ROS-sensitive PD-L1 siRNA cationic selenide nanogels for self-inhibition of autophagy and prevention of immune escape.

In the field of cancer therapy, inhibiting autophagy has emerged as a promising strategy. However, pharmacological disruption of autophagy can lead to the upregulation of programmed death-ligand 1 (PD-L1), enabling tumor immune evasion. To address this issue, we developed innovative ROS-responsive cationic poly(ethylene imine) (PEI) nanogels using selenol chemistry-mediated multicomponent reaction (MCR) technology.

Ultra-Fast Selenol-Yne Click (SYC) Reaction Enables Poly(selenoacetal) Covalent Adaptable Network Formation.

The emergence of covalent adaptable networks (CANs) based on dynamic covalent bonds (DCBs) presents a promising avenue for achieving resource recovery and utilization. In this study, we discovered a dynamic covalent bond called selenacetal, which is obtained through a double click reaction between selenol and activated alkynes. Density functional theory (DFT) calculations demonstrated that the ΔG for the formation of selenoacetals ranges from 12 to 18 kJ mol, suggesting its potential for dynamic reversibility.

Advanced Multifunctional Hydrogels for Enhanced Wound Healing through Ultra-Fast Selenol-SAr Chemistry.

Fabrication of versatile hydrogels in a facile and effective manner represents a pivotal challenge in the field of biomaterials. Herein, a novel strategy is presented for preparing on-demand degradable hydrogels with multilevel responsiveness. By employing selenol-dichlorotetrazine nucleophilic aromatic substitution (SAr) to synthesize hydrogels under mild conditions in a buffer solution, the necessity of additives or posttreatments can be obviated.

Tuning the Mechanical Properties of 3D-printed Objects by the RAFT Process: From Chain-Growth to Step-Growth.

Photoinduced 3D printing based on the reversible addition-fragmentation chain transfer (RAFT) process has emerged as a robust method for creating diverse functional materials. However, achieving precise control over the mechanical properties of these printed objects remains a critical challenge for practical application. Here, we demonstrated a RAFT step-growth polymerization of a bifunctional xanthate and bifunctional vinyl acetate.

A Self-Adaptive Biomimetic Periosteum Employing Nitric Oxide Release for Augmenting Angiogenesis in Bone Defect Regeneration.

The periosteum plays a vital role in the regeneration of critical-size bone defects and highly comminuted fractures, promoting the differentiation of osteoblasts, accelerating the reconstruction of the vascular network, and guiding bone tissue regeneration. However, the materials loaded with exogenous growth factors are limited by the release and activity of the elements. Therefore, the material structure must be carefully designed for the periosteal function.

Thermally Responsive Selenide-containing Materials Based on Transalkylation of Selenonium Salts.

Covalent adaptable networks (CANs) possess unique properties as a result of their internal dynamic bonds, such as self-healing and reprocessing abilities. In this study, we report a thermally responsive C-Se dynamic covalent chemistry (DCC) that relies on the transalkylation exchange between selenonium salts and selenides, which undergo a fast transalkylation reaction in the absence of any catalyst. Additionally, we demonstrate the presence of a dissociative mechanism in the absence of selenide groups.

Selenide-linked polydopamine-reinforced hybrid hydrogels with on-demand degradation and light-triggered nanozyme release for diabetic wound healing.

Background: Multifunctional hydrogels with controllable degradation and drug release have attracted extensive attention in diabetic wound healing. This study focused on the acceleration of diabetic wound healing with selenide-linked polydopamine-reinforced hybrid hydrogels with on-demand degradation and light-triggered nanozyme release.

Methods: Herein, selenium-containing hybrid hydrogels, defined as DSeP@PB, were fabricated via the reinforcement of selenol-end capping polyethylene glycol (PEG) hydrogels by polydopamine nanoparticles (PDANPs) and Prussian blue nanozymes in a one-pot approach in the absence of any other chemical additive or organic solvent based on diselenide and selenide bonding-guided crosslinking, making them accessible for large-scale mass production.

Fast Living 3D Printing via Free Radical Promoted Cationic RAFT Polymerization.

The application of reversible deactivation radical polymerization techniques in 3D printing is emerging as a powerful method to build "living" polymer networks, which can be easily postmodified with various functionalities. However, the building speed of these systems is still limited compared to commercial systems. Herein, a digital light processing (DLP)-based 3D printing system via photoinduced free radical-promoted cationic reversible addition-fragmentation chain transfer polymerization of vinyl ethers, which can build "living" objects by a commercial DLP 3D printer at a relatively fast building speed (12.

