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Abstract: By combination of high trapping radical efficiency of thioketone with resonance of allylic radicals, a novel mediated agent, 1,3,3‐triphenylprop‐2‐ene‐1‐thione (TPPT) is successfully synthesized. The results of studying TPPT‐mediated radical polymerization of styrene (St) respectively at 70 °C and 100 °C reveal that at 70 °C, the monomer conversion is very low (less than 5%), the molecular weights do not change obviously with the monomer conversion, and their molecular weights are also low. However, the polymerization at 100 °C displays first‐order kinetics and a linear increase of the molecular weight with conversion. Several methods are used to study polymerization mechanisms and the results are interesting. The TPPT can efficiently capture the growing PS radicals to form PS‐TPPT radicals, this highly stable radical can be cross‐terminated by the primary radical R• (or the growing PS radicals) to form PS‐TPPT‐R (or PS‐TPPT‐PS), but this termination reaction is irreversible, and the dormant PS‐TPPT‐PS chains cannot be cleaved to regenerate the propagating radicals in the polymerization at 70 °C. However, the growing PS radical can be regenerated from the dormant chains at 100 °C, and the factors influencing the polymerization of St are studied. [ABSTRACT FROM AUTHOR]

Similar to the traditional self-assembly strategy, polymerization induced self-assembly and reorganization (PISR) can produce a myriad of polymeric morphologies through morphology transitions. Besides the chain length ratio ( R) of the hydrophobic to the hydrophilic blocks, the chain mobility in the intermediate nano-objects, which is a requisite for morphology transition, is a determining factor in the formation of the final morphology. Although various morphologies have been fabricated, hexagonally packed hollow hoops (HHHs) with highly ordered internal structure have not, to the best of our knowledge, been prepared by PISR. In this article, the fabrication of HHHs through morphology transition from large compound vesicles to HHHs is reported. HHHs with highly regular internal structure may have significance in theoretical research and practical applications of nanomaterials. [ABSTRACT FROM AUTHOR]

Different from concentric vesicleswithout spacing between thewalls, the concentric vesicles with uniform spacing between the wallswere rarely fabricated. We successfully fabricate the spaced concentricvesicles (SCVs) via RAFT dispersion polymerization, and continuouspropagation of the residual polymer chains inside the large vesiclesinduces self-assembling to form SCVs. Concentration of the residualpolymer chains in the solution of the nascent-formed vesicles is thedetermining factor for formation of SCVs, and continuous propagationof less or too more residual polymer chains will not form SCVs butform other morphologies. Generally, the concentration of the residualpolymer chains after formation of vesicles is too low to self-assemble,so formation of SCVs is impossible. By adjusting the ratio of St/methanolor macro-RAFT agent P4VP-b-PS/P4VP, the concentrationof residual polymer chains can be controlled, and further controlof the morphologies is achieved. Formation of the inner vesicles byself-assembling inside the large vesicles requires high molecularweight of the polymer chains due to their very low concentration.The polymers of inner vesicles possess very high molecular weight(×106g/mol) in comparison with the polymer of outmostvesicles (×105g/mol). Polymerization kinetic studyreveals very high increasing rate of the molecular weight inside thevesicles probably owing to long duration of the chain radicals, andthe polymerization rate (Rp) inside thevesicles is faster than the Rpin theoutmost vesicles, but both rates are in the same order. [ABSTRACT FROM AUTHOR]

Functional nanowires with photochromic spiropyran (SP) species are prepared by reversible addition-fragmentation transfer (RAFT) dispersion polymerization of styrene using poly(4-vinylpyridine- co-spiropyranyl methacrylate) as a macro-RAFT agent, and then electrospinning technology is used to fabricate fibers from the functional nanowires. The photoisomerization of SP in the nanowires and fibers is studied, and reversible photo­chromism for both nanowires and fibers is observed. Since the merocyanine (ME form) of the SP emits fluorescence and the SP form is non-fluorescent, the fluorescence of the nanowires and the fibers can be switched on and off upon alternating UV and visible-light irradiation. [ABSTRACT FROM AUTHOR]

Redox-responsiveamphiphilic diblock copolymers, poly(6-O-methacryloyl-d-galactopyranose-co-2-(N,N-dimethylaminoethyl) methacrylate)-b-poly(pyridyldisulfide ethyl methylacrylate) (P(MAGP-co-DMAEMA)-b-PPDSMA) were obtained by deprotectionof poly((6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-d-galactopyranose)-co-DMAEMA)-b-PPDSMA [P(MAlpGP-co-DMAEMA)-b-PPDSMA], which were prepared via reversible addition–fragmentationchain transfer (RAFT) polymerization of PDSMA using P(MAlpGP-co-DMAEMA) as macro-RAFT agent. Dynamic light scattering(DLS) and transmission electron microscopy (TEM) studies showed thatdiblock copolymers P(MAGP-co-DMAEMA)-b-PPDSMA can self-assemble into micelles. Doxorubicin (DOX) couldbe encapsulated by P(MAGP-co-DMAEMA)-b-PPDSMA upon micellization and released upon adding glutathione (GSH)into the micelle solution. The galactose functional groups in thePMAGP block had specific interaction with HepG2 cells, and P(MAGP-co-DMAEMA)-b-PPDSMA can act as gene deliveryvehicle. So, this kind of polymer has potential applications in hepatoma-targetingdrug and gene delivery and biodetection. [ABSTRACT FROM AUTHOR]

