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Jan Z, Hočevar M, Kononenko V, Michelini S, Repar N, Caf M, Kocjančič B, Dolinar D, Kralj S, Makovec D, Iglič A, Drobne D, Jenko M, Kralj-Iglič V. Inflammatory, Oxidative Stress and Small Cellular Particle Response in HUVEC Induced by Debris from Endoprosthesis Processing. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16093287. [PMID: 37176169 PMCID: PMC10179554 DOI: 10.3390/ma16093287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023]
Abstract
We studied inflammatory and oxidative stress-related parameters and cytotoxic response of human umbilical vein endothelial cells (HUVEC) to a 24 h treatment with milled particles simulating debris involved in sandblasting of orthopedic implants (OI). We used different abrasives (corundum-(Al2O3), used corundum retrieved from removed OI (u. Al2O3), and zirconia/silica composite (ZrO2/SiO2)). Morphological changes were observed by scanning electron microscopy (SEM). Concentration of Interleukins IL-6 and IL-1β and Tumor Necrosis Factor α (TNF)-α was assessed by enzyme-linked immunosorbent assay (ELISA). Activity of Cholinesterase (ChE) and Glutathione S-transferase (GST) was measured by spectrophotometry. Reactive oxygen species (ROS), lipid droplets (LD) and apoptosis were measured by flow cytometry (FCM). Detachment of the cells from glass and budding of the cell membrane did not differ in the treated and untreated control cells. Increased concentration of IL-1β and of IL-6 was found after treatment with all tested particle types, indicating inflammatory response of the treated cells. Increased ChE activity was found after treatment with u. Al2O3 and ZrO2/SiO2. Increased GST activity was found after treatment with ZrO2/SiO2. Increased LD quantity but not ROS quantity was found after treatment with u. Al2O3. No cytotoxicity was detected after treatment with u. Al2O3. The tested materials in concentrations added to in vitro cell lines were found non-toxic but bioactive and therefore prone to induce a response of the human body to OI.
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Affiliation(s)
- Zala Jan
- University of Ljubljana, Faculty of Health Sciences, Laboratory of Clinical Biophysics, SI-1000 Ljubljana, Slovenia
| | - Matej Hočevar
- Institute of Metals and Technology, SI-1000 Ljubljana, Slovenia
| | - Veno Kononenko
- University of Ljubljana, Biotechnical Faculty, Nanobiology Group, SI-1000 Ljubljana, Slovenia
| | - Sara Michelini
- University of Ljubljana, Biotechnical Faculty, Nanobiology Group, SI-1000 Ljubljana, Slovenia
| | - Neža Repar
- University of Ljubljana, Biotechnical Faculty, Nanobiology Group, SI-1000 Ljubljana, Slovenia
| | - Maja Caf
- Department for Materials Synthesis, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Pharmacy, SI-1000 Ljubljana, Slovenia
| | - Boštjan Kocjančič
- University of Ljubljana, Faculty of Medicine, Chair of Orthopaedics, SI-1000 Ljubljana, Slovenia
- MD-RI Institute for Materials Research in Medicine, SI-1000 Ljubljana, Slovenia
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Drago Dolinar
- University of Ljubljana, Faculty of Medicine, Chair of Orthopaedics, SI-1000 Ljubljana, Slovenia
- MD-RI Institute for Materials Research in Medicine, SI-1000 Ljubljana, Slovenia
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Slavko Kralj
- Department for Materials Synthesis, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Pharmacy, SI-1000 Ljubljana, Slovenia
| | - Darko Makovec
- Department for Materials Synthesis, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Aleš Iglič
- University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Physics, SI-1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Medicine, Laboratory of Clinical Biophysics, SI-1000 Ljubljana, Slovenia
| | - Damjana Drobne
- University of Ljubljana, Biotechnical Faculty, Nanobiology Group, SI-1000 Ljubljana, Slovenia
| | - Monika Jenko
- MD-RI Institute for Materials Research in Medicine, SI-1000 Ljubljana, Slovenia
