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Bacterial proliferation and the disordered extracellular matrix (ECM) at the wound site are the major reasons for delayed healing and abnormal scarring. The development of new multifunctional dressing materials that can effectively prevent scar formation without delaying wound healing remains a challenge. In this study, we construct a verteporfin-loaded biodegradable hydrogel (VP-gel) using hyaluronic acid and thiol-terminated 4-arm polyethylene glycol (PEG). The injectable VP-gel sustainably releases small doses of verteporfin in the wound microenvironment that generates reactive oxygen species (ROS) under red light irradiation to kill bacteria efficiently. Importantly, the sustained release of VP could also regulate TGF-β family-induced cellular responses and the downstream signaling molecule Smad2 in fibroblasts to reduce myofibroblast differentiation, promoting ECM reconstruction and scarless wound healing. Immunohistochemical examination of wound healing and histomorphology in a mouse full-thickness wound model demonstrates excellent acceleration effects of VP-gel for infected wound healing. Therefore, VP-gel with anti-scarring and antibacterial activity, as well as enhanced infection wound healing ability shows great potential in the clinical treatment of scar healing for infected wounds.

Sonodynamic therapy has attracted widespread attention for cancer treatment because of its noninvasiveness and high tissue-penetration ability. Generally, ultrasound irradiation of sonosensitizers produces separated electrons (eSupplementary material (the UV-vis-NIR absorption spectra of the DPBF and the RhB, biological effect assessment of the Au-rGO-ZnO@PVP, and the inhibition rate of tumor under different treatments during the animal study) is available in the online version of this article at 10.1007/s12274-022-4599-5.

A functional nanoplatform Cu@P–B was constructed, which could release disulfiram prodrug and CuO2 to generate the poisonous copper complex and elevate ROS to kill tumor cells, providing a new perspective in cancer therapy.

Antimicrobial resistance in Gram-negative bacteria has become one of the leading causes of morbidity and mortality and a serious worldwide public health concern due to the fact that Gram-negative bacteria have an additional outer membrane protecting them from an unwanted compound invading. It is still very difficult for antimicrobials to reach intracellular targets and very challenging to treat Gram-negative bacteria with the current strategies. Here, we found that (o-(bromomethyl)phenyl)boronic acid was incorporated into poly((2-N,N-diethyl)aminoethyl acrylate) (PDEA), forming a copolymer (poly(o-Bn-DEA)) having both phenylboronic acid (B) and ((2-N,N-diethyl)amino) (DEA) units. Poly(o-Bn-DEA) exhibits very strong intramolecular B-N coordination, which could highly promote the covalent binding of phenylboronic acid with lipopolysaccharide (LPS) on the outer membrane of E. coli and lodge poly(o-Bn-DEA) on the LPS layer on the surface of E. coli. Meanwhile, the strong electrostatic interaction between poly(o-Bn-DEA) and the negatively charged lipid preferred tugging the poly(o-Bn-DEA) into the lipid bilayer of E. coli. The combating interactions between covalent binding and electrostatic interaction form a tug-of-war action, which could trigger the lysis of the outer membrane, thereby killing Gram-negative E. coli effectively without detectable resistance.

Advances in nanotechnology depend upon expanding the ability to create biologically inspired complex materials with well-defined multidimensional structures. Fabrication of hybrid hierarchical stru...

Polymerization-induced self-assembly (PISA) has been established as an efficient method to fabricate polymeric vesicles. In most PISA cases, the formation of vesicles is solely driven by the solvop...

In comparison with the post-polymerization cross-linking strategy, in situ cross-linking by divinyl comonomers in polymerization-induced self-assembly (PISA) is a more straightforward and convenient approach to produce structurally stabilized nano-objects. However, cross-linking usually lowers the chain mobility and hence prevents morphology transition, so formation of higher order morphologies (worm-like micelles or vesicles) by the in situ cross-linking strategy in PISA has always been a great challenge. In this work, not only cross-linked structures but also a promoting effect on morphology transition has been observed during the in situ cross-linking PISA. Worm-like micelles, lamella and vesicles with stabilized (cross-linked) structures are produced by RAFT dispersion copolymerization of 2-(diisopropylamino)ethyl methacrylate (DIPEMA) and the divinyl comonomer cystaminebismethacrylamide (CBMA). The morphology transition is not prevented due to the slower consumption of CBMA than that of the DIPEMA, and the cross-linking process is mostly delayed to the late stage of polymerization. What is surprising, compared with RAFT dispersion polymerization of DIPEMA in the absence of CBMA, is that polymeric nano-objects with higher order morphologies are generated in most cases of the RAFT dispersion copolymerization of DIPEMA and CBMA. The slower consumption of CBMA generates branched structures of the solvophobic blocks, which significantly promote the morphology transition. Cleavage of the cross-linkers (disulfide linkage) by incubating with glutathione (GSH) leads to the morphology transition of the nano-objects to the lower order ones, which further demonstrates the promoting effect on morphology transition in in situ cross-linking PISA.

