1
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Handl V, Waldherr L, Arbring Sjöström T, Abrahamsson T, Seitanidou M, Erschen S, Gorischek A, Bernacka-Wojcik I, Saarela H, Tomin T, Honeder SE, Distl J, Huber W, Asslaber M, Birner-Grünberger R, Schäfer U, Berggren M, Schindl R, Patz S, Simon DT, Ghaffari-Tabrizi-Wizsy N. Continuous iontronic chemotherapy reduces brain tumor growth in embryonic avian in vivo models. J Control Release 2024; 369:668-683. [PMID: 38548064 DOI: 10.1016/j.jconrel.2024.03.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024]
Abstract
Local and long-lasting administration of potent chemotherapeutics is a promising therapeutic intervention to increase the efficiency of chemotherapy of hard-to-treat tumors such as the most lethal brain tumors, glioblastomas (GBM). However, despite high toxicity for GBM cells, potent chemotherapeutics such as gemcitabine (Gem) cannot be widely implemented as they do not efficiently cross the blood brain barrier (BBB). As an alternative method for continuous administration of Gem, we here operate freestanding iontronic pumps - "GemIPs" - equipped with a custom-synthesized ion exchange membrane (IEM) to treat a GBM tumor in an avian embryonic in vivo system. We compare GemIP treatment effects with a topical metronomic treatment and observe that a remarkable growth inhibition was only achieved with steady dosing via GemIPs. Daily topical drug administration (at the maximum dosage that was not lethal for the embryonic host organism) did not decrease tumor sizes, while both treatment regimes caused S-phase cell cycle arrest and apoptosis. We hypothesize that the pharmacodynamic effects generate different intratumoral drug concentration profiles for each technique, which causes this difference in outcome. We created a digital model of the experiment, which proposes a fast decay in the local drug concentration for the topical daily treatment, but a long-lasting high local concentration of Gem close to the tumor area with GemIPs. Continuous chemotherapy with iontronic devices opens new possibilities in cancer treatment: the long-lasting and highly local dosing of clinically available, potent chemotherapeutics to greatly enhance treatment efficiency without systemic side-effects. SIGNIFICANCE STATEMENT: Iontronic pumps (GemIPs) provide continuous and localized administration of the chemotherapeutic gemcitabine (Gem) for treating glioblastoma in vivo. By generating high and constant drug concentrations near the vascularized growing tumor, GemIPs offer an efficient and less harmful alternative to systemic administration. Continuous GemIP dosing resulted in remarkable growth inhibition, superior to daily topical Gem application at higher doses. Our digital modelling shows the advantages of iontronic chemotherapy in overcoming limitations of burst release and transient concentration profiles, and providing precise control over dosing profiles and local distribution. This technology holds promise for future implants, could revolutionize treatment strategies, and offers a new platform for studying the influence of timing and dosing dependencies of already-established drugs in the fight against hard-to-treat tumors.
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Affiliation(s)
- Verena Handl
- Gottfried Schatz Research Center - Medical Physics and Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Linda Waldherr
- Gottfried Schatz Research Center - Medical Physics and Biophysics, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, Austria, Auenbruggerplatz 30, 8036 Graz, Austria
| | - Theresia Arbring Sjöström
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Tobias Abrahamsson
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Maria Seitanidou
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Sabine Erschen
- Gottfried Schatz Research Center - Medical Physics and Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Astrid Gorischek
- Gottfried Schatz Research Center - Medical Physics and Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Iwona Bernacka-Wojcik
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Helena Saarela
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Tamara Tomin
- Institute of Chemical Technologies and Analytics, Technische Universität Wien, 1060 Vienna, Austria
| | - Sophie Elisabeth Honeder
- Institute of Chemical Technologies and Analytics, Technische Universität Wien, 1060 Vienna, Austria; Diagnostic and Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
| | - Joachim Distl
- Gottfried Schatz Research Center - Medical Physics and Biophysics, Medical University of Graz, 8010 Graz, Austria
| | - Waltraud Huber
- Otto Loewi Research Center, Division of Immunology, Research Unit CAM Lab, Medical University of Graz, 8010 Graz, Austria
| | - Martin Asslaber
- Diagnostic and Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
| | - Ruth Birner-Grünberger
- Institute of Chemical Technologies and Analytics, Technische Universität Wien, 1060 Vienna, Austria; Diagnostic and Research Institute of Pathology, Medical University of Graz, 8010 Graz, Austria
| | - Ute Schäfer
- Research Unit for Experimental Neurotraumatology, Medical University of Graz, 8010 Graz, Austria
| | - Magnus Berggren
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden
| | - Rainer Schindl
- Gottfried Schatz Research Center - Medical Physics and Biophysics, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, Austria, Auenbruggerplatz 30, 8036 Graz, Austria.
| | - Silke Patz
- Research Unit for Experimental Neurotraumatology, Medical University of Graz, 8010 Graz, Austria.
| | - Daniel T Simon
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 60174 Norrköping, Sweden.
| | - Nassim Ghaffari-Tabrizi-Wizsy
- Otto Loewi Research Center, Division of Immunology, Research Unit CAM Lab, Medical University of Graz, 8010 Graz, Austria.
