最新刊期
卷 52 ， 期 8 ， 2021
- 摘要：Stimuli-responsive polymers are defined as polymers whose structure and properties can be changed in response to minor changes in the surrounding physical or chemical environment and have become increasingly attractive as biomaterials. Reactive oxygen species (ROS) are a series of chemically reactive oxygen-containing molecules, which play an indispensable physiological role in cell signal transduction, acting as secondary messengers. It has been suggested that ROS levels in the cancer cells are much higher than those in the normal cells, and thus, ROS have been selected as a starting point or target for cancer therapy. Tellurium belongs to the chalcogen along with sulfur and selenium. Compared to sulfur and selenium, the relatively large atomic size and low electronegativity of tellurium give it many unique properties, such as redox sensitivity and coordination ability. In recent years, our research group pioneered in the research of ROS-responsive tellurium-containing polymers and their application in drug delivery. The work presented in this feature article, starting from the difference of oxidation responsiveness of tellurium and selenium, explored the ultra-sensitive ROS-response of tellurides. Then we studied the application of tellurium-containing polymers in drug delivery, focusing on the delivery of platinum drugs. For example, polymers with tellurium in the main chain can simultaneously deliver Cisplatin and indocyanine green to achieve a combination of cancer chemotherapy and photodynamic therapy, while side-chain tellurium/platinum-containing polymer can realize a combination of cancer chemotherapy and radiotherapy. Besides, the tellurium/platinum assembly can achieve controlled drug release through a dual response mechanism of ROS and coordination. Finally, we put forward the prospect of the development of tellurium-containing polymers, such as the development of controllable synthesis of tellurium-containing polymers based on chain polymerization, the development of tellurium-containing polymers and tellurium/platinum-containing assembly with different topological structures, and the exploration of the long-term toxicity of tellurium-containing molecules in biological applications.关键词：Tellurium;ROS response;Coordination response;Drug delivery
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发布时间：2022-09-30 - 摘要：In recent years, molecular self-assembly has been moving into employing more complex building blocks to emulate the complex life processes in nature. Among them, progress made in using proteins as the building blocks to construct assemblies could inspire us with a better understanding of the life-related self-assembly processes and ultimately endows us with the wisdom to design functional proteinaceous material comparable to nature. However, due to the intrinsic complexity and conformation variability of protein building blocks, artificial protein assemblies with well-defined structure have been hard to construct. Herein, this article reviews the inducing ligand strategy, which was a new strategy proposed by our group to construct protein assemblies with well-defined structure. We first introduce the research progress of the protein assembly in the literature. Then we discuss the discovery of the inducing ligand strategy, the structure, morphologies and functions of the various protein assemblies obtained via this strategy. By using this strategy, various assembled structures with precise protein packing including 1D nanofibers, 2D nanosheets and 3D crystals have been developed. Among those, the most attractive one could be the helical microtubule structures obtained by using SBA and inducing ligand. Meanwhile, the possible mechanism of this protein assembly strategy has been discussed. Finally, the inducing ligand strategy is prospected.关键词：Protein assembly;Self-assembly strategy;Ordered morphology;Precise control;Nanomaterials
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发布时间：2022-09-30 - 摘要：The supramolecular and polymeric self-assemblies provide a powerful means for the development of new high-performance functional materials. However, the precise control of self-assembly requires a deep understanding on the role of van der Waals, hydrogen bonding, electrostatic, host-guest and π-π interactions, and also on the kinetic pathways. Computer simulations, especially molecular dynamics simulations, provide a unique technique to study the self-assembly structures and their evolving processes. This review summarizes the multi-scale models and methods in the dynamic simulations for supramolecular and polymeric self-assemblies, discusses the characteristics, applications and advantages of different simulation methods, and focuses on the tailored models and methods developed by us together with the