A new approach for the immobilization of poly(acrylic) acid as a chemically reactive cross-linker on the surface of poly(lactic) acid-based biomaterials

A new approach for the immobilization of poly(acrylic) acid (PAA) as a chemically reactive cross-linker on the surface of poly(lactic) acid-based (PLA) biomaterials is described. The proposed technique includes non-covalent attachment of a PAA layer to the surface of PLA-based biomaterial via biomaterial surface treatment with solvent/non-solvent mixture followed by the entrapment of PAA from its solution. Surface morphology and wettability of the obtained PLA-PAA composite materials were investigated by AFM and the sitting drop method respectively. The amount of the carboxyl groups on the composites surface was determined by using the fluorescent compounds (2-(5-aminobenzo[d]oxazol-2-yl)phenol (ABO) and its acyl derivative N-(2-(2-hydroxyphenyl)benzo[d]oxazol-5-yl)acetamide (AcABO)). It was shown that it is possible to obtain PLA-PAA composites with various surface relief and tunable wettability (57°, 62° and 66°). The capacity of the created PAA layer could be varied from 1.5 nmol/cm2 to 0.1 μmol/cm2 depending on the modification conditions. Additionally, using bovine serum albumin (BSA) it was demonstrated that such composites could be modified with proteins with high binding density (around 0.18 nmol/cm2). Obtained fluoro-labeled PLA-PAA materials, as well as PLA-PAA composites themselves, are valuable since they can be used for biodegradable polymer implants tracking in living systems and as drug delivery systems

A new approach for the immobilization of poly(acrylic) acid as a chemically reactive cross-linker on the surface of poly(lactic) acid-based biomaterials

A new approach for the immobilization of poly(acrylic) acid (PAA) as a chemically reactive cross-linker on the surface of poly(lactic) acid-based (PLA) biomaterials is described. The proposed technique includes non-covalent attachment of a PAA layer to the surface of PLA-based biomaterial via biomaterial surface treatment with solvent/non-solvent mixture followed by the entrapment of PAA from its solution. Surface morphology and wettability of the obtained PLA-PAA composite materials were investigated by AFM and the sitting drop method respectively. The amount of the carboxyl groups on the composites surface was determined by using the fluorescent compounds (2-(5-aminobenzo[d]oxazol-2-yl)phenol (ABO) and its acyl derivative N-(2-(2-hydroxyphenyl)benzo[d]oxazol-5-yl)acetamide (AcABO)). It was shown that it is possible to obtain PLA-PAA composites with various surface relief and tunable wettability (57°, 62° and 66°). The capacity of the created PAA layer could be varied from 1.5 nmol/cm2 to 0.1 μmol/cm2 depending on the modification conditions. Additionally, using bovine serum albumin (BSA) it was demonstrated that such composites could be modified with proteins with high binding density (around 0.18 nmol/cm2). Obtained fluoro-labeled PLA-PAA materials, as well as PLA-PAA composites themselves, are valuable since they can be used for biodegradable polymer implants tracking in living systems and as drug delivery systems

Enhanced properties of poly(ε-caprolactone)/polyvinylpyrrolidone electrospun scaffolds fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol

Poly(ε-caprolactone)/polyvinylpyrrolidone (PCL/PVP) scaffolds with various composition were fabricated from 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solution using the same electrospinning parameters in order to reveal the effect of polymer ratio on the material properties. The obtained materials were characterized using scanning electron microscopy, contact angle measurements, X-ray diffraction, Fourier-transformed infrared spectroscopy, and tensile testing. The strengthening effect of PVP was observed: Young modulus of PCL/PVP scaffold with 50/50 polymer ratio was found at 105.4 ± 8.4 MPa which is six times higher comparing to those of PCL scaffold. PVP-containing scaffolds were extremely hydrophilic with PVP concentration of 5 wt% (vs. 25 wt% in previous reports) leading to full wetting of the material. in vitro studies showed an improved viability of HeLa cells cultured with the composites containing higher concentrations of PVP. Owing to the application of HFIP, PCL-based materials were loaded with cyclophosphamide for the first time and the PVP-containing materials demonstrated the intensified initial release of the model compound. Utilizing HFIP for the fabrication of PCL/PVP scaffolds significantly widens their application for drug delivery systems due to a good solubility of proteins, drugs, and other biologically active compounds in this solvent

Pyridazinones and structurally related derivatives with anti-inflammatory activity

