1
|
Forte G, Consiglio G, Satriano C, Maugeri L, Petralia S. A nanosized photothermal responsive core-shell carbonized polymer dots based on poly(N-isopropylacrylamide) for light-triggered drug release. Colloids Surf B Biointerfaces 2022; 217:112628. [PMID: 35716451 DOI: 10.1016/j.colsurfb.2022.112628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 06/08/2022] [Accepted: 06/11/2022] [Indexed: 11/28/2022]
Abstract
Core-shell nanocomposites are one of the most important achievements in the fast-growing field of nanotechnology. The combination of multi-responsive nano-shell with luminescent and photothermal core has led to promising applications in various fields such as optics, electronics and medicine. In this work, a nanosized core-shell system composed by carbonized dots core and poly(N-isopropylacrylamide) shell was developed and the photothermal triggered release of doxorubicin was demonstrated. The system was fully characterized by H1-NMR, DLS, Z-potential, AFM, optical absorption and fluorescence measurements. A photothermal conversion efficiency (η) value of about 67.9% and a doxorubicin photo-release rate value of about 1.0% min-1 were measured. Molecular dynamic (MD) simulations data were in agreement with experimental results, at 310 K the coil-to-globule transition and a consequent desorption of doxorubicin from the polymer were observed. Both the radius of gyration and the fluctuation of the distance doxorubicin-PNIPAM pointed that the temperature above the LCST and the acid pH facilitated the polymer transition. Moreover, MD simulations and experimental data suggested an influence on the lower critical solution temperature (LCST) exerted by the number of polymer chains anchored to the carbon core.
Collapse
Affiliation(s)
- Giuseppe Forte
- Department of Drug Science and Health, University of Catania, Via S. Sofia, 64, 95125 Catania, Italy.
| | - Giuseppe Consiglio
- Department of Chemical Science, University of Catania, Via S. Sofia, 64, 95125 Catania, Italy
| | - Cristina Satriano
- Department of Chemical Science, University of Catania, Via S. Sofia, 64, 95125 Catania, Italy
| | - Ludovica Maugeri
- A.O.U Policlinico "G. Rodolico San Marco", Via S. Sofia, 5125 Catania, Italy
| | - Salvatore Petralia
- Department of Drug Science and Health, University of Catania, Via S. Sofia, 64, 95125 Catania, Italy.
| |
Collapse
|
2
|
Han Z, Hilburg SL, Alexander-Katz A. Forced Unfolding of Protein-Inspired Single-Chain Random Heteropolymers. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Zexiang Han
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Shayna L. Hilburg
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alfredo Alexander-Katz
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
3
|
Xiong K, Mitomo H, Su X, Shi Y, Yonamine Y, Sato SI, Ijiro K. Molecular configuration-mediated thermo-responsiveness in oligo(ethylene glycol) derivatives attached on gold nanoparticles. NANOSCALE ADVANCES 2021; 3:3762-3769. [PMID: 36133023 PMCID: PMC9418479 DOI: 10.1039/d1na00187f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/25/2021] [Indexed: 05/24/2023]
Abstract
Biomolecular systems actively control their local environment on a sub-nm scale via changes in molecular configuration from their flexible structures and derive emergent functions. Although this functional emergence based on local environmental control is attracting a great deal of attention in chemistry, it remains challenging to realize this artificially. Herein, we report the tuning of the thermo-responsive properties of oligo(ethylene glycol) (OEG) derivatives attached on gold nanoparticles via local environmental control not only by the hydrophobic moiety at their terminus but also by their molecular configuration. OEG-attached alkane thiol-modified AuNPs showed thermo-responsive assembly/disassembly in water through the hydration/dehydration of the OEG portions in a manner dependent both on the hydrophobicity at their terminus and the surface curvature of the core nanoparticles. Further, the assembly temperature (T A) was also tuned by ligand mixing with a non-thermo-responsive ligand with a shorter OEG length. Molecular dynamics simulations show that the distribution of the hydrophobic terminus in the normal direction along the gold surface varied in accordance with the surface curvature, indicating variations in molecular configuration. It is expected that a bent configuration could accelerate the thermo-responsiveness of OEG by allowing them greater accessibility to the hydrophobic terminus. Experimental and simulation results support the notion that local OEG density tuning by surface curvature or ligand mixing with a different OEG length leads to different degrees of accessibility to the hydrophobic terminus via changes in molecular configuration, promoting local environmental control-directed assembly temperature tuning.
