Engineering pH-Responsive Nanocarriers via an Optimized Synthesis of PMOXA-b-PDPA Amphiphilic Diblock Copolymers.

pH-responsive nanocarriers have gain significant attention due to their ability to provide controlled cargo delivery with high precision in response to specific stimuli. However, the polymers used in the self-assembly of these nanocarriers must be carefully designed to meet the requirements of bio-relevant delivery. Here, we present an optimized synthesis of poly(2-methyl-2-oxazoline)-block-poly(2-(diisopropylamino)ethyl methacrylate) (PMOXA-b-PDPA) block copolymers tailored for obtaining carriers with vesicle architecture and thin membranes for an improved release behavior.

Hydrogel-polymersome composites as a sensing platform for monitoring food spoilage.

The development of advanced functional soft materials for applications in preserving food quality and detecting spoilage is in focus today. While various smart food packaging options are available, there are still challenges to be addressed due to several limitations of current food quality sensors, such as a lack of multifunctionality, use of potentially harmful synthetic sensing molecules or short shelf life of natural analogues. Herein, we present a dual-functional hydrogel-polymersome composite (HPC) system that integrates two complementary sensing functionalities into a single platform.

Solid-Supported Polymer Membranes: How Different Deposition Methods Influence Their Inner Morphology and Properties.

Solid-supported polymer membranes (SSPMs) resulting from the self-assembly of amphiphilic block copolymers are in focus for the development of functional surfaces with enhanced stability and more chemical versatility compared to lipid-based membranes. Different methods are used to generate such polymer planar membranes, but their internal organization and the resulting properties have not yet been compared to identify the differences and guide the selection of appropriate membranes for specific applications. Here, we present SSPMs prepared by two deposition methods─the Langmuir monolayer transfer and the solvent-assisted polymer deposition─and evaluate their internal organization and key properties.

Thermocatalytic epoxidation by cobalt sulfide inspired by the material's electrocatalytic activity for oxygen evolution reaction.

New discoveries in catalysis by earth-abundant materials can be guided by leveraging knowledge across two sub-disciplines of heterogeneous catalysis: electrocatalysis and thermocatalysis. Cobalt sulfide has been reported to be a highly active electrocatalyst for the oxygen evolution reaction (OER). Under these oxidative conditions, cobalt sulfide forms oxidized surfaces that outperform directly prepared cobalt oxide in OER catalysis.

Glycooligomer-Functionalized Catalytic Nanocompartments Co-Loaded with Enzymes Support Parallel Reactions and Promote Cell Internalization.

A major shortcoming associated with the application of enzymes in drug synergism originates from the lack of site-specific, multifunctional nanomedicine. This study introduces catalytic nanocompartments (CNCs) made of a mixture of PDMS--PMOXA diblock copolymers, decorated with glycooligomer tethers comprising eight mannose-containing repeating units and coencapsulating two enzymes, providing multifunctionality by their in situ parallel reactions. Beta-glucuronidase (GUS) serves for local reactivation of the drug hymecromone, while glucose oxidase (GOx) induces cell starvation through glucose depletion and generation of the cytotoxic HO.

Synthetic molecular motor activates drug delivery from polymersomes.

The design of stimuli-responsive systems in nanomedicine arises from the challenges associated with the unsolved needs of current molecular drug delivery. Here, we present a delivery system with high spatiotemporal control and tunable release profiles. The design is based on the combination of an hydrophobic synthetic molecular rotary motor and a PDMS--PMOXA diblock copolymer to create a responsive self-assembled system.

Trends in the Synthesis of Polymer Nano- and Microscale Materials for Bio-Related Applications.

Polymeric nano- and microscale materials bear significant potential in manifold applications related to biomedicine. This is owed not only to the large chemical diversity of the constituent polymers, but also to the various morphologies these materials can achieve, ranging from simple particles to intricate self-assembled structures. Modern synthetic polymer chemistry permits the tuning of many physicochemical parameters affecting the behavior of polymeric nano- and microscale materials in the biological context.

Amphiphilic Poly(vinyl alcohol) Membranes Leaving Out Chemical Cross-Linkers: Design, Synthesis, and Function of Tailor-Made Poly(vinyl alcohol)-b-poly(styrene) Copolymers.

Tailor-made poly(vinyl alcohol)-b-poly(styrene) copolymers (PVA-b-PS) for separation membranes are synthesized by the combination of reversible-deactivation radical polymerization techniques. The special features of these di-block copolymers are the high molecular weight (>70 kDa), the high PVA content (>80 wt%), and the good film-forming property. They are soluble only in hot dimethyl sulfoxide, but by the "solvent-switch" technique, they self-assemble in aqueous media to form micelles.