Harvesting and transforming water energy into electricity via nanostructured materials, which is termed hydrovoltaic power generation (HPG), has attracted increasing interest in the past few decades. However, the current limitation of HPG devices taking advantage of the electrokinetic effect is their poor power density within microwatts per square meter. Herein, a novel catalytic graphene aerogel film decorated with an interlayer catalyst of α-FeOOH was developed successfully. Upon the addition of H2O2 to a saline (NaCl) droplet, an exceptionally high voltage of 0.63 V was achieved, which is around 20 times higher than the previously reported value using single-layer graphene. The experimental and theoretical results showed that the high hydrovoltaic performance originates from three contributions. Firstly, the large droplet/graphene interfaces, benefitting from the high specific surface area of the aerogel and the bubbling effect produced by the catalytic decomposition of H2O2via α-FeOOH. Secondly, the enhanced electrokinetic effect, i.e., increased hydrated ion radius of NaCl and suppressed shielding effect between cations and anions in the presence of H2O2, which dramatically extends the NaCl concentration window from 0.6 M to 5.0 M. Thirdly, utilizing the advantage of electrochemical reactions related to H2O2 in the saline (NaCl) droplet to greatly increase the short-circuit current of the HPG device. The outcome of these contributions is a much higher ion utilization efficiency under a high saline concentration, which breaks the output bottleneck of power density caused by using a low saline concentration. Our work extends the device component from single-layer graphene to a 3D porous graphene aerogel, making a significant step forward for the future development of HPG devices.

In this article, we reported the hybrid copolymerization of ethylene and cyclic ketene acetals (CKAs) mediated by dithiocarbamate, in which the propagating radicals could open the rings of CKAs to incorporate cleavable ester units into the polyethylene backbone. The molecular weights and ester incorporation in the produced copolymers could be easily regulated. Furthermore, lipase could degrade the ester-containing polyethylene (PE)-based copolymers into short fragments effectively.

Bacterial infections have become a common global health problem, causing a wide range of properties and life loss. The development of a highly efficient, low-toxicity and targeted bacterial agent is urgently needed. As a conventional antibacterial agent, silver nanoparticles have been used for a long time, but they are still unable to achieve targeted bacterial killing. Herein, we have prepared surface positively (Ag(+) nanoparticles) and negatively (Ag(-) nanoparticles) charged silver nanoparticles by reduction of AgNO3 to construct Ag(-)/Ag(+) clusters. The zeta potential of the Ag(-)/Ag(+) nanoclusters could be controlled by changing the ratio of Ag(-) nanoparticles to Ag(+) nanoparticles. The surface negatively changed silver nanoparticles were prepared from the reaction of methyl maleic anhydride with the amino on the surface positively changed silver nanoparticles. In the acidic environment, Ag(-) nanoparticles undergo charge reversal, and Ag(-)/Ag(+) clusters with negatively charged nanoparticles and big-size are transformed into positively charged nanoparticles with small size. The in vitro experimental results demonstrate that the positively charged nanoparticles can be well adsorbed on the negatively charged bacteria, exhibiting a high bactericidal ability. Furthermore, the in vivo skin wound healing experiment showed that the Ag(-)/Ag(+) clusters could serve as an efficient antibacterial agent to combat bacterial infection.

