最新刊期
卷 54 ， 期 5 ， 2023
王佛松先生纪念
- 摘要：Adjuvants are substances added to vaccines to enhance the specific immune response to antigens in a non-specific way, and are important components of vaccines and immunotherapy. In order to solve the problems of poor targeting, high systemic exposure and biological toxicity of the currently marketed adjuvants including small molecules and biologics, polymeric materials with immunostimulatory activity and biosafety are becoming a hot research topic. In this feature article, we reviewed polymeric adjuvant materials of natural or synthetic origin that had been discovered in recent years with immunostimulatory activity, as well as polymeric materials used to encapsulate or conjugate with small molecule adjuvants. We proposed the concept of "polymeric immune adjuvant materials", and pointed out that polymeric immune adjuvant materials not only can act as pattern recognition receptor agonists to activate the immune system with a safer and more controllable manner than small molecule adjuvants, but also can be combined with small molecule adjuvants in a physically encapsulated or chemically bonded manner to control the in vivo delivery and release behavior of the antigen and small molecule adjuvants, thus enhancing the immune responses. We hope the discussion in this feature article could help the understanding of polymeric immune adjuvant materials and promote the further development of immunotherapy and vaccines.关键词：Immunotherapy;Vaccines;Adjuvants;Polymers;Biomedical materials
- 385
- |
- 101
- |
- 0
发布时间：2024-01-18
Feature Article
- 摘要：Living bacteria have the characteristics of biocompatibility, motility and can autonomously sense physiological signals, which can be used as therapeutic agents or drug carriers for the treatment of a variety of intractable diseases, including bioimaging, disease treatment, and tissue repair and regeneration. However, bacteria still have shortcomings for medical applications. For examples, some bacteria are often fragile to unfriendly environmental stimulation, leading to unnecessary bacterial death and reduced treatment effectiveness. Recently, various physicochemical and bioengineered modification strategies have been developed for individual bacteria to improve the bioavailability and efficacy, as well as achieve targeted delivery of conventional drugs. In this review, we highlight recent advance in engineered bacteria-based living biomaterials for biomedical applications in terms of engineered bacteria, biomedical application, and clinical transformation. According to the charge state, chemical groups, proteins and antigens of the bacterial surface, we systematically introduce the engineered bacteria modified with physicochemical and bioengineered strategies, especially for single bacteria. In addition, we highlight engineered bacteria-based living biomaterials for emerging diagnosis and advanced therapy, including imaging, biosensor, disease treatment, and tissue repair and regeneration, etc. Furtherly, in the clinical translation, we summarize the new progress of engineered bacteria in the treatment of tumor and gastrointestinal diseases, as well as the great success of engineered bacteria in various clinical trials. Finally, the opportunities and challenges in the future medical application of engineered bacteria have been briefly prospected. This review offers the progress in the application of engineered bacteria based on living biomaterials in biomedical application, which has potential for the development of bacterial therapy in the future.关键词：Living biomaterial;Biomedical application;Engineered bacteria;Chemical modification;Gene editing
- 463
- |
- 132
- |
- 0
发布时间：2024-01-18 - 摘要：Polyethylene and α-olefins have been major products in petrochemical industry, in which their catalysts have been recognized as key points within the industrial processes. The iron, the most abundant element of transition metals in the Earth's crust, has attracted considerable attention from researchers due to its minimal price, low toxicity and favourable biocompatibility. Surprisingly, iron complexes as catalysts show excellent performance in the catalytic systems such as oligomerization or/and polymerization of ethylene. Relied on their electronic and steric influences of substituents within ligand compounds used, iron complexes not only show different catalytic activities of ethylene reactivity but also produce different products from oligomers with low molecular weights to polyethylenes with various