scholarly journals Novel Biodegradable Polyanhydrides Based on Betulin Disuccinate and Sebacic Acid for Medical Purpose

Proceedings ◽  
2020 ◽  
Vol 67 (1) ◽  
pp. 17
Author(s):  
Daria Niewolik ◽  
Barbara Bednarczyk-Cwynar ◽  
Piotr Ruszkowski ◽  
Katarzyna Jaszcz
Keyword(s):  
Drug Delivery ◽  
Cell Lines ◽  
Hydrolytic Degradation ◽  
Sebacic Acid ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Melt Polycondensation ◽  
Wide Range ◽  
The Us ◽  
Exclusion Chromatography

The paper describes synthesis and the characterization of novel biodegradable betulin-based polyanhydrides, exhibiting anti-cancer activity. Polyanhydrides were obtained by a melt polycondensation of a disuccinate betulin (3,28-di-O-succinyl betulin) and sebacic acid with the use of acetic anhydride. Mentioned polyanhydrides were then thoroughly characterized by 1H NMR and 13C NMR, size exclusion chromatography, differential scanning calorimetry and FT-IR spectroscopy. The content of sebacic acid in obtained copolymers was from 20 to 80 wt%. The use of sebacic acid as a comonomer increases the crystallinity of polymers. Under physiological conditions copolymers undergo hydrolytic degradation to betulin disuccinate, whose biological activity is known and confirmed and to sebacic acid approved by the US Food and Drug Administration (FDA) for use in drug delivery systems. Polyanhydrides were also tested for cytostatic activity against a wide range of cancer cell lines (HeLa, A-549, U-87MG, KB and HepG2), proving its efficiency in inhibiting the growth of selected cell lines. Obtained polymers can be used as carriers in drug delivery system, in form of microspheres. Microspheres with diameter within the range of Dn = 15–30 µm were prepared by using emulsion (O/W) solvent evaporation method.

NEW ELASTOMERIC MATERIALS FROM BIOMASS: STEREOSELECTIVE POLYMERIZATION OF LINEAR TERPENES AND THEIR COPOLYMERIZATION WITH BUTADIENE BY USING A COBALT COMPLEX WITH PHOSPHANE LIGANDS

2020 ◽  
Vol 93 (4) ◽  
pp. 605-614
Author(s):  
David Hermann Lamparelli ◽  
Veronica Paradiso ◽  
Carmine Capacchione
Keyword(s):  
Room Temperature ◽  
Cobalt Complex ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
New Materials ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Elastomeric Materials ◽  
Exclusion Chromatography ◽  
Stereoregular Polymers

ABSTRACT The polymerization of bio-renewable terpenes such as β-ocimene (O), β-myrcene (M), and β-farnesene (F) promoted by CoCl2(PCyPh2)2 (1) in combination with modified methylalumoxane at room temperature is reported. Stereoregular polymers of O, M, and F were obtained. 1 also promoted, showing good stereoselectivity, the copolymerization of O and M with butadiene (B) in a wide range of compositions by suitably varying the alimentation feed: up to 67 and 75 mol% of O and M incorporated for poly(ocimene-butadiene) and poly(myrcene-butadiene) copolymers, respectively. These new materials with elastomeric properties (glass transition temperatures observed in the range of −5.7 to −72.5 °C) were fully characterized by differential scanning calorimetry, size exclusion chromatography, and nuclear magnetic resonance spectroscopy (1H, 13C, and two-dimensional experiments).

scholarly journals Effect of Posttranslational Modifications on the Structure and Activity of FTO Demethylase

2021 ◽  
Vol 22 (9) ◽  
pp. 4512
Author(s):  
Michał Marcinkowski ◽  
Tomaš Pilžys ◽  
Damian Garbicz ◽  
Jan Piwowarski ◽  
Damian Mielecki ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Size Exclusion Chromatography ◽  
Posttranslational Modifications ◽  
Size Exclusion ◽  
Saxs Data ◽  
Wide Range ◽  
Exclusion Chromatography ◽  
Demethylase Activity ◽  
Structure And Activity