With the widespread use of antibiotics, the number of severe infections caused by unknown pathogens is increasing and novel antibacterial agents with high antibacterial efficiency and selective bacterial killing are urgently needed. In this work, we developed a new kind of functional material based on silver nanoparticles (AgNPs), whose surfaces were functionalized with phenylboronic acid (AgNPs-PBA

Bacterial biofilms, as a fortress to protect bacteria, enhance resistance to antibiotics because of their limited penetration, which has become a major threat to current anti-infective therapy. Antimicrobial polycations have received wide attention to kill planktonic bacteria because of their unique antimicrobial mechanism without drug resistance but it is still hard to kill the bacteria in the deep of the biofilm. Unlike linear polymers, the cyclic topology has been demonstrated with enhanced penetration in tissues, which is attributed to the lack of end groups, constrained conformation and a smaller hydrodynamic volume, opening a new sight of polycations in the antibacterial application against biofilms. Here, polycations with different topologies including linear and cyclic polycations were synthesized and their killing activity against planktonic and biofilm bacteria was studied. The experimental results showed the enhanced antibacterial activity of cyclic polycations for planktonic bacteria, which is presumably attributed to their smaller hydrodynamic volume, higher local density of positive charge and more interactions between cation units and the bacterial membrane than their linear analogues. Besides, cyclic polycations exhibit enhanced killing effect for biofilm bacteria and inhibition effect for biofilms with 5-7 times and 2-3 times enhancements than the linear polycations, respectively. Furthermore, an

Aerogel fibers, the simultaneous embodiment of aerogel 3D network and fibrous geometry, have shown great advantages over natural and synthetic fibers in thermal insulation. However, as a fast gelation to ensure aerogel fiber spinning generally induces rapid local clustering of precursor particles (

Ring-opening polymerization of lactones has served as one of the most resourceful and versatile methods for the production of polyesters. However, the photocontrolled ring-opening polymerization of lactones with the advantages of being inexpensive, green, and noninvasive, is still rarely reported. In this work, we developed a series of composite photoacid generators containing a common photocatalyst and an onium salt to induce the living/controlled cationic ring-opening polymerization of lactones using benzyl alcohol or butyl alcohol as an initiator under visible light. The wavelength of the light could be easily adjustable by applying different photocatalysts. Moreover, radical species are generated concurrently during the electron transfer processes; as a result, simultaneous living/controlled cationic ring-opening polymerization of lactones and reversible addition–fragmentation chain transfer radical (RAFT) polymerization can be performed using hydroxy group capped trithiocarbonate to produce hybrid block copolymers. Photocontrolled ring-opening polymerization of lactones with the advantages of being inexpensive, green, and noninvasive, is still rarely reported. In this work, we developed a series of composite photoacid generators containing a common photocatalyst and an onium salt to induce the living/controlled cationic ring-opening polymerization of lactones using alcohol compound as an initiator under visible light. The wavelength of the light could be easily adjustable by applying different photocatalysts. Moreover, simultaneous living/controlled cationic ring-opening polymerization of lactones and reversible addition–fragmentation chain transfer radical (RAFT) polymerization of methyl acrylate can be performed using hydroxy group capped trithiocarbonate to produce hybrid block copolymers in one step.

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.

Polymerization-induced self-assembly (PISA) has been established as a robust strategy to synthesize block copolymer nano-objects with various morphologies, sizes, and surface chemistry, which greatly enlarges the library of functional nano-objects for further applications. The structural stability of nano-objects is an important concern when they are used in drug delivery, nanoreactors, Pickering emulsifiers, etc. Generally, chemical cross-linking via either post-polymerization or in situ cross-linking strategies has been demonstrated to be a viable strategy to improve the structural stability of the nano-objects. In this review, we focus on the PISA-generated nano-objects with enhanced structural stability via either post-polymerization or in situ cross-linking strategies and their applications.

Black phosphorus (BP) has exhibited excellent biocompatibility and high photothermal conversion efficiency under near-infrared light, which makes it very promising for photothermal therapy. However, practical applications are highly hampered because it lacks a targeting property and rapidly degrades in cancer cells, especially in response to strong intracellular oxidative stress. Here, we reported that the mitochondrial targeting peptide functionalized black phosphorus nanosheets covered with an acid-labile polymer shell (doubly functionalized black phosphorus (DFBP) nanosheets) exhibited good stability. DFBP nanosheets not only have excellent ability of accumulating in tumor tissue via surface charge switching but also can target mitochondria. The doubly functionalized black phosphorus nanosheets resulted in robust cancer cell uptake but very poor normal cell accumulation.