| | - Veronika Kralj-Iglič
- University of Ljubljana, Faculty of Health Sciences, Laboratory of Clinical Biophysics, SI-1000 Ljubljana, Slovenia
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Assessment of Small Cellular Particles from Four Different Natural Sources and Liposomes by Interferometric Light Microscopy. Int J Mol Sci 2022; 23:ijms232415801. [PMID: 36555442 PMCID: PMC9779747 DOI: 10.3390/ijms232415801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/28/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022] Open
Abstract
Small particles in natural sources are a subject of interest for their potential role in intercellular, inter-organism, and inter-species interactions, but their harvesting and assessment present a challenge due to their small size and transient identity. We applied a recently developed interferometric light microscopy (ILM) to assess the number density and hydrodynamic radius (Rh) of isolated small cellular particles (SCPs) from blood preparations (plasma and washed erythrocytes) (B), spruce needle homogenate (S), suspension of flagellae of microalgae Tetraselmis chuii (T), conditioned culture media of microalgae Phaeodactylum tricornutum (P), and liposomes (L). The aliquots were also assessed by flow cytometry (FCM), dynamic light scattering (DLS), ultraviolet-visible spectrometry (UV-vis), and imaging by cryogenic transmission electron microscopy (cryo-TEM). In Rh, ILM showed agreement with DLS within the measurement error in 10 out of 13 samples and was the only method used here that yielded particle density. Cryo-TEM revealed that representative SCPs from Tetraselmis chuii flagella (T) did not have a globular shape, so the interpretation by Rh of the batch methods was biased. Cryo-TEM showed the presence of thin filaments in isolates from Phaeodactylum tricornutum conditioned culture media (P), which provides an explanation for the considerably larger Rh obtained by batch methods than the sizes of particles observed by cryo-TEM images. ILM proved convenient for assessment of number density and Rh of SCPs in blood preparations (e.g., plasma); therefore, its use in population and clinical studies is indicated.
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Kogej K, Božič D, Kobal B, Herzog M, Černe K. Application of Dynamic and Static Light Scattering for Size and Shape Characterization of Small Extracellular Nanoparticles in Plasma and Ascites of Ovarian Cancer Patients. Int J Mol Sci 2021; 22:ijms222312946. [PMID: 34884751 PMCID: PMC8657631 DOI: 10.3390/ijms222312946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 12/14/2022] Open
Abstract
In parallel to medical treatment of ovarian cancer, methods for the early detection of cancer tumors are being sought. In this contribution, the use of non-invasive static (SLS) and dynamic light scattering (DLS) for the characterization of extracellular nanoparticles (ENPs) in body fluids of advanced serous ovarian cancer (OC) and benign gynecological pathology (BP) patients is demonstrated and critically evaluated. Samples of plasma and ascites (OC patients) or plasma, peritoneal fluid, and peritoneal washing (BP patients) were analyzed. The hydrodynamic radius (Rh) and the radius of gyration (Rg) of ENPs were calculated from the angular dependency of LS intensity for two ENP subpopulations. Rh and Rg of the predominant ENP population of OC patients were in the range 20–30 nm (diameter 40–60 nm). In thawed samples, larger particles (Rh mostly above 100 nm) were detected as well. The shape parameter ρ of both particle populations was around 1, which is typical for spherical particles with mass concentrated on the rim, as in vesicles. The Rh and Rg of ENPs in BP patients were larger than in OC patients, with ρ ≈ 1.1–2, implying a more elongated/distorted shape. These results show that SLS and DLS are promising methods for the analysis of morphological features of ENPs and have the potential to discriminate between OC and BP patients. However, further development of the methodology is required.