strategy to improve the computation accuracy and efficiency. We also show the research progress on supramolecular and polymeric self-assemblies using these methods. The general outline of this review is as follows:Section 1: The large-scale dynamics simulations achieved by tailored coarse-grained models combined with GPU-accelerated computing are crucial for the studies of supramolecular and polymeric self-assemblies that usually happen at mesoscopic scale (length = 10-1000 nm, time = 10-9 to 10-3 s). Therefore, in this section a simple technical summary for large-scale dynamics simulation methods and high-performance computing techniques is included.Section 2: The self-assemblies of polymer-grafted nanoparticles triggered by such as changing the solution conditions can form super-lattice crystals, micelles or vesicles. These assemblies show important potentials in the applications ranging from semiconductor materials and optical materials to medical development, cancer treatment, and drug delivery. This section presents a concise review of our recent simulation advances in the fabrication and self-assemblies of polymer-grafted nanoparticles.Section 3: The self-assemblies of polymers and supramolecules in solution are a spontaneous organization process driven by the minimization of free energy, which often shows multi-scale characteristics. The ordered structures formed by the self-assemblies, such as layered, columnar, spherical, fibrous micelles and vesicles, are important to develop new functional materials. The advances achieved by us on the multiscale modeling of amphiphilic polymers and supramolecules and the dynamics simulations of their self-assemblies are summarized in this section, which offer a unique approach to investigating this topic.关键词：Dynamics simulation;Self-assembly;Supramolecule;Polymer
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发布时间：2022-09-30 - 摘要：Poly(phenylacetylene) (PPA) derivatives are important dynamic helical polymers with rich and adjustable helical conformations, which have received ever-increasing attention due to their potential applications in the fields of chiral recognition, enantiomeric resolution, asymmetric catalysis, multi-channel sensor, circularly polarized luminescence, etc. This feature article summarizes the recent research progress of our group on poly-(3,5-disubstituted phenylacetylene), including the influencing factors and regulation rules of cis-cisoid helical conformation, a novel doublet chirality transfer (DCT) mode, the adjustable chiral amplification, as well as its interesting self-assembly behavior. By introducing intramolecular hydrogen bonding or n→π* interactions, cis-cisoid helix can be obtained and stabilized in solution, the formation of which can be tuned by changing the size of pendant groups, solvents, additives, and temperature, etc. Based on this disubstitution structure, a new model of doublet chirality transfer is put forward, which can be used to design various PPA functional materials and attenuate the possible antagonism. To achieve a good DCT, high cis structure of main chain, and strong intramolecular hydrogen bonds are indispensible. Different chiral amplifications in a single copolymer system, normal and abnormal "sergeants-and-soldiers" effects, can be achieved by tuning the conformational transition between cis-cisoid and cis-transoid helices, which can be well-explained by using the modified Ising model. Moreover, interesting self-assembly behavior including the self-assembly of amphiphilic rod-rod block copolymers and the conformational transition-induced self-assembly are observed in poly(3,5-disubstituted phenylacetylene). For the former, by modulating the composition of block copolymers, water contents, and initial copolymer concentration, the aggregates can transform from the spherical micelles to the worm-like micelles, multi-arm worm-like micelles, and vesicles. For the latter, hydrogen bonds driven conformation autoregulation and sol-gel transition are achieved for PPA homopolymer. The self-assembly structures can sequentially evolve from vesicles to nanobelts to helical strands during the process of conformational transition for PPA block copolymers. Finally, the future research directions of poly(3,5-disubstituted phenylacetylene) as chiral functional materials are prospected.关键词：Poly(3,5-disubstituted phenylacetylene);Helical conformation;Chirality transfer;Chiral amplification;Self-assembly
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发布时间：2022-09-30
Feature Articles
