Petru Poni Institute of Macromolecular Chemistry

A phenolic Mannich base derived from 1′-hydroxy-2′-acetonaphthone (HAN) as a substrate and morpholine as an amine reagent was synthesized and structurally characterized. The sensing ability toward various metal ions of the s-, p- and d-block of this molecule that has the binding site for metal ions in the starting ortho-hydroxyphenone preserved was examined. Interaction between this phenolic Mannich base and Al³⁺, Cr³⁺, Cu²⁺ and Co²⁺ leads to modifications of the sensing molecule's absorption spectrum. Fluorescence spectroscopy showed that Al³⁺ acts as a fluorescence enhancer, whereas Cu²⁺ functions as a fluorescence quencher for the aminomethylated derivative. The phenolic Mannich base may be employed either as a sensitive “turn-on” chemosensor for Al³⁺ or as a sensitive “turn-off” chemosensor for Cu²⁺. However, in the presence of these ions at identical concentrations, the Mannich base becomes a selective chemosensor for Al³⁺. The sensing ability of this phenolic Mannich base toward rare earth ions showed that Eu³⁺, Dy³⁺ and Gd³⁺ induce changes in the absorption spectrum of the Mannich base. Fluorescence spectroscopy showed that the response of the sensing molecule toward Eu³⁺ and Dy³⁺ is weak, and this phenolic Mannich base may be used as a “turn-off” chemosensor for these two lanthanide ions only in a narrow concentration range (1–16 × 10⁻⁵ M).

Pluronic F127 copolymer is used as the main component to design injectable gels for therapeutic applications. Xanthan gum is added as an excipient to improve gel properties under physiological conditions. A polyphenol bioactive compound, curcumin, is selected as therapeutic agent with beneficial effects on metabolism and many diseases. The encapsulation efficiency and stability of formulations are investigated in an aqueous environment and in acetic acid solutions. The interactions between the hydrophobic polyphenol and the polymer matrix are investigated through rheology, DLS, and FTIR spectroscopy. The viscoelasticity of gels, correlated with the network structure, is influenced by xanthan gum or acetic acid addition. FTIR analysis of curcumin incorporated into the gel provides the evidence for interaction of the phenyl rings of both keto‐enol and di‐keto tautomers with the polymeric matrix. The spherical curcumin‐encapsulated micelles provided antioxidant properties. The kinetics of curcumin release from the Pluronic F127‐based gels suggests anomalous transport phenomena controlled by diffusion through the network and hydrodynamic effects. Both gel and lyophilized form of micellar encapsulated curcumin composites exhibited good stability for long‐term storage under ambient conditions.

There is an emerging necessity for improved therapies against Candida‐related infections, with significant implications for global healthcare. Current antifungal agents, limited in number, target specific pathways, but resistance remains a concern. Flucytosine (5FC) exhibits antifungal activity, particularly against Candida. However, monotherapy efficacy is limited, necessitating combination treatments. Herein, we report PEGylated squalene‐based nanocarriers for 5FC loading, aiming to enhance its monotherapy efficacy against Candida strains. The loading of 5FC within micelles was achieved using the ultrasound‐assisted solvent evaporation method. The 5FC‐loaded micelles, together with non‐loaded micelles, were thoroughly characterized and analyzed. STEM and DLS analysis confirmed the core‐shell morphology with nanometric dimensions along with improved colloidal stability. The quantification of drug loading efficiency and drug loading capacity was calculated using the UV‐Vis technique. The in vitro drug‐release studies in simulated physiological conditions showed sustained release within 48 hours. Moreover, the release kinetics calculated using mathematical models showed a Fickian diffusion drug release mechanism in simulated physiological conditions with a slower diffusion rate. The in vitro antifungal activity was tested on Candida albicans, Candida glabrata, and Candida parapsilosis. The results showed improved antifungal activity for the nanotherapeutic and unchanged in vitro toxicity toward normal cells, suggesting promising advancements in 5FC therapy.

