Nanogalvanic Cells Release Highly Reactive Electrons in Tumors to Effectively Eliminate Tumors

External stimuli triggering chemical reactions in cancer cells to generate highly reactive chemical species are very appealing for cancer therapy, in which external irradiation activating sensitizers to transfer energy or electrons to surrounding oxygen or other molecules is critical for generating cytotoxic reactive species. However, poor light penetration into tissue, low activity of sensitizers, and reliance on oxygen supply restrict the generation of cytotoxic chemical species in hypoxic tumors, which lowers the therapeutic efficacy. Here, we present galvanic cell nanomaterials that can directly release highly reactive electrons in tumors without external irradiation or photosensitizers. The released reactive electrons directly react with surrounding biomolecules such as proteins and DNA within tumors to destroy them or react with other surrounding (bio)molecules to yield cytotoxic chemical species to eliminate tumors independent of oxygen. Administering these nanogalvanic cells to mice results in almost complete remission of subcutaneous solid tumors and deep metastatic tumors. The results demonstrate that this strategy can further arouse an immune response even in a hypoxic environment. This method offers a promising approach to effectively eliminate tumors, similar to photodynamic therapy, but does not require oxygen or irradiation to activate photosensitizers. This article is protected by copyright. All rights reserved.

DPA-Zinc around Polyplexes Acts Like PEG to Reduce Protein Binding While Targeting Cancer Cells

Gene therapy holds great promise as an effective treatment for many diseases of genetic origin. Gene therapy works by employing cationic polymers, liposomes, and nanoparticles to condense DNA into polyplexes via electronic interactions. Then, a therapeutic gene is introduced into target cells, thereby restoring or changing cellular function. However, gene transfection efficiency remains low in vivo due to high protein binding, poor targeting ability, and substantial endosomal entrapment. Artificial sheaths containing PEG, anions, or zwitterions can be introduced onto the surface of gene carriers to prevent interaction with proteins; however, they reduce the cellular uptake efficacy, endosomal escape, targeting ability, thereby, lowering gene transfection. Here, it is reported that linking dipicolylamine-zinc (DPA-Zn) ions onto polyplex nanoparticles can produce a strong hydration water layer around the polyplex, mimicking the function of PEGylation to reduce protein binding while targeting cancer cells, augmenting cellular uptake and endosomal escape. The polyplexes with a strong hydration water layer on the surface can achieve a high gene transfection even in a 50% serum environment. This strategy provides a new solution for preventing protein adsorption while improving cellular uptake and endosomal escape.

Easy Access to Diverse Multiblock Copolymers with On-Demand Blocks via Thioester-Relayed In-Chain Cascade Copolymerization

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.

Tumor Microenvironment Triggered the In Situ Synthesis of an Excellent Sonosensitizer in Tumor for Sonodynamic Therapy

An ultrasound-triggered sonodynamic therapy has shown great promise for cancer therapy. However, its clinical applications are very limited because the traditional sonosensitizers tend to suffer from very poor efficiency combined with low retention in cancer cells and low tumor selectivity. Therefore, sonosensitizers with higher effectivity, higher tumor cell retention, and higher tumor cell specificity are highly required. Herein, we constructed a Ti2C(OH)X nanosheet, which was a poor sonosensitizer but had a long circulation in the blood system. However, it was very interesting to find that the tumor microenvironment could in situ turn Ti2C(OH)X nanosheet into a novel and excellent sonosensitizer with a nanofiber structure in tumors, exhibiting excellent ability to generate reactive oxygen species (ROS) under ultrasound. Moreover, the nanofiber structure made it very difficult to get out of cancer cells, highly enhancing the retention of the sonosensitizer in the tumor, thereby enabling it to effectively and selectively kill cancer cells in vivo. Our findings demonstrate that the strategy of the tumor microenvironment triggering the in situ synthesis of an effective sonosensitizer in tumor provided a promising means to simultaneously increase the efficiency, sonosensitizer retention in cancer cells, and cancer selectivity, thereby effectively killing cancer cells but causing little damage to healthy tissues via the sonodynamic therapy.