Degradable Selenium-Containing Polymers for Low Cytotoxic Antibacterial Materials.

Developing biodegradable cationic polymers with high antibacterial efficiency and low cytotoxicity is of great significance in biological applications. Selenium is an essential trace element for the human body, and selenium-containing compounds are promising in various health-related applications. To combine selenium with biodegradability, selenide-functionalized polycaprolactones (PCL) with different hydrophobic substituents were synthesized followed by selenoniumization.

Thermally Driven Diselenide Metathesis: Polarization Process vs Radical Process.

Diselenide, as a dynamic covalent bond, has been widely applied in functional materials due to its response to light, heat, sonication, pH, and other stimuli. Herein, a polarization-induced metathesis mechanism for diselenides under heating conditions in the dark is proposed. First, a radical trap experiment is used to prove that the exchange reaction of diselenides in the dark does not involve any radicals.

Catalyst-Free, Visible-Light-Induced Step-Growth Polymerization by a Photo-RAFT Single-Unit Monomer Insertion Reaction.

Photoinduced polymerization is an attractive technique with the advantages of easy operation, mild conditions, and excellent temporospatial controllability. However, the application of this technique in step-growth polymerization is highly challenging. Here, we present a catalyst-free, visible-light-induced step-growth polymerization method utilizing a photo-RAFT single-unit monomer insertion reaction between the xanthate and vinyl ether groups.

Manganese-Catalyzed Batch and Continuous Flow Cationic RAFT Polymerization Induced by Visible Light.

We present a robust manganese-catalyzed cationic reversible addition-fragmentation chain transfer (RAFT) polymerization induced by visible light. Well-defined poly(vinyl ether)s with controlled molecular weight and molecular weight distributions (MWDs) can be conveniently prepared at room temperature without monomer purification. The commercially available manganese carbonyl bromide is used as the photocatalyst for cationic RAFT polymerization.

Photoinduced Free Radical Promoted Cationic RAFT Polymerization toward "Living" 3D Printing.

Three-dimensional (3D) printing utilizing controlled polymerization systems is emerging as a powerful approach to fabricate "living" objects, which can be further modified with various functionalities. Here, we report photoinduced free radical-promoted cationic reversible addition-fragmentation chain transfer (RAFT) polymerization under broad wavelengths from ultraviolet (UV) to near-infrared (NIR) light. A commercially available iron catalyst, cyclopentadienyl iron dicarbonyl dimer (Fe(Cp)(CO)), was used as the photocatalyst, and several diphenyliodonium salts were examined as oxidants.

Controlling Polymer Molecular Weight Distribution through a Latent Mediator Strategy with Temporal Programming.

Polymer molecular weight distribution (MWD) is a key parameter of polymers. Here we present a robust method for controlling polymer MWD in controlled cationic polymerizations. A latent mediator strategy was designed and combined with temporal programming to regenerate mediators at different times during polymerization.

Synthesis of Selenium-Containing Polystyrene Microspheres and Using as Catalyst for Oxidation of Acrolein.

Selenium-containing polystyrene (DSe-PS) microspheres were synthesized by soap-free emulsion polymerization using 1,2-bis(2,3,5,6-tetrafluoro-4-vinylphenyl)diselane (FVPDSe) and divinylbenzene (DVB) as crosslinking agents. The particle size of the obtained DSe-PS was characterized by a scanning electron microscope and dynamic light scattering. The results showed that the diameter of the obtained DSe-PS microspheres could be adjusted by changing the ratio of the monomer and crosslinker/water.

An On-Demand Dissoluble Chitosan Hydrogel Containing Dynamic Diselenide Bond.

A new kind of on-demand dissolution hydrogel is successfully synthesized by modification of chitosan using γ-selenobutyrolactone. The chitosan hydrogel with different selenium contents is formed by ring opening of γ-selenobutyrolactone with the amines of D-glucosamine units on the chitosan backbone. The structure of the hydrogel was confirmed by H NMR, XRD and XPS.

Controllable Radical Polymerization of Selenide Functionalized Vinyl Monomers and Its Application in Redox Responsive Photonic Crystals.

