Preparation of antifouling ultrafiltration membranes from copolymers of polysulfone and zwitterionic poly(arylene ether sulfone)s

The past few decades have witnessed rapid gains in our demands of antifouling membranes such as water purification membranes and hemodialysis membranes.A variety of methodologies have been proposed for improving the antifouling performance and the hemocompatibility of the membranes.In this study,a series of copolymers(PSF-PESSB)containing polysulfone(PSF)and poly(arylene ether sulfone)bearing pendant zwitterionic sulfobetaine groups(PESSB)were prepared via one-pot polycondensation.Subsequently,the ultrafiltration(UF)membranes were prepared from different zwitterion-containing copolymers.The prepared membranes showed high thermal stability and mechanical properties.Besides,it also displayed attractive antifouling performance and blood compatibility.Compared with the original PSF membrane,the amount of protein absorption on the modified membrane was reduced;the flux recovery ratio and the resistance to blood cells were significantly improved.The results of this work suggest that PSF-PESSB membranes are expected to be applied in blood purification.The introduction of zwitterion-containing polymers to membranes paves ways for developing advanced hemodialysis technologies for crucial process.

Role of nanoparticle-mediated immunogenic cell death in cancer immunotherapy

An essential concept of cancer immunotherapy is that immunogenic cell death(ICD),characterized by the release of tumor-associated antigens(TAAs)and tumor-specific antigens(TSAs)like neoantigens,danger-associated molecular patterns(DAMPs),and pro-inflammatory cytokines,facilitates the presentation of TAAs and TSAs to adaptive immune cells,eliciting an emerging or reinstating a pre-existing anti-cancer immune response.

The Hole Transport Characteristics of 1,4,5,8,9 and 11-Hexaazatriphenylene-Hexacarbonitrile by Blending

The hole transport characteristics of molecule blends of 1, 4, 5, 8, 9 and 11-hexaazatriphenylene-hexacarbonitrile （HAT-CN）： N,N＇-di（naphthalene-l-yl）-N,N＇-diphenyl-benzidine （NPB） and HAT-CN： 4,4＇-cyclohexylidenebis[N,N- bis（4-methylphenyl）benzenamine] （TAPC） with various NPB and TAPC mixing concentrations （5 90wt%） are studied. When the concentration is in the range of 5-80wt%, it is found that the hole conductions in the two blends are space-charge-limited current （SCLC） with free trap distributions. The current-voltage characteristics of the two blends show SCLC with exponentiM trap distributions at the concentration of 90wt%. The hole mo- bilities of the two blends are very close （10^-4-10^-3 cm2 V^-1 s-X ）, the dependence of electric field and temperature can be described by the modified Poole-Frenkel model. The hole mobility and activation energy of the two blends depending on concentration are similar.

Repair, protection and regeneration of peripheral nerve injury

Reading guide 1778Repair of long-segment peripheral nerve defects1779Bionic reconstruction of hand function after adult brachial plexus root avulsion1780Optimized design of regeneration material for the treatment of peripheral nerve injury1781Synergism of electroactive polymeric materials and electrical stimulation promotes peripheral nerve repair1783Schwann cell effect on peripheral nerve repair and regeneration .

Poly(Glycidyl Methacrylates)-grafted Zinc Oxide Nanowire by Surface-initiated Atom Transfer Radical Polymerization

Poly(glycidyl methacrylates)(PGMA) was grafted from zinc oxide(ZnO) nanowires via surface-initiated atom transfer radical polymerization(SI-ATRP) technique.Firstly,the ZnO nanowires were synthesized by the one-pot hydrothermal technique.Subsequently,the ZnO was functionalized with 3-aminopropyl triethoxysilane,which was converted to macroinitiator by the esterification of them with 2-bromopropionyl bromide.PGMA grafted ZnO nanowires(PGMA-ZnO) were then synthesized in an ATRP of the GMA with CuCl/2,2`-bipyridine as the catalyst system.Kinetics studies revealed an approximate linear increase in weight of polymer with reaction time,indicating that the polymerization process owned some "living" character.The structure and composition of PGMA-ZnO were characterized with scanning electron microscope(SEM),energy-dispersive X-ray(EDX) spectrometer,fourier transform infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA).

The Preparation and Properties of Starch Based Shape Memory Hydrogel

In this work,the–catechol and–thiol modified starch was prepared by the esterification and amino condensation reaction,then a fully starch based hydrogel was prepared via the thiol-catechol Michael addition reaction.The starch hydrogel gained shape memory behaviors by coordinate with Fe^(3+)ions at alkaline condition.1H-NMR had been used to character the structure of the starch derivatives and its character peaks.The hydrogel’s modulus had also been measured before and after coordinating with Fe^(3+)ions in linear area and the result showed that both the hydrogel’s storage modulus and loss modulus kept constant in linear area from 0.1 rad/s to 100 rad/s,which demonstrated a good network was formed inside the hydrogel.Furthermore,the shape memory behaviors had been tested by changing the pH value in solution.The result showed that the hydrogel can keep its temporary shape in high pH condition and recover to its original state after the shaped hydrogel immersed into acidic solution.This hydrogel might have great application prospects in the field of biomedical and engineering.