The FTO protein is involved in a wide range of physiological processes, including adipogenesis and osteogenesis. This two-domain protein belongs to the AlkB family of 2-oxoglutarate (2-OG)- and Fe(II)-dependent dioxygenases, displaying N6-methyladenosine (N6-meA) demethylase activity. The aim of the study was to characterize the relationships between the structure and activity of FTO. The effect of cofactors (Fe2+/Mn2+ and 2-OG), Ca2+ that do not bind at the catalytic site, and protein concentration on FTO properties expressed in either E. coli (ECFTO) or baculovirus (BESFTO) system were determined using biophysical methods (DSF, MST, SAXS) and biochemical techniques (size-exclusion chromatography, enzymatic assay). We found that BESFTO carries three phosphoserines (S184, S256, S260), while there were no such modifications in ECFTO. The S256D mutation mimicking the S256 phosphorylation moderately decreased FTO catalytic activity. In the presence of Ca2+, a slight stabilization of the FTO structure was observed, accompanied by a decrease in catalytic activity. Size exclusion chromatography and MST data confirmed the ability of FTO from both expression systems to form homodimers. The MST-determined dissociation constant of the FTO homodimer was consistent with their in vivo formation in human cells. Finally, a low-resolution structure of the FTO homodimer was built based on SAXS data.

scholarly journals Human Plasma and Recombinant Hemopexins: Heme Binding Revisited

2021 ◽  
Vol 22 (3) ◽  
pp. 1199
Author(s):  
Elena Karnaukhova ◽  
Catherine Owczarek ◽  
Peter Schmidt ◽  
Dominik J. Schaer ◽  
Paul W. Buehler
Keyword(s):  
Protein S ◽  
Soret Band ◽  
Cell System ◽  
Size Exclusion ◽  
Heme Binding ◽  
Systematic Analysis ◽  
Molar Ratios ◽  
Recombinant Production ◽  
Wide Range ◽  
Exclusion Chromatography

Plasma hemopexin (HPX) is the key antioxidant protein of the endogenous clearance pathway that limits the deleterious effects of heme released from hemoglobin and myoglobin (the term “heme” is used in this article to denote both the ferrous and ferric forms). During intra-vascular hemolysis, heme partitioning to protein and lipid increases as the plasma concentration of HPX declines. Therefore, the development of HPX as a replacement therapy during high heme stress could be a relevant intervention for hemolytic disorders. A logical approach to enhance HPX yield involves recombinant production strategies from human cell lines. The present study focuses on a biophysical assessment of heme binding to recombinant human HPX (rhHPX) produced in the Expi293FTM (HEK293) cell system. In this report, we examine rhHPX in comparison with plasma HPX using a systematic analysis of protein structural and functional characteristics related to heme binding. Analysis of rhHPX by UV/Vis absorption spectroscopy, circular dichroism (CD), size-exclusion chromatography (SEC)-HPLC, and catalase-like activity demonstrated a similarity to HPX fractionated from plasma. In particular, the titration of HPX apo-protein(s) with heme was performed for the first time using a wide range of heme concentrations to model HPX–heme interactions to approximate physiological conditions (from extremely low to more than two-fold heme molar excess over the protein). The CD titration data showed an induced bisignate CD Soret band pattern typical for plasma and rhHPX versions at low heme-to-protein molar ratios and demonstrated that further titration is dependent on the amount of protein-bound heme to the extent that the arising opposite CD couplet results in a complete inversion of the observed CD pattern. The data generated in this study suggest more than one binding site in both plasma and rhHPX. Furthermore, our study provides a useful analytical platform for the detailed characterization of HPX–heme interactions and potentially novel HPX fusion constructs.

A study on the kinetics and thermal properties of polystyrene/diatomite nanocomposites prepared via in situ ATRP

2018 ◽  
Vol 33 (2) ◽  
pp. 180-197 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Linear Increase ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography

Pristine mesoporous diatomite was employed to prepare polystyrene/diatomite composites. Diatomite platelets were used for in situ polymerization of styrene by atom transfer radical polymerization to synthesize tailor-made polystyrene nanocomposites. X-Ray fluorescence spectrometer analysis and thermogravimetric analysis (TGA) were employed for evaluating some inherent properties of pristine diatomite platelets. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite platelets. Evaluation of pore size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Linear increase of ln ( M0/M) with time for all the samples shows that polymerization proceeds in a living manner. Addition of 3 wt% pristine mesoporous diatomite leads to an increase of conversion from 72% to 89%. Molecular weight of polystyrene chains increases from 11,326 g mol−1 to 14134 g mol−1 with the addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.13 to 1.38. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 81.9°C to 87.1°C by adding 3 wt% of mesoporous diatomite platelets.