A novel double-hydrophilic block copolymer P(MEO2MA- co-OEGMA)- b-PAMA has been successfully synthesized by two-step RAFT polymerization. Then, the amino groups of PAMA blocks in the copolymers react with 1-pyrenecarboxaldehyde via a 'Schiff-base' reaction, and the resulting copolymers are self-assembled to form spherical micelles in aqueous solution. Because the 'Schiff-base' linkage is pH sensitive, the release rate of pyrene depends upon the pH of solution. Complete release is achieved at pH 1, and the control release is much faster at pH 5.5 than that at pH 7.4. With progress of pyrene release, the micelles are disassembled gradually and disappeared completely at last. This double-hydrophilic copolymer is a promising candidate of drug carrier for the aldehyde- containing hydrophobic drugs. [ABSTRACT FROM AUTHOR]

Photo- and pH-responsive amphiphilic hyperbranched starcopolymers,poly(6-O-methacryloyl-1,2;3,4-di-O-isopropylidene-d-galactopyranose)[poly(2-(N,N-dimethylaminoethyl) methacrylate)-co-poly(1′-(2-methacryloxyethyl)-3′,3′-dimethyl-6-nitro-spiro(2H-1-benzo-pyran-2,2′-indoline))]ns [HPMAlpGP(PDMAEMA-co-PSPMA)n], were synthesized by reversible addition–fragmentationchain transfer (RAFT) polymerization of the DMAEMA and the SPMA usinghyperbranched PMAlpGP as a macro RAFT agent. In aqueous solution,the copolymers self-assembled to form core–shell micelles withHPMAlpGP core and PDMAEMA-co-PSPMA shell. The hydrophobicfluorescent dye nitrobenzoxadiazolyl derivative (NBD) was loaded intothe spiropyran-containing micelles. The obtained micelles not onlyhave the photochromic properties, but also modulate the fluorescenceof NBD through fluorescence resonance energy transfer (FRET), whichwas also observed in living cells. Slight fluorescence intensity decreaseof the spiropyran in merocyanine (ME) form was observed after fiveUV–visible light irradiation cycles. The cytotoxicity of theHPMAlpGP(PDMAEMA-co-PSPMA)nmicelles was lower than that of 25k PEI. All the results revealedthat these photoresponsive nanoparticles are a good candidate forcell imaging and may find broad applications in biological areas suchas biological diagnosis, imaging, and detection. [ABSTRACT FROM AUTHOR]

Abstract: Hyperbranched poly(2-((bromobutyryl)oxy)ethyl acrylate) (HPBBEA) was grafted onto the exterior surface of mesoporous silica nanoparticles (MSNs) by surface-initiated self-condensing atom transfer radical vinyl polymerization (SCATRVP). The MSNs with ATRP initiator anchored on the exterior surface (MSN-Br) were prepared by the reaction of 5,6-dihydroxyhexyl-functionalized MSNs (MSN-OH) with α-bromoisobutyryl bromide. Afterwards, MSN-Br was utilized as initiator in the SCATRVP of inimer BBEA, resulting in core–shell nanoparticles with MSN core and HPBBEA shell (MSN-g-HPBBEA). The molecular weight of HPBBEA increased with the increasing ratio of BBEA to MSN-Br. In view of the high density of bromoester groups on the surface of HPBBEA shell, MSN-HPBBEA was used to initiate the successive polymerization of (2-dimethylamino-ethylmethacrylate) (DMAEMA), forming core–shell nanoparticles MSN-g-HPBBEA-g-PDMAEMA. The resultant products were characterized by FT-IR, NMR, HRTEM and thermogravimetric analysis (TGA), etc. The pH-responsive property of MSN-g-HPBBEA-g-PDMAEMA was characterized by measuring the hydrodynamics radius at different pH values, and this core–shell nanostructure may have potential applications in biomedicine and biotechnology. [Copyright &y& Elsevier]

Amphiphilic block copolymers, poly(ethylene oxide)-b-poly(N-acryloxysuccinimide) (PEO-b-PNAS) with various molecular weights have been successfully synthesized by atom transfer radical polymerization (ATRP) of NAS using functionalized PEO (PEO-Br) as ATRP macroinitiator. The self-assembling of the block copolymers in water, which is a good solvent for PEO and a non-solvent for PNAS, yielded spherical core-shell micelles with PNAS as core and PEO as shell. The cross-linked reaction of oxysuccinimide in PNAS chains with ethylenediamine occurred in the core of micelles, and the core cross-linked micelles were formed. The flower-like and dendritic aggregates were formed by self-assembling of the core cross-linked micelles on the glass slides or silicon wafers. Longer PNAS block in the block copolymers and higher evaporation temperature formed bigger spherical particles. The optical microscope was used to follow the formation and growth of the flower-like aggregates from the colloidal solution and the main driving forces for the self-assembling are solution fluid and interactions between PEO chains. [ABSTRACT FROM AUTHOR]

