Bis(pyridinium) trans-tetrachlorido­dioxidouranate(VI) dioxane solvate

In the crystal structure of the title compound, (C5H6N)2[UCl4O2]·C4H8O2, the pyridinium cations occupy general positions and the anions and the solvent dioxane mol­ecule are located on centres of inversion. The dioxane mol­ecules are connected to two symmetry-related pyridinium cations via O—H⋯O hydrogen bonding. There are additional inter­molecular C—H⋯Cl contacts, which are indicative of weak C—H⋯Cl inter­actions

Disordered structure of propane-1,2-diaminium dichloride

In the title compound, C3H12N2 2+·2Cl−, the cations are disordered over two well resolved positions in a 0.525 (13):0.475 (13) ratio. The disorder involves two C atoms which assume positions that make an almost mirror-sym­metrical system. Similar disorder is observed both at room temperature and at 120 (1) K. The conformation of the NCCN chain in both components is close to trans (the torsion angles ca ±170°), while that of CCCN chain is close to gauche (±50°). In the crystal, a network of relatively strong N—H⋯Cl hydrogen bonds connects the cations and anions into one-cation-deep layers parallel to (001); there are R 2 4(8) and R 2 4(11) ring motifs within the plane. The planes are only loosely connected by van der Waals contacts and electrostatic inter­actions between cations and anions

(Bio)degradable polymeric materials for sustainable future—Part 3: Degradation studies of the PHA/wood flour-based composites and preliminary tests of antimicrobial activity

© 2020 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/ma13092200The need for a cost reduction of the materials derived from (bio)degradable polymers forces research development into the formation of biocomposites with cheaper fillers. As additives can be made using the post-consumer wood, generated during wood products processing, re-use of recycled waste materials in the production of biocomposites can be an environmentally friendly way to minimalize and/or utilize the amount of the solid waste. Also, bioactive materials, which possess small amounts of antimicrobial additives belong to a very attractive packaging industry solution. This paper presents a study into the biodegradation, under laboratory composting conditions, of the composites that consist of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate)] and wood flour as a polymer matrix and natural filler, respectively. Thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy were used to evaluate the degradation progress of the obtained composites with different amounts of wood flour. The degradation products were characterized by multistage electrospray ionization mass spectrometry. Also, preliminary tests of the antimicrobial activity of selected materials with the addition of nisin were performed. The obtained results suggest that the different amount of filler has a significant influence on the degradation profile.Published onlin

Fabrication and in-vivo study of micro-colloidal zanthoxylum acanthopodium-loaded bacterial cellulose as a burn wound dressing

© 2020 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/polym12071436Bacterial cellulose (BC) is a biopolymer commonly used for wound dressing due to its high biocompatible properties either in-vitro or in-vivo. The three-dimensional fiber structure of BC becomes an advantage because it provides a template for the impregnation of materials in order to improve BC’s properties as a wound dressing, since BC has not displayed any bioactivity properties. In this study, micro-colloidal Zanthoxylum acanthopodium (MZA) fruit was loaded into BC fibers via an in-situ method. Z. acanthopodium is known to have anti-inflammatory, antioxidant and antimicrobial activities that can support BC to accelerate the wound healing process. The FTIR, XRD and SEM analysis results showed that the loading process of MZA and the composite fabrication were successfully carried out. The TGA test also showed that the presence of MZA in BC fibers decreased Tmax composite from BC, from 357.8 to 334.5 °C for BC-MZA3. Other aspects, i.e., water content, porosity, hemocompatibility and histology studies, also showed that the composite could potentially be used as a wound dressing.This research was fully funded by the Ministry of Research, Technology and Higher Education through 2018 PMDSU Research Scheme (Grant no: 1/UN5.2.3.1/PPM/KP-DRPM-PMDSU II/2018).Published onlin

Synthesis of hydrogels made of poly-γ-glutamic acid (γ-PGA) for potential applications as probiotic-delivery vehicles

© 2020 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/app10082787Numerous hydrogels made of poly-γ-glutamic acid (γ-PGA) and various cross-linkers have been explored, but only limited data on hydrogels made of γ-PGA and poly(ethylene glycol) (PEG) are available. In this study, γ-PGA, a biodegradable and edible biopolyamide, was successfully cross-linked with selected PEGs to obtain a series of hydrogels. The swelling behaviour of these hydrogels was investigated under various pH conditions. It was also found that the structure of the cross-linker (linear or branched) affected the hydrogels’ swelling behaviour. In addition, in disc diffusion assay, hydrogel discs loaded with antibiotic were tested against Staphylococcus aureus and Escherichia coli. Prolonged activity of hydrogels loaded with antibiotics in comparison to paper discs containing antibiotics was observed. Moreover, the protective effect of hydrogels on entrapped probiotic cells subjected to low pH was investigated. The hydrogel swelling ratio and amount influenced the survival rate of the protected bacteria. Considering potential biomedical applications of hydrogels, cytotoxicity was evaluated towards two cell lines, MSTO and PANC 1

Characterization of bacterial cellulose-based wound dressing in different order impregnation of chitosan and collagen