Cell-Derived Vesicles with Increased Stability and On-Demand Functionality by Equipping Their Membrane with a Cross-Linkable Copolymer.

Cell-derived vesicles retain the cytoplasm and much of the native cell membrane composition. Therefore, they are attractive for investigations of membrane biophysics, drug delivery systems, and complex molecular factories. However, their fragility and aggregation limit their applications.

Tailoring Polymer-Based Nanoassemblies for Stimuli-Responsive Theranostic Applications.

Polymer assemblies on the nanoscale represent a powerful toolbox for the design of theranostic systems when combined with both therapeutic compounds and diagnostic reporting ones. Here, recent advances in the design of theranostic systems for various diseases, containing-in their architecture-either polymers or polymer assemblies as one of the building blocks are presented. This review encompasses the general principles of polymer self-assembly, from the production of adequate copolymers up to supramolecular assemblies with theranostic functionality.

Inverting glucuronidation of hymecromone by catalytic nanocompartments.

Glucuronidation is a metabolic pathway that inactivates many drugs including hymecromone. Adverse effects of glucuronide metabolites include a reduction of half-life circulation times and rapid elimination from the body. Herein, we developed synthetic catalytic nanocompartments able to cleave the glucuronide moiety from the metabolized form of hymecromone in order to convert it to the active drug.

Membrane protein channels equipped with a cleavable linker for inducing catalysis inside nanocompartments.

Precisely timed initiation of reactions and stability of the catalysts are fundamental in catalysis. We introduce here an efficient closing-opening method for nanocompartments that contain sensitive catalysts and so achieve a controlled and extended catalytic activity. We developed a chemistry-oriented approach for modifying a pore-forming membrane protein which allows for a stimuli-responsive pore opening within the membrane of polymeric nanocompartments.

Physically cross-linked chitosan/dextrin cryogels entrapping Thymus vulgaris essential oil with enhanced mechanical, antioxidant and antifungal properties.

Herein, we entrapped Thymus vulgaris essential oil (EO) within the physically cross-linked sponge-like architecture of cryogels by ice template-assisted freeze-drying. Their 3D cryogenically-structured network was built through hydrogen bonding formed by blending two naturally-derived polysaccharides, chitosan and dextrin. The embedment of EOs within the cryogel matrix generates porous films with an increased elasticity that allows their fast shape recovery after full compression.

Design of Bio-Conjugated Hydrogels for Regenerative Medicine Applications: From Polymer Scaffold to Biomolecule Choice.

Bio-conjugated hydrogels merge the functionality of a synthetic network with the activity of a biomolecule, becoming thus an interesting class of materials for a variety of biomedical applications. This combination allows the fine tuning of their functionality and activity, whilst retaining biocompatibility, responsivity and displaying tunable chemical and mechanical properties. A complex scenario of molecular factors and conditions have to be taken into account to ensure the correct functionality of the bio-hydrogel as a scaffold or a delivery system, including the polymer backbone and biomolecule choice, polymerization conditions, architecture and biocompatibility.

Composite cryo-beads of chitosan reinforced with natural zeolites with remarkable elasticity and switching on/off selectivity for heavy metal ions.

Combining ion-imprinting technology with pH-dependent adsorptive features of acid- or salt-activated zeolites brings up the opportunity to develop composite polymer materials with 'desired' sorption properties and performances. In this respect, we present here Co-imprinted composite cryo-beads with switching on/off selectivity towards the template ions, engineered by selecting the appropriate zeolite-treatment conditions and/or controlling the initial sorption pH values. Co chelating efficiency of all cryo-beads was investigated either at pH 4 or 6 depending on zeolite conditioning strategy.

Stabilizing Enzymes within Polymersomes by Coencapsulation of Trehalose.

Enzymes are essential biocatalysts and very attractive as therapeutics. However, their functionality is strictly related to their stability, which is significantly affected by the environmental changes occurring during their usage or long-term storage. Therefore, maintaining the activity of enzymes is essential when they are exposed to high temperature during usage or when they are stored for extended periods of time.

The rise of bio-inspired polymer compartments responding to pathology-related signals.