Differentiation of wastewater effluent organic matter (EfOM) from natural organic matter (NOM) using multiple analytical techniques

2008 ◽  
Vol 57 (7) ◽  
pp. 1009-1015 ◽  
Author(s):  
Seong-Nam Nam ◽  
Gary Amy
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Analytical Techniques ◽  
Size Exclusion ◽  
Effluent Organic Matter ◽  
Fluorescence Excitation ◽  
Wide Range ◽  
Exclusion Chromatography

Using three analytical techniques of size exclusion chromatography (SEC), fluorescence excitation-emission matrix (EEM), and dissolved organic nitrogen (DON) measurement, differentiating characteristics of effluent organic matter (EfOM) from natural organic matter (NOM) have been investigated. SEC reveals a wide range of molecular weight (MW) for EfOM and high amount of high MW polysaccharides, and low MW organic acids compared to NOM. Clear protein-like peaks using fluorescence EEM were a major feature of EfOM distinguishing it from NOM. Fluorescence index (FI), an indicator to distinguish autochthonous origin from allochthonous origin, differentiated EfOM from NOM by exhibiting higher values, indicating a microbial origin. In EfOM samples, DON present in higher amounts than NOM.

Mechanical properties and hydrolytic degradation of methoxy poly(ethylene glycol)-b-poly(DL-lactide-coglycolide- co-ε-caprolactone) diblock copolymer films

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Nongnit Morakot ◽  
Jirasak Threeprom ◽  
Yodthong Baimark
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Ethylene Glycol ◽  
Diblock Copolymers ◽  
Hydrolytic Degradation ◽  
Size Exclusion ◽  
Block Length ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Poly Ethylene

AbstractBiodegradable films of methoxy poly(ethylene glycol)-b-poly(DL-lactideco- glycolide-co-ε-caprolactone) diblock copolymers (MPEG-b-PDLLGCL) were prepared by solution casting method. Effects of MPEG block length and DLL:G:CL ratio of the MPEG-b-PDLLGCL films on their mechanical properties and hydrolytic degradation were studied and discussed. It was found that the mechanical properties of films were strongly dependent on glass transition temperatures (Tg) of the diblock copolymers. The hydrolytic degradation was investigated in phosphatebuffered solution at 37°C. The degraded films were characterized using gravimetry (%water uptake and %weight loss), 1H-NMR spectroscopy, differential scanning calorimetry and size exclusion chromatography. The %weight loss of the degraded films increased and molecular weight decreased on increasing the MPEG block length and incorporating the G and CL units, according to their %water uptakes. The MPEG content of the degraded film decreased and the Tg increased with hydrolytic degradation time.

Hemoglobin in five genetically diverse Frankia strains

2002 ◽  
Vol 48 (12) ◽  
pp. 1048-1055 ◽  
Author(s):  
Jason Beckwith ◽  
John D Tjepkema ◽  
Robert E Cashon ◽  
Christa R Schwintzer ◽  
Louis S Tisa
Keyword(s):  
Hemoglobin Concentration ◽  
Dissociation Rate ◽  
Size Exclusion ◽  
Facilitated Diffusion ◽  
Truncated Hemoglobin ◽  
Oxygen Dissociation ◽  
Wide Range ◽  
Exclusion Chromatography ◽  
N Treatment ◽  
Dissociation Rate Constants

Five strains of Frankia were selected to represent a wide range of genetic diversity and examined for presence of hemoglobin. All five strains produced hemoglobin when grown on media without (–N) or with (+N) combined nitrogen. This indicates that hemoglobin is common in Frankia and is not directly associated with nitrogen fixation. Frankia strain EAN1pec was examined in more detail. It showed greater hemoglobin concentration when grown at 2% O2 than at 20% O2 in the –N treatment but no effect of oxygen on hemoglobin concentration in the +N treatment. At both oxygen levels, it produced substantially more biomass in +N than in –N culture. It also produced significantly more biomass when the medium contained 0.2% CO2 than in the absence of CO2. The molecular mass of the hemo- globin as determined by size exclusion chromatography was 13.4 ± 0.2 kDa (mean ± SE, n = 3) and is consistent with that of a truncated hemoglobin. The hemoglobin had absorption spectra that were typical of a hemoglobin. The oxygen dissociation rate constants for the hemoglobin were 131.2 ± 5.8 s–1 for –N culture and 166 ± 8.2 s–1 for +N culture. These rapid rates are consistent with a function in facilitated diffusion of oxygen.Key words: Frankia, hemoglobin, truncated hemoglobin.