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Affiliation(s)
- Ksenija Kogej
- Faculty of Chemistry and Chemical Technology, Department of Chemistry and Biochemistry, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
- Correspondence:
| | - Darja Božič
- Faculty of Chemistry and Chemical Technology, Department of Chemistry and Biochemistry, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Borut Kobal
- Division of Gynecology and Obstetrics, Department of Gynecology, University Medical Centre Ljubljana, SI-1000 Ljubljana, Slovenia; (B.K.); (M.H.)
- Faculty of Medicine, Department of Gynecology and Obstetrics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Maruša Herzog
- Division of Gynecology and Obstetrics, Department of Gynecology, University Medical Centre Ljubljana, SI-1000 Ljubljana, Slovenia; (B.K.); (M.H.)
- Faculty of Medicine, Department of Gynecology and Obstetrics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Katarina Černe
- Faculty of Medicine, Department of Pharmacology and Experimental Toxicology, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
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Kumar Y, Gupta AK, Natarajan U. Conformational and intermolecular structure of stereoregular isomers of poly(acrylic acid) (PAA) and Na+-poly(acrylate) polyelectrolyte (Na+-PAA) in dilute aqueous solution: a molecular dynamics simulation study. MOLECULAR SIMULATION 2020. [DOI: 10.1080/08927022.2020.1846036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Yogendra Kumar
- Macromolecular Modeling and Simulation Laboratory, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
| | - Abhishek K. Gupta
- Macromolecular Modeling and Simulation Laboratory, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
| | - Upendra Natarajan
- Macromolecular Modeling and Simulation Laboratory, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
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Benlahouès A, Brissault B, de Anda AR, Penelle J. Synthesis, Characterization, and Solid-State Properties of (CH 2–CH 2–C(COOH) 2) n: A Highly Symmetrical, Semicrystalline Carbon-Chain Poly(carboxylic acid). Macromolecules 2020. [DOI: 10.1021/acs.macromol.9b02665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Antoine Benlahouès
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
| | - Blandine Brissault
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
| | - Agustin Rios de Anda
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
| | - Jacques Penelle
- Institut de Chimie et des Matériaux Paris-Est (East Paris Institute for Chemistry & Materials Science), Université Paris-Est and CNRS, 2-8 rue H. Dunant, F-94320 Thiais, France
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Božič D, Hočevar M, Kononenko V, Jeran M, Štibler U, Fiume I, Pajnič M, Pađen L, Kogej K, Drobne D, Iglič A, Pocsfalvi G, Kralj-Iglič V. Pursuing mechanisms of extracellular vesicle formation. Effects of sample processing. ADVANCES IN BIOMEMBRANES AND LIPID SELF-ASSEMBLY 2020. [DOI: 10.1016/bs.abl.2020.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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7
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Hriberšek P, Kogej K. Tacticity and Counterion Modulated Temperature Response of Weak Polyelectrolytes: The Case of Poly(methacrylic acid) Stereoisomers in Aqueous Solutions. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Patricija Hriberšek
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana SI-1000, Slovenia
| | - Ksenija Kogej
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana SI-1000, Slovenia
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Viscosity of Plasma as a Key Factor in Assessment of Extracellular Vesicles by Light Scattering. Cells 2019; 8:cells8091046. [PMID: 31500151 PMCID: PMC6769602 DOI: 10.3390/cells8091046] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/19/2019] [Accepted: 09/04/2019] [Indexed: 12/31/2022] Open
Abstract
Extracellular vesicles (EVs) isolated from biological samples are a promising material for use in medicine and technology. However, the assessment methods that would yield repeatable concentrations, sizes and compositions of the harvested material are missing. A plausible model for the description of EV isolates has not been developed. Furthermore, the identity and genesis of EVs are still obscure and the relevant parameters have not yet been identified. The purpose of this work is to better understand the mechanisms taking place during harvesting of EVs, in particular the role of viscosity of EV suspension. The EVs were harvested from blood plasma by repeated centrifugation and washing of samples. Their size and shape were assessed by using a combination of static and dynamic light scattering. The average shape parameter of the assessed particles was found to be ρ ~ 1 (0.94–1.1 in exosome standards and 0.7–1.2 in blood plasma and EV isolates), pertaining to spherical shells (spherical vesicles). This study has estimated the value of the viscosity coefficient of the medium in blood plasma to be 1.2 mPa/s. It can be concluded that light scattering could be a plausible method for the assessment of EVs upon considering that EVs are a dynamic material with a transient identity.