Abstract: Reversible addition-fragmentation chain transfer (RAFT) functionalities were anchored to the exterior surface of mesoporous silica nanoparticles (MSNs) without changing the mesoporous structure, RAFT polymerization of styrene was subsequently conducted to graft polystyrene (PSt) onto the exterior surface of MSNs, forming a novel core–shell nanostructure with a mesoporous core and a polymer nanoshell. Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) were used to characterize the produced mesoporous core–shell nanostructure, the results showed that the thickness of the nanoshell increased with the increasing time of polymerization. [Copyright &y& Elsevier]

Abstract: A new method to graft a large number of long polymer chains or small functional molecules onto multi-walled carbon nanotubes (MWNTs) indirectly is reported. First, MWNTs were slightly functionalized by reversible addition–fragmentation chain transfer (RAFT) copolymerization of styrene and maleic anhydride using the dithioester groups attached to MWNTs as RAFT agents. The highly reactive maleic anhydride groups could further react with a large number of long polymer chains or small functional molecules with hydroxyl or amino group easily. The resulted MWNTs have good solubility in organic solvents and water; the perfect structure of MWNTs is altered very little from the information of Raman spectra. [Copyright &y& Elsevier]

A novel reversible addition–fragmentation chain transfer (RAFT) agent, S,S′-bis(2-hydroxylethyl-2′-butyrate)trithiocarbonate (BHEBT), was first successfully synthesized in the presence of an anion-exchange resin with OH- form, and then it was used as chain transfer agent in RAFT polymerizations of styrene or methyl acrylate, the dihydroxyl-terminated polymers with controlled molecular weights and narrow molecular weight distributions were produced, which was confirmed by GPC, 1H NMR spectra and kinetic analysis. Furthermore, these obtained telechelic polymers with trithiocarbonate group in the middle of the chains were used as macro chain transfer agents in the further RAFT polymerizations, and well-defined telechelic dihydroxyl-terminated triblock copolymers have been prepared successively. The structures were confirmed by their IR and 1H NMR spectra. [Copyright &y& Elsevier]

The copolymerization of styrene (St) with maleic anhydride (MAh) performed at 22 °C in the presence of dibenzyl trithiocarbonate exhibits controlled nature evidenced by: narrow molecular weight distribution, controlled molecular weight and first-order polymerization kinetics. The composition analysis of the copolymers obtained by 13C NMR spectra shows the molar fraction of St in obtained copolymers is almost equal to 0.5 throughout the copolymerization. The sequence structure of the copolymer was obtained from DEPT experiments by recording the spectra at π/4 and 3π/4, and then combining them together, the results showed that the copolymers obtained possessed well-defined alternating structure. The experiment shows that charge-transfer-complex formed from St and MAh participates in both initiation and chain growth throughout the copolymerization. [Copyright &y& Elsevier]

A simple and facile strategy has been developed for synthesis of nanomaterials viapolymerization in high concentration; multiple morphologies can be created and tuned just by variation of the feed ratio and reaction conditions. [ABSTRACT FROM AUTHOR]

Drug delivery systems (DDS) based on functionalized polymeric nanoparticles have attracted considerable attention. Although great advances have been reported in the past decades, the fabrication efficiency and reproducibility of polymeric nanoparticles are barely satisfactory due to the intrinsic limitations of the traditional self‐assembly method, which severely prevent further applications of the intelligent DDS. In the last decade, a new self‐assembly method, which is usually called polymerization‐induced self‐assembly (PISA), has become a powerful strategy for the fabrication of the polymeric nanoparticles with bespoke morphology. The PISA strategy efficiently simplifies the fabrication of polymeric nanoparticles (combination of the polymerization and self‐assembly in one pot) and allows the fabrication of polymeric nanoparticles at a relatively high concentration (up to 50 wt%), making it realistic for large‐scale production of polymeric nanoparticles. In this review, the developments of PISA‐based polymeric nanoparticles for drug delivery are discussed. Drug delivery systems based on functionalized polymeric nanoparticles have attracted considerable attention. For fabrication of polymeric nanoparticles, polymerization‐induced self‐assembly (PISA) offers decisive advantages over conventional protocols in terms of efficiency and cost‐effectiveness. Recently, the nascent investigation of functional PISA‐generated nanocarriers with stimulus‐responsive drug release has already found applications in the biomedical area, which is discussed in this review. [ABSTRACT FROM AUTHOR]