Collapse
Affiliation(s)
- Kun Xiong
- Graduate School of Life Sciences, Hokkaido University Kita 10, Nishi 8, Kita-Ku Sapporo 060-0810 Japan
| | - Hideyuki Mitomo
- Research Institute for Electronic Science, Hokkaido University Kita 21, Nishi 10, Kita-Ku Sapporo 001-0021 Japan
- Global Institution for Collaborative Research and Education, Hokkaido University Kita 21, Nishi 11, Kita-Ku Sapporo 001-0021 Japan
| | - Xueming Su
- Graduate School of Chemical Engineering and Sciences, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Yier Shi
- Graduate School of Life Sciences, Hokkaido University Kita 10, Nishi 8, Kita-Ku Sapporo 060-0810 Japan
| | - Yusuke Yonamine
- Research Institute for Electronic Science, Hokkaido University Kita 21, Nishi 10, Kita-Ku Sapporo 001-0021 Japan
- Global Institution for Collaborative Research and Education, Hokkaido University Kita 21, Nishi 11, Kita-Ku Sapporo 001-0021 Japan
| | - Shin-Ichiro Sato
- Graduate School of Chemical Engineering and Sciences, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo 060-8628 Japan
- Faculty of Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Kuniharu Ijiro
- Research Institute for Electronic Science, Hokkaido University Kita 21, Nishi 10, Kita-Ku Sapporo 001-0021 Japan
- Global Institution for Collaborative Research and Education, Hokkaido University Kita 21, Nishi 11, Kita-Ku Sapporo 001-0021 Japan
| |
Collapse
|
4
|
Understanding the temperature induced aggregation of silica nanoparticles decorated with temperature-responsive polymers: Can a small step in the chemical structure make a giant leap for a phase transition? J Colloid Interface Sci 2021; 590:249-259. [PMID: 33548608 DOI: 10.1016/j.jcis.2021.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 01/14/2021] [Accepted: 01/17/2021] [Indexed: 11/20/2022]
Abstract
Temperature-responsive nanomaterials have gained increasing interest over the past decade due their ability to undergo conformational changes in situ, in response to a change in temperature. One class of temperature-responsive polymers are those with lower critical solution temperature, which phase separate in aqueous solution above a critical temperature. When these temperature-responsive polymers are grafted to a solid nanoparticle, a change in their surface properties occurs above this critical temperature, from hydrophilic to more hydrophobic, giving them a propensity to aggregate. This study explores the temperature induced aggregation of silica nanoparticles functionalised with two isomeric temperature-responsive polymers with lower critical solution temperature (LCST) behavior, namely poly(N-isopropyl acrylamide) (PNIPAM), and poly(2-n-propyl-2-oxazoline) (PNPOZ) with similar molecular weights (5000 Da) and grafting density. These nanoparticles exhibited striking differences in the temperature of aggregation, which is consistent with LCST of each polymer. Using a combination of small-angle neutron scattering (SANS) and dynamic light scattering (DLS), we probed subtle differences in the aggregation mechanism for PNIPAM- and PNPOZ-decorated silica nanoparticles. The nanoparticles decorated with PNIPAM and PNPOZ show similar aggregation mechanism that was independent of polymer structure, whereby aggregation starts by the formation of small aggregates. A further increase in temperature leads to interaction between these aggregates and results in full-scale aggregation and subsequent phase separation.
Collapse
|
5
|
Sose AT, Cornell HD, Gibbons BJ, Burris AA, Morris AJ, Deshmukh SA. Modelling drug adsorption in metal-organic frameworks: the role of solvent. RSC Adv 2021; 11:17064-17071. [PMID: 35479687 PMCID: PMC9033158 DOI: 10.1039/d1ra01746b] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 04/30/2021] [Indexed: 01/05/2023] Open
Abstract
Solvent plays a key role in biological functions, catalysis, and drug delivery. Metal-organic frameworks (MOFs) due to their tunable functionalities, porosities and surface areas have been recently used as drug delivery vehicles. To investigate the effect of solvent on drug adsorption in MOFs, we have performed integrated computational and experimental studies in selected biocompatible MOFs, specifically, UiO-AZB, HKUST-1 (or CuBTC) and NH2-MIL-53(Al). The adsorption of three drugs, namely, 5-fluorouracil (5-FU), ibuprofen (IBU), and hydroxyurea (HU) were performed in the presence and absence of the ethanol. Our computational predictions, at 1 atmospheric pressure, showed a reasonable agreement with experimental studies performed in the presence of ethanol. We find that in the presence of ethanol the drug molecules were adsorbed at the interface of solvent and MOFs. Moreover, the computationally calculated adsorption isotherms suggested that the drug adsorption was driven by electrostatic interactions at lower pressures (<10-4 Pa). Our computational predictions in the absence of ethanol were higher compared to those in the presence of ethanol. The MOF-adsorbate interaction (U HA) energy decreased with decrease in the size of a drug molecule in all three MOFs at all simulated pressures. At high pressure the interaction energy increases with increase in the MOFs pore size as the number of molecules adsorbed increases. Thus, our research shows the important role played by solvent in drug adsorption and suggests that it is critical to consider solvent while performing computational studies.
Collapse
Affiliation(s)
- Abhishek T Sose
- Department of Chemical Engineering, Virginia Tech Blacksburg VA 24060 USA
| | | | | | - Ashley A Burris
- Department of Chemistry, Virginia Tech Blacksburg VA, 24060 USA
| | - Amanda J Morris
- Department of Chemistry, Virginia Tech Blacksburg VA, 24060 USA
| | - Sanket A Deshmukh
- Department of Chemical Engineering, Virginia Tech Blacksburg VA 24060 USA
| |
Collapse
|
6
|
Khoiroh I, Lee SY, Pirdashti M, Lee MJ. Insight into structural properties of polyethylene glycol monolaurate in water and alcohols from molecular dynamics studies. RSC Adv 2020; 10:21760-21771. [PMID: 35516635 PMCID: PMC9054503 DOI: 10.1039/c9ra09688d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 05/29/2020] [Indexed: 11/21/2022] Open
Abstract
By means of molecular dynamics (MD) simulations, we explored the structural properties of polyethylene glycol monolaurate (PEGML) in water and in various aliphatic alcohols (methanol, ethanol, 2-propanol, 2-butanol, tert-butanol, and 1-pentanol). The PEGML and the alcohols were simulated using the optimized potentials for liquid simulations, all-atom (OPLS-AA) force field and water using the extended simple point charge (SPC/E) model. From the isothermal-isobaric (NPT, constant number of particles, constant pressure, and constant temperature) ensemble, we extracted the densities from the simulations and compared them with those from experimental results in order to confirm the validity of the selected force fields. The densities from MD simulations are in good agreement with the experimental values. To gain more insight into the nature of interactions between the PEGML and the solvent molecules, we analyzed the hydrogen-bonds, the electrostatic (Coulomb) interactions, and the van der Waals (Lennard-Jones) interaction energies extracted from MD simulations. The results were further strengthened by computing the solvation free energy by employing the free energy perturbation (FEP) approach. In this method, the free energy difference was computed by using the Bennet Acceptance Ratio (BAR) method. Moreover, the radial distribution functions were analyzed in order to gain more understanding of the solution behavior at the molecular level.