© 2020 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/biom10111511Bacterial cellulose (BC), chitosan (Chi), and collagen (Col) are known as biopolymers which have met some properties that are required as wound dressing. This study focused on investigating the fabrication of BC-based wound dressing with chitosan and collagen, since chitosan has red blood cells binding and anti-bacterial properties, while collagen can support cell and tissue growth for skin wounds. The BC-based wound dressing was prepared by impregnating BC fibers in the chitosan and/or collagen solution for 24 h. FTIR was used to confirm the intermolecular interaction of amine and hydroxyl group of chitosan and/or collagen in BC-based wound dressing. Furthermore, the XRD diffractogram of the wound dressing show broader peaks at 14.2°, 16.6°, and 22.4° due to the presence of chitosan and collagen molecules in BC fibers. These results were then supported by SEM images which confirmed that chitosan and collagen were well penetrated into BC fibers. TGA curves revealed that BC/Chi/Col has better thermal properties based on the Tmax compare to BC/Col/Chi. Feasibility of the mats to be applied as wound dressing was also supported by other tests, i.e., water content, porosity, and hemocompatibility, which indicates that the wound dressing is classified as nonhemolytic materials. However, BC/Col/Chi was considered a more potential wound dressing to be applied compared to BC/Chi/Col since it has larger pores and showed better antibacterial properties (larger zones of inhibition) against S. aureus and E. coli via disk diffusion tests.Published onlin

The mould war: developing an armamentarium against fungal pathogens utilising thymoquinone, ocimene, and miramistin within bacterial cellulose matrices

© 2021 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/ma14102654An increase in antifungal resistance has seen a surge in fungal wound infections in patients who are immunocompromised resulting from chemotherapy, disease, and burns. Human pathogenic fungi are increasingly becoming resistant to a sparse repertoire of existing antifungal drugs, which has given rise to the need to develop novel treatments for potentially lethal infections. Bacterial cellulose (BC) produced by Gluconacetobacter xylinus has been shown to possess many properties that make it innately useful as a next-generation biopolymer to be utilised as a wound dressing. The current study demonstrates the creation of a pharmacologically active wound dressing by loading antifungal agents into a biopolymer hydrogel to produce a novel wound dressing. Amphotericin B is known to be highly hepatotoxic, which reduces its appeal as an antifungal drug, especially in patients who are immunocompromised. This, coupled with an increase in antifungal resistance, has seen a surge in fungal wound infections in patients who are immunodeficient due to chemotherapy, disease, or injury. Antifungal activity was conducted via Clinical & Laboratory Standards Institute (CLSI) M27, M38, M44, and M51 against Candida auris, Candida albicans, Aspergillus fumigatus, and Aspergillus niger. This study showed that thymoquinone has a comparable antifungal activity to amphotericin B with mean zones of inhibition of 21.425 ± 0.925 mm and 22.53 ± 0.969 mm, respectively. However, the mean survival rate of HEp-2 cells when treated with 50 mg/L amphotericin B was 29.25 ± 0.854% compared to 71.25 ± 1.797% when treated with 50 mg/L thymoquinone. Following cytotoxicity assays against HEp-2 cells, thymoquinone showed a 71.25 ± 3.594% cell survival, whereas amphotericin B had a mean cell survival rate of 29.25 ± 1.708%. The purpose of this study was to compare the efficacy of thymoquinone, ocimene, and miramistin against amphotericin B in the application of novel antifungal dressings.Partial financial support from the European Regional Development Fund Project EnTRESS No. 01R16P00718

Evaluation of the oral cavity state and Candida occurence in generally healthy Polish and foreign dental students

Aim of the study. This study aimed at comparing the oral cavity condition and Candida prevalence in generally healthy Polish and foreign dentistry students and evaluating the relationship between Candida occurrence and the oral cavity condition. Material and methods. 79 dentistry students with no systemic diseases, aged 20–25 (mean 23.5), were examined in the present study. Two groups of examined subjects were specified: 43 Polish students (group I) and 36 foreign students (group II). Group II has been divided into subgroups: IIa – students from Taiwan and IIb – students from Europe and USA. Occurence of oral mucosa lesions, periodontal treatment needs (CPITN), caries prevalence (DMFT) and oral hygiene (OHIs) were investigated. Evaluation of Candida occurrence on the oral mucosa was included in the study. Results. Comparison of the oral cavity condition in Polish and foreign students showed no significant difference, with the exception of the number of teeth with active caries, that was significantly higher in foreign students (D 1,2) than in Polish students (D 0.4). Mean indices rates in the group I were: CPITN 0.9; PUWz 8.7; OHI-s 0.4 in the group II 1.0; 7.0; 0,5, respectively. The most commonly observed oral mucosa lesions, in both groups, were white coated tongue and buccal white line. Candida was found in 38,0% of the subjects, its prevalence was similar in both groups (I – 34.9%, II – 41.7%). No correlation between Candida occurence and oral cavity state was detected. Higher frequency of active caries in Candida carriers was the exception

Environmental cleaning mission Bioconversion of oxidatively fragmented polyethylene plastic waste to value-added copolyesters

The innovative recycling method, we are proposing, relies upon the controlled oxidative fragmentation of waste LDPE plastic to the inexpensive substrates for future sustainable production of PHAs with the aid of Cupriavidus necator. LDPE oxidized fragments (PE-F) were obtained from the re-engineering LDPE film by means of pro-oxidant/pro-degradant additives, followed by treatment under natural UV light. Cupriavidus necator was grown in either tryptone soya broth (TSB) or basal salt medium (BSM) supplemented with PE-F for 48 h. PHA production was higher in TSB supplemented with PE-F (29%) than in TSB alone (only 0.6%). No PHA was detected in either BSM alone or BSM supplemented with PE-F. The recovered PHA was characterized using GPC, NMR, and electrospray ionization tandem mass spectrometry (ESI-MS/MS). These analytical tools applied confirmed that the resulting PHA was a terpolymer having an average molar mass of 624 kg/mol and consisting of 3-hydroxybutyrate (HB), 3-hydroxyvalerates (HV) and 3-hydroxyhexanoate (HH) co-monomer units randomly distributed along the chain backbone