Persistent inflammation contributes to a number of diseases; therefore, control of the inflammatory response is an important therapeutic goal. In an effort to identify novel anti-inflammatory compounds, we screened a library of pyridazinones and structurally related derivatives that were used previously to identify N-formyl peptide receptor (FPR) agonists. Screening of the compounds for their ability to inhibit lipopolysaccharide (LPS)-induced nuclear factor κB (NF-κB) transcriptional activity in human THP1-Blue monocytic cells identified 48 compounds with anti-inflammatory activity. Interestingly, 34 compounds were FPR agonists, whereas 14 inhibitors of LPS-induced NF-κB activity were not FPR agonists, indicating that they inhibited different signaling pathways. Further analysis of the most potent inhibitors showed that they also inhibited LPS-induced production of interleukin 6 (IL-6) by human MonoMac-6 monocytic cells, again verifying their anti-inflammatory properties. Structure–activity relationship (SAR) classification models based on atom pair descriptors and physicochemical ADME parameters were developed to achieve better insight into the relationships between chemical structures of the compounds and their biological activities, and we found that there was little correlation between FPR agonist activity and inhibition of LPS-induced NF-κB activity. Indeed, Cmpd43, a well-known pyrazolone-based FPR agonist, as well as FPR1 and FPR2 peptide agonists had no effect on the LPS-induced NF-κB activity in THP1-Blue cells. Thus, some FPR agonists reported to have anti-inflammatory activity may actually mediate their effects through FPR-independent pathways, as it is suggested by our results with this series of compounds. This could explain how treatment with some agonists known to be inflammatory (i.e., FPR1 agonists) could result in anti-inflammatory effects. Further research is clearly needed to define the molecular targets of pyridazinones and structurally related compounds with anti-inflammatory activity and to define their relationships (if any) to FPR signaling events

Изучение свойств 1,4-нафтохинонов спектроскопическими методами

The quinone fragment is not only quite common for many synthetic and natural compounds, but also has a connection with the occurrence of various types of biological activity. This fact is related to their ability to accept one or two electrons with the formation of the corresponding radical anion or radical dianion. Since the electron-acceptor ability of quinone can be changed by the direct addition of the substituent to its structure, the analysis of the spectral characteristics of alkyl- or arylamino derivatives of 1,4-naphthoquinone is of great interest. In this work, the spectral characteristics of 2,3-dichloro-1,4-naphthoquinone (NQ) and compounds synthesized on its basis, namely, 2-chloro-3- ((4-hydroxyphenyl)amino)-1,4-naphthoquinone (NQ1) and 4-((3-chloro-1,4-naphthoquinon-2-yl) amino)phenyl sulfurofluoridate (NQS) were studied by spectrophotometry. The influence of pH on the intensity and absorption maximum wavelength of the analyzed compounds was studied. Under selected working conditions linear dependences of absorbance on concentration in the ranges 3·10–6 – 2·10–5; 3·10–7 – 2·10–6 and 2·10–7 – 2·10–6 М were obtained with the regression equations y = 0,0417x + 0,0477 (R² = 0,9993); y = 0,389x + 0,0095 (R² = 0,9997); and y = 0,3215x + 0,0452 (R² = 0,9997) for NQ, NQ1 and NQS respectively. A method of quantitative determination of compounds in the substance by spectrophotometry was developed with the detection limits (LOD) of NQ, NQ1 and NQS equal to 8,8·10–7, 9,4·10–8 and 7,3·10–8 М, respectively. The accuracy of the proposed technique was verified by the standard addition method methodОрганические соединения, имеющие в своей структуре хиноновый фрагмент, достаточно часто встречаются во многих синтетических и природных объектах. Их биологическая активность связана со способностью принимать один или два электрона с образованием соответствующего анион- радикала или дианион- радикала. Так как электроакцепторная способность хинона может быть изменена добавлением заместителя в его структуру, анализ спектральных характеристик алкил- или ариламинопроизводных 1,4-нафтохинона представляет большой интерес. В данной работе методом ИК-спектроскопии были получены спектральные характеристики 2,3-дихлор-1,4-нафтохинона (NQ) и синтезированных на его основе соединений, а именно 2-хлор-3-((4-гидроксифенил) амино)-1,4-нафтохинона (NQ1) и 4-((3-хлор-1,4-нафтохинон-2- ил)амино)-фенилсульфофторидата (NQS), а также методом спектрофотометрии изучены спектры поглощения и описаны оптические свойства этих соединений. Проведено исследование влияния рН раствора на интенсивность и длину волны максимума поглощения исследуемых соединений. При подобранных рабочих условиях получены линейные зависимости интенсивности оптической плотности от концентрации в диапазонах 3·10–6 – 2·10–5; 3·10–7 – 2·10–6 и 2·10–7 – 2·10–6 М с уравнениями регрессии y = 0,0417x + 0,0477 (R² = 0,9993); y = 0,389x + 0,0095 (R² = 0,9997); и y = 0,3215x + 0,0452 (R² = 0,9997) для NQ, NQ1 и NQS соответственно. Разработана методика количественного определения соединений в субстанции методом спектрофотометрии с пределами обнаружения (LOD) NQ, NQ1 и NQS, равными 8,8·10–7, 9,4·10–8 и 7,3·10–8 М соответственно. Правильность методики количественного определения анализируемых соединений в субстанции проверялась методом «введено-найдено

<i>Mycobacterium tuberculosis</i> Type II Toxin-Antitoxin Systems: Genetic Polymorphisms and Functional Properties and the Possibility of Their Use for Genotyping