- 摘要：Poly(disubstituted acetylenes) (PDSAs) have shown excellent performance in gas permeability, polarized light emission, and fluorescent elastomers, and therefore have attracted great attention from researchers in relevant fields. Among a variety of PDSAs, the development history of poly(1-chloro-2-phenylacetylene)s is an ideal epitome of the progress of polyacetylenes. In this mini review, from traditional polymerization catalysts of late transition metal complexes to newly developed Pd-based catalyst systems, from nonpolar substituents to various polar functional groups on monomers, from inner apolar solvents to common polar solvents as polymerization media, different aspects of the polymerization of 1-chloro-1-alkynes, especially 1-chloro-2-phenylacetylenes are retrospected with a series of examples. Meanwhile, this review lays another clue, or the efforts on pursuing for PDSAs possessing ultrahigh permeability and good separation property of gases such as H2, N2, O2, CO2 and CH4, an utmost important application of polymer materials. The greatly enhanced tolerance to polar groups of the Pd-based catalyst systems, in contrast with the traditional catalyst complexes, allows to introduce polar functionalities and active sites into the structure of PDSAs, thereby offering the chances to tackle the problem of the very low selectivity to different gas pairs. The realistic demands for gas collection and separation prompt the development of novel catalyst systems and synthetic strategies to PDSAs with intrinsic microporous structures. Moreover, due to the unique conjugated polyene main-chain and regioregular configuration, PDSAs are conceived as one of the promising candidates for the construction of PIMs. Finally, perspectives and suggestions of the functional design and synthetic efforts are presented.关键词：Poly(disubstituted acetylene)s;1-Chloro-2-phenylacetylene;Pd-based complex catalyst;Polymers with intrinsic microporous;Gas permeability
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发布时间：2022-09-30 - 摘要：Flexible solar cells hold broad application prospects in the fields of space energy, outdoor equipment, building integration photovoltaic, and wearable smart devices due to their light weight, flexible and wearable properties, which can be easily integrated with different surfaces with varied shapes. The high defect tolerance of perovskite materials allows functional doping for adjustable electrical and mechanical properties. Combined with its solution processability and excellent charge transport characteristics, the perovskite materials showed unique advantages as flexible devices. Currently, the reported efficiency of single-junction flexible perovskite solar cells has exceeded 20%, which is one of the most efficient flexible photovoltaic technologies. However, the intrinsic brittle ceramic properties of the perovskite polycrystalline film induced poor mechanical bending stability in devices, which is the bottleneck before its application. Meanwhile, the stress mismatch across multiple functional layers in devices during bending induce rapid device degradation, which restricts the overall stability and reliability of the flexible perovskite solar cells. Recently, great efforts have been made by researchers for high mechanical stability of flexible perovskite solar cells. This article comprehensively reviewed the research progress in improving the mechanical stability of flexible perovskite solar cells in recent years by optimizing flexible substrates, developing new flexible transparent electrodes, adjusting crystal grains, modifying grain boundaries and interfacial engineering. Besides, the challenges and prospection of flexible perovskite solar cells are also analyzed.关键词：Flexible perovskite solar cells;Mechanical stability;Bending stability;Stretchability
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发布时间：2022-09-30 - 摘要：As a new type of fluorescent carbon nanodots, carbonized polymer dots (CPDs) have attracted extensive attention in recent years due to their unique hybrid structure and functionalities of carbon core and polymer shell. This review systematically summarizes and analyzes the relevant literature, and reveals that CPDs have the properties of both traditional carbon dots and polymers. CPDs, showing aggregated/crosslinked and carbonized polymer hybrid nanostructures, are often produced from small molecules, polymers, or biomass by assembling, polymerization, crosslinking, and carbonization via "bottom-up" methods. We emphasize the important role of polymerization and carbonization during the formation of CPDs, which is the essence of the CPDs. Due to the abundance of carbon sources and various synthetic strategies, the structure and properties of CPDs are diverse. Moreover, we discuss the photoluminescence mechanism of CPDs, and systematically conclude that the complicated influence factors of photoluminescence can be mainly classified as molecule state, carbon core state, surface state and crosslink enhanced emission (CEE) effect. CPDs are endowed with many unique optical, electrical and other physical and chemical properties, which are attributed to the polymer/carbon hybrid structure. Finally, based on the structure and performance control on CPDs, the applications of CPDs in different fields such as sensing, optoelectronic devices, catalysis and biomedicine are reviewed, and the development prospect of CPDs is discussed.关键词：Carbonized polymer dots;Carbon dots;Photoluminescence mechanism;Carbon core;Polymer shell