Multiblock copolymers are envisioned as promising materials with enhanced properties and functionality compared with their diblock/triblock counterparts. However, the current approaches can construct multiblock copolymers with a limited number of blocks but tedious procedures. Here, we report a thioester‐relayed in‐chain cascade copolymerization strategy for the easy preparation of multiblock copolymers with on‐demand blocks, in which thioester groups with on‐demand numbers are built in the polymer backbone by controlled/living polymerizations. These thioester groups further serve as the in‐chain initiating centers to trigger the acyl group transfer ring‐opening polymerization of episulfides independently and concurrently to extend the polymer backbone into multiblock structures. The compositions, number of blocks, and block degree of polymerization can be easily regulated. This strategy can offer easy access to a library of multiblock copolymers with ≈100 blocks in only 2 to 4 steps. [ABSTRACT FROM AUTHOR]

Multiblock copolymers are envisioned as promising materials with enhanced properties and functionality compared with their diblock/triblock counterparts. However, the current approaches can construct multiblock copolymers with a limited number of blocks but tedious procedures. Here, we report a thioester‐relayed in‐chain cascade copolymerization strategy for the easy preparation of multiblock copolymers with on‐demand blocks, in which thioester groups with on‐demand numbers are built in the polymer backbone by controlled/living polymerizations. These thioester groups further serve as the in‐chain initiating centers to trigger the acyl group transfer ring‐opening polymerization of episulfides independently and concurrently to extend the polymer backbone into multiblock structures. The compositions, number of blocks, and block degree of polymerization can be easily regulated. This strategy can offer easy access to a library of multiblock copolymers with ≈100 blocks in only 2 to 4 steps. [ABSTRACT FROM AUTHOR]

Worm‐like micelles have attracted great interest due to their anisotropic structures. However, the experimental conditions for obtaining worm‐like micelles are very restricted, which usually causes seriously poor reproducibility. In this work, significantly enhanced accessibility of worm‐like micelles is realized by in situ crosslinking polymerization‐induced self‐assembly (PISA). The reproducibility of worm‐like micelles is greatly improved due to the significantly enlarged experimental windows of worm‐like micelles in the morphology diagram. Moreover, the reliability of the methodology to enhance the accessibility of worm‐like micelles has been demonstrated in various in situ crosslinking PISA systems. The greatly enhanced accessibility and reproducibility of worm‐like micelles is undoubtedly cost‐effective especially in scale‐up production, which paves the way for further application of worm‐like micelles with various compositions and functionalities. [ABSTRACT FROM AUTHOR]

Worm‐like micelles have attracted great interest due to their anisotropic structures. However, the experimental conditions for obtaining worm‐like micelles are very restricted, which usually causes seriously poor reproducibility. In this work, significantly enhanced accessibility of worm‐like micelles is realized by in situ crosslinking polymerization‐induced self‐assembly (PISA). The reproducibility of worm‐like micelles is greatly improved due to the significantly enlarged experimental windows of worm‐like micelles in the morphology diagram. Moreover, the reliability of the methodology to enhance the accessibility of worm‐like micelles has been demonstrated in various in situ crosslinking PISA systems. The greatly enhanced accessibility and reproducibility of worm‐like micelles is undoubtedly cost‐effective especially in scale‐up production, which paves the way for further application of worm‐like micelles with various compositions and functionalities. [ABSTRACT FROM AUTHOR]

Providing access to diverse polymer structures is highly desirable, which helps to explore new polymer materials. Poly(thioester sulfonamide)s, combining both the advantages of thioesters and amides, however, are rarely available in polymer chemistry. Here, the ring‐opening copolymerization (ROCOP) of cyclic thioanhydride with N‐sulfonyl aziridine using mild phosphazene base, resulting in well‐defined poly(thioester sulfonamide)s with highly alternative structures, high yields, and controlled molecular weights, is reported. Additionally, benefiting from the mild catalytic process, this ROCOP can be combined with ROCOP of N‐sulfonyl aziridines with cyclic anhydrides to produce novel block copolymers. [ABSTRACT FROM AUTHOR]

Graft copolymers with pendant macrocycles were synthesized via “graft onto” method. First, cyclic polystyrene (PS) was achieved by the combination of atom transfer radical polymerization (ATRP) and Cu-catalyzed azide–alkyne cycloaddition (CuAAc), and then an alkynyl group was introduced to cyclic PS. Meanwhile, poly(3-azide-2-hydroxypropyl methacrylate) (PGMA-N 3 ) was synthesized by ATRP of glycidyl methacrylate (GMA) and successive ring-opening of pendant epoxide ring with NaN 3 . The graft copolymer was achieved by the following click reaction between PGMA-N 3 and alkynyl-containing cyclic PS. GPC and 1 H NMR were utilized to characterize the obtained graft copolymers, and a maximal grafting density of 20% was observed. Thermal behaviors of linear PS, cyclic PS and PGMA grafted with cyclic PS (PGMA-g-cPS) were investigated by differential scanning calorimeter (DSC), and T g of PGMA-g-cPS is higher than those of linear and cyclic PS. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The size and size distribution of polymeric nanoparticles have great impact on their physicochemical and biological properties. Polymerization‐induced self‐assembly (PISA) has been demonstrated to be an efficient method to fabricate various polymeric nanoparticles, among which polymeric vesicles have attracted great interest due to their unique hollow structure. However, polymeric vesicles with relatively broad size distributions and random size are normally formed, which is problematic for many potential applications. Herein, we report the synthesis of polymeric vesicles with low‐polydispersity and controllable size by polymerization‐induced self‐assembly. A mixed macro RAFT agent of three different poly(ethylene glycol) (PEGm‐CPADB) was used to mediate the RAFT dispersion copolymerization of 7‐(2‐methacryloyloxyethoxy)‐4‐methylcoumarin (CMA) and benzyl methacrylate (BzMA), which generated vesicles with low‐polydispersity (< 0.1) and controllable size in the scope of sub‐100 nm. In comparison, RAFT dispersion copolymerization of CMA and BzMA using a single PEG‐CPADB as the macro RAFT agent generated vesicles with adjustable but obviously larger size and broader size distributions (> 0.1). The results demonstrate that the ternary stabilizers play a crucial role in the formation of small and low‐polydispersity vesicles. [ABSTRACT FROM AUTHOR]

