Reactive oxygen species-responsive polymer drug delivery systems

Applying reactive polymer materials sensitive to biological stimuli has recently attracted extensive research interest. The special physiological effects of reactive oxygen species (ROS) on tumors or inflammation and the application of ROS-responsive polymers as drug-delivery systems in organisms have attracted much attention. ROS is a vital disease signal molecule, and the unique accumulation of ROS-responsive polymers in pathological sites may enable ROS-responsive polymers to deliver payload (such as drugs, ROS-responsive prodrugs, and gene therapy fragments) in a targeted fashion. In this paper, the research progress of ROS-responsive polymers and their application in recent years were summarized and analyzed. The research progress of ROS-responsive polymers was reviewed from the perspective of nanoparticle drug delivery systems, multi-responsive delivery systems, and ROS-responsive hydrogels. It is expected that our work will help understand the future development trends in this field.

One-Pot Multicomponent Polymerization, Metal-, and Non-Metal-Catalyzed Synthesis of Organoselenium Compounds

The one-pot multicomponent synthetic strategy of organoselenium compounds represents an alternative and robust protocol to the conventional multistep methods. During the last decade, a potential advance has been made in this domain. This review discusses the latest advances in the polymerization, metal, and metal-free one-pot multicomponent synthesis of organoselenium compounds.

Ronald C.D. Breslow (1931-2017): A career in review

Reviewed herein are key research accomplishments of Professor Ronald Charles D. Breslow (1931-2017) throughout his more than 60 year research career. These accomplishments span a wide range of topics, most notably physical organic chemistry, medicinal chemistry, and bioorganic chemistry. These topics are reviewed, as are topics of molecular electronics and origin of chirality, which combine to make up the bulk of this review. Also reviewed briefly are Breslow's contributions to the broader chemistry profession, including his work for the American Chemical Society and his work promoting gender equity. Throughout the article, efforts are made to put Breslow's accomplishments in the context of other work being done at the time, as well as to include subsequent iterations and elaborations of the research.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Diselenide–yne polymerization for multifunctional selenium-containing hyperbranched polymers

Diselenide–yne polymerization for multifunctional selenium-containing hyperbranched polymers.

Selenium-Functionalized Graphene Oxide That Can Modulate the Balance of Reactive Oxygen Species

Graphene oxide (GO) is an important two-dimensional material since it is water-soluble and can be functionalized to adapt to different applications. However, the current covalent functionalization methods usually require hash conditions, long duration, and sometimes even multiple steps, while noncovalent functionalization is inevitably unstable, especially under a physiological environment where competing species exist. Diselenide bond is a dynamic covalent bond and can respond to both redox conditions and visible light irradiation in a sensitive manner. Thus, in this work by combining the stimuli response of diselenide bond and the oxidative/radical attackable nature of GO, we achieved the in situ covalent functionalization of GO simply by stirring GO with diselenide-containing molecules in aqueous solution. The covalent functionalization was proved by Fourier transform infrared, time-of-flight secondary ion mass spectrometry, atomic force microscopy, thermogravimetric analysis, and so forth, and the functionalization mechanism was deduced to involve both redox reaction and radical addition reaction according to the X-ray photoelectron spectrscopy, atomic emission spectroscopy, and Raman spectroscopy. Moreover, we modified GO with a biocompatible diselenide-containing polymer (mPEGSe)₂ and found selenium-functionalized GO could modulate the balance of reactive oxygen species (ROS). GOSe could decrease ROS level by accelerating the reduction of peroxides when the ROS concentration is high while boosting the ROS level by in situ generating ROS when its concentration is relatively low.

Selenolactone as a Building Block toward Dynamic Diselenide-Containing Polymer Architectures with Controllable Topology

A versatile protocol for the synthesis of a variety of multiresponsive diselenide-containing polymeric architectures was investigated. It consists of a one-pot, two-step process with the generation of a selenol by in situ nucleophilic ring opening of selenolactone with a broad range of amine-containing structures, followed by the transformation of the obtained compounds to the corresponding diselenide through a spontaneous oxidation coupling reaction. After elaboration of this one-pot reaction, a number of routes based on selenolactones have been developed for the successful synthesis of functional, linear, branched, cyclic, and cross-linked polymers via a mild, straightforward process. Moreover, the polymer end groups can be easily modified by changing the ratio of amine and selenolactone or sequential Michael addition of selenol to the methacrylic ester. At last, the self-healing properties of the diselenide-containing networks were determined by exposing a cut sample of the polymer to UV light.

From seleno-mediated radical polymerization to seleno-containing branched polymers and dynamic hydrogel

A protocol of introducing redox responsive Se–Se bond into well-defined hydrogel backbone.

Calcium mediated C–F bond substitution in fluoroarenes towards C–chalcogen bond formation

An efficient C–F bond substitution in electron-deficient fluoroarenes by chalcogens has been achieved using calcium chloride.

Metal-containing and related polymers for biomedical applications

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

Facile One-Pot Synthesis of Tellurium Nanorods as Antioxidant and Anticancer Agents

Nanorods have been utilized in targeted therapy, controlled release, molecular diagnosis, and molecule imaging owing to their large surface area and optical, magnetic, electronic, and structural properties. However, low stability and complex synthetic methods have substantially limited the application of tellurium nanorods for use as antioxidant and anticancer agents. Herein, a facile one-pot synthesis of functionalized tellurium nanorods (PTNRs) by using a hydrothermal synthetic system with a polysaccharide-protein complex (PTR), which was extracted from Pleurotus tuber-regium, as a capping agent is described. PTNRs remained stable in water and in phosphate-buffered saline and exhibited high hemocompatibility. Interestingly, these nanorods possessed strong antioxidant activity for scavenging 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS(.+) ) and 2,2-diphenyl-1-picrylhydrazylhydrate (DPPH) free radicals and demonstrated novel anticancer activities. However, these nanorods exhibited low cytotoxicity toward normal human cells. In addition, the PTNRs effectively induced a decrease in the mitochondrial membrane potential in a dose-dependent manner, which indicated that mitochondrial dysfunction might play an important role in PTNR-induced apoptosis. Therefore, this study provides a one-pot strategy for the facile synthesis of tellurium nanorods with novel antioxidant and anticancer application potentials.

Reactions of nitroxides 16. First nitroxides containing tellurium atom

Five- and six-membered nitroxides with a tellurium containing moiety were synthesized by the addition of nitroxyl amines to phenyltellanyl alkylene isothiocyanates.

Tellurium-containing nanoparticles for controlled delivery of cisplatin based on coordination interaction

Tellurium containing nanoparticles were designed and synthesized for the delivery of cisplatin.

Reactive oxygen species (ROS)-responsive tellurium-containing hyperbranched polymer

Tellurium-containing hyperbranched polymers form aggregates, which are a new kind of material responsive to reactive oxygen species at a physiological level.

Oxidation-responsive polymers for biomedical applications

This article summarizes recent progress in the design and synthesis of various oxidation-responsive polymers and their application in biomedical fields.