Collapse
Affiliation(s)
- Ianatul Khoiroh
- Department of Chemical & Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia Jalan Broga 43500 Semenyih Selangor Darul Ehsan Malaysia +60-3-8924-8017 +60-3-8924-8361
| | - Sze Ying Lee
- Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman Sungai Long Campus Kajang 43000 Selangor Malaysia
| | - Mohsen Pirdashti
- Chemical Engineering Department, Faculty of Engineering, Shomal University PO Box 731 Amol Iran
| | - Ming-Jer Lee
- Department of Chemical Engineering, National Taiwan University of Science and Technology 43 Keelung Road, Section 4 Taipei 106-07 Taiwan
| |
Collapse
|
7
|
Ortiz de Solorzano I, Bejagam KK, An Y, Singh SK, Deshmukh SA. Solvation dynamics of N-substituted acrylamide polymers and the importance for phase transition behavior. SOFT MATTER 2020; 16:1582-1593. [PMID: 31951239 DOI: 10.1039/c9sm01798d] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Functional groups present in thermo-responsive polymers are known to play an important role in aqueous solutions by manifesting their coil-to-globule conformational transition in a specific temperature range. Understanding the role of these functional groups and their interactions with water is of great interest as it may allow us to control both the nature and temperature of this coil-to-globule transition. In this work, polyacrylamide (PAAm), poly(N-isopropylacrylamide) (PNIPAm), and poly(N-isopropylmethacrylamide) (PNIPMAm) solvated in water are studied with the goal of discovering the structure of the solvent and its interaction with these polymers in determining the polymer conformations. Specifically, all-atom molecular dynamics (MD) simulations were performed on polymer chains with 30 monomer units (30-mers) at 295 K, 310 K and 320 K, which is below and above the lower critical solution temperature (LCST) of PNIPAm (LCST = 305 K) and PNIPMAm (LCST = 315 K), respectively. The MD simulation trajectories suggest that changes in the functional groups in the backbone and side-chains alter the water solvation shell around the polymer. This results in a change in the residence time probability and hydrogen bond characteristics of water at simulated temperatures. Specifically, water molecules reside for longer times near PAAm (no LCST) and PNIPMAm (LCST = 315 K) chains as compared to PNIPAm. This might be one of the possible causes for the higher LCST of PNIPMAm as compared to that of PNIPAm. These results can guide experimentalists and theoreticians to design new polymer structures with tailor-made LCST transitions while controlling the water solvation shell around the functional group.
Collapse
Affiliation(s)
- Isabel Ortiz de Solorzano
- Department of Chemical Engineering, Aragon Institute of Nanoscience (INA), University of Zaragoza, Campus Río Ebro-Edificio I+D, C/Poeta Mariano Esquillor S/N, 50018-Zaragoza, Spain
| | | | | | | | | |
Collapse
|
8
|
Pérez-Ramírez HA, Odriozola G. A coil-to-globule transition capable coarse-grained model for poly(N-isopropylacrylamide). Phys Chem Chem Phys 2020; 22:17913-17921. [PMID: 32744283 DOI: 10.1039/d0cp03101a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We present a model for mesoscopic molecular dynamics simulations of poly(N-isopropyl-acrylamide) (pNIPAM).
Collapse
Affiliation(s)
- H. A. Pérez-Ramírez
- Área de Física de Procesos Irreversibles
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana-Azcapotzalco
- 02200 Ciudad de México
- Mexico
| | - G. Odriozola
- Área de Física de Procesos Irreversibles
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana-Azcapotzalco
- 02200 Ciudad de México
- Mexico
| |
Collapse
|
9
|
Camara M, Liao H, Xu J, Zhang J, Swai R. Molecular dynamics study of the intercalation and conformational transition of poly (N-vinyl caprolactam), a thermosensitive polymer in hydrated Na-montmorillonite. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.121718] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
10
|
Iesavand H, Rahmati M, Afzali D, Modiri S. Investigation on absorption and release of mercaptopurine anticancer drug from modified polylactic acid as polymer carrier by molecular dynamic simulation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 105:110010. [PMID: 31546426 DOI: 10.1016/j.msec.2019.110010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 06/10/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022]
Abstract
The absorption and release of 6-mercaptopurine anticancer drug was investigated in biodegradable and biocompatible polymer of polylactic acid (PLA) using molecular dynamics simulation. For this purpose, the amount of mixing energy, radius of gyration, mean squared displacement and radial distribution function were computed and compared in concentrations of 5-36 wt% of 6-mercaptopurine drug. The simulation results show that increasing the concentration of the drug reduces mixing energy and PLA polymer carrier is able to carry 35.8 wt% of 6-mercaptopurine anticancer drug. Based on these results, the amount of 6-mercaptopurine release from PLA carrier 35.8 wt% of it in water environment is zero due to hydrophobic property of PLA and 6-mercaptopurine. Finally, polyethylene glycol (PEG) polymer with different percentages (10-30 wt%) was used to modify PLA carrier. The simulation results show that the rate of drug release increases by increasing the concentration of PEG polymer in the modified PLA carrier and also with increasing the percentage of drug loaded in the carrier and also the optimum weight percentage of PEG in modified PLA carrier for 35.8 wt% of drug concentration is 11 wt% and the rate of drug release is slower and equal to 4.4 molecules/ns.
