1
|
Schmidt R, Kiefer H, Dalgliesh R, Gradzielski M, Netz RR. Nanoscopic Interfacial Hydrogel Viscoelasticity Revealed from Comparison of Macroscopic and Microscopic Rheology. NANO LETTERS 2024; 24. [PMID: 38591912 PMCID: PMC11057034 DOI: 10.1021/acs.nanolett.3c04884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/10/2024]
Abstract
Deviations between macrorheological and particle-based microrheological measurements are often considered to be a nuisance and neglected. We study aqueous poly(ethylene oxide) (PEO) hydrogels for varying PEO concentrations and chain lengths that contain microscopic tracer particles and show that these deviations reveal the nanoscopic viscoelastic properties of the particle-hydrogel interface. Based on the transient Stokes equation, we first demonstrate that the deviations are not due to finite particle radius, compressibility, or surface-slip effects. Small-angle neutron scattering rules out hydrogel heterogeneities. Instead, we show that a generalized Stokes-Einstein relation, accounting for an interfacial shell around tracers with viscoelastic properties that deviate from bulk, consistently explains our macrorheological and microrheological measurements. The extracted shell diameter is comparable to the PEO end-to-end distance, indicating the importance of dangling chain ends. Our methodology reveals the nanoscopic interfacial rheology of hydrogels and is applicable to different kinds of viscoelastic fluids and particles.
Collapse
Affiliation(s)
- Robert
F. Schmidt
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, 10623 Berlin, Germany
| | - Henrik Kiefer
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Robert Dalgliesh
- STFC, ISIS, Rutherford
Appleton
Laboratory, Chilton, Oxfordshire OX11 0QX, United Kingdom
| | - Michael Gradzielski
- Stranski-Laboratorium
für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17. Juni 124, 10623 Berlin, Germany
| | - Roland R. Netz
- Fachbereich
Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| |
Collapse
|
2
|
Lysenkov E, Klepko V, Bulavin L, Lebovka N. Physico-Chemical Properties of Laponite®/Polyethylene-oxide Based Composites. CHEM REC 2024; 24:e202300166. [PMID: 37387571 DOI: 10.1002/tcr.202300166] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/05/2023] [Indexed: 07/01/2023]
Abstract
This review aims to provide a literature overview as well as the authors' personal account to the studies of Laponite® (Lap)/Polyethylene-oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico-chemical properties. To the readers' convenience, the contents are subdivided into different sections, related with consideration of PEO properties and its solubility in water, behavior of Lap systems(structure of Lap-platelets, properties of aqueous dispersions of Lap and aging effects in them), analyzing ofproperties LAP/PEO systems, Lap platelets-PEO interactions, adsorption mechanisms, aging effects, aggregation and electrokinetic properties. The different applications of Lap/PEO composites are reviewed. These applications include Lap/PEO based electrolytes for lithium polymer batteries, electrospun nanofibers, environmental, biomedical and biotechnology engineering. Both Lap and PEO are highly biocompatible with living systems and they are non-toxic, non-yellowing, and non-inflammable. Medical applications of Lap/PEO composites in bio-sensing, tissue engineering, drug delivery, cell proliferation, and wound dressings are also discussed.
Collapse
Affiliation(s)
- Eduard Lysenkov
- Petro Mohyla Black Sea National University, Mykolaiv, Ukraine
| | - Valery Klepko
- Institute of Macromolecular Chemistry, Kyiv, Ukraine
| | - Leonid Bulavin
- Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
| | - Nikolai Lebovka
- Institute of Biocolloidal Chemistry named after F. D. Ovcharenko, Kyiv, Ukraine
| |
Collapse
|
3
|
Morariu S, Brunchi CE, Honciuc M, Iftime MM. Development of Hybrid Materials Based on Chitosan, Poly(Ethylene Glycol) and Laponite ® RD: Effect of Clay Concentration. Polymers (Basel) 2023; 15:polym15040841. [PMID: 36850125 PMCID: PMC9959284 DOI: 10.3390/polym15040841] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
In the context of increasing interest in biomaterials with applicability in cosmetics and medicine, this research aims to obtain and characterize some hybrid materials based on chitosan (CS) (antibacterial, biocompatible, and biodegradable), poly(ethylene glycol) (PEG) (non-toxic and prevents the adsorption of protein and cell) and Laponite® RD (Lap) (bioactive). The rheological properties of the starting dispersions were investigated and discussed related to the interactions developed between components. All samples exhibited gel-like properties, and the storage modulus of CS/PEG dispersion increased from 6.6 Pa to 657.7 Pa by adding 2.5% Lap. Structural and morphological characterization of the films, prepared by solution casting method, was performed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and polarized light microscopy (POM). These analyses proved the incorporation of Lap into CS/PEG films and revealed the morphological changes of the films by the addition of clay. Thereby, at the highest Lap concentration (43.8%), the "house of cards" structure formed by Lap platelets, which incorporate chitosan chains, as evidenced by SEM and POM. Two stages of degradation between 200 °C and 410 °C were evidenced for the films with Lap concentration higher than 38.5%, explained by the existence of a clay-rich phase (given by the clay network) and chitosan-rich one (due to the intercalation of chitosan in the clay network). CS/PEG film with 43.8% Lap showed the highest swelling degree of 240.7%. The analysis of the obtained results led to the conclusion that the addition of clay to the CS/PEG films increases their stability in water and gives them greater thermal stability.