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2
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Matreux T, Aikkila P, Scheu B, Braun D, Mast CB. Heat flows enrich prebiotic building blocks and enhance their reactivity. Nature 2024; 628:110-116. [PMID: 38570715 PMCID: PMC10990939 DOI: 10.1038/s41586-024-07193-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 02/09/2024] [Indexed: 04/05/2024]
Abstract
The emergence of biopolymer building blocks is a crucial step during the origins of life1-6. However, all known formation pathways rely on rare pure feedstocks and demand successive purification and mixing steps to suppress unwanted side reactions and enable high product yields. Here we show that heat flows through thin, crack-like geo-compartments could have provided a widely available yet selective mechanism that separates more than 50 prebiotically relevant building blocks from complex mixtures of amino acids, nucleobases, nucleotides, polyphosphates and 2-aminoazoles. Using measured thermophoretic properties7,8, we numerically model and experimentally prove the advantageous effect of geological networks of interconnected cracks9,10 that purify the previously mixed compounds, boosting their concentration ratios by up to three orders of magnitude. The importance for prebiotic chemistry is shown by the dimerization of glycine11,12, in which the selective purification of trimetaphosphate (TMP)13,14 increased reaction yields by five orders of magnitude. The observed effect is robust under various crack sizes, pH values, solvents and temperatures. Our results demonstrate how geologically driven non-equilibria could have explored highly parallelized reaction conditions to foster prebiotic chemistry.
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Affiliation(s)
- Thomas Matreux
- Systems Biophysics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Paula Aikkila
- Systems Biophysics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bettina Scheu
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Dieter Braun
- Systems Biophysics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Christof B Mast
- Systems Biophysics, Ludwig-Maximilians-Universität München, Munich, Germany.
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3
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Pu D, Panahi A, Natale G, Benneker AM. Colloid thermophoresis in the dilute electrolyte concentration regime: from theory to experiment. SOFT MATTER 2023; 19:3464-3474. [PMID: 37129579 DOI: 10.1039/d2sm01668k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Colloid thermophoresis in aqueous media is vital for numerous applications in nanoscience and life sciences. To date, a general description of colloid thermophoresis in DI water has not been determined. Here, we describe a theoretical model within the framework of the Fokker-Planck formalism and the flickering cluster concept to describe the hydration entropy effect on the thermophoretic behaviour of colloids suspended in DI water and compare this to new experimental results. We built an experimental platform to allow for rapid and robust temperature control and investigate the thermophoretic behaviour of silica microspheres with different sizes at various background temperatures for comparison. In this work, the ionic shielding effect is accounted for by using the well-known Duhr-Dhont's model, and the hydration layer effect is determined using the developed theoretical model. For the latter, our model reveals that the sign of the Soret coefficient is governed by the interplay between the binding energy and the chemical potential of water molecules, which were found to be in the same order of magnitude. We show that our analysis accurately describes the experimental behaviour of colloidal particles that opens a new avenue for developing versatile trapping and separation techniques for various colloidal particles in aqueous systems according to their size and background temperature.
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Affiliation(s)
- Di Pu
- Department of Chemical and Petroleum Engineering, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
| | - Amirreza Panahi
- Department of Chemical and Petroleum Engineering, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
| | - Giovanniantonio Natale
- Department of Chemical and Petroleum Engineering, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
| | - Anne M Benneker
- Department of Chemical and Petroleum Engineering, 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada.
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4
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Dirscherl CF, Ianeselli A, Tetiker D, Matreux T, Queener RM, Mast CB, Braun D. A heated rock crack captures and polymerizes primordial DNA and RNA. Phys Chem Chem Phys 2023; 25:3375-3386. [PMID: 36633199 DOI: 10.1039/d2cp04538a] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Life is based on informational polymers such as DNA or RNA. For their polymerization, high concentrations of complex monomer building blocks are required. Therefore, the dilution by diffusion poses a major problem before early life could establish a non-equilibrium of compartmentalization. Here, we explored a natural non-equilibrium habitat to polymerize RNA and DNA. A heat flux across thin rock cracks is shown to accumulate and maintain nucleotides. This boosts the polymerization to RNA and DNA inside the crack. Moreover, the polymers remain localized, aiding both the creation of longer polymers and fostering downstream evolutionary steps. In a closed system, we found single nucleotides concentrate 104-fold at the bottom of the crack compared to the top after 24 hours. We detected enhanced polymerization for 2 different activation chemistries: aminoimidazole-activated DNA nucleotides and 2',3'-cyclic RNA nucleotides. The copolymerization of 2',3'-cGMP and 2',3'-cCMP in the thermal pore showed an increased heterogeneity in sequence composition compared to isothermal drying. Finite element models unravelled the combined polymerization and accumulation kinetics and indicated that the escape of the nucleotides from such a crack is negligible over a time span of years. The thermal non-equilibrium habitat establishes a cell-like compartment that actively accumulates nucleotides for polymerization and traps the resulting oligomers. We argue that the setting creates a pre-cellular non-equilibrium steady state for the first steps of molecular evolution.
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Affiliation(s)
- Christina F Dirscherl
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
| | - Alan Ianeselli
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
| | - Damla Tetiker
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
| | - Thomas Matreux
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
| | - Robbin M Queener
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
| | - Christof B Mast
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
| | - Dieter Braun
- Systems Biophysics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80799 Munich, Germany.