Collapse
Affiliation(s)
- Homa Iesavand
- Department of Chemical Engineering, Graduate University of Advanced Technology, Kerman, Iran
| | - Mahmoud Rahmati
- Department of Chemical Engineering, Graduate University of Advanced Technology, Kerman, Iran.
| | - Dariush Afzali
- Department of Environment, Institute of Science and High Technology and Environmental Sciences, Kerman, Iran
| | - Sina Modiri
- Department of Chemical Engineering, Graduate University of Advanced Technology, Kerman, Iran
| |
Collapse
|
11
|
Atomistic molecular dynamics simulations of the LCST conformational transition in poly(N-vinylcaprolactam) in water. J Mol Graph Model 2019; 90:51-58. [PMID: 31009934 DOI: 10.1016/j.jmgm.2019.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/06/2019] [Accepted: 04/09/2019] [Indexed: 11/22/2022]
Abstract
Thermoresponsive poly(N-vinylcaprolactam) (PVCL) has received growing interest due to a temperature-induced phase transition, which switches its solubility in aqueous solutions. However, the lower critical solution temperature (LCST) of PVCL is greatly influenced by the molecular weight, morphology and the environment. Therefore, despite of numerous experimental studies of the thermal response of PVCL, a driving force and a molecular origin of conformation transitions in solution remain far less studied. To get a better understanding of the coil-to-globule conformation transition of PVCL in aqueous solution, we examined the structure and conformation dynamics of a single-chain PVCL30 in a temperature range of 280-360 K by using atomistic molecular dynamics (MD) simulations. The united-atom GROMOS G53a6 force field was re-parameterized and fine-tuned by DFT calculations to reproduce the experimental LCST transition of PVCL. Our MD model reproduces the LCST transition of PVCL30 to occur within a temperature range of 34.6-38.5°. MD simulation results suggest a significant difference between the hydration state of the carbonyl group of PVCL below and above the LCST threshold. The analysis of the number of hydrogen bonds of PVCL with water molecules demonstrates that dehydration of the polymer plays an important role and drives the temperature-induced polymer collapse. Finally, the developed MD model and FF parameters were successfully tested for large-scale systems, such as mixture PVCL30 oligomer and single-chain PVCL816 polymer, respectively.
Collapse
|
12
|
|
13
|
Consiglio G, Forte G. Molecular dynamics study of coil-to-globule transition in a thermo-responsive oligomer bound to various surfaces: hydrophilic surfaces stabilize the coil form. Phys Chem Chem Phys 2018; 20:29754-29763. [PMID: 30462107 DOI: 10.1039/c8cp05396k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural and dynamical properties of 40-mer of thermo-responsive polymer PNIPAM covalently bound to different surfaces have been studied, at different temperatures, by means of molecular dynamics simulations. Evolution of the radius of gyration, Rg, of the polymer chain and radial distribution functions (RDFs) calculated for the carbon atoms of the PNIPAM backbone with water oxygens and for the hydrogen atom of the amide groups with water oxygens indicate that functionalized surfaces affect the coil-to-globule transition of PNIPAM, by means of electrostatic interactions, increasing the lower critical solution temperature (LCST) of the polymer. Such interactions, mainly represented by a H-bond, hinder the transition in the globular form while hydrophobic groups on the surface, such as -OCH3, contribute to the globular collapse. A significant alteration in the arrangement of water molecules around the polymer is testified by: (i) the absence of the second peak in the RDF between the C atoms of the PNIPAM backbone and the O atoms of water at the same temperature at which the radius of gyration decreases; (ii) the height of both the first and the second peak of the RDF between the H atom of the amide groups and water O atoms decreases when the temperature increases above the LCST. Finally, the H-bond autocorrelation function indicates that: (i) hydrogen bonds between the bound-to-surface PNIPAM acceptor groups (O[double bond, length as m-dash]C[double bond splayed right]) and the H atoms of water molecules are less persistent than H-bonds formed between the free PNIPAM acceptor groups and water; (ii) H-bonds between the PNIPAM acceptor groups and hydroxyl groups on the quartz surface are longer lived than those formed on graphene oxide.
Collapse
Affiliation(s)
- Giuseppe Consiglio
- Dipartimento di Scienze Chimiche, Università di Catania, I-95125 Catania, Italy.
| | | |
Collapse
|
14
|
Moshref-Javadi M, Simon GP, Medhekar NV. Atomistic insights into the adsorption and stimuli-responsive behavior of poly(N-isopropylacrylamide)-graphene hybrid systems. Phys Chem Chem Phys 2018; 20:28592-28599. [PMID: 30406254 DOI: 10.1039/c8cp04191a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-covalent functionalization of graphene materials with responsive polymers is a promising approach for synthesizing new, hybrid composites with improved dispersibility and functional properties. However, the interplay between various components of the hybrid systems, their structural configurations, and stimuli-responsive behavior are not yet well understood at the atomic level. Here, we investigate the temperature-responsive behavior of physisorbed poly(N-isopropylacrylamide) (PNIPAM) on to graphene (G) and graphene oxide (GO) sheets in aqueous solution using large scale molecular dynamics simulations. It was observed that PNIPAM can be spontaneously anchored to the surfaces of both G and GO at 290 K with a macromolecular coil shape. However, the configuration of PNIPAM on G is markedly different in comparison with that on GO, leading to its distinct thermoresponsive behavior. Specifically, the adsorption on G gives rise to an increase in the temperature of the coil-to-globule transition when compared to the native polymer, the origin of which can be interpreted in terms of the interactions and the solvation behavior. The results obtained here are of significance to the design and manipulation of graphene-based stimuli-responsive hybrid systems with optimal functional properties.
Collapse
Affiliation(s)
- Mahdi Moshref-Javadi
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia.
| | | | | |
Collapse
|
15
|
Bejagam KK, An Y, Singh S, Deshmukh SA. Machine-Learning Enabled New Insights into the Coil-to-Globule Transition of Thermosensitive Polymers Using a Coarse-Grained Model. J Phys Chem Lett 2018; 9:6480-6488. [PMID: 30372083 DOI: 10.1021/acs.jpclett.8b02956] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a computational framework that integrates coarse-grained (CG) molecular dynamics (MD) simulations and a data-driven machine-learning (ML) method to gain insights into the conformations of polymers in solutions. We employ this framework to study conformational transition of a model thermosensitive polymer, poly( N-isopropylacrylamide) (PNIPAM). Here, we have developed the first of its kind, a temperature-independent CG model of PNIPAM that can accurately predict its experimental lower critical solution temperature (LCST) while retaining the tacticity in the presence of an explicit water model. The CG model was extensively validated by performing CG MD simulations with different initial conformations, varying the radius of gyration of chain, the chain length, and the angle between the adjacent monomers of the initial configuration of PNIPAM (total simulation time = 90 μs). Moreover, for the first time, we utilize the nonmetric multidimensional scaling (NMDS) method, a data-driven ML approach, to gain further insights into the mechanisms and pathways of this coil-to-globule transition by analyzing CG MD simulation trajectories. NMDS analysis provides entirely new insights and shows multiple metastable states of PNIPAM during its coil-to-globule transition above the LCST.
