The optimized CS/CMS-lysozyme micro-gels demonstrated a loading efficiency of 849% as a consequence of the strategic adjustment to the CMS/CS ratio. The particle preparation process, characterized by its mild approach, successfully maintained 1074% of the relative activity compared to free lysozyme, thereby boosting antibacterial activity against E. coli, a result attributable to the combined effects of CS and lysozyme. The particle system's evaluation revealed no toxicity towards human cellular function. Simulated intestinal fluid digestion, over a six-hour period, demonstrated an in vitro digestibility of almost 70%. The results suggest that cross-linker-free CS/CMS-lysozyme microspheres are a promising antibacterial additive for treating enteric infections, with a significant effective dose of 57308 g/mL, released rapidly in the intestinal tract.
In 2022, the prestigious Nobel Prize in Chemistry was awarded to Carolyn Bertozzi, Morten Meldal, and Barry Sharpless, in recognition of their development of click chemistry and biorthogonal chemistry. The advent of click chemistry, pioneered by the Sharpless laboratory in 2001, led synthetic chemists to favor click reactions over other synthetic methodologies for creating new functions. This research brief will summarize our laboratory's work on the Cu(I)-catalyzed azide-alkyne click (CuAAC) reaction, as established by Meldal and Sharpless, along with the thio-bromo click (TBC) and the less-frequently utilized TERminator Multifunctional INItiator (TERMINI) dual click (TBC) reactions, the latter two originating from our laboratory's research. Accelerated modular-orthogonal methodologies, employing these click reactions, will serve to assemble complex macromolecules and biologically relevant self-organizing structures. The discussion will encompass the self-assembly of amphiphilic Janus dendrimers and Janus glycodendrimers, along with their biomimetic counterparts dendrimersomes and glycodendrimersomes. Furthermore, straightforward approaches for assembling macromolecules with defined and complex architectures, such as dendrimers constructed from commercially available monomers and building blocks, will be investigated. This perspective, marking the 75th anniversary of Professor Bogdan C. Simionescu, is dedicated to the memory of his father, Professor Cristofor I. Simionescu, my (VP) Ph.D. mentor. Professor Cristofor I. Simionescu, mirroring his son's example, seamlessly combined the realms of science and science administration throughout his career, dedicating his life to these intertwined pursuits.
The creation of wound-healing materials exhibiting anti-inflammatory, antioxidant, or antibacterial attributes is crucial for enhanced healing. The preparation and characterisation of soft, bioactive ionic gel patches are described in this work. Poly(vinyl alcohol) (PVA) was combined with four ionic liquids featuring a cholinium cation and distinct phenolic acid anions: cholinium salicylate ([Ch][Sal]), cholinium gallate ([Ch][Ga]), cholinium vanillate ([Ch][Van]), and cholinium caffeate ([Ch][Caff]). The iongels' structure, which incorporates ionic liquids with a phenolic motif, involves a dual role: crosslinking the PVA polymer and acting as a bioactive agent. Flexible, elastic, ionic-conducting, and thermoreversible materials were the iongels that were obtained. In addition, the iongels displayed high biocompatibility, evidenced by their non-hemolytic and non-agglutinating nature when introduced into the bloodstreams of mice, essential attributes for their deployment in wound healing. Escherichia Coli was the target of antibacterial activity observed in all iongels, with PVA-[Ch][Sal] registering the largest inhibition halo. Polyphenol presence in the iongels was a key contributor to their high antioxidant activity, with the PVA-[Ch][Van] iongel registering the strongest antioxidant response. Ultimately, the iongels exhibited a reduction in NO production within LPS-stimulated macrophages, with the PVA-[Ch][Sal] iongel demonstrating the most potent anti-inflammatory effect (>63% at a concentration of 200 g/mL).
The synthesis of rigid polyurethane foams (RPUFs) relied solely on lignin-based polyol (LBP), obtained through the oxyalkylation of kraft lignin with propylene carbonate (PC). Employing design of experiments procedures alongside statistical analysis, the formulations were refined to achieve a bio-based RPUF possessing both low thermal conductivity and low apparent density, suitable for use as a lightweight insulating material. The ensuing foams' thermo-mechanical properties were examined in relation to those of a commercially available RPUF and a counterpart RPUF (RPUF-conv), which was produced using a conventional polyol. The bio-based RPUF, developed through an optimized formulation, possesses low thermal conductivity (0.0289 W/mK), low density (332 kg/m³), and a reasonably well-organized cell morphology. While bio-based RPUF exhibits marginally diminished thermo-oxidative stability and mechanical characteristics compared to RPUF-conv, it remains a viable option for thermal insulation. Regarding fire resistance, this bio-based foam has been substantially improved, with an 185% reduction in average heat release rate (HRR) and a 25% increase in burn time compared to RPUF-conv. This bio-derived RPUF exhibits a noteworthy potential for replacing petroleum-based RPUF in insulation applications. Regarding the production of RPUFs, this is the first documented case of employing 100% unpurified LBP, obtained by oxyalkylating LignoBoost kraft lignin.