Collapse
|
4
|
Current Understanding of Hydrogel for Drug Release and Tissue Engineering. Gels 2022; 8:gels8050301. [PMID: 35621599 PMCID: PMC9141029 DOI: 10.3390/gels8050301] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 01/01/2023] Open
Abstract
Due to their good absorption, satisfactory biocompatibility, and high safety, hydrogels have been widely used in the field of biomedicine, including for drug delivery and tissue regeneration. In this review, we introduce the characteristics and crosslinking methods of natural and synthetic hydrogels. Then, we highlight the design and principle of intelligent hydrogels (i.e., responsive hydrogels) used for drug release. Moreover, we introduce the application of the application of hydrogels in drug release and tissue engineering, and the limitations and research directions of hydrogel in drug release and tissue engineering are also considered. We hope that this review can provide a reference for follow-up studies in related fields.
Collapse
|
5
|
Uniform and porous nacre-like cellulose nanofibrils/nanoclay composite membrane as separator for highly safe and advanced Li-ion battery. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119622] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
6
|
Gold KA, Saha B, Rajeeva Pandian NK, Walther BK, Palma JA, Jo J, Cooke JP, Jain A, Gaharwar AK. 3D Bioprinted Multicellular Vascular Models. Adv Healthc Mater 2021; 10:e2101141. [PMID: 34310082 PMCID: PMC9295047 DOI: 10.1002/adhm.202101141] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/13/2021] [Indexed: 02/06/2023]
Abstract
3D bioprinting is an emerging additive manufacturing technique to fabricate constructs for human disease modeling. However, current cell-laden bioinks lack sufficient biocompatibility, printability, and structural stability needed to translate this technology to preclinical and clinical trials. Here, a new class of nanoengineered hydrogel-based cell-laden bioinks is introduced, that can be printed into 3D, anatomically accurate, multicellular blood vessels to recapitulate both the physical and chemical microenvironments of native human vasculature. A remarkably unique characteristic of this bioink is that regardless of cell density, it demonstrates a high printability and ability to protect encapsulated cells against high shear forces in the bioprinting process. 3D bioprinted cells maintain a healthy phenotype and remain viable for nearly one-month post-fabrication. Leveraging these properties, the nanoengineered bioink is printed into 3D cylindrical blood vessels, consisting of living co-culture of endothelial cells and vascular smooth muscle cells, providing the opportunity to model vascular function and pathophysiology. Upon cytokine stimulation and blood perfusion, this 3D bioprinted vessel is able to recapitulate thromboinflammatory responses observed only in advanced in vitro preclinical models or in vivo. Therefore, this 3D bioprinted vessel provides a potential tool to understand vascular disease pathophysiology and assess therapeutics, toxins, or other chemicals.