The integration of nanomaterials into the textile industry has significantly advanced the development of high-performance fabrics, offering enhanced properties such as UV blocking, fire resistance, breathability, hydrophobicity, antimicrobial activity, and dust rejection. In this context, our research explores the development and characterization of electrospun membranes composed of polyether ether ketone (PEEK) and various polyimides (PIs (1–6)), focusing on their application in protective clothing. The combination of phosphorus-containing polyimides and PEEK, along with the electrospinning process, enhances the distinctive properties of both PEEK and polyimides, leading to composite membranes that stand out according to key parameters essential for maintaining physiological balance. The structural and morphological characteristics of these membranes have been evaluated using Fourier transform infrared spectroscopy (FTIR) to identify the functional groups and scanning electron microscopy (SEM) to examine their morphology. These analyses provide critical insights into these materials’ properties, which influence key performance parameters such as moisture management, breathability, and barrier functions. The membranes’ breathability and impermeability were assessed through the water vapor transmission rate (WVTR), contact angle measurements, water and air permeability, and flame resistance tests. The results obtained indicate that PEEK/polyimide composite membranes meet the complex requirements of modern protective textiles, ensuring both safety and comfort for users through their optimized structural properties and enhanced functional capabilities.

This study investigates novel biomaterials developed for bone regeneration, using cellulose and collagen type I matrices enhanced with hydroxyapatite or InterOss. These materials demonstrate significantly improved mechanical properties, notably the compressive modulus, indicating their potential for effective structural support in bone regeneration. Incorporating hydroxyapatite into these matrices markedly improves their physical properties, increasing the Brunauer–Emmett–Teller area and monolayer capacity, thereby facilitating superior cell adhesion and proliferation. This enhancement promotes more effective osteoblast activity and viability over extended periods compared to matrices containing InterOss. Furthermore, the scaffolds comprising cellulose modified with (3-amino-4-methylphenyl) boronic acid exhibit significantly enhanced antibacterial properties, effectively inhibiting both Gram-positive and Gram-negative bacteria, which is crucial for preventing post-surgical infections. Materials that incorporate hydroxyapatite (HA) have displayed a rougher and more intricate surface compared to those that include InterOss® particles, suggesting that HA promotes the development of an enhanced mineralized skeleton within the composites. Cytocompatibility studies revealed that the scaffold containing cellulose, collagen, and hydroxyapatite provided the most favorable environment for sustaining cell viability, with significant improvements noted from day 7 onwards. Despite initial cytotoxicity challenges, long-term exposure showed improved cell viability, suggesting degradation of cytotoxic products over time. This research underscores the clinical potential of these biomaterials in bone regeneration, highlighting their ability to enhance structural integrity, support osteogenic activity, and prevent bacterial infections, thus promising to improve patient outcomes in bone-related therapies.

Nowadays, the development of devices based on organic materials is an interesting research challenge. The performance of such devices is strongly influenced by material selection, material properties, design, and the manufacturing process. Usually, buckminsterfullerene (C60) is employed as electron transport material in organic photovoltaic (OPV) devices due to its high mobility. However, considering its low solubility, there have been many attempts to replace it with more soluble non-fullerene compounds. In this study, bulk heterojunction thin films with various compositions of zinc phthalocyanine (ZnPc), a perylene diimide derivative, or C60 were prepared by matrix-assisted pulsed laser evaporation (MAPLE) technique to assess the influence of C60 replacement on fabricated heterostructure properties. The investigations revealed that the optical features and the electrical parameters of the organic heterostructures based on this perylene diimide derivative used as an organic acceptor were improved. An increase in the JSC value (4.3 × 10⁻⁴ A/cm²) was obtained for the structures where the perylene diimide derivative acceptor entirely replaced C60 compared to the JSC value (7.5 × 10⁻⁸ A/cm²) for the heterostructure fabricated only with fullerene. These results are encouraging, demonstrating the potential of non-fullerene compounds as electron transport material in OPV devices.

