Aqueous photo-RAFT polymerization under ambient conditions: synthesis of protein-polymer hybrids in open air.

A photoinduced reversible addition-fragmentation chain-transfer (photo-RAFT) polymerization technique in the presence of sodium pyruvate (SP) and pyruvic acid derivatives was developed. Depending on the wavelength of light used, SP acted as a biocompatible photoinitiator or promoter for polymerization, allowing rapid open-to-air polymerization in aqueous media. Under UV irradiation (370 nm), SP decomposes to generate CO2 and radicals, initiating polymerization. Under blue (450 nm) or green (525 nm) irradiation, SP enhances the polymerization rate via interaction with the excited state RAFT agent. This method enabled the polymerization of a range of hydrophilic monomers in reaction volumes up to 250 mL, eliminating the need to remove radical inhibitors from the monomers. In addition, photo-RAFT polymerization using SP allowed for the facile synthesis of protein-polymer hybrids in short reaction times (<1 h), low organic content (≤16%), and without rigorous deoxygenation and the use of transition metal photocatalysts. Enzymatic studies of a model protein (chymotrypsin) showed that despite a significant loss of protein activity after conjugation with RAFT chain transfer agents, the grafting polymers from proteins resulted in a 3-4-fold recovery of protein activity.

The Influence of PVP Polymer Topology on the Liquid Crystalline Order of Itraconazole in Binary Systems.

This study presents a novel approach by utilizing poly(vinylpyrrolidone)s (PVPs) with various topologies as potential matrices for the liquid crystalline (LC) active pharmaceutical ingredient itraconazole (ITZ). We examined amorphous solid dispersions (ASDs) composed of ITZ and (i) self-synthesized linear PVP, (ii) self-synthesized star-shaped PVP, and (iii) commercial linear PVP K30. Differential scanning calorimetry, X-ray diffraction, and broad-band dielectric spectroscopy were employed to get a comprehensive insight into the thermal and structural properties, as well as global and local molecular dynamics of ITZ-PVP systems. The primary objective was to assess the influence of PVPs' topology and the composition of ASD on the LC ordering, changes in the temperature of transitions between mesophases, the rate of their restoration, and finally the solubility of ITZ in the prepared ASDs. Our research clearly showed that regardless of the PVP type, both LC transitions, from smectic (Sm) to nematic (N) and from N to isotropic (I) phases, are effectively suppressed. Moreover, a significant difference in the miscibility of different PVPs with the investigated API was found. This phenomenon also affected the solubility of API, which was the greatest, up to 100 µg/mL in the case of starPVP 85:15 w/w mixture in comparison to neat crystalline API (5 µg/mL). Obtained data emphasize the crucial role of the polymer's topology in designing new pharmaceutical formulations.

Visible-light-induced ATRP under high-pressure: synthesis of ultra-high-molecular-weight polymers.

In this study, a high-pressure-assisted photoinduced atom transfer radical polymerization (p ≤ 250 MPa) enabled the synthesis of ultra-high-molecular-weight polymers (UHMWPs) of up to 9 350 000 and low/moderate dispersity (1.10 < D < 1.46) in a co-solvent system (water/DMSO), without reaction mixture deoxygenation.

The unique role of pore wall nanostructurization in the intrachannel photo-ATRP for fine-tuning PMMA tacticity.

In this paper, efficient MMA photo O-ATRP protocols conducted inside nanoreactors varying in nanostructured interfaces are reported for the first time. We showed that the microstructure of recovered polymers could be easily tuned just by implementing a given type of nanochannel (d = 10, 19-28, 35, 160 nm).

High pressure as a novel tool for the cationic ROP of γ-butyrolactone.

In this study, we report the acid-catalyzed and high pressure assisted ring-opening polymerization (ROP) of γ-butyrolactone (GBL). The use of a dually-catalyzed approach combining an external physical factor and internal catalyst (trifluoromethanesulfonic acid (TfOH) or p-toluenesulfonic acid (PTSA)) enforced ROP of GBL, which is considered as hardly polymerizable monomer still remaining a challenge for the modern polymer chemistry. The experiments performed at various thermodynamic conditions (T = 278-323 K and p = 700-1500 MPa) clearly showed that the high pressure supported polymerization process led to obtaining well-defined macromolecules of better parameters (M n = 2200-9700 g mol-1; D = 1.05-1.46) than those previously reported. Furthermore, the parabolic-like dependence of both the molecular weight (M W) and the yield of obtained polymers on variation in temperature and pressure at either isobaric or isothermal conditions was also noticed, allowing the determination of optimal conditions for the polymerization process. However, most importantly, this strategy allowed to significantly reduce the reaction time (just 3 h at room temperature) and increase the yield of obtained polymers (up to 0.62 gPGBL/gGBL). Moreover, despite using a strongly acidic catalyst, synthesized polymers remained non-toxic and biocompatible, as proven by the cytotoxicity test we performed in further analysis. Additional investigation (including MALDI-TOF measurements) showed that the catalyst selection affected not only M W and yield but also the linear/cyclic form content in obtained macromolecules. These findings show the way to tune the properties of PGBL and obtain polymer suitable for application in the biomedical industry.