molecular weights. In another word, the microstructures of the resulting products can be controlled by finely tuning the electronic effects and steric hindrance of the ligands used to achieve a variety of products with highly linear and molecular weight differences from α-olefins and highly linear polyethylene. In addition, most polyethylenes obtained have been approved with narrow distributions, especially for some types of polyethylene wax. In this review, the progress of iron complex catalysts for ethylene oligomerization or/and polymerization is reviewed, indicating the effects of ligand frameworks and their modifications through using different substituents as well as the differences in the catalytic activities and the microstructural properties of the obtained products. It would be temporarily short of its interest and attractiveness in academy, however, its industrial application would drive funds and keep its further investigations. To enhance the living life of any science, the 2-(imino)phenanthroline-iron catalysts were used in ethylene oligomerization to successfully produce α-olefins in a 50 kt/y process by Sinopec Maoming Branch in September 2021, which promoted Sinopec to construct a further developed process with 200 kt/y in Tianjin at November of 2021. It is the first iron catalyst being used in the petrochemical industry, moreover, it is the first process for a full range of α-olefins achieved in Asian area until now. Therefore, the iron complex catalysts are highly promising and useful in advanced products including α-olefins, polyethylene wax and linear polyethylenes.关键词：Iron complexes;Ethylene oligomerization;Ethylene polymerization;Polyethylene;α-Olefins
- 415
- |
- 146
- |
- 0
发布时间：2024-01-18
Review
- 摘要：Amphiphilic brush block copolymers (BBCPs) have demonstrated interesting self-assembly behaviors different from their coil-like linear analogues, and their rigid molecular conformation make it straightforward to fabricate ordered nanostructured materials useful in many important applications such as photonics, therapeutics, etc. However, influence of side chain topology on self-assembled nanostructures as well as physical properties remained unclear due to the lack of amphiphilic BBCPs bearing different topological side chains. Herein, we successfully synthesize a group of novel amphiphilic BBCPs with wedge-like dendritic side chains, i.e., lipophilic benzyl ether (Bn) and hydrophilic triethylene glycol (TEG). Firstly, two generations of norbornene-terminated macromonomers are obtained by esterification, nucleophilic substitution, imidization reactions, etc. Secondly, dendronized BBCPs bearing two generations of side chains are prepared through sequential ring-opening metathesis polymerization (ROMP). Chemical structures of the obtained BBCPs are clearly characterized using proton nuclear magnetic resonance spectroscopy (1H-NMR). Absolute molecular weights are determined using gel permeation chromatography (GPC) equipped with a multi-angle laser scattering detector (MALS), and single GPC peaks as well as small polydispersity indices (PDI<1.20) indicate a constant number of catalytic centers during the polymerization process. Weight average molecular weight are tunable from 164 kDa to 431 kDa by varying the feed ratio of monomer to catalyst. Moreover, side chain effect on molecular conformation in solution is investigated using GPC-MALS. Random coil conformation is observed for the first-generation polymers as indicated by the small slope values of linearly fitted lines in double-logarithmic plots of radii of gyration versus molecular weight, while the second-generation polymers with larger side chains exhibit a rod-like molecular conformation, which are further confirmed using atom force microscopy (AFM). This work provides a highly efficient synthetic route to amphiphilic dendronized BBCPs with precisely tailored topological side chains and molecular conformations, which enables the fabrication of novel nanostructured polymer materials with diverse physical properties for different applications.关键词：Block copolymer;Ring-opening metathesis polymerization;Molecular conformation
- 239
- |
- 77
- |
- 0