Cationic polymers with high charge density could effectively condense the DNA and achieve gene transfection; however, it often brings non-negligible cytotoxicity. Notably, the high charge density gene vector fails in the serum environment, limiting further application in vivo. In this paper, an efficient and reliable non-viral gene vector of poly (amidoamine) (PAA) was designed by introducing diacryolyl-2,6-diaminopyridine (DADAP) onto the PAA backbone through Michael-addition polymerization, which provides high transfection efficiency in a serum-containing environment. Diacryolyl-2,6-diaminopyridine and cationic parts provided multiple interactions between gene vectors and DNA, including hydrogen bond and electrostatic interactions. The introduction of hydrogen bonding can effectively reduce the charge density of polyplexes without reducing the DNA condensing ability, incorporating the diaminopyridine group and cationic part in PAA chains successfully consolidated cellular uptake, endosome destabilization, and transfection efficiency for the PAA/DNA complexes with low cytotoxicity. The constructed vector with multiple interactions presented 6 times higher transfection efficiency in serum-free and 9 times in serum-containing environment than that of branched polyethyleneimine (PEI 25K) in 293T cells in vitro. Therefore, introducing the hydrogen band to form low charge density polyplexes with high transfection efficiency and low cytotoxicity has a great potential in gene delivery.

In nature, the chemical energy and electrons stored in ATP and NADPH generated during irradiation can facilitate biochemical reactions under dark conditions. However, in artificial photoreaction systems, it is still very difficult to perform photoreactions under dark conditions due to the fact that the photogenerated charge pairs can recombine immediately upon ceasing the irradiation. Preventing the recombination of photogenerated charge pairs still constitutes a major challenge at present. Here, it is reported that functionalized carbon nitride nanomaterials having many heptazine rings with a positive charge distribution, which can tightly trap photogenerated electrons, efficiently prevent the recombination of photogenerated charges. These stored charges are exceedingly long-lived (up to months) and can drive photopolymerization without light irradiation, even after one month. The system introduced here demonstrates a new approach for storing light energy as long-lived radicals, enabling photoreactions under dark conditions.

Ti2C(OH)2 can relieve the hypoxia in tumors via generating O2 from endogenous H2O2 and inhibiting mitochondrial respiratory in cancer cell.

Antimicrobial resistance in Gram-negative bacteria has become one of the leading causes of morbidity and mortality and a serious worldwide public health concern due to the fact that Gram-negative bacteria have an additional outer membrane protecting them from an unwanted compound invading. It is still very difficult for antimicrobials to reach intracellular targets and very challenging to treat Gram-negative bacteria with the current strategies. Here, we found that (

The development of efficient and inexpensive materials for light energy conversion is very important for achieving sustainable energy supply and carbon neutrality. Polymeric carbon nitride has become a promising material for light energy conversion due to its advantages of simple preparation and high physical and chemical stability. However, the pristine polymeric carbon nitride only absorbs light with a wavelength of less than 450 nm, and the energy conversion for low-energy photons is very limited. Here, by introducing the pyromellitic dianhydride component to construct an in-plane heterostructure, the conjugated structure of polymeric carbon nitride is successfully expanded. This in-plane carbon nitride-carbon nanoribbon (C3 N4 -C) heterostructure has an ultrawide absorption range from 200 to 2000 nm. Compared with the original material, the photothermal conversion performance of C3 N4 -C is significantly improved under the irradiation of Xe lamp or infrared laser. Furthermore, C3 N4 -C exhibits good potential for synergistic photothermal and chemotherapy. This work provides a simple strategy to construct expanded conjugate structure for improved light absorption and energy conversion materials based on polymeric carbon nitride.

The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

Synthesizing artificial polymers with precise sequence structures, such as their biological analogues, is a serious challenge and of great importance in polymer science. Recently, step-growth polymerization and chain growth polymerization have been the main synthesis methods for preparing artificial sequence-regulated polymers. However, it is difficult to obtain sequence-controlled polymers with sufficient molecular diversity via step-growth polymerization; on the other hand, chain-growth polymerization generally requires laborious repetitive monomer feeding. In this focus review, the sequential multicomponent reactions for preparing periodic sequence-controlled polymers with sufficient molecular diversity and complexity and the interconvertible hybrid copolymerizations producing hybrid multiblock copolymers rapidly in one pot are highlighted. We have developed sequential multicomponent reaction and interconvertible hybrid copolymerization methods to prepare sequence-controlled polymers. The sequential multicomponent reaction combines more than two different multicomponent reactions in one pot to prepare periodic sequence˗controlled polymers with sufficient molecular diversity. The interconvertible hybrid copolymerization method uses trithiocarbonate compounds to combine radical polymerization of vinyl monomers and anionic ring-opening polymerization of thiirane monomers, resulting in hybrid multiblock sequence-regulated polymers.