Synthesis of poly(thioester sulfonamide)s via the Ring-Opening Copolymerization of Cyclic Thioanhydride with N-Sulfonyl Aziridine Using Mild Phosphazene base

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, have been rarely available in polymer chemistry. Here, we report 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. 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. This article is protected by copyright. All rights reserved.

Influence of Solvent on RAFT-mediated Polymerization of Benzyl Methacrylate (BzMA) and How to Overcome the Thermodynamic/Kinetic Limitation of Morphology Evolution during Polymerization-Induced Self-Assembly

Polymerization-induced self-assembly (PISA) has been demonstrated to be a powerful strategy to produce polymeric nano-objects of various morphologies. Dependent on the solubility of monomers, PISA is usually classified into two...

Hybrid copolymerization of acrylate and thiirane monomers mediated by trithiocarbonate

The composition and structure of polymers have great influence on their performances.

Fabrication of Nano-objects with Morphology-Correlated Room-Temperature Phosphorescence and Their Application in Information Encryption

Room-temperature phosphorescence (RTP) polymers have attracted much attention due to their advantages, such as easy processing, low cost, and good biocompatibility. Herein, we present a new strategy for the design...

Correction: Single nanosheet can sustainably generate oxygen and inhibit respiration simultaneously in cancer cells

Correction for 'Single nanosheet can sustainably generate oxygen and inhibit respiration simultaneously in cancer cells' by Wei-Qiang Huang et al., Mater. Horiz., 2021, DOI: .

Single nanosheet can sustainably generate oxygen and inhibit respiration simultaneously in cancer cells

In a tumor, the abnormal cancer cell proliferation results in an insufficient O₂ supply, and meanwhile cancer cells consume O₂ very fast. The imbalance between a low oxygen supply and overwhelming oxygen consumption results in a low oxygen concentration in solid tumors. Therefore, in order to relieve hypoxia in tumors, it is necessary to not only sustainably generate O₂, but also inhibit mitochondrial respiration simultaneously. Here, we found that a single Ti₂C(OH)₂ nanomaterial not only can sustainably generate O₂ but also simultaneously highly inhibits mitochondrial respiration via binding phosphorylation proteins onto the surface in cancer cells. Ce6 was linked onto Ti₂C(OH)₂, forming Ti₂C(OH)₂-Ce6. Ti₂C(OH)₂-Ce6 could highly relieve hypoxia in tumors via the combination of sustainable O₂ generation and respiration inhibition, produce enough ¹O₂ to kill cancer cells via PDT, and also effectively convert the absorbed light energy into thermal energy to kill cancer cell via PTT, thereby highly enhancing the cancer therapy.

Dithiocarbamate-mediated controlled copolymerization of ethylene with cyclic ketene acetals towards polyethylene-based degradable copolymers

In this article, degradable polyethylene (PE)-based copolymers containing ester units in the backbone were prepared through the hybrid copolymerization of ethylene and cyclic ketene acetals (CKAs) mediated by dithiocarbamate successfully.

In situ cross-linking polymerization-induced self-assembly not only generates cross-linked structures but also promotes morphology transition by the cross-linker

Not only cross-linked structures but also a promoting effect on morphology transition has been observed during the in situ cross-linking PISA by RAFT dispersion copolymerization of 2-(diisopropylamino)ethyl methacrylate and cystaminebismethacrylamide.

Synthesis of a multicyclic polymer with hyperbranched structure by click polymerization of an AB2 cyclic macromonomer

A multicyclic polymer with a hyperbranched structure was successfully synthesized.

Facile Multicomponent Polymerization and Postpolymerization Modification via an Effective Meldrum's Acid-Based Three-Component Reaction

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.