Collapse
Affiliation(s)
- Karli A Gold
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Biswajit Saha
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | | | - Brandon K Walther
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA.,Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Jorge A Palma
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Javier Jo
- Electrical and Computer Engineering, College of Engineering, The University of Oklahoma, Norman, OK, 73019, USA
| | - John P Cooke
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Abhishek Jain
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA.,Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, 77030, USA.,Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, TX, 77807, USA
| | - Akhilesh K Gaharwar
- Biomedical Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA.,Interdisciplinary Program in Genetics, Texas A&M University, College Station, TX, 77843, USA.,Material Science and Engineering, College of Engineering, Texas A&M University, College Station, TX, 77843, USA.,Center for Remote Health Technologies and Systems, Texas A&M University, College Station, TX, 77843, USA
| |
Collapse
|
7
|
Hydrodynamic diameter and zeta potential of nanostructured lipid carriers: Emphasizing some parameters for correct measurements. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126610] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
8
|
Stealey ST, Gaharwar AK, Pozzi N, Zustiak SP. Development of Nanosilicate-Hydrogel Composites for Sustained Delivery of Charged Biopharmaceutics. ACS APPLIED MATERIALS & INTERFACES 2021; 13:27880-27894. [PMID: 34106676 PMCID: PMC8483607 DOI: 10.1021/acsami.1c05576] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nanocomposite hydrogels containing two-dimensional nanosilicates (NS) have emerged as a new technology for the prolonged delivery of biopharmaceuticals. However, little is known about the physical-chemical properties governing the interaction between NS and proteins and the release profiles of NS-protein complexes in comparison to traditional poly(ethylene glycol) (PEG) hydrogel technologies. To fill this gap in knowledge, we fabricated a nanocomposite hydrogel composed of PEG and laponite and identified simple but effective experimental conditions to obtain sustained protein release, up to 23 times slower as compared to traditional PEG hydrogels, as determined by bulk release experiments and fluorescence correlation spectroscopy. Slowed protein release was attributed to the formation of NS-protein complexes, as NS-protein complex size was inversely correlated with protein diffusivity and release rates. While protein electrostatics, protein concentration, and incubation time were important variables to control protein-NS complex formation, we found that one of the most significant and less appreciated variable to obtain a sustained release of bioactive proteins was the buffer chosen for preparing the initial suspension of NS particles. The buffer was found to control the size of nanoparticles, the absorption potential, morphology, and stiffness of hydrogels. From these studies, we conclude that the PEG-laponite composite fabricated is a promising new platform for sustained delivery of positively charged protein therapeutics.
Collapse
Affiliation(s)
- Samuel T Stealey
- Biomedical Engineering Program, School of Engineering, Saint Louis University, Saint Louis, Missouri 63103, United States
| | - Akhilesh K Gaharwar
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Nicola Pozzi
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63103, United States
| | - Silviya Petrova Zustiak
- Biomedical Engineering Program, School of Engineering, Saint Louis University, Saint Louis, Missouri 63103, United States
| |
Collapse
|
9
|
Gordillo-Galeano A, Ponce A, Mora-Huertas CE. Surface structural characteristics of some colloidal lipid systems used in pharmaceutics. J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2021.102345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
10
|
Bernhard S, Tibbitt MW. Supramolecular engineering of hydrogels for drug delivery. Adv Drug Deliv Rev 2021; 171:240-256. [PMID: 33561451 DOI: 10.1016/j.addr.2021.02.002] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/27/2021] [Accepted: 02/03/2021] [Indexed: 02/06/2023]
Abstract
Supramolecular binding motifs are increasingly employed in the design of biomaterials. The ability to rationally engineer specific yet reversible associations into polymer networks with supramolecular chemistry enables injectable or sprayable hydrogels that can be applied via minimally invasive administration. In this review, we highlight two main areas where supramolecular binding motifs are being used in the design of drug delivery systems: engineering network mechanics and tailoring drug-material affinity. Throughout, we highlight many of the established and emerging chemistries or binding motifs that are useful for the design of supramolecular hydrogels for drug delivery applications.