Intratumoral glucose depletion-induced cancer starvation represents an important strategy for anticancer therapy, but it is often limited by systemic toxicity, nonspecificity, and adaptive development of parallel energy supplies. Herein, we introduce a concept of cascaded catalytic nanomedicine by combining targeted tumor starvation and deoxygenation-activated chemotherapy for an efficient cancer treatment with reduced systemic toxicity. Briefly, nanoclustered cascaded enzymes were synthesized by covalently cross-linking glucose oxidase (GOx) and catalase (CAT) via a pH-responsive polymer. The release of the enzymes can be first triggered by the mildly acidic tumor microenvironment and then be self-accelerated by the subsequent generation of gluconic acid. Once released, GOx can rapidly deplete glucose and molecular oxygen in tumor cells while the toxic side product, i.e., H2O2, can be readily decomposed by CAT for site-specific and low-toxicity tumor starvation. Furthermore, the enzymatic cascades also created a local hypoxia with the oxygen consumption and reductase-activated prodrugs for an additional chemotherapy. The current report represents a promising combinatorial approach using cascaded catalytic nanomedicine to reach concurrent selectivity and efficiency of cancer therapeutics.

The synthesis and applications of dual- or multi stimuli-responsive polymers have gained increasing attention. One-pot strategy by combination two different polymerization mechanisms is promising for the synthesis of dually stimuli-responsive polymers in a rapid route. In this work, we report a convertible anionic ring-opening and RAFT polymerization by using asymmetrical trithiocarbonate as both an initiator for the anionic ring-opening polymerization and a chain transfer agent for RAFT polymerization to produce poly(propylene sulfide) (PPS)- poly(N-isopropylmethacrylamide) block-like copolymers. Furthermore, the ROS and temperature responsibility of the formed copolymer are also evaluated.

Hybrid copolymerization of two or more structurally distinct monomers (e.g., cyclic monomers and vinyl-type monomers) is very interesting because it can produce new types of copolymers and open up new research directions in the field of polymer chemistry. However, it has long been a challenge because the reactivity and polymerization mechanism of different monomers are extremely different. Here, we report a new hybrid copolymerization via an interconvertible living free radical and anion ring-opening polymerization mechanism, in which the copolymerization of cyclic monomers and vinyl-type monomers can be achieved. Via this novel hybrid copolymerization, the cyclic monomers and vinyl monomers, which generally cannot be copolymerized, now can be copolymerized into one polymer chain. Furthermore, the monomer arrangement in the chains could be easily regulated by the interconverting behavior. This new hybrid copolymerization will provide a powerful means for producing materials that have not been accessible by any other means.

The tumor hypoxic microenvironment (THME) has a profound impact on tumor progression, and modulation of the THME has become an essential strategy to promote photodynamic therapy (PDT). Here, an oxygen self-supplied nanodelivery system that is based on nanometal-organic frameworks (nMOFs) with embedded AuNPs (Au@ZIF-8) on the nMOF surface as a catalase (CAT)-like nanozyme and encapsulating Ce6 inside as a photosensitizer was found to mitigate tumor hypoxia and reinforce PDT. As soon as Au@ZIF-8 reaches the tumor site, the AuNP nanozyme can catalyze excessive H2O2 to produce O2 to alleviate tumor hypoxia, promoting the production of 1O2 with strong toxicity toward tumor cells under irradiation. Our study demonstrates that nMOFs embellished with a nanozyme have great potential for overcoming the THME for cancer therapeutics, which provides a facile strategy for accurate bioimaging and cancer therapy in vivo.

Aerogel is a kind of high-performance lightweight open-porous solids with ultralow density, high specific surface area, and broad application in many emerging fields including biotechnology, energy, environment, aerospace, etc. A giant challenge remains in preventing of the hydrophilic aerogel framework shrinkage when replacing of solvent with air in its extremely abundant nanosized pores during its fabrication process in ambient conditions. In this work, started from a linear polymeric precursor with further condensation reaction, superhydrophilic silica aerogels with self-reinforced microstructure and the least volume shrinkage have been successfully obtained via ambient pressure drying process without use of any additives in the presence of a low surface tension solvent. The resulting superhydrophilic silica aerogels possess specific surface area up to 1065 m2/g, pore volume up to 2.17 cm3/g and density down to 84 mg/cm3, and these values are comparable to those of their counterparts obtained by supercritical CO2 drying process. Moreover, as an application demonstration, the bioinspired hydrogels with desirable mechanical flexibility and adhesive performance at extremely harsh environment (e.g., below -50 °C) have been successfully synthesized by mimicking carrier of a functional bioagent with the resulting superhydrophilic silica aerogel microparticles. Our work has made a significant step forward for future high-performance hydrophilic aerogels with self-enhanced microstructures and the resulting superhydrophilic aerogels have shown great potentials in making functional hydrogels with bionic properties.