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发布时间：2022-09-30 - 摘要：Polypeptides are a kind of polymers with amino acids and their derivatives as structural units. Given their excellent properties, such as various structural units, excellent biosafety, facile modification, sensitive bioresponsiveness, and unique secondary structures, polypeptides have superior advantages for biomedical applications. Cystine is a dimer of cysteine linked by a disulfide bond, which can be synthesized into a bifunctional cysteine N-carboxylanhydride (Cys2 NCA) monomer by cyclization reaction. Through the ring-opening polymerization of Cys2 NCA and another monofunctional amino acid NCAs, a series of disulfide-crosslinked polypeptide nanomaterials could be controllably synthesized with diverse chemical structures, adjustable particle sizes, excellent stability, and biological responsiveness to achieve the controlled delivery of imaging agents and bioactive molecules. Based on the recent studies of our group, this review summarized the research progress of single-component, double-component, and multi-component cystine-based polypeptide nanomaterials. To be specific, the functions of single-component cystine-based polypeptide nanomaterials are limited. The double-component polypeptide nanomaterials, which are developed on the basis of single-component ones, show improved drug loading rates, expanded types of loading drugs, and a more stable nanostructures. In order to achieve a more exclusive function as a drug delivery platform, we expect to use the synergy and cascade action of different functionalized amino acids to produce multi-component polypeptide nanomaterials. The multi-component nanoplatform might provide reliable solutions for precision medicine. At last, their opportunities and challenges in clinical application and the new medical application fields were predicted.关键词：Cystine;Polypeptide;Nanomaterial;Controlled synthesis;Functionalization;Bioresponsiveness
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发布时间：2022-09-30
Reviews
- 摘要：Layer-by-layer assembly (LbL) polyelectrolyte film driven by electrostatic interaction is fabricated from alternate deposition, which has garnered broad interest all over the world in the fields of anti-bacteria, anti-fouling, separation, sensor, etc. The mobility of polymeric chains plays a vital role in the dynamic and structural control of polyelectrolyte film. Owing to the intrinsic sensitivity of electrostatic interaction for the external environment, the mobility of polymeric chains could be adjusted, and then their structures could be dynamically tuned. However, few studies have illuminated the specific role of polyanion or polycation in these procedures. Our proposal is based on a polyelectrolyte film with azobenzene (Azo) interaction, whose structure could be dynamically and reversibly controlled under the action of ultraviolet (UV) irradiation, acid treatment, and water plasticization. Herein, azobenzene were grafted onto poly(acrylic acid) (PAA) through amidation reaction. The poly(ethyleneimine)/PAA-Azo (PEI/PAA-Azo) film, which contained two kinds of noncovalent interactions, was fabricated by the LbL technique. Porous structures were constructed in PEI/PAA-Azo film after UV irradiation in a bath of the acid solution, while the film kept solid without UV irradiation after acid treatment. Patterned porous PEI/PAA-Azo film was obtained after regional UV irradiation and acid treatment. Thanks to the reversibility of azobenzene interaction and electrostatic interaction, the patterned porous structures were constructed reversibly. Furthermore, CdSe/ZnS quantum dots were spatially encapsulated into the film to develop a pattern that was visible in UV light but invisible in visible light. Through lubricate-infusion in porous regions, a patterned anti-fouling surface was fabricated, where patterned biofilm was cultured successfully. This study presented a feasible strategy for realizing the importance of polyanion mobility for the structure and dynamics of polyelectrolyte film, and it opened a broad window for the applications (such as information storage, information security, and bacterial bioengineering) of polyelectrolyte film.关键词：Layer-by-layer assembly;Polyelectrolyte film;Dynamic structures;Azobenzene;Porous structures
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发布时间：2022-09-30 -