Ionic conductive hydrogels (ICHs) prepared from natural bioresources are promising candidates for constructing flexible electronics for both commercialization and environmental sustainability due to their intrinsic characteristics. However, simultaneous realization of high stiffness, toughness, conductivity, and multifunctionality while ensuring processing simplicity is extremely challenging. Here, a poly(ionic liquid) (PIL)‐macromolecule functionalization strategy within a NaOH/urea system is proposed to construct high‐performance and versatile polysaccharide‐based ICHs (e.g., cellulosic ICHs). In this strategy, the elaborately designed “soft” (PIL chains) and “hard” (cellulose backbone) structures as well as the dynamic covalent and noncovalent bonds of the cross‐linked networks endow the hydrogel with high mechanical strength (9.46 ± 0.23 MPa compressive modulus), exceptional stretchability (214.3%), and toughness (3.64 ± 0.12 MJ m⁻³). Ingeniously, due to the inherent conductivity, design flexibility, and functional compatibility of the PILs, the hydrogels exhibit high conductivity (6.54 ± 0.17 mS cm⁻¹), self‐healing ability (94.5% ± 2.0% efficiency), antibacterial properties, freezing resistance, water retention, and recyclability. Interestingly, this strategy is extended to fabricate diverse hydrogels from various polysaccharides, including agar, alginate, hyaluronic acid, and guar gum. In addition, multimodal sensing (strain, temperature, and humidity) is realized based on the stimulus‐responsive characteristics of the hydrogels. This strategy opens new perspectives for the design of biomass‐based hydrogels and beyond.

Understanding the intricate interactions of molecular dyes with nucleic acids is pivotal for advancing medical and biochemical applications. In this work, we present a comprehensive study of the interplay between a novel series of bis-acridine orange (BAO) dyes and double-stranded DNA (dsDNA). These BAO dyes were intentionally designed as two acridine orange units connected by neutral linkers featuring a 2,5-disubstituted thiophene moiety. Comparative analysis of BAO compounds with the widely utilized DNA-binding dye EvaGreen (EG) was carried out for fibroblast staining and qPCR analysis. The results show that BAO dyes outperform EG by supporting PCR amplification over a broader concentration range (0.5–5.0 μM). Furthermore, they exhibit an exceptional capability to generate consistent DNA melting curves regardless of DNA concentration fluctuations. Molecular dynamics simulations showed that BAO dyes when interacting with dsDNA unfold from the stacked conformation to the elongated one. The difference in the energy between the conformations is shown to be concomitant with fluorescence enhancement. This study enriches our understanding of the intricate interplay between innovative BAO dyes and dsDNA, fostering their applications in medical and biochemical research, particularly in qPCR methodologies and bioimaging techniques.

Background: Tinea pseudoimbricata is a variant of tinea incognito with multiple erythematous concentric rings (Ring in a ring) and pruritus. Misuse of topical corticosteroids is a major exogenous factor. Aim: We provide an overview on published cases and report the first case series from Romania. Patients and methods: A narrative review of the literature was conducted on PubMed, amended by Researchgate. A series of pediatric cases from Romania with clinical suspicion of tinea pseudoimbricata was investigated by clinical examination, KOH preparations of skin scrapings, and mycological culture when possible. Results: We collected 137 cases of tinea pseudoimbricata from the world literature and added a series of 5 pediatric patients from Romania. The oral treatment with fluconazole was effective in all Romanian patients. Worldwide most reports came from India (86%), 3.5% were from other Asian countries, 3.5% were from the Americas, and 7% were from Europe. M. canis and T. mentagrophytes were identified in two patients from Romania. T. mentagrophytes, T. rubrum and T. tonsurans are the dominant species worldwide, but molecular diagnostics were available for only a minor part of cases. Conclusions: Tinea pseudoimbricata is most common in India. This is the first case series on tinea pseudoimbricata from Romania. Tinea pseudoimbricata is an emerging disease in Europe. Identification of fungi have rarely been done by molecular mycology. This could have caused an overestimation of T. mentagrophytes and an underestimation of T. indotineae.

In the original publication [...]

Scarce dihydro‐1,4‐diazinoisoindole framework bearing two points of diversity was prepared through a cascade process based on concomitant Csp³−N and Csp²−N bond formation. This approach consists of an amidation in basic medium of a tosyl group by nucleophilic substitution followed by Cu‐mediated Goldberg reaction in the same operation. The required β‐bromoenamide bearing a tosyl group was obtained by tosylation of fused brominated N,O‐acetals for the first time in acidic medium using submolar amounts of PTSA. The obtained piperazines are useful building blocks as illustrated by the formation of a pentacyclic product via the intramolecular interception of the enamide function.

