for in situ reduction of silver ions to form AgNPs without external reducing agent. HEMA and PEGMA in micellar shell gave an enhanced stability of AgNPs during blood circulation. The combination of computational modeling and experimental results indicated that both types of micelles could fabricate AgNPs with monodisperse and spherical morphology. Star copolymer micelles stabilized AgNPs had smaller average size, better stability, and higher antibacterial activity than those with linear structure, which may due to higher stability of micelles from star copolymers. Furthermore, the cytotoxicity evaluation test showed that the achieved linear or star copolymers micelles stabilized AgNPs had good biocompatibility. This work provides a facile and universal approach in the rational design of micelles stabilized AgNPs with suitable topology for fighting against a wide range of bacterial infections.

Mesoscopic simulations of drug-loaded diselenide crosslinked micelles: Stability, drug loading and release properties.

Intelligent reversible crosslinked micelles that have a good balance of structure stability in normal tissue and controlled drug release responded to the tumor microenvironment are highly promising novel drug delivery systems. However, to date, there have been very few reports about mesoscale simulations of drug-loaded polymeric reversible crosslinked micelles. Here, dissipative particle dynamics (DPD) simulation, the nearest-neighbor bonding principle, and the nearest media-bead bond breaking principle were used to investigate the influence of physiological environment along with low tumor pH and reduction microenvironment on the stability and doxorubicin (DOX) distribution of the star polymer [PCL-b-P(HEMA-Se-Se˜)-b-PPEGMA]6 diselenide crosslinked micelles with different diselenide crosslinking levels (CLs). The self-assembly process results obtained by DPD simulations reveal the formation of three-layer spherical micelles with the loaded DOX mainly distributed at the interfacial regions of the inner PCL core and middle HEMA layer. The structural stability and DOX loading capacity of the micelles can be improved by appropriately increasing the CL based on the nearest-neighbor bonding principle due to the effect of the pressure exerted by the crosslink that squeezes the loaded drugs from the intermediate and interfacial layers into the micelle core. Furthermore, the effect of breaking of the diselenide bond on the drug release properties was investigated through the use of the nearest media-bead bond breaking principle. A low CL gives rise to intense drug release, increasing the toxic side effects on the system. With the increase in the CL, the micelles show the transformation from local crosslinking to compact crosslinking, leading to slower drug release. Therefore, this work can provide some guidance on the mesoscale for the structural design and controlled construction of reversible crosslinked micelles for smart drug delivery systems.

Controlled construction of gold nanoparticles in situ from ß-cyclodextrin based unimolecular micelles for in vitro computed tomography imaging.

The development of nanomaterials as highly efficient contrast agents for tumor computed tomography (CT) imaging still remains a huge challenge. In this study, a novel and facile approach to fabricate unimolecular micelles-stablized gold nanoparticles (AuNPs) without external reductant for in vitro targeted CT imaging was described. Amphiphilic 21-arm star-like polymers ß-cyclodextrin-g-{poly(2-(dimethylamino)ethyl methacrylate)-poly(2-hydroxyethyl methacrylate)-poly[poly(ethylene glycol) methyl ether methacrylate]} [ß-CD-g-(PDMA-b-PHEMA-b-PPEGMA)] was firstly synthesized and proved to form unimolecular core-middle layer-shell-type micelles in water through experimental and computer simulation results. Taking advantage of the reducing groups of PDMA block, AuNPs were decorated in the micellar PDMA block because of the in situ reduction of gold ions, which were absorbed by the PDMA chains in the core layer with a narrow nanoparticle size distribution. This strategy could prevent aggregation of AuNPs, which were capable of being employing as a highly effective probe for specific CT imaging in vitro. Importantly, the ß-CD-g-(PDMA-b-PHEMA-b-PPEGMA)/AuNPs incubated with HepG2 cells, displayed more intense X-ray attenuation property (>37%) than conventional iodine-based CT imaging agent (Omnipaque) and also possessed a satisfying cytocompatibility in the given concentration range. The facile fabrication procedures and the efficiency of CT imaging render the novel hybrid unimolecular micelles to become potent candidates for applications in tumor-targeted CT imaging.

Aligned Chemically Etched Silver Nanowire Monolayer as Surface-Enhanced Raman Scattering Substrates.

Silver nanowires (AgNWs) were chemically etched to significantly increase the surface roughness and then self-assembled on the liquid/gas interfaces via the interfacial assembly method to obtain aligned chemically etched silver nanowire films. The as-fabricated silver nanowire films were used as novel surface-enhanced Raman scattering (SERS) substrates. The morphologies and plasmon characteristics of the substrates were investigated using multiple measurement methods. The performance of as-fabricated substrates was measured using rhodamine B as a probe. The detection limitation can be as low as 10-11 M. The greatly improved plasmonic properties are attributed to the efficient light coupling and larger electromagnetic field enhancement. The novel set of SERS substrates of aligned chemically etched AgNWs is believed to be important for efficient, homogeneous, and ultrasensitive SERS sensing applications.

Fabrication of Ordered Nanopattern by using ABC Triblock Copolymer with Salt in Toluene.

Ordered nanopatterns of triblock copolymer polystyrene-block-poly(2-vinylpyridine)-block- poly (ethylene oxide)(PS-b-P2VP-b-PEO) have been achieved by the addition of lithium chloride (LiCl). The morphological and structural evolution of PS-b-P2VP-b-PEO/LiCl thin films were systematically investigated by varying different experimental parameters, including the treatment for polymer solution after the addition of LiCl, the time scale of ultrasonic treatment and the molar ratio of Li+ ions to the total number of oxygen atoms (O) in PEO block and the nitrogen atoms (N) in P2VP block. When toluene was used as the solvent for LiCl, ordered nanopattern with cylinders or nanostripes could be obtained after spin-coating. The mechanism of nanopattern transformation was related to the loading of LiCl in different microdomains.

5,6,7-Trichloro-2-meth-oxy-8-hy-droxy-quinoline.

In the title compound, C(10)H(6)Cl(3)NO(2), a mean plane fitted through all non-H atoms has an r.m.s. deviation of 0.035 Å. In the crystal, adjacent mol-ecules are connected by O-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distance = 3.650 (1) Å], resulting in an infinite chain which propagates in the b-axis direction.