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5
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Appeldorn JH, Lemcke S, Speck T, Nikoubashman A. Employing Artificial Neural Networks to Identify Reaction Coordinates and Pathways for Self-Assembly. J Phys Chem B 2022; 126:5007-5016. [DOI: 10.1021/acs.jpcb.2c02232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jörn H. Appeldorn
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
| | - Simon Lemcke
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
| | - Thomas Speck
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
| | - Arash Nikoubashman
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7-9, 55128 Mainz, Germany
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6
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Mohanakumar S, Kriegs H, Briels WJ, Wiegand S. Overlapping hydration shells in salt solutions causing non-monotonic Soret coefficients with varying concentration. Phys Chem Chem Phys 2022; 24:27380-27387. [DOI: 10.1039/d2cp04089a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We develop an intuitive picture that overlapping hydration shells in salt solutions cause non-monotonic Soret coefficients with varying concentration.
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Affiliation(s)
- Shilpa Mohanakumar
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Hartmut Kriegs
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - W. J. Briels
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
- University of Twente, Computational Chemical Physics, Postbus 217, 7500 AE Enschede, The Netherlands
| | - Simone Wiegand
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
- Chemistry Department – Physical Chemistry, University Cologne, D-50939 Cologne, Germany
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7
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Waldherr L, Seitanidou M, Jakešová M, Handl V, Honeder S, Nowakowska M, Tomin T, Karami Rad M, Schmidt T, Distl J, Birner‐Gruenberger R, von Campe G, Schäfer U, Berggren M, Rinner B, Asslaber M, Ghaffari‐Tabrizi‐Wizsy N, Patz S, Simon DT, Schindl R. Targeted Chemotherapy of Glioblastoma Spheroids with an Iontronic Pump. ADVANCED MATERIALS TECHNOLOGIES 2021; 6:2001302. [PMID: 34195355 PMCID: PMC8218220 DOI: 10.1002/admt.202001302] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/15/2021] [Indexed: 05/13/2023]
Abstract
Successful treatment of glioblastoma multiforme (GBM), the most lethal tumor of the brain, is presently hampered by (i) the limits of safe surgical resection and (ii) "shielding" of residual tumor cells from promising chemotherapeutic drugs such as Gemcitabine (Gem) by the blood brain barrier (BBB). Here, the vastly greater GBM cell-killing potency of Gem compared to the gold standard temozolomide is confirmed, moreover, it shows neuronal cells to be at least 104-fold less sensitive to Gem than GBM cells. The study also demonstrates the potential of an electronically-driven organic ion pump ("GemIP") to achieve controlled, targeted Gem delivery to GBM cells. Thus, GemIP-mediated Gem delivery is confirmed to be temporally and electrically controllable with pmol min-1 precision and electric addressing is linked to the efficient killing of GBM cell monolayers. Most strikingly, GemIP-mediated GEM delivery leads to the overt disintegration of targeted GBM tumor spheroids. Electrically-driven chemotherapy, here exemplified, has the potential to radically improve the efficacy of GBM adjuvant chemotherapy by enabling exquisitely-targeted and controllable delivery of drugs irrespective of whether these can cross the BBB.
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Affiliation(s)
- Linda Waldherr
- Gottfried Schatz Research Center – BiophysicsMedical University of GrazGraz8010Austria
| | - Maria Seitanidou
- Laboratory of Organic ElectronicsDepartment of Science and TechnologyLinköping UniversityNorrköping60174Sweden
| | - Marie Jakešová
- Laboratory of Organic ElectronicsDepartment of Science and TechnologyLinköping UniversityNorrköping60174Sweden
| | - Verena Handl
- Department of NeurosurgeryMedical University of GrazGraz8010Austria
| | - Sophie Honeder
- Diagnostic and Research Institute of PathologyMedical University of GrazGraz8010Austria
| | - Marta Nowakowska
- Department of NeurosurgeryMedical University of GrazGraz8010Austria
| | - Tamara Tomin
- Diagnostic and Research Institute of PathologyMedical University of GrazGraz8010Austria
- Institute of Chemical Technologies and AnalyticsTechnische Universität WienVienna1060Austria
| | - Meysam Karami Rad
- Laboratory of Organic ElectronicsDepartment of Science and TechnologyLinköping UniversityNorrköping60174Sweden
| | - Tony Schmidt
- Gottfried Schatz Research Center – BiophysicsMedical University of GrazGraz8010Austria
| | - Joachim Distl
- Gottfried Schatz Research Center – BiophysicsMedical University of GrazGraz8010Austria
| | - Ruth Birner‐Gruenberger
- Diagnostic and Research Institute of PathologyMedical University of GrazGraz8010Austria
- Institute of Chemical Technologies and AnalyticsTechnische Universität WienVienna1060Austria
| | - Gord von Campe
- Department of NeurosurgeryMedical University of GrazGraz8010Austria
| | - Ute Schäfer
- Department of NeurosurgeryMedical University of GrazGraz8010Austria
| | - Magnus Berggren
- Laboratory of Organic ElectronicsDepartment of Science and TechnologyLinköping UniversityNorrköping60174Sweden
| | - Beate Rinner
- Division of Biomedical ResearchMedical University of GrazGraz8036Austria
| | - Martin Asslaber
- Diagnostic and Research Institute of PathologyMedical University of GrazGraz8010Austria
| | | | - Silke Patz
- Department of NeurosurgeryMedical University of GrazGraz8010Austria
| | - Daniel T. Simon
- Laboratory of Organic ElectronicsDepartment of Science and TechnologyLinköping UniversityNorrköping60174Sweden
| | - Rainer Schindl
- Gottfried Schatz Research Center – BiophysicsMedical University of GrazGraz8010Austria
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8
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Mohanakumar S, Luettmer-Strathmann J, Wiegand S. Thermodiffusion of aqueous solutions of various potassium salts. J Chem Phys 2021; 154:084506. [DOI: 10.1063/5.0038039] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Shilpa Mohanakumar
- IBI-4: Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Jutta Luettmer-Strathmann
- Department of Physics and Department of Chemistry, The University of Akron, Akron, Ohio 44325-4001, USA
| | - Simone Wiegand
- IBI-4: Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
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9
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Niether D, Wiegand S. Thermophoresis of biological and biocompatible compounds in aqueous solution. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:503003. [PMID: 31491783 DOI: 10.1088/1361-648x/ab421c] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
With rising popularity of microscale thermophoresis for the characterisation of protein-ligand binding reactions and possible applications in microfluidic devices, there is a growing interest in considering thermodiffusion in the context of life sciences. But although the understanding of thermodiffusion in non-polar mixtures has grown rapidly in recent years, predictions for associated mixtures like aqueous solutions remain challenging. This review aims to give an overview of the literature on thermodiffusion in aqueous systems, show the difficulties in theoretical description that arise from the non-ideal behaviour of water-mixtures, and highlight the relevance of thermodiffusion in a biological context. We find that the thermodiffusion in aqueous systems is dominated by contributions from heat of transfer, hydrogen bond interactions and charge effects. However, the separation of these effects is often difficult, especially in case of biological systems where a systematic exclusion of contributions may not be feasible.