发布时间：2024-01-18 - 摘要：During the recent decades, the endogenous biocomponents contained within natural rubber, such as proteins and phospholipids, are believed to be the causation of its superior properties. A significant amount of work has focused on increasing crosslink density rather than introducing biobased groups. Inspired by the unique properties of natural rubber, one way to improve the performance of synthetic polyisoprene should tune to polyamino acid functionalization. In this work, one kind of high molecular weight polyisoprene, PI-NH2, with amino side chains was prepared by grafting 2-Amino-1-ethanethiol via a thiol-ene click reaction. Then, PI-NH2 as initiators with two kinds of NTA, which were highly active polyamino acid monomers, were utilized in the preparation of two kinds of poly(amino acid) grafted biomimetic synthetic polyisoprene PI-Vals, PI-β-Phes via amino side chains which demonstrates the efficiency and feasibility of this approach. Among them, the tensile strength of PI-Vals can reach 28.6 MPa, and the stress at 300% is 18.9 MPa, which is 10.7% and 9.3% higher than that of SCR20 natural rubber respectively, the tensile strength of PI-β-Phes can reach 28.0 MPa, 8.3% higher than that of SCR20 natural rubber. The dynamic mechanical properties of PI-Vals are characterized by DMA tests, and the loss factor decreases and the energy storage modulus increases compared to those of NR and PI, reflecting a lower hysteresis loss, combined with a significant reduction in heat generation by compression, demonstrating a significant enhancement in dynamic heat generation performance. In addition, this modified preparation strategy for synthetic rubber holds promise for enhancing its range of applications and could serve as an alternative to high-performance rubber with the scarce resources of natural rubber.关键词：Polyamino acid grafted polyisoprene;Thiol-ene Click Reaction;Biomimetic synthetic rubber;N-thiocarboxyanhydrides
- 344
- |
- 90
- |
- 0
发布时间：2024-01-18 - 摘要：Carbon dioxide-based polyols (CO2-polyol) are emerging polyurethane precursors with economical and environmental benefits, however, the limited efficient catalytic systems restrict the sustainable development of this field. In this work, the novel catalytic system of polymeric aluminum porphyrin (PCAT-Al) was applied to the telomerization of CO2 and propylene oxide, where the sebacic acid, trimesic acid, pyromellitic acid, and dipentaerythritol were used as the chain transfer agent (CTA) to achieve the controllable synthesis of CO2-polyols. The catalytic efficiency of PCAT-Al was greater than 3.6 kg/g under different chain transfer agents, and the CO2-polyol with molecular weights ranging from 470 g/mol to 5600 g/mol can be perpared efficiently. Meanwhile, the catalytic efficiency of PCAT-Al reached 6.3 kg/g with high product selectivity (Wpolyol = 98.9 wt% at 100 ℃) for the preparation of CO2-diols with sebacic acid. Notably, PCAT-Al exhibited higher catalytic performance than conventional DMC catalysts in the preparation of branched polyols. The product selectivity in the synthesis of tertiary alcohols, tetrahydric alcohols, and hexahydric alcohols reached 99.3 wt%, 98.2 wt%, and 95.1 wt%, respectively, which were significantly higher than those of the DMC system at 88.8 wt%, 83.0 wt%, and 75.8 wt%, indicating that the PCAT-Al system had excellent controllability of the polymerization reaction. Moreover, PCAT-Al can be used to effectively prepare CO2-diols with ultra-low molecular weight (Mn = 470 g/mol) under high-loading chain transfer due to the excellent proton tolerance. PCAT-Al exhibits catalytic advantages of high activity, high selectivity and excellent proton tolerance in the CO2-polymerization reaction with PO, which is of great importance for the continued development of CO2-polyol.关键词：Polymeric catalyst;CO2-Polyol;Aluminum porphyrin;High selectivity;Structural regulation
- 214
- |
- 67
- |
- 0
发布时间：2024-01-18 - 摘要：Based on (S)-ethynylpyrrolidine, propargylamine and propargyl alcohol, five monosubstituted ethynyl monomers, including (S)-N-[(4-chlorophenyl)carbamoyl]-2-ethynyl pyrrolidine (Ⅰ), (S)-N-(4-chlor robenzoyl)-2-ethynyl pyrrolidine (Ⅱ), 1-(p-chlorophenyl)-3-(2-propynyl)urea (Ⅲ), p-chlorophenyl N-propargylcarbamate (Ⅳ) and propargyl N-(4'-chlorophenyl)carbamate (Ⅴ) were synthesized. Optically active helical copolymers, I50-ran-II50, I80-ran-II20, I95-ran-III5, I95-ran-IV5 and I95-ran-V5, were prepared through coordination polymerization catalyzed by Rh(nbd)BPh4 of I with II to V, respectively. The effect of the structure and composition of the copolymers on the optical activity were studied, and the enantioseparation performance of the copolymers as coated chiral stationary phase toward 9 standard racemates were evaluated by high performance liquid chromatography. I80-ran-II20 has the highest optical activity, showing better chiral recognition performance than other copolymers, and exhibited well chiral resolution ability for benzoin (α=1.40) and cobalt acetylacetonate (α=1.88). The introduction of chiral monomer II has little effect on the helicity of the copolymer backbone, but obviously interferes with the asymmetric arrangement of side groups and reduces the enantioseparation performance. The introduction of achiral propargyl monomers significantly reduces the optical activity and enantioseparation of copolymers regardless of the bond orientation.