Sequence design in terpolymerization ofε-caprolactone,CO_(2) and cyclohexane oxide:Random ester-carbonate distributions lead to large-span tunability

It is of great interest to make a degradable material widely tailorable to replace petroleum-derived products among diverse applications.Here,we report the construction of a new multi-purpose degradable material for the first time via a simple ternary copolymerization system comprisingε-caprolactone(ε-CL),cyclohexane oxide(CHO)and CO_(2).Under low pressure of 1 bar∼5 bar,the ring-opening polymerization(ROP)ofε-CL and ring-opening copolymerization(ROCOP)of CO_(2) and CHO can simultaneously proceed.The carbonate units are randomly distributed on the polymer chain.These random terpolymers have controllable molar mass(10-106 kDa)and compositions(4-33 mol%CO_(2)).And the obtained materials show large-span tunability from tough plastic to elastomer and even adhesive.

A metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid bis(pentafluorophenyl)(phenoxy)borane

A new strategy for the metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid Boron has been first identified.Bis(pentafluorophenyl)(phenoxy)borane was used as a catalyst for the polymerization reaction system.And polytetrahydrofuran with high molecular weight and narrow molecular weight distribution could be obtained.The proposed mechanism was studied by MALDI-TOF,ESI-MS and O-18 isotope labeling analyses as a metal-free coordination insertion mechanism.

Recent advances in living cell nucleic acid probes based on nanomaterials for early cancer diagnosis

The early diagnosis of cancer is vital for effective treatment and improved prognosis. Tumor biomarkers, which can be used for the early diagnosis, treatment, and prognostic evaluation of cancer, have emerged as a topic of intense research interest in recent years. Nucleic acid, as a type of tumor biomarker, contains vital genetic information, which is of great significance for the occurrence and development of cancer. Currently, living cell nucleic acid probes, which enable the in situ imaging and dynamic monitoring of nucleic acids, have become a rapidly developing field. This review focuses on living cell nucleic acid probes that can be used for the early diagnosis of tumors. We describe the fundamental design of the probe in terms of three units and focus on the roles of different nanomaterials in probe delivery.

Preparation of Chemically Recyclable Poly(ether-alt-ester) by the Ring Opening Polymerization of Cyclic Monomers Synthesized by Coupling Glycolide and Epoxides

Polyester and polyether are two key oxygenated polymers, and completely alternative sequence of poly(ester-alt-ether) could efficiently combine the advantages(including flexibility, degradability, etc.) of both segments. Currently, despite their copolymers could be synthesized from one-pot mixture of cyclic esters and epoxides, perfectly alternative microstructure is very challenging to realize and typically restricted to certain monomer pairs. Moving forward, synthesizing poly(ester-alt-ether) from commercially available and largescale monomers would be a significant advance. For example, successfully commercialized poly(glycolic acid)(PGA), which is not easily soluble in polymers due to its high crystallinity and is brittle and difficult to control the degradation cycle, would encounter a new paradigm if engineered into poly(ester-altether). In this work, starting from the design of monomer with hybrid structures, we successfully synthesized a series of 1,4-dioxan-2-one containing different substituents based on glycolide(GA) and epoxides using commercially available Salen-Cr(III) and PPNCl catalytic systems.The new monomers underwent ring-opening polymerization(ROP) to form a series of poly(ester-alt-ether) with perfectly alternating glycolic acid and propylene glycol repeat units under catalytic system of thiourea/base. The poly(ester-alt-ether) have significantly lower glass-transition temperature than PGA. Additionally, the poly(ester-alt-ether) can be chemically recovered to monomer using Sn(Oct)2 or 1,8-diazabicyclo[5.4.0]undecane-7-ene(DBU) as a catalyst in solution, thus establishing a closed-loop life cycle. From monomers derived from GA and epoxides, this work furnishes a novel strategy for the synthesis of poly(ester-alt-ether) with chemical recyclability.

Facile Synthesis of Polyisothioureas via Alternating Copolymerization of Aziridines and Isothiocayanates

Isothiourea is an important class of sulfur-containing molecules showing unique catalytic and biological activities. As such,polyisothiourea is envisioned to be an interesting type of polymer that potentially exhibits a number of interesting properties. However, there is no access to synthesizing well-defined polyisothiourea, and currently isothiourea-containing polymers are mainly prepared by immobilizing onto other polymer's side chain. Herein, we report the first facile synthesis of polyisothioureas via alternating copolymerization of aziridines and isothiocayanates. Mediated by the catalytic system of phosphazene superbases/alcohol, a broad scope of aziridines and isothiocayanates could be transformed into polyisothioureas with adjustable substitutions(11 examples). The structures of obtained polyisothioureas were fully characterized with ^(1)H-NMR, ^(13)C-NMR, and ^(1)H-^(13)C HMBC NMR. Moreover, the polyisothioureas show tunable thermal properties depending on substitutions on the isothiourea linkages. The novel structure of these polyisothioureas will enable a powerful platform for the discovery of nextgeneration functional plastics.