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Affiliation(s)
- D Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
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10
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Wang Z, Niether D, Buitenhuis J, Liu Y, Lang PR, Dhont JKG, Wiegand S. Thermophoresis of a Colloidal Rod: Contributions of Charge and Grafted Polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:1000-1007. [PMID: 30607956 DOI: 10.1021/acs.langmuir.8b03614] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this study, we investigated the thermodiffusion behavior of a colloidal model system as a function of the Debye length, λDH, which is controlled by the ionic strength. Our system consists of an fd-virus grafted with poly(ethylene glycol) (PEG) with a molecular mass of 5000 g mol-1. The results are compared with recent measurements on a bare fd-virus and with results of PEG. The diffusion coefficients of both viruses are comparable and increase with the increasing Debye length. The thermal diffusion coefficient, DT, of the bare virus increases strongly with the Debye length, whereas DT of the grafted fd-virus shows only a very weak increase. The Debye length dependence of both systems can be described with an expression derived for charged rods using the surface charge density and an offset of DT as adjustable parameters. It turns out that the ratio of the determined surface charges is inverse to the ratio of the surfaces of the two systems, which means that the total charge remains almost constant. The determined offset of the grafted fd-virus describing the chemical contributions is the sum of DT of PEG and the offset of the bare fd-virus. At high λDH, corresponding to the low ionic strength, the ST values of both colloidal model systems approach each other. This implies a contribution from the polymer layer, which is strong at short λDH and fades out for the longer Debye lengths, when the electric double layer reaches further than the polymer chains and therefore dominates interactions with the surrounding water.
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Affiliation(s)
- Zilin Wang
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
| | - Doreen Niether
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
| | - Johan Buitenhuis
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
| | - Yi Liu
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
| | - Peter R Lang
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
| | - Jan K G Dhont
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
- Department of Physics , Heinrich-Heine-Universität Düsseldorf , D-40225 Düsseldorf , Germany
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter , Forschungszentrum Jülich GmbH , D-52428 Jülich , Germany
- Department für Chemie-Physikalische Chemie , Universität zu Köln , 50939 Cologne , Germany
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11
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Sehnem AL, Niether D, Wiegand S, Figueiredo Neto AM. Thermodiffusion of Monovalent Organic Salts in Water. J Phys Chem B 2018; 122:4093-4100. [DOI: 10.1021/acs.jpcb.8b01152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Doreen Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
- Department für Chemie - Physikalische Chemie, Universität zu Köln, 50939 Cologne, Germany
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12
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Suhonen PM, Piili J, Linna RP. Quantification of tension to explain bias dependence of driven polymer translocation dynamics. Phys Rev E 2018; 96:062401. [PMID: 29347436 DOI: 10.1103/physreve.96.062401] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Indexed: 11/07/2022]
Abstract
Motivated by identifying the origin of the bias dependence of tension propagation, we investigate methods for measuring tension propagation quantitatively in computer simulations of driven polymer translocation. Here, the motion of flexible polymer chains through a narrow pore is simulated using Langevin dynamics. We measure tension forces, bead velocities, bead distances, and bond angles along the polymer at all stages of translocation with unprecedented precision. Measurements are done at a standard temperature used in simulations and at zero temperature to pin down the effect of fluctuations. The measured quantities were found to give qualitatively similar characteristics, but the bias dependence could be determined only using tension force. We find that in the scaling relation τ∼N^{β}f_{d}^{α} for translocation time τ, the polymer length N, and the bias force f_{d}, the increase of the exponent β with bias is caused by center-of-mass diffusion of the polymer toward the pore on the cis side. We find that this diffusion also causes the exponent α to deviate from the ideal value -1. The bias dependence of β was found to result from combination of diffusion and pore friction and so be relevant for polymers that are too short to be considered asymptotically long. The effect is relevant in experiments all of which are made using polymers whose lengths are far below the asymptotic limit. Thereby, our results also corroborate the theoretical prediction by Sakaue's theory [Polymers 8, 424 (2016)2073-436010.3390/polym8120424] that there should not be bias dependence of β for asymptotically long polymers. By excluding fluctuations we also show that monomer crowding at the pore exit cannot have a measurable effect on translocation dynamics under realistic conditions.
