RSC Applied Polymers最新文献

Gene therapy is widely recognized as a promising method in combating diseases caused by gene abnormalities or deletions. The effects of these deletions and mutations are ameliorated through gene therapy by means of transfection vectors. These delivery vehicles are tasked with protecting the gene and transporting it to the cell nucleus when necessary. Nano-sized hydrogel particles, also known as nanogels, are crosslinked polymeric nanoparticles that are promising materials for such biomedical applications. Whereas most cationic carriers for gene delivery are nitrogen-based, we are interested in utilizing a sulfonium moiety to this end. Diversifying the available gene vectors not only satisfies scientific curiosity, it could also offer improved gene delivery efficiencies. Here we describe the synthesis of glycidyl methacrylate (GMA) nanogels as a platform for subsequent functionalization. Ring-opening reactions with diethyl sulfide were carried out to install permanent cationic sulfonium groups on the nanogels, yielding readily water-soluble nanogels with a zeta potential of ζ = +40 ± 0.5 mV at neutral pH and a mean diameter of D = 29 ± 10 nm as determined by transmission electron microscopy (TEM). The degree of functionalization with sulfonium groups was found to be tunable. These nanogels were subjected to post-synthesis modifications resulting in biocompatible sulfonium nanogels containing a thioglycerol moiety. Polyplexes were formed by successful incubation with plasmid DNA encoding for green fluorescent protein (pCMV-GFP), at various ratios. In a next step, nucleic acid delivery by sulfonium nanogels was probed for various cell lines for the first time, showing poor delivery properties.

For several decades, there has been great interest in the application of polysaccharide nanogels as nanoscale platforms that integrate polymer scaffolds to confer distinctive biochemical properties. Notably, nanogels, utilizing metal coordination as an efficient cross-linking strategy to enhance structural integrity and responsiveness, have emerged as nanoscale catalysts, broadening their utility in controlled drug delivery, sensing, and biomedical applications. In this study, we present a facile method for preparing chemically modified nanogels based on chitosan, facilitated by Cu(II) coordination for a Fenton-like reaction. The chitosan scaffold undergoes modifications through ethylenediaminetetraacetate (EDTA) conjugation and non-enzymatic glycation, yielding water-soluble structures across a wide pH range. Cu(II) chelation facilitates coordination-mediated cross-linking, resulting in the formation of nanogels with multiple Cu(II)-chelated domains that resemble artificial enzymes. The resulting Cu(II)-containing nanostructures exhibit altered catalytic activity attributed to the distinctive chemical environment of self-folded polysaccharide scaffolds. Spectroscopic monitoring reveals different kinetic pathways in Cu(II)-catalysed Fenton-like reactions mediated by self-folded polysaccharide-based nanostructures containing Cu(II)-chelating active sites. These results demonstrate the potential of polysaccharide nanogels as advanced materials with versatile functionalities in catalytic applications.

Poly(methyl methacrylate) (PMMA) is the most commonly used host material for luminescent solar concentrators (LSCs), both in the form of thin films and slabs. Assuming industrial production of LSCs, the amount of polymeric material placed on the market would be considerable, raising questions about the sustainability of the approach. One option to avoid this scenario is to use chemical recycling processes for PMMA, from which a high-purity monomer, suitable for a new polymerization reaction and considerably less impactful in terms of global warming potential (GWP), is regenerated. In this paper, we propose the use of chemically regenerated methyl methacrylate (r-MMA) for the production of bulk LSC plates containing the state-of-the-art fluorophore Lumogen F Red 305 in a range of concentrations from 200 to 500 ppm. The performance of these devices and their chemical, thermal and mechanical properties are found to be equivalent to those obtained from commercially available virgin MMA, despite the impurities inherently present in r-MMA. However, these latter are detrimental to LSCs’ lifetime due to the photodegradation reactions they trigger. However, further purification of the regenerated monomer would allow the sustainability benefits of the production process to be exploited without sacrificing long device lifetimes.

Bilayer hydrogel actuators, composed of two hydrogel sheets exhibiting distinct swelling rates or ratios, have emerged as a promising class of smart materials. Their asymmetrical responsive properties enable controllable deformations, including bending and buckling. Recently, these smart materials have garnered significant attention for their versatile applications, playing crucial roles as manipulators or grippers, walkers and swimmers, and biomimetic devices. This perspective serves as a celebratory piece, illuminating the evolutionary journey of these smart materials and delving into their recent advancements post-2020. It provides readers with a focused spotlight on the current state-of-the-art materials, offering insights into their capabilities and projecting potential expansion avenues in the near future.

Wastewater-based epidemiology (WBE) has been recognized as a promising approach for rapid monitoring of infectious diseases in local communities. Development of adsorption materials that efficiently capture viruses is important in WBE to provide precise information on the prevalence of viral infections. Herein, ionic polymer brushes are synthesized for the tuning of virus adsorption and elution. Quaternary ammonium-based cationic polymer brushes exhibit higher adsorption of enveloped and nonenveloped viruses than a low-molecular-weight amine adduct. Moreover, efficient and selective elution of Aichivirus from the polymer brushes is demonstrated. These cationic polymer brushes may be useful as materials for passive sampling of viruses from water.