Collapse
|
11
|
Zandi N, Sani ES, Mostafavi E, Ibrahim DM, Saleh B, Shokrgozar MA, Tamjid E, Weiss PS, Simchi A, Annabi N. Nanoengineered shear-thinning and bioprintable hydrogel as a versatile platform for biomedical applications. Biomaterials 2021; 267:120476. [PMID: 33137603 PMCID: PMC7846391 DOI: 10.1016/j.biomaterials.2020.120476] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 12/26/2022]
Abstract
The development of bioinks based on shear-thinning and self-healing hydrogels has recently attracted significant attention for constructing complex three-dimensional physiological microenvironments. For extrusion-based bioprinting, it is challenging to provide high structural reliability and resolution of printed structures while protecting cells from shear forces during printing. Herein, we present shear-thinning and printable hydrogels based on silicate nanomaterials, laponite (LA), and glycosaminoglycan nanoparticles (GAGNPs) for bioprinting applications. Nanocomposite hydrogels (GLgels) were rapidly formed within seconds due to the interactions between the negatively charged groups of GAGNPs and the edges of LA. The shear-thinning behavior of the hydrogel protected encapsulated cells from aggressive shear stresses during bioprinting. The bioinks could be printed straightforwardly into shape-persistent and free-standing structures with high aspect ratios. Rheological studies demonstrated fast recovery of GLgels over multiple strain cycles. In vitro studies confirmed the ability of GLgels to support cell growth, proliferation, and spreading. In vitro osteogenic differentiation of pre-osteoblasts murine bone marrow stromal cells encapsulated inside the GLgels was also demonstrated through evaluation of ALP activity and calcium deposition. The subcutaneous implantation of the GLgel in rats confirmed its in vivo biocompatibility and biodegradability. The engineered shear-thinning hydrogel with osteoinductive characteristics can be used as a new bioink for 3D printing of constructs for bone tissue engineering applications.
Collapse
Affiliation(s)
- Nooshin Zandi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-11155, Tehran, Iran; Department of Chemical Engineering, Northeastern University, Boston, Massachuestts, 02115, United States
| | - Ehsan Shirzaei Sani
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, United States
| | - Ebrahim Mostafavi
- Department of Chemical Engineering, Northeastern University, Boston, Massachuestts, 02115, United States
| | - Dina M Ibrahim
- Department of Chemical Engineering, Northeastern University, Boston, Massachuestts, 02115, United States; Energy Materials Laboratory (EML), School of Sciences and Engineering, The American University in Cairo, New Cairo 11835, Egypt
| | - Bahram Saleh
- Department of Chemical Engineering, Northeastern University, Boston, Massachuestts, 02115, United States
| | | | - Elnaz Tamjid
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran
| | - Paul S Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, United States; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, United States; Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, 90095, United States; Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, United States; Center for Minimally Invasive Therapeutics (C-MIT), California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA, 90095, United States
| | - Abdolreza Simchi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-11155, Tehran, Iran; Center for Minimally Invasive Therapeutics (C-MIT), California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA, 90095, United States.
| | - Nasim Annabi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, United States; Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-11155, Tehran, Iran.
| |
Collapse
|
12
|
Al‐Bermany E, Chen B. Preparation and characterisation of poly(ethylene glycol)‐adsorbed graphene oxide nanosheets. POLYM INT 2020. [DOI: 10.1002/pi.6140] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ehssan Al‐Bermany
- Department of Materials Science and Engineering University of Sheffield Sheffield UK
- Department of Physics, College of Education for Pure Sciences University of Babylon Babylon Iraq
| | - Biqiong Chen
- School of Mechanical and Aerospace Engineering Queenʼs University Belfast Belfast UK
| |
Collapse
|
13
|
El Rifaii K, Wensink HH, Bizien T, Gabriel JCP, Michot L, Davidson P. Destabilization of the Nematic Phase of Clay Nanosheet Suspensions by Polymer Adsorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12563-12571. [PMID: 33050693 DOI: 10.1021/acs.langmuir.0c02084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Complex aqueous mixtures comprised of swelling clays and hydrosoluble polymers naturally occur in soils and play a major role in pedogenesis. They are also very often used for formulating oil-well drilling fluids, paints, and personal-care products. The suspensions of some natural clays, thanks to their large nanoparticle aspect ratio, spontaneously form nematic liquid-crystalline phases where the particles align parallel to each other, which affects their flow properties. We observed that adding small amounts of hydrosoluble polymers to these clay suspensions destabilizes the nematic phase with respect to the isotropic (disordered) phase. The polymers that we used (poly(ethylene oxide) and dextran) were too small to adopt particle-bridging conformations and small-angle X-ray scattering experiments showed that the structure of the nematic phase is not altered by polymer doping. However, the adsorption isotherm shows that the macromolecules adsorb onto the clay nanosheets, effectively coating them with a polymer layer. Our extension of Onsager's theory for polymer-coated platelets properly captures the experimental phase diagram and shows how the nematic phase destabilization can be due to the polymer adsorbing more on the platelet faces than at the rim. Because the flow properties of the nematic phase are very different from those of the isotropic phase, the presence or absence of the former phase is an important factor to be determined and considered to explain the rheological behavior of these complex systems.