Rhodanine-based Knoevenagel reaction and ring-opening polymerization for efficiently constructing multicyclic polymers

Cyclic polymers have a number of unique physical properties compared with those of their linear counterparts. However, the methods for the synthesis of cyclic polymers are very limited, and some multicyclic polymers are still not accessible now. Here, we found that the five-membered cyclic structure and electron withdrawing groups make methylene in rhodanine highly active to aldehyde via highly efficient Knoevenagel reaction. Also, rhodanine can act as an initiator for anionic ring-opening polymerization of thiirane to produce cyclic polythioethers. Therefore, rhodanine can serve as both an initiator for ring-opening polymerization and a monomer in Knoevenagel polymerization. Via rhodanine-based Knoevenagel reaction, we can easily incorporate rhodanine moieties in the backbone, side chain, branched chain, etc, and correspondingly could produce cyclic structures in the backbone, side chain, branched chain, etc, via rhodanine-based anionic ring-opening polymerization. This rhodanine chemistry would provide easy access to a wide variety of complex multicyclic polymers.

Polymerization techniques in polymerization-induced self-assembly (PISA)

The development of controlled/“living” polymerization greatly stimulated the prosperity of the fabrication and application of block copolymer nano-objects.

Polymerization-induced self-assembly for the fabrication of polymeric nano-objects with enhanced structural stability by cross-linking

This review discusses the strategies of core-cross-linking in most of the PISA literatures (including post-polymerization cross-linking, photo-cross-linking and in situ cross-linking) and the applications of the cross-linked nano-objects.

Mitochondria-targeted delivery and light controlled release of iron prodrug and CO to enhance cancer therapy by ferroptosis

Mitochondrial malfunction is considered to be a decisive signal of apoptosis.

Awareness of Colorectal Cancer among the Urban Population in the Klang Valley

BACKGROUND

Colorectal cancer (CRC) is the second most common cancer in Malaysia. Awareness of risk factors, symptoms and warning signs of CRC will help in early detection. This paper presents the level of CRC awareness among the urban population in Malaysia.

METHOD

A cross-sectional study was conducted from November 2015 till December 2016 at three government clinics in the Klang Valley. The validated Bowel Cancer Awareness Measure questionnaire in both English and Malay was used. The mean knowledge scores for the warning signs and risk factors of CRC in different socio-demographic groups were compared using ANOVA in SPSS version 23. Statistical significance was set at p<0.05 and a 95% confidence level.

RESULTS

Of the 426 respondents, 29.1% were unable to recall the warning signs and symptoms of CRC. Average recall was less than two warning signs and symptoms (mean 1.62, SD 1.33). The mean total knowledge score for CRC was 9.91 (SD 4.78), with a mean knowledge scores for warning signs and risk factors at 5.27 (SD 2.74) and 4.64 (SD 2.78), respectively. Respondents with a higher level of education were found to have higher level of knowledge regarding the warning signs of CRC. There was a significant positive association between knowledge score for warning signs and level of confidence in detecting warning signs. Regarding the total knowledge score for CRC, 3.3% of respondents scored zero. For warning signs and risk factors, 8.2% and 8.5% of respondents had zero knowledge scores, respectively.

CONCLUSIONS

Generally, awareness of CRC is poor among the urban population of Klang Valley. Greater education and more confidence in detecting warning signs are significantly associated with better knowledge of warning signs. CRC awareness programs should be increased to improve awareness.

Photothermal Therapy Nanomaterials Boosting Transformation of Fe(III) into Fe(II) in Tumor Cells for Highly Improving Chemodynamic Therapy

Chemodynamic therapy based on Fe²⁺-catalyzed Fenton reaction holds great promise in cancer treatment. However, low-produced hydroxyl radicals in tumor cells constitute its severe challenges because of the fact that Fe²⁺ with high catalytic activity could be easily oxidized into Fe³⁺ with low catalytic activity, greatly lowering Fenton reaction efficacy. Here, we codeliver CuS with the iron-containing prodrug into tumor cells. In tumor cells, the overproduced esterase could cleave the phenolic ester bond in the prodrug to release Fe²⁺, activating Fenton reaction to produce the hydroxyl radical. Meanwhile, CuS could act as a nanocatalyst for continuously catalyzing the regeneration of high-active Fe²⁺ from low-active Fe³⁺ to produce enough hydroxyl radicals to efficiently kill tumor cells as well as a photothermal therapy agent for generating hyperthermia for thermal ablation of tumor cells upon NIR irradiation. The results have exhibited that the approach of photothermal therapy nanomaterials boosting transformation of Fe³⁺ into Fe²⁺ in tumor cells can highly improve Fenton reaction for efficient chemodynamic therapy. This strategy was demonstrated to have an excellent antitumor activity both in vitro and in vivo, which provides an innovative perspective to Fenton reaction-based chemodynamic therapy.