<div><p>Various genetic markers such as IS-elements, DR-elements, variable number tandem repeats (VNTR), single nucleotide polymorphisms (SNPs) in housekeeping genes and other groups of genes are being used for genotyping. We propose a different approach. We suggest the type II toxin-antitoxin (TA) systems, which play a significant role in the formation of pathogenicity, tolerance and persistence phenotypes, and thus in the survival of <i>Mycobacterium tuberculosis</i> in the host organism at various developmental stages (colonization, infection of macrophages, etc.), as the marker genes. Most genes of TA systems function together, forming a single network: an antitoxin from one pair may interact with toxins from other pairs and even from other families. In this work a bioinformatics analysis of genes of the type II TA systems from 173 sequenced genomes of <i>M</i>. <i>tuberculosis</i> was performed. A number of genes of type II TA systems were found to carry SNPs that correlate with specific genotypes. We propose a minimally sufficient set of genes of TA systems for separation of <i>M</i>. <i>tuberculosis</i> strains at nine basic genotype and for further division into subtypes. Using this set of genes, we genotyped a collection consisting of 62 clinical isolates of <i>M</i>. <i>tuberculosis</i>. The possibility of using our set of genes for genotyping using PCR is also demonstrated.</p></div

The type II TA systems of mycobacteria were investigated. Schematic diagram of the toxin-antitoxin system.

<p>(A) TA systems are annotated according to the GenBank database, excluding VapBC50 (rv3750c-rv3749c), VapBC49 (rv3180c-rv3181c), HigBA3 (rv3182-rv3183), HigBA2 (rv2022c-rv2021c), MazEF10 (rv0298-rv0299) and VapBC45 (rv2018-rv2019) systems; these systems are annotated according to Sala et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143682#pone.0143682.ref032" target="_blank">32</a>]. The system RelBE3 (rv3358-rv3357, GenBank database, NCBI) is called the YefM/YoeB system by Sala. All of the TA systems depicted here are type II (systems marked with an asterisk are novel TA systems that are not classified to any family, but for which functional activity has been shown [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143682#pone.0143682.ref032" target="_blank">32</a>]). The 13 genes, our proposed set for genotyping, are highlighted in bold. (B) Type II TA systems are encoded by two genes, a toxin and an antitoxin, that form one operon with a promoter located upstream of the first antitoxin gene. PIN domain is the functional part of the toxin gene, the four conserved acidic residues marked at the picture: the three well-conserved acidic residues, at positions 4[D], 40[E] and 93[D], and with fourth acidic residue is less well conserved at position 112[D].</p

Detection of the Ural genotype by qPCR.

<p>Fluorescence in the FAM channel (blue): (1)13_2978, (2) 13–3114, (3) 13–3086, (4) 13_3158, (5) 13_4178, (6) 13_3539, (7) 13_2566, (8) 13_3632, (9) 13_3599, (10) 13_3896, (11) 13_3582, (12) 13_4189, (13) 13_3535, (15) 13_3147; Fluorescence in the HEX channel (green): (14) 13_3147, (16) 13_2978. Fluorescence of the channel FAM (blue) indicates the accumulation of the PCR product containing cytosine (C); the fluorescence of the channel HEX (green) indicates the accumulation of the PCR product containing thymine (T, the variable nucleotide) and indicates the SNP in the <i>vapC10</i> gene (C394→T394) characteristic of the Ural genotype. Line 14 (13_3147) and 16 (13_2978) belong to the Ural genotype. For isolate 13_2978 fluorescence is detected on the two channels (FAM and HEX), this can indicate the presence of impurities (coinfection). qPCR fluorescence in RFU (relative fluorescence units) vs. PCR cycles. Intensity of fluorescence depending on the number of qPCR cycles for strains belonging to the Euro-American lineage.</p

Scheme of typing of <i>M</i>. <i>tuberculosis</i> strains using 13 genes of type II TA systems.

<p>The algorithm for determining the genotype is presented. The scheme shows that, after the first iteration to determine the genotype, the number of genes for the analysis is decreased twofold. Each gene in the brackets is given its position that is replaced, and the appropriate nucleotide is indicated. All replacements are calculated relative to the reference strain H37Rv.</p

Phylogenetic relationship between different genotypes of the <i>M</i>. <i>tuberculosis</i>.

<p>(A) Phylogenetic tree constructed on the basis of polymorphisms (SNP) in all of the considered genes of type II TA systems. An unrooted phylogenetic tree for the 173 strains from this study was constructed based on the presence/absence of SNPs in the nucleotide sequences of 71 TA systems (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143682#pone.0143682.s003" target="_blank">S3 Table</a>); (B) Phylogenetic tree constructed on the basis of SNP in a minimum set of genes of type II TA systems. An unrooted phylogenetic tree for 173 strains constructed based on SNPs in the nucleotide sequences of 13 genes (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143682#pone.0143682.t002" target="_blank">Table 2</a>). In both of cases strains included in the one cluster belong to the same genotype (various genotypes highlighted by color). The trees was constructed by the neighbor-joining approach. The TA systems sequences were retrieved from different databases (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143682#sec002" target="_blank">Materials and Methods</a>). Sequences were multiply aligned by using ClustalW ver. 2.1 software. The trees was calculated using MEGA ver. 6. Bootstrap support > 60% is indicated for the trees.</p