Collapse
Affiliation(s)
- Karin El Rifaii
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Henricus H Wensink
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| | - Thomas Bizien
- SWING beamline, SOLEIL Synchrotron, 91192 Gif-sur-Yvette, France
| | | | - Laurent Michot
- Laboratory of Physical Chemistry of Electrolytes and Interfacial Nanosystems (PHENIX), Sorbonne Universite', CNRS, 75005 Paris, France
| | - Patrick Davidson
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405, Orsay, France
| |
Collapse
|
14
|
Le Coeur C, Lorthioir C, Feoktystov A, Wu B, Volet G, Amiel C. Laponite/poly(2-methyl-2-oxazoline) hydrogels: Interplay between local structure and rheological behaviour. J Colloid Interface Sci 2020; 582:149-158. [PMID: 32814221 DOI: 10.1016/j.jcis.2020.07.068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/11/2020] [Accepted: 07/13/2020] [Indexed: 11/08/2022]
Abstract
HYPOTHESIS Dispersions of Laponite in water may form gels, the rheological properties of which being possibly tuned by the addition of polymer chains. Laponite-based hydrogels with poly(ethylene oxide) (PEO) were the most widely investigated systems and the PEO chains were then found to reduce the elastic modulus. EXPERIMENTS Here, hydrogels based on Laponite and poly(2-methyl-2-oxazoline) (POXA) were considered. The adsorption behavior and the local structures within these nanocomposite gels were investigated by small-angle neutron scattering and NMR. The same materials were macroscopically characterized using rheology. FINDINGS An original evolution of the storage modulus G' with the POXA concentration is evidenced compared to Laponite/PEO hydrogels. At low POXA concentrations, a continuous reduction of G' is observed upon increasing the polymer content, as with PEO, due to the screening of electrostatic interactions between the clay platelets. However, above a critical value of the POXA concentration, G' increases with the polymer content. This difference with PEO-based hydrogels is correlated to the stronger affinity of POXA chains for the clay surfaces, which results in the reduction of the inhomogeneities for the Laponite disks within the gels. Steric repulsions would then counterbalance the effect of electrostatic repulsions and lead to the strengthening of the POXA-based hydrogels.
Collapse
Affiliation(s)
- C Le Coeur
- Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, 2 Rue Henri Dunant, 94320 Thiais, France; Laboratoire Léon Brillouin, CEA-CNRS (UMR-12), CEA Saclay, Université Paris-Saclay, 91191 Gif-sur-Yvette Cedex, France.
| | - C Lorthioir
- Sorbonne Université, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, 4 Place Jussieu, 75005 Paris, France.
| | - A Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, Lichtenbergstraße 1, 85748 Garching, Germany.
| | - B Wu
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, Lichtenbergstraße 1, 85748 Garching, Germany.
| | - G Volet
- Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, 2 Rue Henri Dunant, 94320 Thiais, France; Université d'Evry Val d'Essonne, Rue du Père Jarlan, 91025 Evry Cedex, France.
| | - C Amiel
- Université Paris Est Creteil, CNRS, Institut Chimie et Matériaux Paris Est, 2 Rue Henri Dunant, 94320 Thiais, France.
| |
Collapse
|
15
|
Manilo MV, Lebovka NI, Barany S. Electrokinetic Behavior of Laponite RD in Aqueous Suspensions Containing Poly(ethylene oxide) and Cetyltrimethylammonium Bromide. J Phys Chem B 2020; 124:4372-4378. [PMID: 32364739 DOI: 10.1021/acs.jpcb.0c02782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The aqueous suspensions of Laponite RD (Lap) platelets demonstrate rich phase diagrams. Both poly(ethylene oxide) (PEO) and cetyltrimethylammonium bromide (CTAB) molecules competitively adsorb on the surface of Lap, and strong interactions between PEO and CTAB exist. The stability of ternary systems Lap + PEO + CTAB can be finely regulated by changing the balance of these interactions. The electrokinetic technique was used to study 0.065 and 2% wt Lap suspensions in the presence of different amounts of PEO of various molecular masses Mw (400-20,000 g/mol) and CTAB (0-1 mM). For 0.065% wt Lap suspension, the additives of PEO did not affect the position of the isoelectric point (IEP), but the impact of PEO in the regions below or above the IEP was significant, especially for a large Mw. The observed effects were explained, accounting the model for the adsorption of PEO in the form of loops and tails as well as for the changes in the packing balance of CTAB and PEO on the surface of Lap. For 2% wt suspension, the strong effects of Mw on the ζ-potential and aggregation of particles were explained by screening the repulsive double layers by PEO chains, by bridging the Lap particles via PEO molecules, and by the impact of CTAB molecules on the bridging between Lap aggregates.