Selenium-containing monomer (p-phenylseleno) styrene (p-PhSeSt) is polymerized by reversible addition-fragmentation chain transfer polymerization. Polymer, (P(p-PhSeSt)), with controlled molecular weight and narrow molecular weight is obtained. The selenide moiety in obtained P(p-PhSeSt) can be selectively oxidized to selenoxide or selenone groups by H O or NaClO, respectively.

Near-Infrared, Light-Induced Cationic and Radical RAFT Polymerization Catalyzed by Iron Complex.

A near-infrared (NIR) light induced controlled cationic polymerization is presented here. The halide abstraction reaction between the cyclopentadienyl iron dicarbonyl dimer (Fe(Cp)(CO)) and an organic halide is utilized to generate initial radicals or cations under mild conditions, which can be further combined with both radical and cationic reversible addition-fragmentation chain transfer (RAFT) polymerization. Well-defined poly(vinyl ether)s and polyacrylates are prepared successfully under NIR light by this method.

Visual Ozone Sensor: Structural Color Change of Pendant Selenium-Containing Maleimide Polymers via Oxidation.

Pendant selenium-containing maleimide polymers with different selenium contents are synthesized via a radical copolymerization of styrene and N-butylmaleimide phenyl selenide. The polymer structures are characterized by nuclear magnetic resonance, gel permeation chromatography, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and scanning electron microscopy with an energy-dispersive spectrometer, which results in the desired structures and selenium contents. The refractive indices of the polymers, which change as a function of different contents of selenium and oxidative stimuli by H O or O , are investigated.

On-Demand Dissoluble Diselenide-Containing Hydrogel.

On-demand dissolution of hydrogels is being increasingly studied for their potential use in burn wound dressing applications. Herein, a dynamic diselenide-containing hydrogel is developed through a very simple one-pot and two-step process starting from the selenol functionalization of a partially hydrolyzed poly(2-ethyl-2-oxazoline) with γ-butyroselenolactone. The hydrogel spontaneously cross-links via an in situ oxidation of the selenol functionalities in air.

A Novel Synthesis of Poly(Ester--Selenide)s by Ring-Opening Copolymerization of γ-Selenobutyrolactone and Epoxy Monomer.

Ring-opening copolymerization (ROCOP) is an effective means to prepare functionalized polyester. In this work, a type of selenide-containing polyesters with controllable structure, molecular weight, and molecular weight distribution was successfully prepared by ROCOP of γ-selenobutyrolactone and epoxy compounds. The influence of the catalyst, solvent, and reaction temperature on the reaction efficiency was examined.

Novel AIEgen-Functionalized Diselenide-Crosslinked Polymer Gels as Fluorescent Probes and Drug Release Carriers.

Stimuli-responsive functional gels have shown significant potential for application in biosensing and drug release systems. In this study, aggregation-induced emission luminogen (AIEgen)-functionalized, diselenide-crosslinked polymer gels were synthesized via free radical copolymerization. A series of polymer gels with different crosslink densities or tetraphenylethylene (TPE) contents were synthesized.

Cystine dimethyl ester cross-linked PEG-poly(urethane-urea)/nano-hydroxyapatite composited biomimetic scaffold for bone defect repair.

Polyurethane (PU) and polyurea (PUA) materials have shown significant potential for application in tissue repair. Herein, we design a glycerol ethoxylate (PEG)-based poly(urethane-urea) for bone tissue repair. The polymer precursor was prepared from the reaction of PEG and isophorone diisocyanate (IPDI).

Visible light induced controlled cationic polymerization by in situ generated catalyst from manganese carbonyl.

A robust method for preparing controlled poly(vinyl ethers) utilizing commercially available reagents under visible light is reported. Pentacarbonylbromomanganese (Mn(CO)Br), generated from the conventional photolysis of manganese carbonyl and halide abstraction, is considered as a catalyst to oxidize carbon radical to carbenium ion in this polymerization. Polymerization behavior including the effects of solvents and monomers have been investigated.

Selenol-Based Nucleophilic Reaction for the Preparation of Reactive Oxygen Species-Responsive Amphiphilic Diblock Copolymers.

Selenide-containing amphiphilic copolymers have shown significant potential for application in drug release systems. Herein, we present a methodology for the design of a reactive oxygen species-responsive amphiphilic diblock selenide-labeled copolymer. This copolymer with controlled molecular weight and narrow molecular weight distribution was prepared by sequential organoselenium-mediated reversible addition fragmentation chain transfer (Se-RAFT) polymerization and selenol-based nucleophilic reaction.