Edaravone-loaded poly(amino acid) nanogel inhibits ferroptosis for neuroprotection in cerebral ischemia injury

Neurological injury caused by ischemic stroke is a major cause of permanent disability and death. The currently available neuroprotective drugs fail to achieve desired therapeutic efficacy mainly due to short circulation half-life and poor blood−brain barrier (BBB) permeability. For that, an edaravone-loaded pH/glutathione (pH/GSH) dual-responsive poly(amino acid) nanogel (NG/EDA) was developed to improve the neuroprotection of EDA. The nanogel was triggered by acidic and EDA-induced high-level GSH microenvironments, which enabled the selective and sustained release of EDA at the site of ischemic injury. NG/EDA exhibited a uniform sub-spherical morphology with a mean hydrodynamic diameter of 112.3 ± 8.2 nm. NG/EDA efficiently accumulated at the cerebral ischemic injury site of permanent middle cerebral artery occlusion (pMCAO) mice, showing an efficient BBB crossing feature. Notably, NG/EDA with 50 µM EDA significantly increased neuron survival (29.3%) following oxygen and glucose deprivation by inhibiting ferroptosis. In addition, administering NG/EDA for 7 d significantly reduced infarct volume to 22.2% ± 7.2% and decreased neurobehavioral scores from 9.0 ± 0.6 to 2.0 ± 0.8. Such a pH/GSH dual-responsive nanoplatform might provide a unique and promising modality for neuroprotection in ischemic stroke and other central nervous system diseases.

Studies on Rheological, Thermal, and Mechanical Properties of Polylactide/Methyl Methacrylate-Butadiene-Styrene Copolymer/Poly(propylene carbonate) Polyurethane Ternary Blends

Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied.Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA.The impact strength of 50/10/40 PLA/MBS/PPCU blend(74.7 k J/m^2)was about 7.5 times higher than that of the neat PLA(10.8 k J/m^2),and the elongation at break of 50/10/40 PLA/MBS/PPCU blend(276.5%)was higher by about 45 times that of PLA(6.2%).The tear strength of PLA/MBS/PPCU films was 20 k N/m higher than that of PLA,and the elongation at break(MD/TD)of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%,whereas that of PLA was only 2.7%/3.0%.POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS.With increasing PPCU content from 5%to 20%,the density of spherulite nucleation increased and the size of crystalline particles decreased continuously,but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30%to 40%.The PLA/MBS/PPCU films exhibited excellent mechanical properties,which expanded the application range of these biodegradable films.

Co-delivery of doxorubicin and paclitaxel with linear-dendritic block copolymer for enhanced anti-cancer efficacy

A series of well-defined amphiphilic linear-dendritic block copolymers （telodendrimers, MPEG-b-PAMAM-cholesterol） with 1,2,4 or 8 cholesteryl groups （named as P1, P2, P4, P8, respectively） were synthesized. Their chemical structures were char- acterized with IH NMR and mass spectrum （MALDI-TOF MS）. The telodendrimers could self-assemble into micelles in aqueous solution, and encapsulate chemotherapeutic drug doxorubicin （DOX） and paclitaxel （PTX） for combination therapy. All the telodendrimers could encapsulate DOX with similar capability. However, their drug-loading capability of PTX is in- creased with the increasing number of cholesteryl groups. P8 exhibited much higher PTX loading efficiency than its counter- parts. Thus, P8 was selected for further application of drug delivery in the paper. The drug-loading micellar nanoparticles （NPs） of P8 were spherical in shape and their diameters were less than 150 nm which were determined by dynamic light scattering measurements （DLS） and transmission electron microscope （TEM）. In vitro drug release experiment demonstrated that P8 ex- hibited a controlled release manner for both DOX and PTX, and the two drugs were released simultaneously. In vitro cytotoxi- city experiment further demonstrated that the co-delivery of DOX and PTX in P8 exhibited better anti-cancer efficiency than the delivery systems encapsulated with single drug （DOX or PTX）. This indicates a synergistic effect. The co-delivery system showed potential in future anti-cancer treatment.