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Affiliation(s)
- P M Suhonen
- Department of Computer Science, Aalto University, P.O. Box 15400, FI-00076 Aalto, Finland
| | - J Piili
- Department of Computer Science, Aalto University, P.O. Box 15400, FI-00076 Aalto, Finland
| | - R P Linna
- Department of Computer Science, Aalto University, P.O. Box 15400, FI-00076 Aalto, Finland
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13
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Keil LMR, Möller FM, Kieß M, Kudella PW, Mast CB. Proton gradients and pH oscillations emerge from heat flow at the microscale. Nat Commun 2017; 8:1897. [PMID: 29196673 PMCID: PMC5711904 DOI: 10.1038/s41467-017-02065-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/03/2017] [Indexed: 01/17/2023] Open
Abstract
Proton gradients are essential for biological systems. They not only drive the synthesis of ATP, but initiate molecule degradation and recycling inside lysosomes. However, the high mobility and permeability of protons through membranes make pH gradients very hard to sustain in vitro. Here we report that heat flow across a water-filled chamber forms and sustains stable pH gradients. Charged molecules accumulate by convection and thermophoresis better than uncharged species. In a dissociation reaction, this imbalances the reaction equilibrium and creates a difference in pH. In solutions of amino acids, phosphate, or nucleotides, we achieve pH differences of up to 2 pH units. The same mechanism cycles biomolecules by convection in the created proton gradient. This implements a feedback between biomolecules and a cyclic variation of the pH. The finding provides a mechanism to create a self-sustained proton gradient to drive biochemical reactions.
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Affiliation(s)
- Lorenz M R Keil
- Systems Biophysics, Physics Department, Center for Nanoscience, Ludwig-Maximilians-Universität München, 80799, Munich, Germany
| | - Friederike M Möller
- Systems Biophysics, Physics Department, Center for Nanoscience, Ludwig-Maximilians-Universität München, 80799, Munich, Germany
| | - Michael Kieß
- Systems Biophysics, Physics Department, Center for Nanoscience, Ludwig-Maximilians-Universität München, 80799, Munich, Germany
| | - Patrick W Kudella
- Systems Biophysics, Physics Department, Center for Nanoscience, Ludwig-Maximilians-Universität München, 80799, Munich, Germany
| | - Christof B Mast
- Systems Biophysics, Physics Department, Center for Nanoscience, Ludwig-Maximilians-Universität München, 80799, Munich, Germany.
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14
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Niether D, Kawaguchi T, Hovancová J, Eguchi K, Dhont JKG, Kita R, Wiegand S. Role of Hydrogen Bonding of Cyclodextrin-Drug Complexes Probed by Thermodiffusion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8483-8492. [PMID: 28780866 DOI: 10.1021/acs.langmuir.7b02313] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Temperature gradient-induced migration of biomolecules, known as thermophoresis or thermodiffusion, changes upon ligand binding. In recent years, this effect has been used to determine protein-ligand binding constants. The mechanism through which thermodiffusive properties change when complexes are formed, however, is not understood. An important contribution to thermodiffusive properties originates from the thermal response of hydrogen bonds. Because there is a considerable difference between the degree of solvation of the protein-ligand complex and its isolated components, ligand-binding is accompanied by a significant change in hydration. The aim of the present work is therefore to investigate the role played by hydrogen bonding on the change in thermodiffusive behavior upon ligand-binding. As a model system, we use cyclodextrins (CDs) and acetylsalicylic acid (ASA), where quite a significant change in hydration is expected and where no conformational changes occur when a CD/ASA complex is formed in aqueous solution. Thermophoresis was investigated in the temperature range of 10-50 °C by infrared thermal diffusion forced Rayleigh scattering. Nuclear magnetic resonance measurements were performed at 25 °C to obtain information about the structure of the complexes. All CD/ASA complexes show a stronger affinity toward regions of lower temperature compared to the free CDs. We found that the temperature sensitivity of thermophoresis correlates with the 1-octanol/water partition coefficient. This observation not only establishes the relation between thermodiffusion and degree of hydrogen bonding but also opens the possibility to relate thermodiffusive properties of complexes to their partition coefficient, which cannot be determined otherwise. This concept is especially interesting for protein-ligand complexes where the protein undergoes a conformational change, different from the CD/ASA complexes, giving rise to additional changes in their hydrophilicity.