Synthesis and Properties of ROS-responsive Biodegradable Polyurethanes with Unsaturated Double Bonds
摘要：A novel type of unsaturated polyurethane with reactive oxygen species (ROS) responsiveness was designed and synthesized. Poly(propylene fumarate) (PPF) and poly(thioketal) (PTK) were selected as the soft segments to react with 1, 6-hexamethylene diisocyanate (HDI). The formed prepolymers were chain-extended with L-lysine methyl ester hydrochloride (Lys-OMe) to obtain the polyurethanes (PFTU) that possesses both double bonds and thioketal bonds in its structure. As a comparison, the polyurethanes, i.e. PPFU containing only double bonds and PTKU containing only thiolketal bonds were also synthesized. Differential scanning calorimetry (DSC) tests and thermogravimetric analysis (TGA) showed that the five kinds of polyurethane materials were amorphous and had a good thermal stability under 200 ℃. Stress-strain curves showed that the PPFU were a kind of material with hard and tough properties. The introduction of PTK segments improved the elasticity, and kept the good elongation property of polyurethane. The polyurethanes (PFTU and PTKU) containing PTK segments had much better free radical scavenging ability than the PPFU. With the increase of PTK ratio in the polyurethanes, the degradation rate of the materials in hydrogen peroxide/CuCl2 solution also increased gradually. In addition, results of cytotoxicity test in vitro demonstrated that all the polyurethane materials synthesized in this work did not exhibit obvious cytotoxicity.关键词：ROS-responsiveness;Unsaturated polyurethane;Poly(propylene fumarate);Poly(thioketal);Biodegradale- 338
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发布时间：2022-09-30 - 摘要：Deoxyribonucleic acid (DNA) is a natural polyester polymer with programmable sequences and precise molecular recognition. Therefore, DNA has been widely investigated in functional devices and materials recently. Taking advantage of the structural diversity of DNA, novel functional devices and materials have been endowed with a variety of physical, chemical and biological responsiveness, among which, optical regulation has attracted much attention due to its non-contact and precise temporal-spatial controllability. To bring optical responsiveness to DNA material, it is necessary to introduce rational designed unnatural bases into DNA, which has been a challenging frontier. In this work, a novel thymine phosphoramidite monomer protected by 1-(4,5-dimethoxy-2-nitrobenzyl) ethoxy group (DMONB) has been designed and synthesized. The monomer was synthesized through 6 step reactions to shield the hydrogen bond site of thymine, and the product can be achieved in gram scale with high purity. Then the monomer was applied to synthesize photo-responsive DNA with random sequence through commercial solid phase synthesis procedure, which was purified and detected by RP-HPLC with good stability. The coupling efficiency of the photo-responsive monomer is comparable to the commercially available phosphoramidite monomers, detected by monitoring the 4,4'-dimethoxytriphenylmethyl (DMT) groups. The DMONB group could effectively hinder the DNA hybridization, which was demonstrated by the 10% native polyacrylamide gel electrophoresis. Under UV light for 30 s, the DMONB group could be totally removed and result in the recover of the DNA hybridization, which illustrates that this approach is of high efficiency and fast-responsive. Taking advantage of this controllable hybridization strategy, a fast light-responsive pure DNA supramolecular hydrogel has been designed and prepared, which could realize photo-chemically control the formation of pure DNA supramolecular hydrogel. This photo-induced DNA hydrogel exhibits 730 Pa storage modulus and 100 Pa loss modulus, with reversible thermal responsiveness and shear-thining property, which is similar to previously reported DNA hydrogel by our group. Our research expands the diversity of artificial DNA monomers and provides an alternative way to construct light-responsive functional DNA based materials system.关键词：nucleobase-caging;photo-responsiveness;DNA self-assembly;DNA supramolecular hydrogel