关键词：Helical Polyacetylene;Chiral stationary phase;Substituent Structure;High Performance Liquid Chromatography;Enantioseparation
- 188
- |
- 46
- |
- 0
发布时间：2024-01-18 - 摘要：Wear resistance is an important evaluation index of ultra-high molecular weight polyethylene (UHMWPE) products, and its strengthening mechanism is to prevent molecular chain from sliding and falling off on the friction surface. In essence, the improvement of wear resistance is to form an interaction network of molecular chains. For cross-linked UHMWPE molding materials used as artificial joints, radiation modification will induce free radicals, which is easy to cause oxidative degradation and damage the long-term durability. It is of great significance to develop new method that can replace irradiation cross-linking. In this paper, we choose raw resin with different molecular weights (Mw), and adjust the crystallinity (Xc) in a large range by changing the crystallization thermal history, and adjust the cross-linking density (Vd) by changing the γ radiation dose. The volume wear rates of various samples were measured, and the relationships between the wear rates and the values of Xc, Vd, Mw were established. It is found that the wear rate decreases linearly with the increase of Xc, Vd and Mw. More importantly, for each Mw of UHMWPE, increasing the crystallinity enables wear rate to reduce to a lower level than that of traditional irradiation crosslinking method. The introduction of high crystallinity to improve wear resistance has obvious advantages because it will not cause active free radicals, thus fundamentally eliminating the risk of oxidation. Our study provides a new idea to develop UHMWPE articles with superior wear-resistance for artificial joint field.关键词：Molding material;wear resistance;Crystallinity;Cross-linking;Molecular weight
- 362
- |
- 114
- |
- 1
发布时间：2024-01-18 - 摘要：With the widespread use of poly(lactic acid) (PLA), it has been developed considerably with excellent biocompatibility, biodegradability, and mechanical properties. Nevertheless, the inferior heat resistance and slow crystallization rate seriously restrain the advancement. The stereocomplex crystal (SC), which is formed in the blends of poly(lactic acid) (PLLA) and poly(D-lactic acid) (PDLA), can enhance the homogeneous crystal (HC) nucleation and thermostability of PLA, thus possessing an excellent modification potential. A series of diblock copolymers of PLA and polystyrene (PS) with different molecular weights were synthesized by atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP). The blends of PLLA/PS-b-PDLA were prepared and the relationship between composition and crystallization of PS-b-PDLA copolymers and their blends was investigated. The results showed that the restriction of PS block on the mobility of PDLA increased with higher molecular weight, which was unfavorable to the crystallization process of PDLA. In the non-proportional blends of PLLA/PS-b-PDLA, the introduction of PS blocks with poor chain mobility contributed to the difficulty in HC, while the low molecular weight PS block was beneficial to accelerate the formation of SC by inhibiting the formation of HC, thereby increasing the bulk crystallization rate. The phase separation occurred in the blends of PLLA/PS-b-PDLA with the same ratio. The high molecular weight PS blocks restricted the mobility of the PLA molecular chain and weakened the contact ability between PDLA and PLLA by separated phase behavior. It inhibited the formation of SC. However, the low molecular weight PS blocks had less restriction on PDLA blocks, thus increasing the crystallinity of SC. The distinctive influence of PS-b-PDLA on HC and SC is significant to the research on the crystallization and thermal properties of PLLA-based composites. And it is of great importance for the performance adjustment of biodegradable materials and the expansion of the application field.关键词：Poly(lactic acid);Polystyrene;Block copolymer;Sterecomplex