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Sitar S, Aseyev V, Žagar E, Kogej K. Chain dynamics and intermolecular association in dilute aqueous solutions of isotactic and atactic Poly(Methacrylic acid): Effect of NaCl concentration. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.04.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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10
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Effect of Multivalent Cations on Intermolecular Association of Isotactic and Atactic Poly(Methacrylic Acid) Chains in Aqueous Solutions. Polymers (Basel) 2019; 11:polym11040605. [PMID: 30960589 PMCID: PMC6523823 DOI: 10.3390/polym11040605] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/22/2019] [Accepted: 03/26/2019] [Indexed: 11/18/2022] Open
Abstract
The formation of nanoparticles of two poly(methacrylic acid) (PMA) isomers, atactic (aPMA) and isotactic (iPMA), was investigated in aqueous solutions in the presence of mono- (Na+) and multivalent cations (Mg2+ and La3+). Using dynamic (DLS) and static light scattering (SLS), we show that PMA nanoparticles have characteristics of microgel-like particles with a denser core and a swollen corona. iPMA aggregates are stable at a much higher degree of neutralization (αN) than the aPMA ones, indicating a much stronger association between iPMA chains. This is explained by proposing segregation of ionized and unionized carboxyl groups within the iPMA aggregates and subsequent cooperative hydrogen-bonding between COOH groups. The calculated shape parameter (ρ) suggests different behavior of both isomers in the presence of Mg2+ ions on one hand and Na+ and La3+ on the other. The microgel-like particles formed in the presence of Mg2+ ions have a more even mass distribution (possibly a no core-shell structure) in comparison with those in the presence of Na+ and La3+ ions. Differences between the aggregate structures in the presence of different ions are reflected also in calorimetric experiments and supported by pH and fluorimetric measurements. Reasons for different behavior in the presence of Mg2+ ions lie in specific properties of this cation, in particular in its strong hydration and preference towards monodentate binding to carboxylate groups.
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Yao G, Zhao J, Ramisetti SB, Wen D. Atomistic Molecular Dynamic Simulation of Dilute Poly(acrylic acid) Solution: Effects of Simulation Size Sensitivity and Ionic Strength. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b03549] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guice Yao
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, U.K
| | - Jin Zhao
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, U.K
| | | | - Dongsheng Wen
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, U.K
- School of Aeronautic Science and Engineering, Beihang University, Beijing, 100191, China
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Vezočnik V, Hodnik V, Sitar S, Okur HI, Tušek-Žnidarič M, Lütgebaucks C, Sepčić K, Kogej K, Roke S, Žagar E, Maček P. Kinetically Stable Triglyceride-Based Nanodroplets and Their Interactions with Lipid-Specific Proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:8983-8993. [PMID: 29983071 DOI: 10.1021/acs.langmuir.8b02180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding of the interactions between proteins and natural and artificially prepared lipid membrane surfaces and embedded nonpolar cores is important in studies of physiological processes and their pathologies and is applicable to nanotechnologies. In particular, rapidly growing interest in cellular droplets defines the need for simplified biomimetic lipid model systems to overcome in vivo complexity and variability. We present a protocol for the preparation of kinetically stable nanoemulsions with nanodroplets composed of sphingomyelin (SM) and cholesterol (Chol), as amphiphilic surfactants, and trioleoylglycerol (TOG), at various molar ratios. To prepare stable SM/Chol-coated monodisperse lipid nanodroplets, we modified a reverse phase evaporation method and combined it with ultrasonication. Lipid composition, ζ-potential, gyration and hydrodynamic radius, shape, and temporal stability of the lipid nanodroplets were characterized and compared to extruded SM/Chol large unilamellar vesicles. Lipid nanodroplets and large unilamellar vesicles with theoretical SM/Chol/TOG molar ratios of 1/1/4.7 and 4/1/11.7 were further investigated for the orientational order of their interfacial water molecules using a second harmonic scattering technique, and for interactions with the SM-binding and Chol-binding pore-forming toxins equinatoxin II and perfringolysin O, respectively. The surface characteristics (ζ-potential, orientational order of interfacial water molecules) and binding of these proteins to the nanodroplet SM/Chol monolayers were similar to those for the SM/Chol bilayers of the large unilamellar vesicles and SM/Chol Langmuir monolayers, in terms of their surface structures. We propose that such SM/Chol/TOG nanoparticles with the required lipid compositions can serve as experimental models for monolayer membrane to provide a system that imitates the natural lipid droplets.