Though many responsive polymers havebeen prepared, none of them can both self-immolate and self-cross-linkvia responding to the changes of the environment. Here, we introducea new responsive hyperbranched polymer, which not only can self-immolatebut also can self-cross-link via responding to the external stimuli.Moreover, the obtained polymer can form a bioreducible nanogel inits aqueous solution simply via heating, and the formed nanogel canself-immolate via UV irradiation. [ABSTRACT FROM AUTHOR]

Highlights: [•] PEG chains were linked on hyperbranched poly(amido amine) via Michael addition reaction. [•] The fluorescence of PEGylated hyperbranched poly(amido amine) was investigated. [•] The fluorescent PEGylated hyperbranched poly(amido amine) was used cell imaging. [Copyright &y& Elsevier]

Abstract: Linear pH-sensitive poly(amido amine)s were synthesized via Michael addition polymerization of N-aminoethyl piperazine (AEPZ) or 4-aminomethyl piperidine (AMPD) with 1,12-dodecylene diacrylamide (DDA). Successive Michael addition reaction of acryl-terminated poly(ethylene oxide) (A-PEO) with the secondary amine of linear poly(DDA–AEPZ) that has one secondary amine in every repeating unit afforded PEO-grafted poly(amido amine). Variation of grafting degree could be obtained conveniently via tuning the feed molar ratio of acryl/secondary amine. When this ratio equals to 1.2, all the secondary amines on the backbone of poly(DDA–AEPZ) (or poly(DDA–AMPD)) were consumed and the comb-shaped polymers were formed. The amphiphilic comb-shaped poly(DDA–AEPZ)-g-PEO was molecularly dissolved in water at pH 2.0 (w/v=0.25%), and micelles were formed when pH value of aqueous solution was adjusted to 6.5. 1H NMR data verify the formation of micelles due to the disappearance of signals attributed to poly(DDA–AEPZ). The formation of micelles can be confirmed further by TEM photos, they show that all the particles are approximately spherical and their number-average diameter is around 95nm. [Copyright &y& Elsevier]

Abstract: Comb-shaped graft copolymers with poly(methyl acrylate) as a handle were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP) techniques in three steps. First, copolymers of poly(styrene-co-chloromethyl styrene), poly(St-co-CMS), were prepared by RAFT copolymerization of St and CMS using 1-(ethoxycarbonyl)prop-1-yl dithiobenzoate (EPDTB) as RAFT agent. Second, the polymerization of MA using poly(St-co-CMS)-SC(S)Ph as macromolecular chain transfer agent produced block copolymer poly(St-co-CMS)-b-PMA. Third, cationic ring-opening polymerization of THF was performed using poly(St-co-CMS)-b-PMA/AgClO4 as initiating system to produce comb-shaped copolymers. The structures of the poly(St-co-CMS), poly(St-co-CMS)-b-PMA and final comb-shaped copolymers were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). [Copyright &y& Elsevier]

Providing access to highly diverse polymer structures by multicomponent reactions is highly desirable; efficient Meldrum's acid‐based multicomponent reactions, however, have been rarely highlighted in polymer chemistry. Here, the three‐component reaction of Meldrum's acid, indole, and aldehyde is introduced into polymer synthesis. Direct multicomponent polymerization of Meldrum's acid, dialdehyde, and diindole can perform under mild conditions, resulting in complex Meldrum's acid‐containing polymers with well‐defined structures, and high molecular weights. Additionally, nearly quantitative postpolymerization modification can also perform via this Meldrum's acid‐based multicomponent reaction. These results indicate that Meldrum's acid‐based multicomponent reaction will be a potential tool to prepare novel polymers. [ABSTRACT FROM AUTHOR]