Dynamic chitosan-based hydrogels with enhanced antioxidant activity were synthesized through the formation of reversible imine linkages with 5-methoxy-salicylaldehyde. These hydrogels exhibited a porous structure and swelling capacity, influenced by the crosslinking degree, as confirmed by SEM and POM analysis. The dynamic nature of the imine bonds was characterized through NMR, swelling studies in various media, and aldehyde release measurements. The hydrogels demonstrated significantly improved antioxidant activity compared to unmodified chitosan, as evaluated by the DPPH method. This research highlights the potential of developing pH–responsive chitosan-based hydrogels for a wide range of biomedical applications.

Seed cakes, by-products from the cold press extraction of vegetable oils, are valuable animal feed supplements due to their high content of proteins, carbohydrates, and minerals. However, the presence of anti-nutrients, as well as the rancidification and development of aflatoxins, can impede their intended use, requiring alternative treatment and valorisation methods. Thermal treatment as a procedure for the conversion of seed cakes from walnuts, hemp, pumpkin, flax, and sunflower into valuable products or energy has been investigated in this paper. Thermogravimetry shows the particular behaviour of seed cakes, with several degradation stages at around 230–280 and 340–390 °C, before and after the typical degradation of cellulose. These are related to the volatilisation of fatty acids, which are either free or bonded as triglycerides, and with the thermal degradation of proteins. Torrefaction at 250 °C produced ~75–82 wt% solids, with high calorific values of 24–26 kJ/g and an energy yield above 90%. The liquid products have a complex composition, with most parts of the compounds partitioning between the aqueous phase (strongly dominant) and the oily one (present in traces). The structural components of seed cakes (hemicelluloses, cellulose, and lignin) produce acetic acid, hydroxy ketones, furans, and phenols. In addition to these, most compounds are nitrogen-containing aromatic compounds from the degradation of protein components, which are highly present in seed cakes.

Background: kidney transplant recipients are exposed to multiple pathogenic pathways that may alter short and long-term allograft survival. Metabolomic profiling is useful for detecting potential biomarkers of kidney disease with a predictive capacity. This field is still under development in kidney transplantation and metabolome analysis is faced with analytical challenges. We performed a cross-sectional study including stable kidney transplant patients and aimed to search for relevant associations between baseline plasmatic and urinary metabolites and relevant outcomes over a follow-up period of 3 years. Methods: we performed a cross-sectional study including 72 stable kidney transplant patients with stored plasmatic and urinary samples at the baseline evaluation which were there analyzed by nuclear magnetic resonance in order to quantify and describe metabolites. We performed a 3-year follow-up and searched for relevant associations between renal failure outcomes and baseline metabolites. Between-group comparisons were made after classification by observed estimated glomerular filtration rate slope during the follow-up: positive slope and negative slope. Results: The mean estimated GFR (glomerular filtration rate) was higher at baseline in the patients who exhibited a negative slope during the follow-up (63.4 mL/min/1.73 m² vs. 55.8 mL/min/1.73 m², p = 0,019). After log transformation and division by urinary creatinine, urinary dimethylamine (3.63 vs. 3.16, p = 0.027), hippuric acid (7.33 vs. 6.29, p = 0.041), and acetone (1.88 vs. 1, p = 0.023) exhibited higher concentrations in patients with a negative GFR slope when compared to patients with a positive GFR slope. By computing a linear regression, a significant low-strength regression equation between the log 2 transformed plasmatic level of glycine and the estimated glomerular filtration rate was found (F (1,70) = 5.15, p = 0.026), with an R² of 0.069. Several metabolites were correlated positively with hand grip strength (plasmatic tyrosine with r = 0.336 and p = 0.005 and plasmatic leucine with r = 0.371 and p = 0.002). Other urinary metabolites were found to be correlated negatively with hand grip strength (dimethylamine with r = −0.250 and p = 0.04, citric acid with r = −0.296 and p = 0.014, formic acid with r = −0.349 and p = 0.004, and glycine with r = −0.306 and p = 0.01). Conclusions: some metabolites had different concentrations compared to kidney transplant patients with negative and positive slopes, and significant correlations were found between hand grip strength and urinary and plasmatic metabolites.