Steric Hindrance Ligand Strategy to Aluminum Porphyrin Catalyst for Completely Alternative Copolymerization of CO_2 and Propylene Oxide

Aluminum porphyrin complexes are heavy-metal-free and soil-tolerant green catalysts for the copolymerization of CO2 and propylene oxide（PO）, but they suffer from relatively poor poly（propylene carbonate）（PPC） selectivity. Herein, steric hindrance porphyrin ligand was used to enhance the PPC selectivity. Typically, a bulky anthracene-like group was incorporated into the porphyrin ring to form 5,10,15,20-tetra（1,2,3,4,5,6,7,8-octahydro-1,4：5,8-dimethanoanthracen-9-yl）porphyrin, the aluminum porphyrin complex with this ligand, in combination with bis（triphenylphosphine）iminium chloride as a co-catalyst, produced completely alternate PPC. Additionally, the obtained PPC showed high regioselectivity, with a head-to-tail linkage content（HT） of 92%. Therefore, we demonstrated that introduction of bulky steric ligand into the porphyrin ring could reduce the propylene oxide homopolymerization activity leading to excellent PPC selectivity, and improve regioselectivity for the PO ring-opening during the copolymerization.

From Self-assembled Monolayers to Chemically Patterned Brushes:Controlling the Orientation of Block Copolymer Domains in Films by Substrate Modification

Block copolymer lithography is emerging as one of the leading technologies for patteming nanoscale dense features. In almost all potential applications of this technology, control over the orientation of cylindrical and lamellar domains is required for pattern transfer from the block copolymer film. This review highlights the state-of-art development of brushes to modify the substrates to control the assembly behaviors of block copolymers in films. Selected important contributions to the development of self-assembled monolayers, polymer brushes and mats, and chemically patterned brushes are discussed.

Calcium ion nanomodulators for mitochondria-targeted multimodal cancer therapy

Various calcium ion(Ca^(2+))nanomodulators are designed for multimodal cancer treatment with the mechanism of intramitochondrial Ca^(2+) overload-induced multilevel mitochondrial destruction.This perspective briefly introduces the development of Ca^(2+) nanomodulators in cancer therapy based on two recent studies published by our research group.

ALTERNATING COPOLYMERIZATION OF CYCLOHEXENE OXIDE AND CARBON DIOXIDE UNDER COBALT PORPHYRIN CATALYST

Cobalt porphyrin complexes （TPPConIX） （TPP = 5,10,15,20-tetraphenyl-porphyrin; X = halide） in combination with bis（triphenylphosphine） iminium chloride （PPNC1） were used for the eopolymerization of cyelohexene oxide and CO2. The highest turnover frequency of 67.2 h^-1 was achieved after 13 h at 20℃, and the obtained poly（1,2-cyclohexylene carbonate） （PCHC） showed number average molecular weight （Mn） of 10 × 10^3. Though the obtained PCHC showed atactie structure, the m-centered tetrads content reached 58.1% at CO2 pressure of 1.0 MPa, and decreased to 51.9% at CO2 pressure of 6.0 MPa, indicating that it was inclined to form atactic polymer at high CO2 pressure.

Enolic Schiff Base Zinc Amide Complexes： Highly Active Catalysts for Ring-Opening Polymerization of Lactide and ε-Caprolactone

A series of zinc silylamido complexes based upon NNO tridentate enolic Schiff base framework have been synthesized and characterized. These complexes were tested for the ring opening polymerization of lactide and e-caprolactone, exhibiting notably high activity at ambient temperature, The influence of imine bridge length and substituents of diketone over the course of polymerization was investigated in details. Remarkably, 4a was confirmed to be a rare example of exceedingly active and robust zinc catalysts, achieving major transformation of lactide under extremely low loading （0.025 mol%） within 18 rain. The influence of various monomers as well as the polymerization mechanism have also been discussed.

Environmentally benign metal catalyst for the ring-opening copolymerization of epoxide and CO_(2): state-of-the-art, opportunities, and challenges

Carbon dioxide(CO_(2))is the main greenhouse gas,whereas it is also a nontoxic,abundant,cheap carbon and oxygen resource.The copolymerization of CO_(2) with epoxide presents a sustainable approach to the synthesis of biodegradable polymers,which upcycles the waste into wealth.Metal complex catalyst plays the central role in the reaction,since it provides oxophilic and Lewis acidic active center both for monomer activation and chain end stabilization,and nucleophiles as Lewis base for initiation.However,heavy metal catalyst with certain toxicity such as cobalt undisputedly dominates the copolymerization catalysis which comprises the overall sustainability.To circumvent the potential environmental hazard,developing highly active catalyst composed of green metals is of great importance especially when the polymer was utilized for agriculture purpose.This work reviews the development of sustainable metal catalysts for the production of CO_(2) copolymer,centered by Al,Mg,Ti,Fe,generally acknowledged as low toxic,environmentally benign,biocompatible,and also abundant in earth's crust.Emphasis is placed in recent five years where several historic examples are also included to construct a full picture of the sustainable catalysis explored to date.