Self-organized nano- and microscale polymer compartments such as polymersomes, giant unilamellar vesicles (GUVs), polyion complex vesicles (PICsomes) and layer-by-layer (LbL) capsules have increasing potential in many sensing applications. Besides modifying the physicochemical properties of the corresponding polymer building blocks, the versatility of these compartments can be markedly expanded by biomolecules that endow the nanomaterials with specific molecular and cellular functions. In this review, we focus on polymer-based compartments that preserve their structure, and highlight the key role they play in the field of medical diagnostics: first, the self-assembling abilities that result in preferred architectures are presented for a broad range of polymers.

Removal of heavy metal ions from multi-component aqueous solutions by eco-friendly and low-cost composite sorbents with anisotropic pores.

Copper, nickel, zinc, chromium, and iron ions are the prevailing contaminants in the aqueous effluents resulting from the photo-etching industry. In this context, we investigate here the metal ion sorption performance of an ion-imprinted cryogel (IIC), consisting of low-cost materials coming from renewable resources, towards multi-component metal ion solutions. The IIC sorbent, which is based on a chitosan matrix embedding a natural zeolite, was synthesized using a straightforward strategy by coupling copper-imprinting and unidirectional ice-templating methods.

Could the porous chitosan-based composite materials have a chance to a "NEW LIFE" after Cu(II) ion binding?

Currently, biosorption is considered a leading-edge environmentally-friendly method for the low-cost remediation of wastewaters contaminated with metal ions. However, the safe disposal of metal-loaded biosorbents is still a challenging issue. In this context, our major objective was to explore the possibility of "waste minimization" by reusing the metal-loaded biosorbents in further environmental applications, particularly into the oxidative catalysis of dyes.

Chitosan-based ion-imprinted cryo-composites with excellent selectivity for copper ions.

An original strategy is proposed here to design chitosan-based ion-imprinted cryo-composites (II-CCs) with pre-organized recognition sites and tailored porous structure by combining ion-imprinting and ice-templating techniques. The cryo-composites showed a tube-like porous morphology with interconnected parallel micro-channels, the distance between the channel walls being around 15 μm. Both the entrapment of a natural zeolite and the presence of carboxylate groups, generated by partial hydrolysis of amide moieties, led to II-CCs with controlled swelling ratios (25-40 g/g, depending on pH) and enhanced overall chelating efficiency (260 mg Cu/g composite).

Stimuli-Triggered Activity of Nanoreactors by Biomimetic Engineering Polymer Membranes.

The development of advanced stimuli-responsive systems for medicine, catalysis, or technology requires compartmentalized reaction spaces with triggered activity. Only very few stimuli-responsive systems preserve the compartment architecture, and none allows a triggered activity in situ. We present here a biomimetic strategy to molecular transmembrane transport by engineering synthetic membranes equipped with channel proteins so that they are stimuli-responsive.

Does Membrane Thickness Affect the Transport of Selective Ions Mediated by Ionophores in Synthetic Membranes?

Biomimetic polymer nanocompartments (polymersomes) with preserved architecture and ion-selective membrane permeability represent cutting-edge mimics of cellular compartmentalization. Here it is studied whether the membrane thickness affects the functionality of ionophores in respect to the transport of Ca ions in synthetic membranes of polymersomes, which are up to 2.6 times thicker than lipid membranes (5 nm).

Selective ion-permeable membranes by insertion of biopores into polymersomes.

In nature there are various specific reactions for which highly selective detection or support is required to preserve their bio-specificity or/and functionality. In this respect, mimics of cell membranes and bio-compartments are essential for developing tailored applications in therapeutic diagnostics. Being inspired by nature, we present here biomimetic nanocompartments with ion-selective membrane permeability engineered by insertion of ionomycin into polymersomes with sizes less than 250 nm.

Cellular Trojan horse based polymer nanoreactors with light-sensitive activity.

Stimulus-sensitive systems at the nanoscale represent ideal candidates for improving therapeutic and diagnostic approaches by producing rapid responses to the presence of specific molecules or conditions either by changing properties or by acting "on demand". Here we introduce an optimized light-sensitive nanoreactor based on encapsulation of a photosensitizer inside polymer vesicles to serve as an efficient source of reactive oxygen species (ROS) "on demand". Two types of amphiphilic block copolymers, poly(2-methyloxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyloxazoline), PMOXA-PDMS-PMOXA, and poly(N-vinylpyrrolidone)-block-poly(dimethylsiloxane)-block-poly(N-vinylpyrrolidone), PNVP-PDMS-PNVP, were used to encapsulate Rose Bengal-bovine serum albumin (RB-BSA) inside the cavity of vesicles.