Polymerization‐induced self‐assembly has been demonstrated to be a powerful strategy for fabricating polymeric nanoparticles in the last two decades. However, the stringent requirements for the monomers greatly limit the chemical versatility of PISA‐based functional nanoparticles and expanding the monomer family of PISA is still highly desirable. Herein, a camptothecin analogue (CPTM) is first used as the monomer in PISA. Prodrug nanoparticles with reduction‐responsive camptothecin release behavior are fabricated at 10% solid concentration (100 mg g−1). Poly(N‐(2‐hydroxypropyl)methacrylamide) (PHPMA) and poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) are used as the macro RAFT agents to comediate the RAFT dispersion polymerization of CPTM in ethanol to produce the PHPMA/PDEAEMA‐stabilized nanoparticles. The PDEAEMA chains become hydrophobic and are in the collapsed state at physiological pH values. In contrast, in the vicinity of an acidic tumor, the tertiary amine groups of PDEAEMA chains are rapidly protonated, leading to fast hydrophobic‐hydrophilic transitions and charge reversal. Such fast charge‐reversal results in enhanced cancer cell internalization of the prodrug nanoparticles, thus achieving superior anticancer efficacy. [ABSTRACT FROM AUTHOR]

Visible light‐driving syntheses have emerged as a powerful tool for organic synthesis and for the preparation of macromolecules under mild and environmentally benign conditions. However, precious but nonreusable photosensitizers or photocatalysts are often required to activate the reaction, limiting its practicality. Here, it is reported that poly(1,4‐diphenylbutadiyne) (PDPB) nanofibers exhibit remarkable activity in driving the living free radical polymerization under visible light. Moreover, PDPB nanofibers are very stable under irradiation of visible light and can be reused without appreciable loss of activity even after repeated cycling. The nanofiber will be a promising photocatalyst with excellent reusability and stability for the reactions driven by visible light. [ABSTRACT FROM AUTHOR]

Mitochondrial malfunction is considered to be a decisive signal of apoptosis. It would be a promising strategy to target mitochondria in cancer cells to generate reactive oxygen species (ROS), thus directly inducing mitochondrial damage. We herein reported a mitochondria-targeted, photo-responsive polymer (Mito-PNBE), which can self-assemble into nanoparticles (Fe–CO@Mito-PNBE) encapsulated with diphenylcyclopropenone (light-responsive CO prodrugs) and aminoferrocene-based prodrugs via hydrophobic interactions. Upon UV-irradiation, the rapid release of CO and aminoferrocene-based prodrugs caused by disassembly was observed. On one hand, the released carbon monoxide in mitochondria could enhance ROS generation and accelerate oxidative metabolism. On the other hand, the aminoferrocene-based prodrugs will release Fe3+/Fe2+ ions in the tumor microenvironment, thus triggering the Fenton reaction, which generates more ROS and damages the mitochondria. Thus, the synergistic effect of the two drugs produces enough amounts of ROS in the mitochondria, leading to mitochondrial collapse with an enhanced cancer therapeutic effect. This multifunctional platform has potential in precision cancer therapy. [ABSTRACT FROM AUTHOR]

Synthesizing copolymers with controlled, and even precise sequence structures, such as biological macromolecules, has been a serious challenge in polymer science. Recently, hybrid polymerization has become an attention-getting synthetic method for preparing copolymers with different sequence structures. In this review, we will discuss this method and focus on the sequence structure of the obtained copolymers, which have gone through a process from producing random uncontrollable sequences, to constructing sequence-controlled copolymers and even sequence-on-demand copolymers. [ABSTRACT FROM AUTHOR]

A new strategy combing quantitative reactions and reversible-covalent chemistry is proposed for sequential synthesis of a series of sequence-controlled polymers with different sequences. Using a Michael addition reaction between acrylate and thiol, an aminolysis reaction of five-membered cyclic dithiocarbonate and a thiol substitution reaction of bromomaleimide and thiol, AB-, AB'C- and AB'CD-sequenced molecules are synthesized via AB, AB'C and AB'CD sequential monomer additions, respectively. These three molecules all have furan-protected maleimido group at one end, and the other end of AB-, AB'C- and AB'CD-sequenced molecules is amine, thiol and anthracene groups, respectively. Due to the fact that the furan-protected maleimido group can be efficiently transformed to maleimide group at high temperature via retro Diels-Alder reaction, AB-, AB'C- and AB'CD-sequenced molecules polymerize into sequence-controlled polymers with corresponding sequences at 120 °C. Through this strategy, the synthesis of molecular modules does not require separation and purification, and sequence-controlled polymers with specific sequence can be synthesized in a one-pot process via adding different monomers and adjusting reaction condition. Image 1 • Synthesis of sequence-controlled polymers based on quantitative reactions and reversible-covalent chemistry. • Free of separation and purification in the synthetic process of molecular modules. • Controlling the sequence of synthetic polymers via adding different monomers and adjusting reaction condition. [ABSTRACT FROM AUTHOR]

Sequence-controlled polymers are prepared by the combination of thiol-ene click reaction and amino-yne click reaction. Due to the high selectivity of the amine unit and thiol unit toward thiolactone, methacrylate, propiolate, etc., the sequence of the resulting polymers can be easily controlled by monomer-addition sequence. Moreover, thiol-ene click reaction and amino-yne click reaction can be carried out under mild conditions without need of any catalyst. Different kinds of sequence-controlled copolymers have been prepared by the combination of thiol-ene click reaction and amino-yne click reaction in one pot. NMR spectra and GPC traces confirmed the formation of polymers with high molecular weight and controlled sequence structure. Therefore, we provide a new method for the preparation of functional polymers with well-controlled sequences. [ABSTRACT FROM AUTHOR]