Are hydrogen supramolecular structures being suppressed upon nanoscale confinement? The case of monohydroxy alcohols.

In this paper, the molecular dynamics, H-bonding pattern and wettability of the primary and secondary monohydroxyalcohols, 2-ethyl-1-hexanol (2E1H), 2-ethyl-1-butanol (2E1B) and 5-methyl-3-heptanol (5M3H) infiltrated into native and functionalized silica and alumina pores having pore diameters, d = 4 nm and d = 10 nm, have been studied with the use of Broadband Dielectric (BDS) and Fourier Transform InfraRed (FTIR) spectroscopies, as well as contact angle measurements. We found significant differences in the behavior of alcohols forming chain- (2E1H, 2E1B) or micelle-like (5M3H) supramolecular structures despite of their similarities in the wettability and interfacial energy. It turned out that nanoassociates as well as H-bonds are more or less affected by the confinement dependently on the chemical structure and alcohol order. Moreover, a peculiar behavior of the self-assemblies at the interface was noted in the latter material (5M3H). Finally, it was found that irrespectively to the sample, type of pores, functionalization, the temperature evolution of Debye relaxation times, τD, of the confined systems deviates from the bulk behavior always at similar τD due to vitrification of the interfacial layer. This finding is a clear indication that unexpectedly dynamics (mobility) of the supramolecular structures close to the hydrophilic and hydrophobic surfaces is similar in each system.

Pressure-assisted solvent- and catalyst-free production of well-defined poly(1-vinyl-2-pyrrolidone) for biomedical applications.

In this work, we developed a fast, highly efficient, and environmentally friendly catalytic system for classical free-radical polymerization (FRP) utilizing a high-pressure (HP) approach. The application of HP for thermally-induced, bulk FRP of 1-vinyl-2-pyrrolidone (VP) allowed to eliminate the current limitation of ambient-pressure polymerization of 'less-activated' monomer (LAM), characterized by the lack of temporal control yielding polymers of unacceptably large disperisites and poor result reproducibility. By a simple manipulation of thermodynamic conditions (p = 125-500 MPa, T = 323-333 K) and reaction composition (two-component system: monomer and low content of thermoinitiator) well-defined poly(1-vinyl-2-pyrrolidone)s (PVP) in a wide range of molecular weights and low/moderate dispersities (M n = 16.2-280.5 kg mol-1, D = 1.27-1.45) have been produced. We have found that HP can act as an 'external' controlling factor that warrants the first-order polymerization kinetics for classical FRP, something that was possible so far only for reversible deactivation radical polymerization (RDRP) systems. Importantly, our synthetic strategy adopted for VP FRP enabled us to obtain polymers of very high M n in a very short time-frame (0.5 h). It has also been confirmed that VP bulk polymerization yields polymers with significantly lower glass transition temperatures (T g) and different solubility properties in comparison to macromolecules obtained during the solvent-assisted reaction.

Comprehensive comparison of antioxidant properties of tinctures.

Homemade tinctures, traditional Polish alcoholic beverages called "nalewkas" (similar to alcohol herbal tinctures), which antioxidant capacity have never been studied before, were characterized by electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and ultraviolet visible (UV-vis) spectroscopy. The antioxidant properties of nalewkas made according to homemade recipes were compared to commercially produced nalewkas. The impact of aging on antioxidant properties of nalewkas was investigated. The results showed that all of examined nalewkas exhibited strong antioxidant properties (antioxidant capacity TEACDPPH 466 µmol TE/100 mL - 11890 µmol TE/100 mL). It was found that the value of the antioxidant capacity corresponds to the total phenolic and aromatic proton content. The impact of the production method and the type of fruit used on the TEACDPPH value was also noted. The unripe walnuts with green husks has the highest value of the antioxidant capacity TEACDPPH (11890 µM/100 mL) not only for alcoholic beverages, but also among food products.