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Affiliation(s)
- Doreen Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
| | | | - Jana Hovancová
- Chemistry Department, Pavol Jozef Šafárik Univerzity , 041 80 Košice, Slovakia
| | | | - Jan K G Dhont
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
- Department of Physics, Heinrich-Heine-Universität Düsseldorf , D-40225 Düsseldorf, Germany
| | | | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
- Department für Chemie-Physikalische Chemie, Universität zu Köln , D-50939 Cologne, Germany
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15
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Heuristic Approach to Understanding the Accumulation Process in Hydrothermal Pores. ENTROPY 2017. [DOI: 10.3390/e19010033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Eguchi K, Niether D, Wiegand S, Kita R. Thermophoresis of cyclic oligosaccharides in polar solvents. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2016; 39:86. [PMID: 27663869 DOI: 10.1140/epje/i2016-16086-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/05/2016] [Indexed: 06/06/2023]
Abstract
Cyclodextrins are cyclic oligosaccharides which are interesting as drug delivery systems, because they can be used as containers for pharmaceutical substances. We studied the Ludwig-Soret effect of [Formula: see text]-, [Formula: see text]-, [Formula: see text]- and methyl-[Formula: see text]-cyclodextrin in water and formamide by infrared thermal diffusion forced Rayleigh scattering (IR-TDFRS). In water the Soret coefficient, S T, of [Formula: see text]-, [Formula: see text]- and [Formula: see text]-cyclodextrin increases with increasing temperature and shows a sign change from negative to positive around T = 35 ° C, while S T of methyl-[Formula: see text]-cyclodextrin is positive in the entire investigated temperature. In formamide S T-values of all cyclodextrins coincide and show a slight decrease with temperature. We discuss the obtained results and relate the S T-values to the different hydrogen bonding capabilities of the cyclodextrins and the used solvents. It turns out that the change of S T with temperature correlates with the partition coefficient, logP, which indicates that more hydrophilic substances show a more pronounced temperature sensitivity of S T. Additionally we obtained a surprising result measuring the refractive index contrast factor with temperature, [Formula: see text] of cyclodextrins in formamide, which might be explained by a complex formation between cyclodextrins and formamide.
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Affiliation(s)
- Kazuya Eguchi
- School of Science, Tokai University, 259-1292, Kanagawa, Japan
| | - Doreen Niether
- ICS-3 Soft Condensed Matter, Forschungszentrum Juelich GmbH, D-52428, Juelich, Germany
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Juelich GmbH, D-52428, Juelich, Germany
- Chemistry Department - Physical Chemistry, University Cologne, D-50939, Cologne, Germany
| | - Rio Kita
- School of Science, Tokai University, 259-1292, Kanagawa, Japan.
- Micro/Nano Technology Center, Tokai University, 259-1292, Kanagawa, Japan.
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17
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Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases. Proc Natl Acad Sci U S A 2016; 113:4272-7. [PMID: 27044100 DOI: 10.1073/pnas.1600275113] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007)Proc Natl Acad Sci USA104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of[Formula: see text]wt % that is typical for concentrations in shallow lakes on early Earth.
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18
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Li Z, Zhang L, Qi R, Xie F, Qi S. Improvement of the thermal transport performance of a poly(vinylidene fluoride) composite film including silver nanowire. J Appl Polym Sci 2016. [DOI: 10.1002/app.43554] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Zhao Li
- Department of Applied Chemistry, School of Science; Northwestern Polytechnical University; Xi'an 710072 People's Republic of China
| | - Li Zhang
- Department of Applied Chemistry, School of Science; Northwestern Polytechnical University; Xi'an 710072 People's Republic of China
| | - Rong Qi
- Department of Applied Chemistry, School of Science; Northwestern Polytechnical University; Xi'an 710072 People's Republic of China
| | - Fan Xie
- Department of Applied Chemistry, School of Science; Northwestern Polytechnical University; Xi'an 710072 People's Republic of China
| | - Shuhua Qi
- Department of Applied Chemistry, School of Science; Northwestern Polytechnical University; Xi'an 710072 People's Republic of China
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19
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Li Z, Zhang L, Qi R, Xie F, Qi S. Improved lateral heat spreading performance for polyvinylidene fluoride composite film comprising silver nanowire in light-emitting diode. RSC Adv 2016. [DOI: 10.1039/c6ra04680k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Silver nanowire (AgNW) attracts great attention as a heat dissipation material due to its excellent thermal transfer property which exceeds most traditional heat sink materials.
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Affiliation(s)
- Zhao Li
- Department of Applied Chemistry
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- PR China
| | - Li Zhang
- Department of Applied Chemistry
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- PR China
| | - Rong Qi
- Department of Applied Chemistry
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- PR China
| | - Fan Xie
- Department of Applied Chemistry
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- PR China
| | - Shuhua Qi
- Department of Applied Chemistry
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- PR China
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20
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Lee LS, Kuo YT, Wang CC, Li YC, Huang PY, Lee CI, Wei TH. Mechanism of short-pulse-induced solute migration in comparison to continuous-light-driven thermal diffusion. RSC Adv 2016. [DOI: 10.1039/c5ra25607k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Short-pulse-induced and continuous-light-driven solute migrations are distinguished based on the composite time rate of photo absorption and intra-molecular excess energy redistribution relative to that of inter-molecular excess energy transfer.
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Affiliation(s)
- Li-Shu Lee
- Department of Physics
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
| | - Yu-Ting Kuo
- Department of Physics
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
| | - Chi-Chen Wang
- Department of Physics
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
| | - Yi-Ci Li
- Department of Physics
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
| | - Po-Yuan Huang
- Department of Physics
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
| | - Cheng-I. Lee
- Department of Life Science
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
| | - Tai-Huei Wei
- Department of Physics
- National Chung Cheng University
- Min-Hsiung, Chia-Yi 621
- Taiwan
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21
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Maeda K, Shinyashiki N, Yagihara S, Wiegand S, Kita R. Ludwig-Soret effect of aqueous solutions of ethylene glycol oligomers, crown ethers, and glycerol: Temperature, molecular weight, and hydrogen bond effect. J Chem Phys 2015; 143:124504. [PMID: 26429021 DOI: 10.1063/1.4931115] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The thermal diffusion, also called the Ludwig-Soret effect, of aqueous solutions of ethylene glycol oligomers, crown ethers, and glycerol is investigated as a function of temperature by thermal diffusion forced Rayleigh scattering. The Soret coefficient, ST, and the thermal diffusion coefficient, DT, show a linear temperature dependence for all studied compounds in the investigated temperature range. The magnitudes and the slopes of ST and DT vary with the chemical structure of the solute molecules. All studied molecules contain ether and/or hydroxyl groups, which can act as acceptor or donor to form hydrogen bonds, respectively. By introducing the number of donor and acceptor sites of each solute molecule, we can express their hydrogen bond capability. ST and DT can be described by an empirical equation depending on the difference of donor minus acceptor sites and the molecular weight of the solute molecule.