Hybrid copolymerization via mechanism interconversion between radical vinyl-addition and anion ring-opening polymerization

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.

Synthesis of polymers with on-demand sequence structures via dually switchable and interconvertible polymerizations

The synthesis of polymers with on-demand sequence structures is very important not only for academic researchers but also for industry. However, despite the existing polymerization techniques, it is still difficult to achieve copolymer chains with on-demand sequence structures. Here we report a dually switchable and controlled interconvertible polymerization system; in this system, two distinct orthogonal polymerizations can be selectively switched ON/OFF independent of each other and they can be interconverted promptly and quantitatively according to external stimuli. Thus, the external stimuli can manipulate the insertion of distinct monomers into the resulting copolymer chains temporally, spatially, and orthogonally, allowing the on-demand precise arrangement of sequence structures in the resulting polymers. This dually switchable and interconvertible polymerization system provides a powerful tool for synthesizing materials that are not accessible by other polymerization methods.

Photo-responsive camptothecin-based polymeric prodrug coated silver nanoparticles for drug release behaviour tracking via the nanomaterial surface energy transfer (NSET) effect

A photo-responsive hybrid drug delivery system for drug release behaviour tracking via the nanomaterial surface energy transfer (NSET) effect.

Silver Nanoparticles Covered with pH-Sensitive Camptothecin-Loaded Polymer Prodrugs: Switchable Fluorescence "Off" or "On" and Drug Delivery Dynamics in Living Cells

A unique drug delivery system, in which silver nanoparticles (AgNPs) are covered with camptothecin (CPT)-based polymer prodrug, has been developed, and the polymer prodrug, in which the CPT is linked to the polymer side chains via an acid-labile β-thiopropionate bond, is prepared by RAFT polymerization. For poly(2-(2-hydroxyethoxy)ethyl methacrylate-co-methacryloyloxy-3-thiahexanoyl-camptothecin)@AgNPs [P(HEO₂MA-co-MACPT)@AgNPs], the polymer thickness on the AgNP surface is around 5.9 nm (TGA method). In vitro tests in buffer solutions at pH = 7.4 reveal that fluorescence of the CPT in the hybrid nanoparticles is quenched due to the nanoparticle surface energy transfer (NSET) effect, but under acidic conditions, the CPT fluorescence is gradually recovered with gradual release of the CPT molecules from the hybrid nanoparticles through cleavage of the acid-labile bond. The NSET "on" and "off" is induced by the CPT-AgNP distance change. This unique property makes it possible to track the CPT delivery and release process from the hybrid nanoparticles in the living cells in a real-time manner. The internalization and intracellular releasing tests of the hybrid nanoparticles in the HeLa cells demonstrate that the lysosome containing the hybrid nanoparticles displays CPT blue fluorescence due to release of the CPT under acidic conditions, and the drug-releasing kinetics shows fluorescence increase of the released CPT with incubation time. The cytotoxicity of hybrid nanoparticles is dependent on activity of the acid-labile bond. Therefore, this is a potential efficient drug delivery system in cancer therapy and a useful approach to study the mechanism of release process in the cells.

Artificially Smart Vesicles with Superior Structural Stability: Fabrication, Characterizations, and Transmembrane Traffic

Intelligent vesicles are fabricated at up to 30% solid content via an approach of polymerization-induced self-assembly and reorganization (PISR). Upon irradiation with UV light (365 nm), light-triggered dimerization of the coumarin moieties anchored in the membrane leads to the membrane cross-linking of the vesicles, which endows the vesicles with superior structural stability. Due to the tertiary amine groups in the membrane, the vesicles go through a swelling/deswelling change upon switching the pH values. In acidic aqueous solution, the pores in the membrane of vesicles are opened, which is beneficial for transmembrane traffic. The pore size in the membrane of vesicles is in accordance with the extent of membrane cross-linking, which can be conveniently regulated by the irradiation time of UV light (365 nm). The size range of the substance for transmembrane traffic is effectively enlarged; even 15 nm gold nanoparticles can be postloaded into the vesicles with lower extents of the membrane cross-linking through the diffusion method. Although the pores in the vesicle membrane are opened in acidic aqueous solution, transmembrane traffic is inhibited for the electropositive substance because of electrostatic repulsion but is allowed for the electronegative substance. These reported vesicles herein may be the smartest artificial vesicles to date due to their multiple selective permeability.