Collapse
Affiliation(s)
- Maryna V Manilo
- Research Institute of Applied Earth Sciences and MTA-ME Materials Science Research Group, University of Miskolc 3515, Miskolc, Hungary.,F.D. Ovcharenko Institute of Biocolloidal Chemistry, NAS of Ukraine, 42, Vernadsky Avenue, Kyiv 03142, Ukraine
| | - Nikolai I Lebovka
- F.D. Ovcharenko Institute of Biocolloidal Chemistry, NAS of Ukraine, 42, Vernadsky Avenue, Kyiv 03142, Ukraine
| | - Sandor Barany
- Research Institute of Applied Earth Sciences and MTA-ME Materials Science Research Group, University of Miskolc 3515, Miskolc, Hungary
| |
Collapse
|
16
|
Afghah F, Altunbek M, Dikyol C, Koc B. Preparation and characterization of nanoclay-hydrogel composite support-bath for bioprinting of complex structures. Sci Rep 2020; 10:5257. [PMID: 32210259 PMCID: PMC7093553 DOI: 10.1038/s41598-020-61606-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 02/26/2020] [Indexed: 11/25/2022] Open
Abstract
Three-dimensional bioprinting of cell-laden hydrogels in a sacrificial support-bath has recently emerged as a potential solution for fabricating complex biological structures. Physical properties of the support-bath strongly influence the bioprinting process and the outcome of the fabricated constructs. In this study, we reported the application of a composite Pluronic-nanoclay support-bath including calcium ions as the crosslinking agent for bioprinting of cell-laden alginate-based hydrogels. By tuning the rheological properties, a shear-thinning composite support-bath with fast self-recovery behavior was yielded, which allowed continuous printing of complex and large-scale structures. The printed structures were easily and efficiently harvested from the support-bath without disturbing their shape fidelity. Moreover, the results showed that support-bath assisted bioprinting process did not influence the viability of cells encapsulated within hydrogel. This study demonstrates that Pluronic-nanoclay support-bath can be utilized for bioprinting of complex, cell-laden constructs for vascular and other tissue engineering applications.
Collapse
Affiliation(s)
- Ferdows Afghah
- Sabanci Nanotechnology Research and Application Center, Istanbul, 34956, Turkey
- Sabanci University Faculty of Engineering and Natural Sciences, Istanbul, 34956, Turkey
| | - Mine Altunbek
- Sabanci Nanotechnology Research and Application Center, Istanbul, 34956, Turkey
| | - Caner Dikyol
- Sabanci Nanotechnology Research and Application Center, Istanbul, 34956, Turkey
- Sabanci University Faculty of Engineering and Natural Sciences, Istanbul, 34956, Turkey
| | - Bahattin Koc
- Sabanci Nanotechnology Research and Application Center, Istanbul, 34956, Turkey.
- Sabanci University Faculty of Engineering and Natural Sciences, Istanbul, 34956, Turkey.
- Sabanci University Integrated Manufacturing Technologies Research and Application Center, Istanbul, 34906, Turkey.
| |
Collapse
|
17
|
Gaharwar AK, Cross LM, Peak CW, Gold K, Carrow JK, Brokesh A, Singh KA. 2D Nanoclay for Biomedical Applications: Regenerative Medicine, Therapeutic Delivery, and Additive Manufacturing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1900332. [PMID: 30941811 PMCID: PMC6546555 DOI: 10.1002/adma.201900332] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/23/2019] [Indexed: 05/03/2023]
Abstract
Clay nanomaterials are an emerging class of 2D biomaterials of interest due to their atomically thin layered structure, charged characteristics, and well-defined composition. Synthetic nanoclays are plate-like polyions composed of simple or complex salts of silicic acids with a heterogeneous charge distribution and patchy interactions. Due to their biocompatible characteristics, unique shape, high surface-to-volume ratio, and charge, nanoclays are investigated for various biomedical applications. Here, a critical overview of the physical, chemical, and physiological interactions of nanoclay with biological moieties, including cells, proteins, and polymers, is provided. The state-of-the-art biomedical applications of 2D nanoclay in regenerative medicine, therapeutic delivery, and additive manufacturing are reviewed. In addition, recent developments that are shaping this emerging field are discussed and promising new research directions for 2D nanoclay-based biomaterials are identified.