Collapse
Affiliation(s)
- Karteek K Bejagam
- Department of Chemical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Yaxin An
- Department of Chemical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Samrendra Singh
- CNH Industrial , Burr Ridge , Illinois 60527 , United States
| | - Sanket A Deshmukh
- Department of Chemical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| |
Collapse
|
16
|
Murdoch TJ, Humphreys BA, Johnson EC, Webber GB, Wanless EJ. Specific ion effects on thermoresponsive polymer brushes: Comparison to other architectures. J Colloid Interface Sci 2018; 526:429-450. [DOI: 10.1016/j.jcis.2018.04.086] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 02/06/2023]
|
17
|
Guskova O, Savchenko V, König U, Uhlmann P, Sommer JU. How do immobilised cell-adhesive Arg–Gly–Asp-containing peptides behave at the PAA brush surface? MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1502429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Olga Guskova
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Dresden Center for Computational Materials Science, Technische Universität Dresden, Dresden, Germany
| | - Vladyslav Savchenko
- Fakultät Umweltwissenschaften, Technische Universität Dresden, Dresden, Germany
| | - Ulla König
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
| | - Petra Uhlmann
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Jens-Uwe Sommer
- Leibniz Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Dresden Center for Computational Materials Science, Technische Universität Dresden, Dresden, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
18
|
Chakraborty I, Mukherjee K, De P, Bhattacharyya R. Monitoring Coil–Globule Transitions of Thermoresponsive Polymers by Using NMR Solvent Relaxation. J Phys Chem B 2018; 122:6094-6100. [DOI: 10.1021/acs.jpcb.8b02179] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
19
|
Ding JN, Zhang YJ, Zhong H, Ao CC, Li J, Han JG. An all-atom molecular dynamics study of the anti-interferon signaling of Ebola virus: interaction mechanisms of EBOV VP24 binding to Karyopherin alpha5. MOLECULAR BIOSYSTEMS 2018; 13:1031-1045. [PMID: 28418440 DOI: 10.1039/c7mb00136c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ebola virus (EBOV) is highly lethal due to virally encoded immune antagonists, and the combination of EBOV VP24 with karyopherin alpha (KPNA) will trigger anti-interferon (IFN) signaling. The crystal structure of VP24-KPNA5 has been proposed in recent studies, but the precise binding mechanisms are still unclear. In order to explore the VP24-KPNA5 protein binding micro-mechanisms, Molecular Dynamic (MD) simulations and Molecular Mechanics Generalized Born Surface Area (MM-GB/SA) energy calculation are performed. The obtained results show that EBOV VP24 binding to KPNA5 will rigidify their binding-face, and both proteins will be compacted during binding. According to the analyses of binding free energies of WT and the eight mutant systems, MUT3 makes the most effective contributions to the interaction; additionally MUT4, R398A and the double mutant have the second most effective influence. Hydrogen bond analysis demonstrates that inhibitors which can interfere with the formation of hydrogen bonds D480-T138, E483-R137 and D205-R396 will prevent the anti-IFN effect. Meanwhile, by combining the decomposition of binding free energies (DC) with computational alanine scanning (CAS) results, it is shown that VP24 residues R137 and T138 will be potential targets for EBOV VP24 inhibitors, and KPNA5 residues R396, R398, R480, Y477 and F484 will be potential targets to prevent KPNA5 binding to VP24, which will ultimately block anti-IFN signaling. Our investigations provide theoretical data to understand the binding modes of VP24-KPNA5. The precise binding mechanisms of the complex may shed light on the development of potential novel inhibitors against EBOV infection.
Collapse
Affiliation(s)
- Jing-Na Ding
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
20
|
Dalgakiran E, Tatlipinar H. The role of hydrophobic hydration in the LCST behaviour of POEGMA300 by all-atom molecular dynamics simulations. Phys Chem Chem Phys 2018; 20:15389-15399. [DOI: 10.1039/c8cp02026d] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The role of hydrophobic hydration in the LCST phase transition of POEGMA300 by means of the breakage of cage-like water formations around the side chains.