- 202
- |
- 53
- |
- 0
发布时间：2024-01-18 - 摘要：Dispersions based on fumed silica/polyether oligomers are widely used in varying fields including adhesives, coatings, lithium ion batteries, and liquid armors. It has been found that the complicated interfacial interaction between silica and polyether and the resultant interfacial layers strongly influences the rheological responses of the dispersions while it is a long-standing issue to control the interfacial structure and rheological behavior in both the academy and industry. Investigated herein are the interfacial structure and rheological behaviors of silica/linear poly(propylene oxide) (PPG) oligomer dispersions as a function of molecular weight (0.4-4 kg/mol) of PPG and volume fraction of silica. The results show that a change of molecular weight of PPG in a narrow range strongly influences the molecular adsorption and restriction in the vicinity of silica nanoparticles and the rheology of the dispersions. Moreover, PPG with molecular weight of 0.4 kg/mol forms glassy layers of ((1.0±0.2) nm) on the surface of silica nanoparticles via hydrogen bonding between terminal hydroxyls of PPG and silanols of silica. The percolation of glassy layers at high silica loadings causes the dispersions to undergo a sol-to-gel transition at 10 rad/s. On the other hand, PPG with molecular weight of 1-2 kg/mol forms incomplete glassy layers of (0.8±0.1) nm in thickness and that of 3-4 kg/mol forms restrained layers surrounding silica nanoparticles, both yielding sol-like rheological responses up to silica volume fraction of 0.16 at 10 rad/s. Furthermore, a comparison between thresholds of percolation of glassy layers and sol-to-gel transition suggests that the degree of molecular restriction nearby silica nanoparticles and therefore the rheological behaviors of the dispersions are determined by density of terminal hydroxyls of PPG and the interaction terminal hydroxyls and silanols of silica.关键词：Silica;Poly(propylene oxide);Dispersion;Interface;Rheological behaviors
- 249
- |
- 63
- |
- 0
发布时间：2024-01-18 - 摘要：In lithium ion batteries, the separator plays an important role in preventing the direct short circuit between cathode and anode, and providing channels for ion transportation at the same time, which determines the safety performance of the batteries. In this study, a method for evaluating the safety performance of the separator has been established by using the short circuit time of lithium-copper batteries. The results show that the battery short-circuit time has a high linear correlation with the thickness and internal resistance for the same type of separator. Increasing the separator thickness and internal resistance can prolong the battery’s short-circuit time. For different types of separators with the same thickness, the short circuit time is related to the microporous structure. There is a low linear correlation between the short circuit time of the battery and the puncture strength of the separator. Combined with the morphology of lithium dendrite on the separator surface after the battery short circuit, it is supposed that the battery short circuit is caused by the dendrite growing along the micropores of the separator, rather than puncturing the separator. The lithium-sulfur battery was assembled by using separator with different thicknesses. A significant linear correlation is observed between cycle life and separator thickness, which verifies the effectiveness of the method in the actual battery. At the same time, the results also confirm that the short circuit time of the battery can be greatly prolonged to improve the safety performance of the battery by regulating the lithium deposition behavior and inhibiting the lithium dendrite growth using functional separator, which provides new ideas and theoretical basis for developing and designing new types of composite separator and batteries with high safety.关键词：Lithium ion battery;Short circuit time;Functional composite separator;Battery safety
- 141
- |
- 46
- |
- 0