The sustainable light can generate reduction and oxidation centers in situ through the generation of photoexcited electrons and holes in the presence of photocatalyst. However, the photoexcited electrons and holes have huge Coulombic attraction and high exciton binding energy due to the weak screening effect and dielectric properties in many low-dimensional conjugated polymers, such as carbon nitride. Reducing the exciton binding energy of carbon nitride and promoting the conversion of excitons into free charge carriers are necessary for improving the activity of photocatalytic reactions but still very challenging. Here, by introducing amino-cyano functional groups into carbon nitride, it is demonstrated that excitons can be effectively dissociated into electrons and holes by finely controlling the charge distribution of heptazine ring. It is found that carbon nitride with heptazine rings of positive charge distribution can greatly reduce the exciton binding energy to 24 from 71 meV. Compared with heptazine ring having negative charge distribution, heptazine ring with positive charge distribution can increase photocatalytic hydrogen production of carbon nitride by up to ten times. This work provides an easy way to promote the dissociation of excitons in carbon nitride by regulating the charge distribution.

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.

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.

The size and shape of polymeric vesicles have great impact on their physicochemical and biological properties. Polymerization-induced self-assembly (PISA) is an efficient method to fabricate vesicles. In most PISA-cases, the formation of vesicles is driven by the solvophobic interactions which are lack of versatility on finely structural regulation. Herein, controlling vesicular size and shape is realized in PISA aided by aromatic interactions. Aromatic interactions between the membrane-forming blocks contribute to the augments of membrane tension which lead to the formation of smaller vesicles (as small as 70 nm), but overly enhanced aromatic interactions result in vesicle fusion rather than size decreasing. When the membrane tension is dominated by aromatic interactions and meanwhile high enough to overcome the energetic barriers of fusion, the aromatic interactions drive vesicle fusion in a directional manner to form tubular structures. The precise regulation of vesicular size and shape in PISA would pave the way to fabricate vesicles for a series of size/shape-dependent applications.

Nanomedicine has attracted growing attention due to its designability and functionality, as well as its excellent pharmacokinetics with limited side effects, and recently, combined therapies have become desirable as they can obtain enhanced therapeutic efficacy by using nanomedicine. Herein, we have reported a functional drug delivery system with a dual response to temperature and reactive oxygen species to efficiently eliminate pancreatic cancer cells in a combined therapy strategy. Functional micelles with camptothecin (CPT) in the core and indocyanine green (ICG) on the surface could effectively accumulate in tumor sites through the EPR effect. The ROS in the tumor microenvironment trigger the conversion of an amino-based copolymer to a carboxy based copolymer, releasing the loaded ICG to reduce the size of the micelles with high penetration in tumor tissue. On the one hand, under 808 nm light irradiation, the micelles will produce the heat to kill tumor cells via photothermal therapy. On the other hand, the generated heat could further trigger the transition of a copolymer from a hydrophobic to a hydrophilic state, releasing the loaded CPT into the deep tumor cells to achieve chemotherapy. The in vitro and in vivo experiments revealed that this combined therapy could combat pancreatic cancer cells with an enhanced therapeutic effect.

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.

Summary Polyethylene (PE) is one of the most widely used materials in the world, but it is virtually undegradable and quickly accumulates in nature, which may contaminate the environment. We utilized the cobalt-mediated radical copolymerization (CMRP) of ethylene and cyclic ketene acetals (CKAs) to effectively incorporate ester groups into PE backbone as cleavable structures to make PE-based copolymer degradable under mild conditions. The content of ethylene and ester units in the produced copolymer could be finely regulated by CKA concentration or ethylene pressure. Also, the copolymerization of ethylene and CKA with other functional vinyl monomers can produce functional and degradable PE-based copolymer. All the formed PE-based copolymers could degrade in the presence of trimethylamine (Et3N)., Graphical Abstract, Highlights • We report cobalt-mediated copolymerization for inserting ester unit into PE backbone • The molecular weight of degraded product varied from several hundreds to thousands • This method provides access to a diverse range of degradable functional PE materials, Green Chemistry; Organic Chemistry; Polymers