A RAFT/MADIX method can not only copolymerize ethylene with a diverse range of functionally polar monomers, but can also easily tune the polar composition and the polar monomer distribution along the produced copolymer chains. This highly versatile RAFT/MADIX copolymerization platform provides access to a diverse range of polyethylene materials. [ABSTRACT FROM AUTHOR]

• A copolymer that could target and create fast closable holes in the cell membrane. • Direct delivery of exogenous genes into cell cytosol, avoiding endosome trapping. • Achieving high gene transfection and deep penetration into tumor tissue. Delivering exogenous compounds into cells in vitro or in vivo is a critical yet very challenging step in gene- and cell-based therapies, biomanufacturing, and basic research. Although several nanotechnologies could highly facilitate exogenous compounds into the target cell, they are typically internalized by cells into membrane-bounded endosomes, and most of them are trapped in these endosomes and degraded by endosomes, failing to access the cytosolic cell machinery. Here, we have prepared a copolymer that could target and create fast closable holes in the cell membrane, via which the exogenous genes in nanoparticles can be directly delivered into the cell cytosol, highly bypassing the severe endosome trapping of normal delivery approaches and achieving high gene transfection. Moreover, in cells, the copolymer undergoes fast deboronation to release the absorbed lipid for fast repair of the holes. This cell membrane hole-creating copolymer would provide a very promising means for delivering functional nanoparticles, DNA, RNA, and proteins directly into the cell cytosol, avoiding cargo entrapment in endosomes and maintaining cargo functionality after delivery. [ABSTRACT FROM AUTHOR]

• Functional polyester with zinc is designed and synthesized. • The constructed polyester could recognize the cell membrane of bacteria. • The functional polyester could inhibit the cell wall synthesis. • Caging UDP kills bacteria without detectable resistance. The increasing spread of antimicrobial resistance results in untreatable infections, causing thousands of deaths. Thus, it is urgent to find new antibiotics that kill the causative pathogen via a novel action mechanism without detectable resistance. The pyrophosphate structures of UDP-MurNAc-pentapeptide, lipid I, and lipid II in bacteria cytoplasm are highly conserved but play a key role in bacterial wall synthesis and is a promising target for antibiotics. However, to date, no attempt to target pyrophosphate has been made to kill bacteria. Here, we found that a synthetic cage, denoted as PZn2020, can tightly cage pyrophosphate structures blocking transport of lipid and the biosynthesis of cell wall to kill bacteria. It exhibits sub-μg activity against all gram-negative and gram-positive bacteria tested and avoids detectable resistance with low host toxicity. Such a caging pyrophosphate strategy suggests a path towards developing antibiotics with a new mechanism that is likely to avoid the development of resistance. [ABSTRACT FROM AUTHOR]

Pure cross-linked spherical micelles, nanowires, and vesicles are successfully fabricated from poly(2-hydroxypropyl methacrylate- b- p-(methacryloxyethoxy)benzaldehyde)s (PHPMA- b-PMAEBAs) through reversible addition-fragmentation chain transfer dispersion polymerization of MAEBA in methanol using PHPMA as a macro-CTA and subsequent cross-linking. The cross-linking reaction is conducted by stirring a mixture of 1,4-butanediamine and the resultant nano-objects in methanol at room temperature. For all polymerizations with feed molar ratios of MAEBA/PHPMA ranging from 75/1 to 240/1, the monomer MAEBA conversions are almost complete, and block copolymers with controlled molecular weight are obtained. The transmission electron microscopy, dynamic light scattering, and gel permeation chromatography results reveal that the following three factors significantly influence the morphology of the nano-objects: the feed molar ratio of MAEBA/PHPMA, the copolymer concentration, and the degree of polymerization of PHPMA. The cross-linked nano-objects are very stable in good solvents, the spheres and nanowires slightly decrease in size after cross-linking, whereas the vesicles slightly increase in size. The cross-linked nano-objects are stable in neutral solutions, but they dissociate in weekly acidic solutions. The loading of 1-pyrenemethylamine (PMA) into the vesicles and the unloading of PMA from the vesicles are studied. [ABSTRACT FROM AUTHOR]

Multicomponent reactions are of substantial significance not only for organic synthesis but also for polymer synthesis due to their more bond-forming events per synthetic operation. Generally due to that there are two or more reactions in one multicomponent reaction system, synergistic catalysis, in which the two or more reactions are activated by two or more different catalysts at the same time, is very important for achieving high-efficiency transformations. However, achieving synergistic catalysis via using two or more different catalyst simultaneously is a great challenge. Here, we propose a new reactant-synergistically catalyzed multicomponent reaction, in which the units coming from the reactant can synergistically catalyze the two reactions at the same time. Moreover, this multicomponent reaction can be extended to multicomponent polymerization, which is a very promising method for the preparation of functional polymers with defined-sequence. [ABSTRACT FROM AUTHOR]