To examine the influence of perfluorinated substituents on the characteristics of anion exchange membranes (AEMs), polynorbornene-based AEMs with crosslinked perfluorinated side chains were synthesized using ring-opening metathesis polymerization, followed by crosslinking and quaternization procedures. The resultant AEMs (CFnB), with their crosslinked structure, exhibit the attributes of a low swelling ratio, high toughness, and high water absorption, all at once. The flexible backbone and perfluorinated branch chains of these AEMs were instrumental in promoting ion gathering and side-chain microphase separation, leading to a hydroxide conductivity of up to 1069 mS cm⁻¹ at 80°C, despite low ion content (IEC less than 16 meq g⁻¹). This work proposes a new method for achieving improved ion conductivity at low ion concentrations by incorporating perfluorinated branch chains, and establishes a practical approach for the preparation of high-performance AEMs.
The thermal and mechanical properties of PI-epoxy (EP) blends, with varying polyimide (PI) levels and post-curing treatments, were examined in this study. The blending of EP/PI (EPI) materials resulted in a decrease in crosslinking density, leading to enhanced flexural and impact resistance, a consequence of increased ductility. Conversely, post-curing EPI manifested improved thermal resistance, attributed to an increase in crosslinking density, and a concomitant rise in flexural strength, reaching up to 5789% because of heightened stiffness, despite a considerable reduction in impact strength, falling by as much as 5954%. The enhancement of EP's mechanical properties was attributed to EPI blending, while post-curing of EPI proved effective in boosting heat resistance. The mechanical properties of EP were confirmed to increase due to EPI blending, and the post-curing of EPI materials exhibited an improvement in heat resistance.
Mold manufacturing for rapid tooling (RT) in injection processes has found a relatively new avenue in the form of additive manufacturing (AM). This paper focuses on experiments involving mold inserts and specimens produced by stereolithography (SLA), a type of additive manufacturing process. The performance of the injected parts was examined by comparing a mold insert created using additive manufacturing to one produced via traditional subtractive manufacturing. Specifically, mechanical testing procedures (conforming to ASTM D638) and temperature distribution performance evaluations were undertaken. The tensile test results for specimens from the 3D-printed mold insert showed an improvement of nearly 15% over those produced by the duralumin mold. CPI-613 chemical structure The simulated temperature distribution exhibited a high degree of correspondence with the experimental result; the disparity in average temperatures was a minuscule 536°C. The injection molding sector, globally, can now incorporate AM and RT, thanks to these findings, as optimal alternatives for small to medium-sized production runs.
The plant extract, Melissa officinalis (M.), is central to the subject matter of this current research effort. Fibrous materials derived from a biodegradable polyester-poly(L-lactide) (PLA) and biocompatible polyether-polyethylene glycol (PEG) were successfully employed to electrospin *Hypericum perforatum* (St. John's Wort, officinalis). The most advantageous manufacturing conditions for hybrid fiber materials were discovered. To ascertain the effect of extract concentration (0%, 5%, or 10% by polymer weight) on the morphology and the physico-chemical properties of the resultant electrospun materials, a study was undertaken. The composition of all prepared fibrous mats was entirely defect-free fibers. Statistical measures of fiber diameter for PLA and PLA/M samples are reported. A mixture of PLA/M and officinalis extract, with five percent officinalis by weight. In the officinalis samples (10% by weight), the peak wavelengths were measured to be 1370 nm at 220 nm, 1398 nm at 233 nm, and 1506 nm at 242 nm, respectively. The incorporation of *M. officinalis* into the fibers produced a minor increment in fiber diameters, and concurrently, a rise in water contact angles that reached a value of 133 degrees. By incorporating polyether, the fabricated fibrous material's wetting ability improved, manifesting as hydrophilicity (a water contact angle of 0 degrees being achieved). CPI-613 chemical structure Antioxidant activity was strongly exhibited by fibrous materials incorporating extracts, as measured by the 2,2-diphenyl-1-picrylhydrazyl hydrate free radical procedure. CPI-613 chemical structure The DPPH solution, upon contact with PLA/M, experienced a transformation to yellow, accompanied by a drop in DPPH radical absorbance by 887% and 91%. Officinalis and PLA/PEG/M are integral parts of a novel formulation.