Collapse
Affiliation(s)
- Eray Dalgakiran
- Department of Physics
- Faculty of Arts and Sciences
- Yildiz Technical University
- Istanbul
- Turkey
| | - Hasan Tatlipinar
- Department of Physics
- Faculty of Arts and Sciences
- Yildiz Technical University
- Istanbul
- Turkey
| |
Collapse
|
21
|
Zhang YJ, Ding JN, Zhong H, Han JG. Exploration micromechanism of VP35 IID interaction and recognition dsRNA: A molecular dynamics simulation. Proteins 2017; 85:1008-1023. [PMID: 28205249 DOI: 10.1002/prot.25269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/22/2017] [Accepted: 02/05/2017] [Indexed: 01/25/2023]
Abstract
Multifunctional viral protein (VP35) encoded by the highly pathogenic Ebola viruses (EBOVs) can antagonize host double-stranded RNA (dsRNA) sensors and immune response because of the simultaneous recognition of dsRNA backbone and blunt ends. Mutation of select hydrophobic conserved basic residues within the VP35 inhibitory domain (IID) abrogates its dsRNA-binding activity, and impairs VP35-mediated interferon (IFN) antagonism. Herein the detailed binding mechanism between dsRNA and WT, single mutant, and double mutant were investigated by all-atom molecular dynamics (MD) simulation and binding energy calculation. R312A/R322A double mutations results in a completely different binding site and orientation upon the structure analyses. The calculated binding free energy results reveal that R312A, R322A, and K339A single mutations decrease the binding free energies by 17.82, 13.18, and 13.68 kcal mol-1 , respectively. The binding energy decomposition indicates that the strong binding affinity of the key residues is mainly due to the contributions of electrostatic interactions in the gas phase, where come from the positively charged side chain and the negatively charged dsRNA backbone. R312A, R322A, and K339A single mutations have no significant effect on VP35 IID conformation, but the mutations influence the contributions of electrostatic interactions in the gas phase. The calculated results reveal that end-cap residues which mainly contribute VDW interactions can recognize and capture dsRNA blunt ends, and the central basic residues (R312, R322, and K339) which mainly contribute favorable electrostatic interactions with dsRNA backbone can fix dsRNA binding site and orientation. Proteins 2017; 85:1008-1023. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Yan-Jun Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, People's Republic of China
| | - Jing-Na Ding
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, People's Republic of China
| | - Hui Zhong
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, People's Republic of China
| | - Ju-Guang Han
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, People's Republic of China
| |
Collapse
|
22
|
Furuncuoğlu Özaltın T, Aviyente V, Atılgan C, Demirel L. Multiscale modeling of poly(2-isopropyl-2-oxazoline) chains in aqueous solution. Eur Polym J 2017. [DOI: 10.1016/j.eurpolymj.2016.10.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
23
|
Jadhav SA, Brunella V, Scalarone D, Berlier G. Poly(NIPAM- co-MPS)-grafted multimodal porous silica nanoparticles as reverse thermoresponsive drug delivery system. Asian J Pharm Sci 2017; 12:279-284. [PMID: 32104339 PMCID: PMC7032213 DOI: 10.1016/j.ajps.2017.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/11/2017] [Accepted: 02/20/2017] [Indexed: 10/26/2022] Open
Abstract
Hybrid drug delivery systems (DDS) have been prepared by grafting poly(NIPAM-co-MPS) chains on multimodal porous silica nanoparticles having an inner mesoporous structure and an outer thin layer of micropores. The hybrid thermoresponsive DDS were fully characterized and loaded with a model drug. The in vitro drug release tests are carried out at below and above the lower critical solution temperature (LCST) of the copolymer. The results have revealed that due to the presence of small diameter (~1.3 nm) micropores at the periphery of the particles, the collapsed globules of the thermoresponsive copolymer above its LCST hinders the complete release of the drug which resulted in a reverse thermoresponsive drug release profile by the hybrid DDS.
Collapse
Affiliation(s)
- Sushilkumar A Jadhav
- Department of Chemistry and NIS Research Centre, University of Torino, 10125 Torino, Italy
| | - Valentina Brunella
- Department of Chemistry and NIS Research Centre, University of Torino, 10125 Torino, Italy
| | - Dominique Scalarone
- Department of Chemistry and NIS Research Centre, University of Torino, 10125 Torino, Italy
| | - Gloria Berlier
- Department of Chemistry and NIS Research Centre, University of Torino, 10125 Torino, Italy
| |
Collapse
|
24
|
de Oliveira TE, Mukherji D, Kremer K, Netz PA. Effects of stereochemistry and copolymerization on the LCST of PNIPAm. J Chem Phys 2017; 146:034904. [DOI: 10.1063/1.4974165] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tiago E. de Oliveira
- Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Debashish Mukherji
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Kurt Kremer
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Paulo A. Netz
- Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| |
Collapse
|
25
|
Xiang Y, Xu RG, Leng Y. Molecular Dynamics Simulations of a Poly(ethylene glycol)-Grafted Polyamide Membrane and Its Interaction with a Calcium Alginate Gel. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4424-4433. [PMID: 27094047 DOI: 10.1021/acs.langmuir.6b00348] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Molecular dynamics simulations are carried out to investigate the antifouling property of a polyethylene glycol (PEG)-grafted polyamide (PA) membrane. Our specific interest is the computational study of the interaction between a grafted PEG coating and an alginate gel foulant by a steered molecular dynamics approach. Simulation results show that the PEG coating can hold a tightly bound hydration water layer. When the alginate gel is dragged to approach the PEG coating surface, a strong repulsive hydration force is observed due to the compression of this hydration layer. Detailed calculations of the potential of mean force (PMF) show that the repulsive interaction between the alginate gel and the hydration water layer around the PEG coating has a dominant contribution to the total repulsive PMF. We have also studied the effect of the PEG coverage on the membrane-foulant interactions. We find that the alginate gel has a strong tendency to drift to the uncovered PA membrane surfaces (namely, the PEG hollows). However, direct attachment of the gel to the PA membrane surface can be avoided if the gel size is slightly larger than the PEG hollow site.
Collapse
Affiliation(s)
- Yuan Xiang
- Department of Mechanical & Aerospace Engineering, The George Washington University , Washington, DC 20052, United States
| | - Rong-Guang Xu
- Department of Mechanical & Aerospace Engineering, The George Washington University , Washington, DC 20052, United States
| | - Yongsheng Leng
- Department of Mechanical & Aerospace Engineering, The George Washington University , Washington, DC 20052, United States
| |
Collapse
|
26
|
Mochizuki K, Sumi T, Koga K. Driving forces for the pressure-induced aggregation of poly(N-isopropylacrylamide) in water. Phys Chem Chem Phys 2016; 18:4697-703. [DOI: 10.1039/c5cp07674a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Driving forces for the pressure-induced aggregation of poly(N-isopropylacrylamide) in water are discussed.