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发布时间：2022-09-30 - 摘要：CO2-polyols, comprised of both rigid carbonate and soft ether, contribute to important raw material innovation in the polyurethane industry, however, only rare examples have demonstrated functional CO2-polyols for the purpose of post-modification. In this work, itaconic acid as a novel starter was introduced in the telomerization of propylene oxide and CO2 to afford alkene functionalized CO2-polyol. Parenthetically, the bio-renewable nature of itaconic acid also raised the bio-based carbon ratio in the structure of polyol, which further elevated the sustainability impact of the whole synthetic process. The major challenge of the preparation arose from the compatibility between itaconic acid and the involved CO2/epoxide copolymerization catalyst. The first is that the strong acidity of itaconic acid may retard the catalysis and form certain amount of cyclic carbonate as by-product. The second is to retain the active double bond requires rather low reaction temperature which also decreases the activity. Nevertheless, we adopted a highly active Al(Ⅲ) porphyrin oligomer catalyst to prepare itaconic acid based CO2-polyol. Its multisite cooperative catalysis helped to overcome such obstacles, mediating the telomerization in both effective and well-controlled manner. Turnover frequency values of 2080-2500 h-1 were achieved even in the prerequisite of the full conversion and low temperature (60 oC). The selectivity was also remarkable as the amount of cyclic carbonate was controlled around 1 wt% in all cases. Meanwhile, the afforded polyols had tunable chain length of 1900-3800 g/mol and carbonate fraction of 15.9%-54.3%, which can be customized by adjusting the itaconic acid feed and CO2 pressure. Finally, a proof-of-concept study disclosed the activity of double bond which remained intact in the derived polyurethane. Hence, by the introduction of such unsaturated CO2-polyols, this work may provide a viable synthetic toolbox, allowing the development of functional polyurethanes in nearly any direction.关键词：Carbon dioxide;Itaconic acid;Unsaturated polyol;Polyurethane;Al(Ⅲ) porphyrin oligomer catalyst
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发布时间：2022-09-30 - 摘要：In order to study the relationship between structure and property of organic supramolecular crystals, polymorph is an ideal research model because a single molecule can have various packing mode and supramolecular interaction motifs. Notwithstanding, the polymorph of organic supramolecular crystals with different mechanical properties still remain rare, which limit the exploration of mechanism of mechanical properties. In this report, we raised a strategy to obtain polymorphism with different mechanical flexibilities by controlling the concentration and solvent of dimethyl 5-aminoisophthalate, which could further modify the supramolecular weak interaction. The 1B with blue emission and 1G with green emission were obtained. For 1B crystal, it does not have π-π packing; for 1G, it was H-aggregation that induced red-shift of fluorescence. Both of the crystals could be elastic bendable with low elastic modulus, that is, 1.5 GPa for 1B and 2.1 GPa for 1G. It is interrelated to the weak supramolecular interaction between layer to layer: 1G has C―H…π and H―C…O and 1B has C―H…π. The above supramolecular interactions prevent the crystal from relative slippage. Based on those properties, those materials have potential application as optical waveguide and polarizer. For optical waveguide, both 1B and 1G could possess optical waveguiding property in straight and bend state, where the optical loss coefficient of 1B was 0.374 dB/mm in straight state and 0.388 dB/mm in bend state and that of 1G was 0.233 dB/mm in straight state and 0.242 dB/mm in bend state. Furthermore, the material could also be a polarizer. It is of great importance that crystals of two polymorphs can conduct optical signal efficiently in both straight and bent states which shows their application in flexible optical device. The research is not only of important scientific meaning for the design of polymorphism and mechanical flexibility in organic supramolecular crystals, but also of important instructive significance in optical application of flexible crystals.关键词：Supramolecular interaction;Polymorphs;Mechanical flexibility;elastic modulus;Optical waveguide
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发布时间：2022-09-30 - 摘要：Liposomes delivery drug systems show obvious advantages in the treatment of many diseases. Constructing new types of liposome based drugs is of great importance to develop more efficient novel drug delivery systems. Herein, the present work demonstrated that Au microelectrode was chemically modified with avidin through Au-S bond (Avidin-S-Au microelectrode) and liposomes modified with the biotin (Biotin-liposome) were constructed through molecular assembly. Furthermore, an electrochemical detection device was constructed to recognize liposomes through single nanoparticle collision. Compared with pure liposomes, biotin modified liposome displayed a higher collision frequency and intensity with Avidin-S-Au microelectrode. Importantly, with the increasing concentration of biotin-liposome, the collision frequency increases as well. Taking the single liposome collision to the gold microelectrode into account, one can obtain quantitative information of the liposome size and concentration through the frequency and intensity of single nanoparticle collision. These findings represent an unusual case to achieve high sensitivity detection of individual liposomes with poor electrochemical activity and at very low concentration. The present work creates a simple and effective way to detect the stability of liposomes and their interaction with biomembranes.关键词：Liposome;Molecular assembly;Single particle collision;Electrochemical detection;Molecular recognition