Microgels are spherical hydrogels with physicochemical properties ideal for many biomedical applications. For example, microgels can be used as individual carriers for suspension cell culture or jammed/annealed into granular hydrogels with micron-scale pores highly permissive to molecular transport and cell proliferation/migration. Conventionally, laborious optimization processes are often needed to create microgels with different moduli, sizes, and compositions. This work presents a new microgel and granular hydrogel preparation workflow using gelatin-norbornene-carbohydrazide (GelNB-CH). As a gelatin-derived macromer, GelNB-CH presents cell adhesive and degradable motifs while being amenable to three orthogonal click chemistries, namely the thiol-norbornene photo-click reaction, hydrazone bonding, and the inverse electron demand Diels–Alder (iEDDA) click reaction. The thiol-norbornene photo-click reaction (with thiol-bearing crosslinkers) and hydrazone bonding (with aldehyde-bearing crosslinkers) were used to crosslink the microgels and to realize on-demand microgel stiffening, respectively. The tetrazine-norbornene iEDDA click reaction (with tetrazine-bearing crosslinkers) was used to anneal microgels into granular hydrogels. In addition to materials development, we demonstrated the value of the triple-click chemistry granular hydrogels via culturing human mesenchymal stem cells and pancreatic cancer cells.

The development of advanced materials displaying reversible functionalities, such as self-healing is particularly desirable for energy storage devices, since the cycle life of many rechargeable batteries is limited due to the irreversible mechanical damages over the cycling processes. Hydrogen-bonding self-healing polymers functionalized with ureido pyrimidinone (UPy) has received great interest for energy storage applications, particularly for polymer electrolytes. Herein, we design a star-branched poly(ε-caprolactone-co-trimethylene carbonate) end-capped with UPy groups for both reinforced mechanical and desired self-healing properties in the polymer electrolytes. Despite the versatile implementation and strong bonding association, the benefits of hydrogen-bonding UPy functionalities are diminished after the dissolution of LiTFSI salt in the self-healing polymer matrix. Experimental analysis and molecular dynamics simulations were performed to gain insight into the dynamics of the self-healing polymer electrolyte system. FTIR shows a dramatic decrease in the intensities of the hydrogen-bonded CO signals belonging to UPy motifs after adding LiTFSI salt, indicative of a significant reduction in the total number of hydrogen-bonding and more loosened cross-linked polymer network. This is also noticed as a simultaneous deterioration of the mechanical properties. Molecular dynamics simulations reveal that the complex interplay of CO--Li⁺ coordination bonds and hydrogen bonding between TFSI anions and UPy motifs are responsible for the mechanical deterioration of the self-healing polymer electrolytes.

Addressing the complex issue of plastic waste disposal requires a nuanced approach, as no single solution proves universally effective. This review advocates for a comprehensive strategy, combining mechanical recycling and chemical methods to manage plastic waste while emphasizing the transformative potential of carbonization and activation processes specifically. With a focus on chemical activation, this review explores the synthesis of high surface area activated carbon (AC) from diverse plastic sources including polyesters (e.g., polyethylene terephthalate), polyolefins (e.g., polyethylene, polypropylene), and non-recyclable thermoset resins (e.g., epoxy, phenolics). The resulting AC products exhibit notable potential, with high surface areas exceeding 2000 m² g⁻¹ in some cases. Furthermore, the adsorptive behavior of the plastic derived ACs are discussed with respect to common pollutants such as dyes and CO₂ in addition to emerging pollutants, such as micro/nano-plastics. Overall, this work highlights carbonization and chemical activation as important upcycling methods for plastic wastes that may otherwise end up in landfills or spills into the environment. Given the urgency of plastic waste disposal, it is recommended that the feasibility and scalability of plastic-derived AC production is explored in future work for the potential replacement of conventional AC feedstocks derived from coal or biomass.

We introduce a bioinspired materials system that is capable of effectively coating surfaces, while concomitantly allowing metal ions to be reversibly bound. Specifically, we prepare a nitrogen-ligand carrying L-3,4-dihydroxyphenylalanine (L-DOPA) derivate, which can readily crosslink in aqueous systems with effective adhesion onto silicon wafers as well as stone wool fibers. Critically, the introduced system allows for reversible binding of the metal species (such as zinc cations) from aqueous solution. The reversibly binding surfaces are carefully assessed towards their metal ion binding efficiency – in contrast to non-ligand carrying coatings or uncoated surfaces – via surface sensitive analytical methods such as X-ray photoelectron spectroscopy, making them highly attractive candidates for applications in urban storm water filtration systems.

Glucagon is a peptide hormone that acts via receptor-mediated signaling predominantly in the liver to raise glucose levels by hepatic glycogen breakdown or conversion of noncarbohydrate, 3 carbon precursors to glucose by gluconeogenesis. Glucagon is administered to reverse severe hypoglycemia, a clinical complication associated with type 1 diabetes. However, due to low stability and solubility at neutral pH, there are limitations in the current formulations of glucagon. Trehalose methacrylate-based nanoparticles were utilized as the stabilizing and solubilizing moiety in the system reported herein. Glucagon was site-selectively modified to contain a cysteine at amino acid number 24 to covalently attach to the methacrylate-based polymer containing pyridyl disulfide side chains. PEG₂₀₀₀ dithiol was employed as the crosslinker to form uniform nanoparticles. Glucagon nanogels were monitored in Dulbecco's phosphate-buffered saline (DPBS) pH 7.4 at various temperatures to determine its long-term stability in solution. Glucagon nanogels were stable up to at least 5 months by size uniformity when stored at −20 °C and 4 °C, up to 5 days at 25 °C, and less than 12 hours at 37 °C. When glucagon stability was studied by either HPLC or thioflavin T assays, the glucagon was intact for at least 5 months at −20 °C and 4 °C within the nanoparticles at −20 °C and 4 °C and up to 2 days at 25 °C. Additionally, the glucagon nanogels were studied for toxicity and efficacy using various assays in vitro. The findings indicate that the nanogels were nontoxic to fibroblast cells and nonhemolytic to red blood cells. The glucagon in the nanogels was as active as glucagon alone. These results demonstrate the utility of trehalose nanogels towards a glucagon formulation with improved stability and solubility in aqueous solutions, particularly useful for storage at cold temperatures.