A RAFT/MADIX method finely regulating the copolymerization of ethylene and polar vinyl monomers under mild conditions

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.

Fabrication of Functional Nano-objects through RAFT Dispersion Polymerization and Influences of Morphology on Drug Delivery

To study the influence of self-assembled morphologies on drug delivery, four different nano-objects, spheres, nanorods, nanowires, and vesicles having aldehdye-based polymer as core, were successfully prepared via alcoholic RAFT dispersion polymerization of p-(methacryloxyethoxy)benzaldehyde (MAEBA) using poly((N,N'-dimethylamino)ethyl methacrylate) (PDMAEMA) as a macro chain transfer agent (macro-CTA) for the first time. The morphologies and sizes of the four nano-objects were characterized by TEM and DLS, and the spheres with average diameter (D) of 70 nm, the nanorods with D of 19 nm and length of 140 nm, and the vesicles with D of 137 nm were used in the subsequent cellular internalization, in vitro release, and intracellular release of the drug. The anticancer drug doxorubicin (DOX) was conjugated onto the core polymers of nano-objects through condensation reaction between aldehyde groups of the PMAEBA with primary amine groups in the DOX. Because the aromatic imine is stable under neutral conditions, but is decomposed in a weakly acidic solution, in vitro release of the DOX from the DOX-loaded nano-objects was investigated in the different acidic solutions. All of the block copolymer nano-objects show very low cytotoxicity to HeLa cells up to the concentration of 1.2 mg/mL, but the DOX-loaded nano-objects reveal different cell viability and their IC50s increase as the following order: nanorods-DOX < vesicles-DOX < spheres-DOX. The IC50 of nanowires-DOX is the biggest among the four nano-objects owing to their too large size to be internalized. Endocytosis tests demonstrate that the internalization of vesicles-DOX by the HeLa cells is faster than that of the nanorods-DOX, and the spheres-DOX are the slowest to internalize among the studied nano-objects. Relatively more nanorods localized in the acidic organelles of the HeLa cells lead to faster intracellular release of the DOX, so the IC50 of nanorods is lower than that of the vesicles-DOX.

One-pot sequential multicomponent reaction and a multicomponent polymerization method for the synthesis of topologically different polymers

The synthesis of topologically different polymers via a one-pot sequential multicomponent reaction and multicomponent polymerization is reported.

Au–polymer hybrid microgels easily prepared by thermo-induced self-crosslinking and in situ reduction

Au–polymer hybrid microgels were prepared through thermo-induced self-crosslinking and in situ reduction of a gold precursor.

Unimolecular micelles of camptothecin-bonded hyperbranched star copolymers via β-thiopropionate linkage: synthesis and drug delivery

The pH- and redox-sensitive camptothecin-loaded unimolecular micelles display low cytotoxicity and controlled drug release in a sustained manner.

Anion-dipole interactions make the homopolymers self-assemble into multiple nanostructures

Anion-dipole interactions can make homopolymers self-assemble like an amphiphilic block copolymer. Generally, common homopolymers cannot self-assemble into multiple nanostructures. Here, it is reported that anion-dipole interactions can enable a number of homopolymers to achieve a variety of self-assembly behaviors in aqueous solution. Such interactions and self-assembly features have been exclusively reserved for amphiphilic (block) polymers until now.

Biodegradable large compound vesicles with controlled size prepared via the self-assembly of branched polymers in nanodroplet templates

Generally, it is very difficult to control the size of large compound vesicles. Here, we introduce a novel method for the preparation of biodegradable large compound vesicles with controlled size and narrow size distribution by using aqueous nanodroplets as templates.