Collapse
Affiliation(s)
- Kenji Mochizuki
- Department of Chemistry
- Faculty of Science
- Okayama University
- Okayama 700-8530
- Japan
| | - Tomonari Sumi
- Department of Chemistry
- Faculty of Science
- Okayama University
- Okayama 700-8530
- Japan
| | - Kenichiro Koga
- Department of Chemistry
- Faculty of Science
- Okayama University
- Okayama 700-8530
- Japan
| |
Collapse
|
27
|
Insights into resistance mechanism of the macrolide biosensor protein MphR(A) binding to macrolide antibiotic erythromycin by molecular dynamics simulation. J Comput Aided Mol Des 2015; 29:1123-36. [DOI: 10.1007/s10822-015-9881-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/06/2015] [Indexed: 01/31/2023]
|
28
|
Jadhav SA, Miletto I, Brunella V, Berlier G, Scalarone D. Controlled post-synthesis grafting of thermoresponsive poly(N
-isopropylacrylamide) on mesoporous silica nanoparticles. POLYM ADVAN TECHNOL 2015. [DOI: 10.1002/pat.3534] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Sushilkumar A. Jadhav
- Department of Chemistry and NIS Research Centre; University of Torino; Via P. Giuria 7 10125 Torino Italy
| | - Ivana Miletto
- Department of Chemistry and NIS Research Centre; University of Torino; Via P. Giuria 7 10125 Torino Italy
| | - Valentina Brunella
- Department of Chemistry and NIS Research Centre; University of Torino; Via P. Giuria 7 10125 Torino Italy
| | - Gloria Berlier
- Department of Chemistry and NIS Research Centre; University of Torino; Via P. Giuria 7 10125 Torino Italy
| | - Dominique Scalarone
- Department of Chemistry and NIS Research Centre; University of Torino; Via P. Giuria 7 10125 Torino Italy
| |
Collapse
|
29
|
Min SH, Kwak SK, Kim BS. Atomistic simulation for coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate). SOFT MATTER 2015; 11:2423-2433. [PMID: 25662300 DOI: 10.1039/c4sm02242d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) in aqueous solution was investigated by all-atomistic molecular dynamics simulations. The polymer consistent force field (PCFF) was applied to the PDMAEMA model with a proper protonation state. The structural analysis indicates a distinct difference in the hydration state of particular functional groups of PDMAEMA as well as in the conformational state of PDMAEMA below and above the lower critical solution temperature (LCST). In particular, by monitoring the motion of water molecules, we observe that water molecules in the vicinity of the carbonyl group are relatively restricted to the motion in the globule state due to the extended relaxation time of hydrogen bonds among water molecules. The degree of protonation was also adjusted to study the effect of protonation on the conformational state of PDMAEMA.
Collapse
Affiliation(s)
- Sa Hoon Min
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | | | | |
Collapse
|
30
|
Wang M, Gao Y, Cao C, Chen K, Wen Y, Fang D, Li L, Guo X. Binary Solvent Colloids of Thermosensitive Poly(N-isopropylacrylamide) Microgel for Smart Windows. Ind Eng Chem Res 2014. [DOI: 10.1021/ie502828b] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Mi Wang
- State
Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
- Shanghai Institute of Ceramics, 1295 Dingxi Road, Shanghai 200050, China
| | - Yanfeng Gao
- Shanghai Institute of Ceramics, 1295 Dingxi Road, Shanghai 200050, China
- School
of Materials Science and Engineering, Shanghai University, 99 Shangda
Rd., Baoshan, Shanghai 200444, China
| | - Chuanxiang Cao
- Shanghai Institute of Ceramics, 1295 Dingxi Road, Shanghai 200050, China
| | - Kaimin Chen
- College
of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Yicun Wen
- State
Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Dingye Fang
- State
Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Li Li
- State
Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Xuhong Guo
- State
Key Laboratory of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
- Key
Laboratory of Materials-Oriented Chemical Engineering of Xinjiang
Uygur Autonomous Region, Shihezi University, Xinjiang 832000, PR China
| |
Collapse
|
31
|
Christofferson AJ, Yiapanis G, Leung AHM, Prime EL, Tran DNH, Qiao GG, Solomon DH, Yarovsky I. Dynamic performance of duolayers at the air/water interface. 2. Mechanistic insights from all-atom simulations. J Phys Chem B 2014; 118:10927-33. [PMID: 25153318 DOI: 10.1021/jp506098d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The novel duolayer system, comprising a monolayer of ethylene glycol monooctadecyl ether (C18E1) and the water-soluble polymer poly(vinylpyrrolidone) (PVP), has been shown to resist forces such as wind stress to a greater degree than the C18E1 monolayer alone. This paper reports all-atom molecular dynamics simulations comparing the monolayer (C18E1 alone) and duolayer systems under an applied force parallel to the air/water interface. The simulations show that, due to the presence of PVP at the interface, the duolayer film exhibits an increase in chain tilt, ordering, and density, as well as a lower lateral velocity compared to the monolayer. These results provide a molecular rationale for the improved performance of the duolayer system under wind conditions, as well as an atomic-level explanation for the observed efficacy of the duolayer system as an evaporation suppressant, which may serve as a useful guide for future development for thin films where resistance to external perturbation is desirable.