发布时间：2024-01-18 - 摘要：In this report, we prepared two kinds of polymeric nanoparticles with visible light-responsive units on the surface by using visible light-responsive donor-acceptor Stenhouse adducts (DASAs) and studied their light responsiveness. First, we synthesized the polymer of PGMD modified with DASA molecule. The result indicates that PGMD is soluble in water-miscible organic solvents (such as DMSO) and it can convert to hydrophilic state under visible light irradiation. Therefore, the block copolymer PCL-b-PGMD with PGMD segment can self-assemble to form micelles in water, and it can co-assemble with PCL-b-PEG to form mixed-shell micelles (MSPMs) in water. However, the polymer segment PGMD modified with DASA molecules on the surface of MSPMs cannot be switched to the hydrophobic state reversibly. In order to obtain the polymer nanoparticles with reversible response, we prepared the mixed-shell silica nanoparticles with hydrophobic triene state DASA molecules and hydrophilic PEG short chains on the surface, and the mixed-shell silica nanoparticles were prepared through the silane coupling agent hydrolysis modification method. The result demonstrates that the mixed-shell silica nanoparticles can be stably dispersed in water, and the DASA molecules modified on the surface of the mixed-shell silica nanoparticles still retain its great responsiveness. This work provides a great idea for designing responsive polymer nanoparticles with tunable property surface.关键词：visible light-responsive;mixed-shell micelles;polymer nanoparticles;Donor-acceptor Stenhouse adducts
- 196
- |
- 61
- |
- 0
发布时间：2024-01-18 - 摘要：We synthesized a water soluble glycol chitosan polymer grafted with cholesterol through substitution reaction, and the polymer was applied to form a polymer-liposome complex (PLC). According to dynamic light scattering (DLS) and transmission electron microscope (TEM) characterization, the diameter of the PLC was about 100 nm and the morphology was similar to the plain liposome. The cholesterol group can induce the polymer backbone to attach to the surface of the liposome membrane and the integration cability of the glycol chitosan-cholesterol (GCC) was characterized by laser confocal scanning microscope (LCSM). The zeta potential of the liposome containing negative charged phospholipid was -23.2 mV. With integration of the glycol chitosan-cholesterol, the zeta potential significantly increased to -1.78 mV, which indicated that the attached water-soluble polymer can shield the surface charge of the membrane. By encapsulating fluorescent molecules in the liposome or mixing fluorescent phospholipid during the lipid preparation process, fluorescence resonance energy transfer (FRET) experiment was introduced to test the stability of the PLC. Charge-induced liposome fusion occurred by adding positively charged ions or liposome into negatively charged liposome solution. The PLC has shown the ability to resist the fusion process which can keep the integrity and monodispersity of the liposome. However, the plain liposome was observed in aggregates visible to the naked eyes after adding hetero-charged ions in several minutes. The FRET variation results indicated that the addition of the GCC can slow down the hetero-charged liposome fusion process. In addition, the PLC can also protect against the liposome leakage induced by surfactant, which resulted from synergistic effect of polymer multiple-units. Incubated with 20% FBS under 37 ℃, the PLC showed well stability in 3 days, while the PDI and the size of the plain liposome were increased obviously during incubation. The preparation process of this polymer-liposome complex strategy is simple and fast, and it has shown good stability in in vitro experiments. This system has potential applications in long circulation drug delivery.关键词：Liposome;Stability;Polymer;Complex
- 398
- |
- 83
- |
- 0
发布时间：2024-01-18 - 摘要：Nanoflowers (NFs) have received much attention due to their hierarchical structures and diverse functions or applications. However, up to now, most reported NFs are synthesized based on inorganic compounds, and the reports on organic polymeric NFs are greatly limited. Here, a crystalline alternating copolymer P(DHB-a-DDT) is synthesized by the click polymerization of 1,3-butadiene diepoxide (BDE) and 1,10-decanedithiol (DDT). It is found that P(DHB-a-DDT) could self-assemble into NFs on a large scale by cooling in a mixed solvent (DMF/MeCN = 1/1, V/V) from 80 ℃ to room temperature. The formation mechanism demonstrated that NFs are porous and composed of nanosheets. The size of NFs could be tuned from 3.3 μm to 12.6 μm by changing the polymer concentration. The self-assembled NFs can be controlled by the factors of polymer concentration, the volume ratio of DMF/MeCN, type of precipitant and polymer composition. Further, the functionalization of NFs is easy to carry out. For example, NFs loaded with Ag particles (AgNP-NFs) are prepared readily by the coordination of sulfur and silver