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Affiliation(s)
- Valerija Vezočnik
- Department of Biology, Biotechnical Faculty , University of Ljubljana , Jamnikarjeva 101 , Ljubljana 1000 , Slovenia
| | - Vesna Hodnik
- Department of Biology, Biotechnical Faculty , University of Ljubljana , Jamnikarjeva 101 , Ljubljana 1000 , Slovenia
| | - Simona Sitar
- Department of Polymer Chemistry and Technology , National Institute of Chemistry , Hajdrihova 19 , Ljubljana 1000 , Slovenia
| | - Halil I Okur
- Laboratory for Fundamental BioPhotonics, Institute of Bio-Engineering, and Institute of Material Science, School of Engineering, and Lausanne Centre for Ultrafast Science , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
| | | | - Cornelis Lütgebaucks
- Laboratory for Fundamental BioPhotonics, Institute of Bio-Engineering, and Institute of Material Science, School of Engineering, and Lausanne Centre for Ultrafast Science , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty , University of Ljubljana , Jamnikarjeva 101 , Ljubljana 1000 , Slovenia
| | - Ksenija Kogej
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology , University of Ljubljana , Večna pot 113 , Ljubljana 1000 , Slovenia
| | - Sylvie Roke
- Laboratory for Fundamental BioPhotonics, Institute of Bio-Engineering, and Institute of Material Science, School of Engineering, and Lausanne Centre for Ultrafast Science , École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne , Switzerland
| | - Ema Žagar
- Department of Polymer Chemistry and Technology , National Institute of Chemistry , Hajdrihova 19 , Ljubljana 1000 , Slovenia
| | - Peter Maček
- Department of Biology, Biotechnical Faculty , University of Ljubljana , Jamnikarjeva 101 , Ljubljana 1000 , Slovenia
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Kogej K, Štirn J, Reščič J. Reappearance of slow mode in mixtures of polyethylene glycol and poly(sodium methacrylate). SOFT MATTER 2018; 14:5039-5047. [PMID: 29863212 DOI: 10.1039/c8sm00473k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mixtures of an anionic polyelectrolyte, poly(sodium methacrylate), NaPMA, and a neutral polymer, polyethylene glycol, PEG, were investigated by dynamic and static light scattering techniques at different concentrations and chain-lengths of PEG. The NaPMA standard with a narrow molecular weight distribution was chosen for the study. The so called slow-mode behaviour, characteristic of salt-free NaPMA solutions, vanishes as the simple salt, NaCl in this case, is added in a sufficient amount. However, in NaPMA-NaCl-PEG mixtures, the slow-mode signal is observed again. We assume that the dielectric constant of the mixture with PEG, which is substantially lower than that of pure water, causes the reappearance of the slow-mode signal through reinforced electrostatic interactions between NaPMA polyions. Monte Carlo simulations of a coarse-grained model of the system confirm stronger correlations between NaPMA molecules and thus qualitatively agree with experimental results.
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Affiliation(s)
- Ksenija Kogej
- Faculty of Chemistry and Chemical Technology, Večna pot 113, SI-1000 Ljubljana, Slovenia.