In this study, we have prepared aself-cross-linking PEG-basedbranched polymer, which easily forms a bioreducible nanoshell aroundpolyplexes of cationic polymer and DNA, simply via heating the polyplexdispersions in the presence of this self-cross-linking branched polymer.This nanoshell can prevent the polyplex from dissociation and aggregationin physiological fluids without inhibiting the electrostatic interactionsbetween the polymer and DNA. Furthermore, glutathione (GSH) can actas a stimulus to open the nanoshell after it has entered the cell.The polyplexes coated with the bioreducible nanoshell show an obviousenhancement in gene transfection in vivo compared with bare polyplexes. [ABSTRACT FROM AUTHOR]

A new and easy method of stimuli-triggered growth and removal of a bioreducible nanoshell on nanoparticles is reported. The results show that pH or temperature could induce the aggregation of disulfide-contained branched polymers at the surface of nanoparticles; subsequently, the aggregated polymers could undergo intermolecular disulfide exchange to cross-link the aggregated polymers, forming a bioreducible polymer shell around nanoparticles. When these nanoparticles with a polymer shell are treated with glutathione (GSH) or d,l-dithiothreitol (DTT), the polymer shell could be easily removed from the nanoparticles. The potential application of this method is demonstrated by easily growing and removing a bioreducible shell from liposomes, and improvement of in vivo gene transfection activity of liposomes with a bioreducible PEG shell. [ABSTRACT FROM AUTHOR]

A versatile one-pot strategy for the preparation of reversibly cross-linked polymer-coated mesoporous silica nanoparticles (MSNs) via surface reversible addition-fragmentation chain transfer (RAFT) polymerization is presented for the first time in this paper. The less reactive monomer oligo(ethylene glycol) acrylate (OEGA) and the more reactive cross-linker N,N′-cystaminebismethacrylamide (CBMA) are chosen to be copolymerized on the external surfaces of RAFT agent-functionalized MSNs to form the cross-linked polymer shells. Owing to the reversible cleavage and restoration of disulfide bonds via reduction/oxidation reactions, the polymer shells can control the on/off switching of the nanopores and regulate the drug loading and release. The redox-responsive release of doxorubicin (DOX) from this drug carrier is realized. The protein adsorption, in vitro cytotoxicity assays, and endocytosis studies demonstrate that this biocompatible vehicle is a potential candidate for delivering drugs. It is expected that this versatile grafting strategy may help fabricate satisfying MSN-based drug delivery systems for clinical application. [ABSTRACT FROM AUTHOR]

Polymerization-induced self-assembly (PISA) is an efficient and robust strategy to fabricate polymeric nano-objects. PISA enables us to prepare polymeric nano-objects in situ during the course of polymerization in concentrated solution (up to 50% w/w), making industrial production of polymeric assemblies in large-scale possible. In this work, reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of styrene (St) and N-methacryloxysuccinimide (NMAS) was conducted with poly(2-hydroxyethyl acrylate) (PHEA) as a macro-chain transfer agent (macro-CTA) in methanol. Compared with the PHEA-mediated alcoholic dispersion polymerization of St, RAFT dispersion copolymerization of St and NMAS promoted morphology transition of nano-objects to form higher order morphologies (such as worms and vesicles). Moreover, the introduction of NMAS units into the solvophobic blocks provided functional handles for post-PISA modification of the resultant nano-objects via the active ester-amine reaction. The reaction of 1,6-hexanediamine with NMAS units in P(St- co -NMAS) blocks was conducted to afford cross-linked nano-objects with robust structural stability. [Display omitted] • Polymerization-induced self-assembly. • Promoted morphology transition. • Cross-linking. [ABSTRACT FROM AUTHOR]

A simple and efficient method to construct a hyperbranched multicyclic polymer is introduced. First, a tailored trithiocarbonate with two terminal anthracene units and three azide groups is successfully synthesized, and this multifunctional trithiocarbonate is used as chain transfer agent (CTA) to afford anthracene‐telechelic polystyrene (PS) via reversible addition‐fragmentation chain transfer (RAFT) polymerization. After that, linear PS is irradiated under 365 nm UV light to achieve the cyclization process. The monocyclic polymer further reacts with sym‐dibenzo‐1,5‐cyclooctadiene‐3,7‐diyne via "A2+B3" strategy based on a self‐accelerating click reaction to produce hyperbranched multicyclic polymer. The structures and properties of the polymers are characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), UV–vis spectrophotometry, and triple‐detection size‐exclusion chromatography (TD‐SEC). The number of monocyclic units of the resultant hyperbranched multicyclic polymer reaches about 21 based on multi‐angle laser light scattering (MALLS) measurements. The plot of intrinsic viscosity versus molecular weight reveals that the α value of the unique hyperbranched multicyclic polymer is lower than both hyperbranched polymers and cyclic polymers. [ABSTRACT FROM AUTHOR]