ions followed with in situ reduction. The SEM image show that AgNP-NFs maintained the flower-like morphology, and there are many small Ag nanoparticles (AgNPs) on the surface and in the cavity of AgNP-NFs with the average diameter of (88.4±34.5) nm. As a result, AgNP-NFs with low Ag content of 11.9 wt% exhibit enhanced surface-enhanced Raman scattering (SERS) with a detection limit of 1×10-8 mol/L using R6G as the probe molecule,which is two orders of magnitude lower than that of exfoliated AgNPs. Furthermore, AgNP-NFs can be used in single-particle SERS detection with high sensitivity and low detection cost because of their micron size, good dispersibility and porous structure. These findings extend the self-assembled behavior of alternating copolymers (ACPs) and enrich the types of polymeric NFs as well as their functions.关键词：Nanoflowers;Alternating copolymer;Self-assembly;Surface-enhanced Raman Scattering
- 221
- |
- 60
- |
- 0
发布时间：2024-01-18 -
Frost-resistant and Antifogging Polymeric Composite Films Capable of Healing Fractured Nanofibers 增强出版
摘要：Micro- and/or nanoscaled structures have endowed artificial polymeric materials with various unique functions. However, these materials are vulnerable to mechanical damage, which can destroy their inherent micro- and/or nanoscaled structures and result in the loss of their original functions. Therefore, to extend the service life of artificial polymeric materials whose functions depend on micro/nanostructures, it is highly important to fabricate polymeric materials that can heal damaged micro/nanoscaled structures. In this work, we report the fabrication of self-healing antifogging and frost-resisting films capable of healing the fractured nanofibrils. The films are fabricated by dip-coating of clean substrate from aqueous solution of poly(acrylic acid)-block-poly(acrylamide) (PAA-b-PAAm) and poly(diallyldimethylammonium chloride) (PDDA) complexes, followed by annealing under a humid environment of ~25 ℃ and relative humidity of ~100% (denoted as PAA-b-PAAm/PDDA). The complexation of PAA-b-PAAm and PDDA in aqueous solutions can assemble into nanorods, which are comprised of electrostatically cross-linked PAA blocks and PDDA chains as the hydrophobic cores and hydrogen-bonded PAAm chains as the hydrophilic coronas. These nanorods in the complex solutions can fuse into oriented nanofibers in the dip-coated PAA-b-PAAm/PDDA films during the dip-coating and the annealing processes. Nanofibrillar structures of the hydrophilic PAA-b-PAAm/PDDA film can increase the contact area between water droplets and film surfaces to facilitate water dispersion and adsorption, thereby endowing the film with excellent antifogging and frost-resisting properties. Because of the dynamic nature of electrostatic and hydrogen-bonding interactions, the PAA-b-PAAm/PDDA films can not only heal physical cuts with several tens of micrometer width, but also reconnect the fractured nanofibers to restore their original ordered nanostructures. The ability to heal macroscopic damages and restore inherent nanostructures can largely extend the service life and enhance the reliability of the antifogging and frost-resisting PAA-b-PAAm/PDDA films. The present work paves a way for the fabrication of polymeric materials that can heal micro/nanostructures and thus restore their original functions.关键词：Self-healing materials;Antifogging films;Block copolymers;Supramolecular materials- 275
- |
- 86
- |
- 1
发布时间：2024-01-18 - 摘要：Carriers play crucial roles in improving the drug delivery efficacy and antitumor activity. Here, two kinds of phospholipid-based carriers, including PEGylated phosphatidyl ethanolamine DSPE-PEG and phosphatidyl choline DPPC, were leveraged to encapsulate dimeric paclitaxel prodrugs to obtain the formulations. The impact of phospholipid-based carriers on the colloidal stability, cytotoxicity, bio-distribution and antitumor efficacy was systemically investigated. Compared with DPPC, DSPE-PEG could form uniform nanoformulations (DeP NPs). The average particle size and zeta-potential of DeP NPs were determined to be 201.1 nm and -13.8 mV, respectively, by dynamic light scattering (DLS). The transmission electron microscopy (TEM) images confirmed their well-defined nanostructures. DeP NPs could remain stable in solutions containing 5% glucose, 10% FBS, and RPMI-1640 without serum. The hydrophobic interaction dominates the assembly of DSPE-PEG with PTX prodrug. Upon treated with 10 mmol/L H2O2, DeP NPs exhibited the oxidative responsive PTX release. DeP NPs could effectively be internalized by tumor cells, and exhibited more potent cytotoxicity towards cancer cells compared with normal cells. Furthermore, DeP NPs possessed good accumulation of drug at tumor sites and desirable antitumor performance. Our work provides valuable insight into the construction of phospholipid-based carriers material to deliver hydrophobic drugs.关键词：Phospholipid;Paclitaxel;Dimeric prodrug;Nanodrugs;Chemotherapy