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发布时间：2022-09-30 - 摘要：This work reports a nano-sized multicomponent composite of cationic poly(diallyldimethylammonium chloride) incorporating with ionic components of biocompatible block copolymer poly(poly(ethylene glycol) methyl ether methacrylate-b-methacrylic acid) (PPBM), gadolinium-coordinated polyoxometalate cluster K7(Gd(H2O)3P2W17O61) and K6(α-P2W18O62) at the reduction state, as a polymer-covered theranostic nanoplatform for MRI-guided chemo-photothermal combination tumor therapy. The as-prepared composites PDDA-PPBM-rPOMs with a hydrodynamic diameter of 67 nm show good structural stability and biocompatibility against HeLa cells. The internal electrostatic crosslinking structure and the surplus negative charges of the polymers/polyoxometalates composites facilitated the loading of antitumor drug doxorubicin (DOX). The PDDA-PPBM-rPOMs composites before and after drug loading both possess enhanced MRI efficacy as MRI contrast agents with high longitudinal relaxivities up to about 50 L·mmol-1·s-1. With the aid of reduced K6(α-P2W18O62) as photothermal therapy agent, the DOX loaded composites displayed unique photothermal conversion capacity. Meanwhile, the DOX loaded in the composite exhibited significant pH responsive drug release behavior. Cytotoxicity and flow cytometric apoptosis experiments showed that the drug-loaded composite can effectively inhibit tumor cell growth and achieve a photothermal-chemical synergistic therapeutic effect under laser irradiation, which provided a new strategy for the further development of polyoxometalate-based multifunctional composite for the integration of tumor diagnosis and treatment.关键词：Magnetic resonance imaging;Combined photothermal-chemotherapy;Polymer;Polyoxometalate;Drug release
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发布时间：2022-09-30 -
Mechanically Robust and Healable Poly(vinyl alcohol)-based Shape Memory Supramolecular Plastics 增强出版
摘要：The fabrication of shape memory polymers (SMPs) with robust mechanical properties, stable shape memory performance, and the capability to heal mechanical damage and fatigue of shape memory effect is highly desired but remains challenging. In this work, mechanically robust poly(vinyl alcohol) (PVA)-based shape memory supramolecular plastics capable of healing mechanical damage and fatigue of shape memory effect are fabricated by dispersing pyridine-functionalized polyhedral oligomeric silsesquioxane (Py-POSS) in PVA matrix. Due to the hydrogen bonds among PVA and Py-POSS, the stability of the physically cross-linked PVA network are effectively enhanced. The mechanical properties of the PVA/Py-POSSx supramolecular plastics, where x represents the weight ratio of Py-POSS to PVA, can be well-tailored by tailoring the mass ratio of the dispersed Py-POSS. The PVA/Py-POSS2.7 exhibits the highest mechanical strength, with the tensile strength and storage modulus being ~85.7 MPa and ~6.0 GPa, respectively. Meanwhile, the PVA/Py-POSS2.7 exhibits ultra-high shape memory effect with a shape recovery ratio (Rr) and shape fixing ratio (Rf) around ~99%. Due to the reversibility of hydrogen bonds, mobility of PVA chains can be greatly improved in the presence of water, which allows the PVA/Py-POSS2.7 to heal the fatigued shape memory function. The total recovery ratio (Rr,tot) of the PVA/Py-POSS2.7 is maintained above 93% after 90 folding/recovery cycles by conducting the healing step in a 90% RH environment after every 10 shape memory cycles. Based on the same mechanism, the mechanical damage on the PVA/Py-POSS2.7 can also be fully healed with the assistance of water. The healed PVA/Py-POSS2.7 exhibits the same shape memory function as the original sample does. The combination of ultra-high mechanical strength and healability enables the PVA/Py-POSS2.7 to maintain its excellent shape memory performance during long time and repeated usage. Integrating nanofillers that have reversible interactions with polymer materials provide an effective avenue for fabricating high-performance SMPs with enhanced reliability and prolonged service time.关键词：Poly(vinyl alcohol);Shape memory polymers;Self-healing;Supramolecular plastics- 701
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发布时间：2022-09-30
Articles
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