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14
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Temperature dependence of solution properties of anionic polyelectrolyte-cationic surfactant complexes in ethanol. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2016.09.092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Effect of Lewis acids on the stereoregularity of N,N-dimethyl acrylamide: A computational approach. Eur Polym J 2016. [DOI: 10.1016/j.eurpolymj.2016.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Kogej K. Thermodynamic Analysis of the Conformational Transition in Aqueous Solutions of Isotactic and Atactic Poly(Methacrylic Acid) and the Hydrophobic Effect. Polymers (Basel) 2016; 8:polym8050168. [PMID: 30979264 PMCID: PMC6432447 DOI: 10.3390/polym8050168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 04/15/2016] [Accepted: 04/20/2016] [Indexed: 11/17/2022] Open
Abstract
The affinity of amphiphilic compounds for water is important in various processes, e.g., in conformational transitions of biopolymers, protein folding/unfolding, partitioning of drugs in the living systems, and many others. Herein, we study the conformational transition of two isomer forms of poly(methacrylic acid) (PMA), isotactic (iPMA) and atactic (aPMA), in water. These isomers are chemically equivalent and differ only in the arrangement of functional groups along the chain. A complete thermodynamic analysis of the transition of the PMA chains from the compact to the extended form (comprising the conformational transition) in water in the presence of three alkali chlorides is conducted by determining the free energy, enthalpy, and entropy changes of the process as a function of temperature, and therefrom also the heat capacity change. The heat capacity change of the transition is positive (+20 J/K mol) for aPMA and negative (−50 J/K mol) for iPMA. This result suggests a different affinity of PMA isomers for water. The conformational transition of iPMA is parallel to the transfer of polar solutes into water, whereas that of aPMA agrees with the transfer of nonpolar solutes into water.
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Affiliation(s)
- Ksenija Kogej
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
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Wang X, Li L. How does the anionic surfactant SDS affect the association of hydrophobically end-modified PNIPAM chains in aqueous solution? POLYMER 2016. [DOI: 10.1016/j.polymer.2016.02.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Gupta AK, Natarajan U. Tacticity effects on conformational structure and hydration of poly-(methacrylic acid) in aqueous solutions-a molecular dynamics simulation study. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1086485] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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19
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Sitar S, Aseyev V, Kogej K. Microgel-like aggregates of isotactic and atactic poly(methacrylic acid) chains in aqueous alkali chloride solutions as evidenced by light scattering. SOFT MATTER 2014; 10:7712-7722. [PMID: 25137480 DOI: 10.1039/c4sm01448k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A comparative light-scattering study of isotactic and atactic poly(methacrylic acid), iPMA and aPMA, respectively, in aqueous solutions with added alkali chlorides, XCl (X = Li, Na, Cs), at 25 °C and XCl concentration of 0.1 mol L(-1), demonstrates that both PMA isomers are strongly associated at low degrees of neutralization, αN (= 0 for aPMA and 0.25 for iPMA), in the presence of all XCls. The shape parameter ρ and the scattering functions suggest that aggregates have the characteristics of microgel particles, with a dense core surrounded by a less dense shell. The extent of aggregation depends on the stereoregular structure of the polymer and on the type of the added cation. Li(+) and Na(+) ions support aggregation better than Cs(+) ions. Besides, iPMA chains are more strongly aggregated than aPMA chains and form particles with a denser core. A model of the aggregation process is suggested for iPMA. At high αN, a slow diffusive process (so-called extraordinary or anomalous mode in diffusion of polyelectrolytes), arising from electrostatic interactions between charged chains, is observed for both PMAs. Results suggest that under the same experimental conditions iPMA is effectively more charged than aPMA. The role of ions in the slow-mode phenomenon is less pronounced than in aggregation.
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Affiliation(s)
- Simona Sitar
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, P.O. Box 537, SI-1001, Ljubljana, Slovenia.
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