- 323
- |
- 47
- |
- 0
发布时间：2024-01-18 - 摘要：Smart coatings are ideal for the next generation of anti-corrosion coatings with excellent self-healing and anti-corrosion capabilities, which can repair coating scratches in a timely and autonomous manner. In this work, polyaniline microcapsules loaded with linseed oil were prepared via combining emulsion template method, photopolymerization and interfacial polymerization of aniline. The microcapsules were incorporated into water-based epoxy resin coating to construct a dual self-healing anti-corrosion coating with excellent photothermal conversion ability. When coating was damaged, the repair agent (linseed oil) in microcapsules was released to repair the scratch. Under near-infrared (NIR) light irradiation, polyaniline could effectively absorb light energy and generate sufficient heat, which raise the temperature above the glass transition temperature (Tg) and thus heal the coating defect. Polyaniline could not only improve the excellent photothermal conversion capability of the coating, but also greatly enhance its anticorrosion ability. Infrared thermal imager recorded the temperature change of the coating under NIR illumination and determined the photothermal conversion performance of the coating. The surface morphology, electrochemical measurement and salt spray test results proved that the coating with 10% polyaniline microcapsule presented an excellent self-healing performance within 3 s of NIR irradiation. In addition, after 300 h of salt spray test, no corrosion products were produced by the coating, while the corrosion phenomenon was obvious in the epoxy coating. EIS measurements results show that the |Z|f=0.01Hz value of the Polyaniline microcapsules coating after repair was nearly 4 orders of magnitude different from the |Z|f=0.01Hz value of the pure epoxy coating. The triple synergistic effect of the release of the repair agent in the microcapsule, the photothermal effect of polyaniline and its anticorrosive ability makes the coating have ultra-fast healing time, excellent self-healing ability and anticorrosive effect. The ultra-fast response time and high healing efficiency, as well as excellent corrosion protection properties endow this coating with promising applications in anti-corrosion field.关键词：Microcapsule;Polyaniline;Photothermal;Double-action self-healing;Corrosion protection
- 236
- |
- 74
- |
- 1
发布时间：2024-01-18 - 摘要：Aerogels have been extensively used in a variety of fields, such as thermal insulation, catalyst supports, adsorption and separation, and so on. Aerogels often need modification of their microstructure and mechanical properties to satisfy particular requirements. However, creating green technology to produce aerogels with high strength and toughness based on natural polymers remains a significant issue. In this work, we present a strategy for constructing chitosan aerogels with high strength and toughness by controlling the lateral aggregation and recrystallization of chitosan chains with salt ions, thereby influencing the morphology, pore structure, and mechanical properties of chitosan aerogels via the Hofmeister effect. The mechanical properties of chitosan hydrogels and aerogels may be efficiently manipulated by altering the anions and cations of salts, as shown by the Hofmeister effect. Chitosan aerogels have a maximum tensile strength of (23.1±0.4) MPa, Young's modulus of (198.0±43.8) MPa, and fracture work of (9.6±0.9) MJ/m3, and a maximum specific surface area of 410 m2/g. This straightforward method simplifies the production of chitosan aerogels with high strength and toughness, which have potential uses in flexible electrical devices, tissue engineering materials, drug/protein carriers, and catalysts.关键词：Chitosan;Aerogels;Hofmeister effect;Aggregation state structure;Mechanical properties
- 281
- |
- 88
- |
- 0
发布时间：2024-01-18
Research Article
- Postal code：100190
- Tel：010-62588927 Email：gfzxb@iccas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05002797号-8
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0