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Affiliation(s)
- Kousaku Maeda
- Department of Physics, Tokai University, Hiratsuka, Kanagwa 259-1292, Japan
| | - Naoki Shinyashiki
- Department of Physics, Tokai University, Hiratsuka, Kanagwa 259-1292, Japan
| | - Shin Yagihara
- Department of Physics, Tokai University, Hiratsuka, Kanagwa 259-1292, Japan
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany and Department für Chemie - Physikalische Chemie, Universität zu Köln, 50939 Cologne, Germany
| | - Rio Kita
- Department of Physics, Tokai University, Hiratsuka, Kanagwa 259-1292, Japan
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22
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Wang Z, Afanasenkau D, Dong M, Huang D, Wiegand S. Molar mass and temperature dependence of the thermodiffusion of polyethylene oxide in water/ethanol mixtures. J Chem Phys 2015; 141:064904. [PMID: 25134596 DOI: 10.1063/1.4891720] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, we study the molar mass dependence of the thermodiffusion of polyethylene oxide at different temperatures in ethanol, water/ethanol mixture (c(water) = 0.7), and water in a molar mass range up to M(w) = 180,000 g/mol. Due to the low solubility of polyethylene oxide oligomers in ethanol the measurements are limited up to M(w) = 2200 g/mol. The specific water/ethanol concentration 0.7 has been chosen, because at this weight fraction the thermal diffusion coefficient, D(T), of water/ethanol vanishes so that the system can be treated as a pseudo binary mixture. The addition of ethanol will degrade the solvent quality, so that we expect a change of the interaction energies between polymer and solvent. The analysis of the experimental data within a theoretical model shows the need of a refined model, which takes specific interactions into account.
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Affiliation(s)
- Zilin Wang
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Dzmitry Afanasenkau
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Minjie Dong
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Danni Huang
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- ICS-3 Soft Condensed Matter, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
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23
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Alonso de Mezquia D, Wang Z, Lapeira E, Klein M, Wiegand S, Mounir Bou-Ali M. Thermodiffusion, molecular diffusion and Soret coefficient of binary and ternary mixtures of n-hexane, n-dodecane and toluene. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2014; 37:106. [PMID: 25376978 DOI: 10.1140/epje/i2014-14106-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 09/11/2014] [Accepted: 10/02/2014] [Indexed: 06/04/2023]
Abstract
In this study, the thermodiffusion, molecular diffusion, and Soret coefficients of 12 binary mixtures composed of toluene, n-hexane and n-dodecane in the whole range of concentrations at atmospheric pressure and temperatures of 298.15 K and 308.15 K have been determined. The experimental measurements have been carried out using the Thermogravitational Column, the Sliding Symmetric Tubes and the Thermal Diffusion Forced Rayleigh Scattering techniques. The results obtained using the different techniques show a maximum deviation of 9% for the thermodiffusion coefficient, 8% for the molecular diffusion coefficient and 2% for the Soret coefficient. For the first time we report a decrease of the thermodiffusion coefficient with increasing ratio of the thermal expansion coefficient and viscosity for a binary mixture of an organic ring compound with a short n-alkane. This observation is discussed in terms of interactions between the different components. Additionally, the thermogravitational technique has been used to measure the thermodiffusion coefficients of four ternary mixtures consisting of toluene, n-hexane and n-dodecane at 298.15 K. In order to complete the study, the values obtained for the molecular diffusion coefficient in binary mixtures, and the thermodiffusion coefficient of binary and ternary mixtures have been compared with recently derived correlations.
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Affiliation(s)
- David Alonso de Mezquia
- Manufacturing Department, MGEP Mondragon Goi Eskola Politeknikoa, Loramendi 4 Apartado 23, 20500, Mondragon, Spain
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24
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Maeda K, Shinyashiki N, Yagihara S, Wiegand S, Kita R. How does thermodiffusion of aqueous solutions depend on concentration and hydrophobicity? THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2014; 37:94. [PMID: 25339283 DOI: 10.1140/epje/i2014-14094-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/15/2014] [Accepted: 09/29/2014] [Indexed: 06/04/2023]
Abstract
The thermal diffusion of aqueous solutions of mono-, di-ethylene glycols, poly(ethylene glycol), methanol, and glycerol is investigated systematically as a function of concentration using the Thermal Diffusion Forced Rayleigh Scattering (TDFRS). For all investigated binary mixtures, the Soret coefficient, S(T), decays with increasing concentration of the non-aqueous component showing two regions. For aqueous solution of ethylene glycol, at a very low solute content the decay is steep, while it becomes less steep for higher solute concentration. All mixtures show a sign change of S(T) with concentration. The sign change concentration is discussed with respect to chemical structures of solute molecules and the partition coefficient, log p. It turns out that the number of hydroxyl groups plays an important role. For the investigated aqueous mixtures, we find empirical linear relations between the sign change concentration and the ratio of the number of hydroxyl groups to the number of carbon atoms as well as the partition coefficient, log p.