Collapse
Affiliation(s)
- Andrew J Christofferson
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University , GPO Box 2476, Melbourne, VIC 3001, Australia
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Juurinen I, Galambosi S, Anghelescu-Hakala AG, Koskelo J, Honkimäki V, Hämäläinen K, Huotari S, Hakala M. Molecular-Level Changes of Aqueous Poly(N-isopropylacrylamide) in Phase Transition. J Phys Chem B 2014; 118:5518-23. [DOI: 10.1021/jp501913p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Iina Juurinen
- Department
of Physics, University of Helsinki, P.O.B. 64, FI-00014, Helsinki, Finland
| | - Szabolcs Galambosi
- Department
of Physics, University of Helsinki, P.O.B. 64, FI-00014, Helsinki, Finland
| | - Adina G. Anghelescu-Hakala
- VTT Technical Research Centre of Finland, Patruunantie 19, FI-05200, Rajamäki, Finland
- Department
of Chemistry, Laboratory of Polymer Chemistry, University of Helsinki, P.O.B. 55, FI-00014, Helsinki, Finland
| | - Jaakko Koskelo
- Department
of Physics, University of Helsinki, P.O.B. 64, FI-00014, Helsinki, Finland
| | - Veijo Honkimäki
- European Synchrotron Radiation Facility, F-38043, Grenoble Cedex 9, France
| | - Keijo Hämäläinen
- Department
of Physics, University of Helsinki, P.O.B. 64, FI-00014, Helsinki, Finland
| | - Simo Huotari
- Department
of Physics, University of Helsinki, P.O.B. 64, FI-00014, Helsinki, Finland
| | - Mikko Hakala
- Department
of Physics, University of Helsinki, P.O.B. 64, FI-00014, Helsinki, Finland
| |
Collapse
|
33
|
Scherzinger C, Schwarz A, Bardow A, Leonhard K, Richtering W. Cononsolvency of poly-N-isopropyl acrylamide (PNIPAM): Microgels versus linear chains and macrogels. Curr Opin Colloid Interface Sci 2014. [DOI: 10.1016/j.cocis.2014.03.011] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
34
|
Deshmukh SA, Kamath G, Suthar KJ, Mancini DC, Sankaranarayanan SKRS. Non-equilibrium effects evidenced by vibrational spectra during the coil-to-globule transition in poly(N-isopropylacrylamide) subjected to an ultrafast heating-cooling cycle. SOFT MATTER 2014; 10:1462-1480. [PMID: 24651446 DOI: 10.1039/c3sm51750k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Molecular dynamics simulations in conjunction with finite element calculations are used to explore the conformational dynamics of a thermo-sensitive oligomer, namely poly(N-isopropylacrylamide) (PNIPAM), subjected to an ultra-fast heating-cooling cycle. Finite element (FE) calculations were used to predict the temperature profile resulting from laser-induced heating of the polymer-aqueous system. The heating rate (∼0.6 K ps(-1)) deduced from FE calculations was used to heat an aqueous solution of PNIPAM consisting of 30 monomeric units (30-mer) from 285 K to 315 K. Non-equilibrium effects arising from the ultra-fast heating-cooling cycle results in a hysteresis during the coil-to-globule transition. The corresponding atomic scale conformations were characterized by monitoring the changes in the vibrational spectra, which provided a reliable metric to study the coil-to-globule transition in PNIPAM and vice-versa across the LCST. The vibrational spectra of bonds involving atoms from the oligomer backbone and the various side-groups (amide I, amide II, and the isopropyl group of PNIPAM) of the oligomers were analyzed to study the conformational changes in the oligomer corresponding to the observed hysteresis. The differences in the vibrational spectra calculated at various temperatures during heating and cooling cycles were used to understand the coil-to-globule and globule-to-coil transitions in the PNIPAM oligomer and identify the changes in the relative interactions between various atoms in the backbone and in the side groups of the oligomer with water. The shifts in the computed vibrational spectral peaks and the changes in the intensity of peaks for the different regions of PNIPAM, seen across the LCST during the heating cycle, are in good agreement with previous experimental studies. The changes in the radius of gyration (Rg) and vibrational spectra for amide I and amide II regions of PNIPAM suggest a clear coil-to-globule transition at ∼301 K during the heating cycle from 285 K to 315 K. During the heating cycle, a comparison of the vibrational spectra of isopropyl groups in PNIPAM at 285 K and 315 K suggests dehydration of the isopropyl moieties at 315 K. This implies that the oligomer-water interactions are dominant below the LCST whereas oligomer-oligomer interactions pre-dominate above the LCST. On the other hand, during the cooling cycle minor changes in the Rg and vibrational spectra of the PNIPAM oligomer in going from 315 K to 285 K indicate that the interactions between oligomer-oligomer and between the oligomer and water are less perturbed during the cooling cycle. Our simulations suggest that the observed hysteresis is a consequence of ultrafast heating-cooling kinetics, which allows insufficient relaxation times for the solvated oligomer.
Collapse
Affiliation(s)
- Sanket A Deshmukh
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439, USA.
| | | | | | | | | |
Collapse
|
35
|
Yiapanis G, Christofferson AJ, Plazzer M, Weir MP, Prime EL, Qiao GG, Solomon DH, Yarovsky I. Molecular mechanism of stabilization of thin films for improved water evaporation protection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14451-9. [PMID: 24215111 DOI: 10.1021/la402275p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
All-atom molecular dynamics simulations and experimental characterization have been used to examine the structure and dynamics of novel evaporation-suppressing films where the addition of a water-soluble polymer to an ethylene glycol monooctadecyl ether monolayer leads to improved water evaporation resistance. Simulations and Langmuir trough experiments demonstrate the surface activity of poly(vinyl pyrrolidone) (PVP). Subsequent MD simulations performed on the thin films supported by the PVP sublayer show that, at low surface pressures, the polymer tends to concentrate at the film/water interface. The simulated atomic concentration profiles, hydrogen bonding patterns, and mobility analyses of the water-polymer-monolayer interfaces reveal that the presence of PVP increases the atomic density near the monolayer film, improves the film stability, and reduces the mobility of interfacial waters. These observations explain the molecular basis of the improved efficacy of these monolayer/polymer systems for evaporation protection of water and can be used to guide future development of organic thin films for other applications.
Collapse
Affiliation(s)
- George Yiapanis
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University , GPO Box 2476, Victoria, 3001, Australia
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Pang X, Wang K, Cui S. Single-chain mechanics of poly(N-isopropyl-acrylamide) in the water/methanol mixed solvent. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.05.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|