Combined Main- and Side-Chain Azobenzene Polyesters: A Potential For Photoinduced Nonlinear Waveguides

1999 ◽  
Vol 561 ◽  
Author(s):  
F. Sahlén ◽  
T. Geisler ◽  
S. Hvilsted ◽  
N. C. R. Holme ◽  
P. S. Ramanujam ◽  
...  
Keyword(s):  
Refractive Index ◽  
Third Harmonic Generation ◽  
Size Exclusion ◽  
Side Chain ◽  
Visible Spectroscopy ◽  
Scanning Calorimetry ◽  
Nonlinear Waveguides ◽  
Third Harmonic ◽  
Exclusion Chromatography ◽  
Uv Visible

ABSTRACTNew combined main- and side-chain azobenzene polyesters, which exhibit an intensity dependent refractive index, have been prepared in order to optically fabricate nonlinear waveguides. Novel sulfone azobenzenes, a diester, (4-[[5-(ethoxycarbonyl)pentyl]sulfonyl]-4'-[[5-(ethoxycarbonyl)pentyl]methylamino] azobenzene, and a diol, 4-[[(8-hydroxy-7-methylhydroxy)-octyl]sulfonyl]-4'-N, N-dimethylamino azobenzene, have been used to prepare new polyesters by transesterification in the molten state. The polyesters have been characterized by UV-visible spectroscopy, differential scanning calorimetry (DSC), size exclusion chromatography (SEC), third harmonic generation (THG) and optical anisotropy measurements. The molar masses of the polyesters were in the range of 5000-10000 g mol−1, which was sufficient in order to spin coat thin films. From THG measurements the polymers are shown to possess an offresonance electronic X(3) of the order 10−12 esu corresponding to a nonlinear refractive index of 2.3×10−14 cm2/W.

scholarly journals Synthesis, Characterization andIn VitroAnticancer Evaluation of Itaconic Acid Based Random Copolyester

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
J. Gowsika ◽  
R. Nanthini
Keyword(s):  
Itaconic Acid ◽  
Hydrolytic Degradation ◽  
Gel Permeation Chromatography ◽  
Xrd Analysis ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Melt Polycondensation

The present study deals with the synthesis and characterization of an aliphatic copolyester, poly [butylene fumarate-co-butylene itaconate] (PIFB) copolymer was obtained from itaconic acid, fumaric acid, and 1,4-butanediol using titanium tetraisopropoxide (TTiPO) through a two step process of transesterification and melt polycondensation. The synthesized aliphatic random copolyester was characterized with the help of FT-IR,1H-NMR,13C-NMR, viscosity measurements, Gel Permeation Chromatography (GPC) and X-ray diffraction (XRD) analysis. Thermal properties have been analyzed using thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). Hydrolytic degradation studies were carried out in acid and alkaline regions of various pH values. The synthesized copolymer was subjected toin vitroanticancer activity studies against human breast cancer (MCF-7) cell line.

scholarly journals Towards Novel Fluorinated Methacrylic Coatings for Cultural Heritage: A Combined Polymers and Surfaces Chemistry Study

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1190 ◽  
Author(s):  
Valentina Sabatini ◽  
Eleonora Pargoletti ◽  
Valeria Comite ◽  
Marco Aldo Ortenzi ◽  
Paola Fermo ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Accelerated Aging ◽  
Water Repellency ◽  
Size Exclusion ◽  
Butyl Methacrylate ◽  
Capillary Absorption ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Coated Materials ◽  
Exclusion Chromatography

In this work, new co- and ter-polymers of methyl methacrylate (MMA), ethyl methacrylate (EMA), and N-butyl methacrylate (nBuMA), containing just 1% mol × mol−1 of a fluorinated co-monomer, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-octyl methacrylate (POMA), were synthesized. After an UV accelerated aging test, the photo-chemical stability of the polymers prepared was determined by 1H NMR and FT-IR spectroscopy, size exclusion chromatography, differential scanning calorimetry and wettability measurements. The polymers were applied to Botticino tiles to achieve better performances in terms of water repellency and consequently deterioration resistance. One-year prolonged exposure to a real environment was conducted and the properties of the coated materials and their performances were studied using different surface techniques such as water contact angle (WCA) and colorimetric measurements (CIELaB), capillary absorption, permeability (RVP) tests and soluble salts determination. The effectiveness of the fluorinated methacrylic coatings was clearly demonstrated; among all the resins, the co-polymer MMA_POMA seems to be the most performing one. Furthermore, both the UV photo-chemical resistance and the easiness of removal was successfully studied.

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