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Affiliation(s)
- Kousaku Maeda
- Graduate School of Science and Technology, Tokai University, Hiratsuka, 259-1292, Kanagawa, Japan,
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25
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Naumann P, Datta S, Sottmann T, Arlt B, Frielinghaus H, Wiegand S. Isothermal behavior of the Soret effect in nonionic microemulsions: size variation by using different n-alkanes. J Phys Chem B 2014; 118:3451-60. [PMID: 24568715 DOI: 10.1021/jp412126n] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work we investigate the thermodiffusion behavior of microemulsion droplets of the type H2O/n-alkane/C12E5 (pentaethylene glycol monododecyl ether) using the n-alkanes: n-octane, n-decane, n-dodecane, and n-tetradecane. In order to determine the thermodiffusion behavior of these microemulsion droplets, we apply the infrared thermal diffusion forced Rayleigh scattering (IR-TDFRS) technique. We measure the Soret coefficient (ST) as function of the structure upon approaching the emulsification failure boundary (efb) and as a function of the radius of the spherical o/w microemulsion droplets close to the efb. By varying the chain length of the n-alkanes, we are able to study the thermodiffusion behavior of spherical o/w microemulsion droplets of different sizes at the same temperature. In the investigated range a linear dependence of the Soret coefficient as function of the radius was found. By use of a proposed relationship between the Soret coefficient and the temperature dependence of the interfacial tension, the transition layer l could be determined for the first time. Additionally, small angle neutron scattering (SANS) experiments are performed to determine the size and to prove that the shape of the microemulsion droplets is spherical close to the efb. Accordingly, the scattering curves could be quantitatively described by a combination of a spherical core-shell form factor and sticky hard sphere structure factor.
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Affiliation(s)
- Philipp Naumann
- ICS-Soft Condensed Matter, Forschungszentrum Jülich GmbH , D-52428 Jülich, Germany
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26
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Römer F, Wang Z, Wiegand S, Bresme F. Alkali halide solutions under thermal gradients: soret coefficients and heat transfer mechanisms. J Phys Chem B 2013; 117:8209-22. [PMID: 23758489 DOI: 10.1021/jp403862x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report an extensive analysis of the non-equilibrium response of alkali halide aqueous solutions (Na(+)/K(+)-Cl(-)) to thermal gradients using state of the art non-equilibrium molecular dynamics simulations and thermal diffusion forced Rayleigh scattering experiments. The coupling between the thermal gradient and the resulting ionic salt mass flux is quantified through the Soret coefficient. We find the Soret coefficient is of the order of 10(-3) K(-1) for a wide range of concentrations. These relatively simple solutions feature a very rich behavior. The Soret coefficient decreases with concentration at high temperatures (higher than T ∼ 315 K), whereas it increases at lower temperatures. In agreement with previous experiments, we find evidence for sign inversion in the Soret coefficient of NaCl and KCl solutions. We use an atomistic non-equilibrium molecular dynamics approach to compute the Soret coefficients in a wide range of conditions and to attain further microscopic insight on the heat transport mechanism and the behavior of the Soret coefficient in aqueous solutions. The models employed in this work reproduce the magnitude of the Soret coefficient, and the general dependence of this coefficient with temperature and salt concentration. We use the computer simulations as a microscopic approach to establish a correlation between the sign and magnitude of the Soret coefficients and ionic solvation and hydrogen bond structure of the solutions. Finally, we report an analysis of heat transport in ionic solution by quantifying the solution thermal conductivity as a function of concentration. The simulations accurately reproduce the decrease of the thermal conductivity with increasing salt concentration that is observed in experiments. An explanation of this behavior is provided.
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Affiliation(s)
- Frank Römer
- Department of Chemistry, Imperial College London, SW7 2AZ, London, UK
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27
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Abstract
For the emergence of early life, the formation of biopolymers such as RNA is essential. However, the addition of nucleotide monomers to existing oligonucleotides requires millimolar concentrations. Even in such optimistic settings, no polymerization of RNA longer than about 20 bases could be demonstrated. How then could self-replicating ribozymes appear, for which recent experiments suggest a minimal length of 200 nt? Here, we demonstrate a mechanism to bridge this gap: the escalated polymerization of nucleotides by a spatially confined thermal gradient. The gradient accumulates monomers by thermophoresis and convection while retaining longer polymers exponentially better. Polymerization and accumulation become mutually self-enhancing and result in a hyperexponential escalation of polymer length. We describe this escalation theoretically under the conservative assumption of reversible polymerization. Taking into account the separately measured thermophoretic properties of RNA, we extrapolate the results for primordial RNA polymerization inside a temperature gradient in pores or fissures of rocks. With a dilute, nanomolar concentration of monomers the model predicts that a pore length of 5 cm and a temperature difference of 10 K suffice to polymerize 200-mers of RNA in micromolar concentrations. The probability to generate these long RNAs is raised by a factor of >10(600) compared with polymerization in a physical equilibrium. We experimentally validate the theory with the reversible polymerization of DNA blocks in a laser-driven thermal trap. The results confirm that a thermal gradient can significantly enlarge the available sequence space for the emergence of catalytically active polymers.
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