Collapse
Affiliation(s)
- Akhilesh K Gaharwar
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
- Material Science and Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
- Center for Remote Health Technologies and Systems, Texas A&M University, College Station, TX, 77843, USA
| | - Lauren M Cross
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Charles W Peak
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Karli Gold
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - James K Carrow
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Anna Brokesh
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Kanwar Abhay Singh
- Biomedical Engineering, Dwight Look College of Engineering, Texas A&M University, College Station, TX, 77843, USA
| |
Collapse
|
18
|
Dodero A, Williams R, Gagliardi S, Vicini S, Alloisio M, Castellano M. A micro-rheological and rheological study of biopolymers solutions: Hyaluronic acid. Carbohydr Polym 2019; 203:349-355. [DOI: 10.1016/j.carbpol.2018.09.072] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/05/2018] [Accepted: 09/27/2018] [Indexed: 12/13/2022]
|
19
|
Effects of interfacial interactions and interpenetrating brushes on the electrospinning of cellulose nanocrystals-polystyrene fibers. J Colloid Interface Sci 2018; 528:419-430. [DOI: 10.1016/j.jcis.2018.04.089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 11/20/2022]
|
20
|
Arenas-Guerrero P, Delgado ÁV, Donovan KJ, Scott K, Bellini T, Mantegazza F, Jiménez ML. Determination of the size distribution of non-spherical nanoparticles by electric birefringence-based methods. Sci Rep 2018; 8:9502. [PMID: 29934624 PMCID: PMC6015062 DOI: 10.1038/s41598-018-27840-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/11/2018] [Indexed: 12/03/2022] Open
Abstract
The in situ determination of the size distribution of dispersed non-spherical nanoparticles is an essential characterization tool for the investigation and use of colloidal suspensions. In this work, we test a size characterization method based on the measurement of the transient behaviour of the birefringence induced in the dispersions by pulsed electric fields. The specific shape of such relaxations depends on the distribution of the rotational diffusion coefficient of the suspended particles. We analyse the measured transient birefringence with three approaches: the stretched-exponential, Watson-Jennings, and multi-exponential methods. These are applied to six different types of rod-like and planar particles: PTFE rods, goethite needles, single- and double-walled carbon nanotubes, sodium montmorillonite particles and gibbsite platelets. The results are compared to electron microscopy and dynamic light scattering measurements. The methods here considered provide good or excellent results in all cases, proving that the analysis of the transient birefringence is a powerful tool to obtain complete size distributions of non-spherical particles in suspension.
Collapse
Affiliation(s)
| | - Ángel V Delgado
- Department of Applied Physics, Univ. Granada, Granada, 18071, Spain
| | - Kevin J Donovan
- School of Physics and Astronomy, Queen Mary Univ. London, London, E14NS, UK
| | - Kenneth Scott
- School of Physics and Astronomy, Queen Mary Univ. London, London, E14NS, UK
| | - Tommaso Bellini
- Department Med. Biotechnol. and Translat. Med., Univ. Milan, Milan, I20090, Italy
| | - Francesco Mantegazza
- Department Medicina e Chirurgia, Univ. Milano-Bicocca, Vedano al Lambro, MB, 20854, Italy
| | - María L Jiménez
- Department of Applied Physics, Univ. Granada, Granada, 18071, Spain.
| |
Collapse
|
21
|
Peak CW, Stein J, Gold KA, Gaharwar AK. Nanoengineered Colloidal Inks for 3D Bioprinting. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:917-925. [PMID: 28981287 DOI: 10.1021/acs.langmuir.7b02540] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanoengineered hydrogels offer the potential to design shear-thinning bioinks for three-dimensional (3D) bioprinting. Here, we have synthesized colloidal bioinks composed of disk-shaped two-dimensional (2D) nanosilicates (Laponite) and poly(ethylene glycol) (PEG). The addition of Laponite reinforces the PEG network and increases viscosity, storage modulus, and network stability. PEG-Laponite hydrogels display shear-thinning and self-recovery characteristics due to rapid internal phase rearrangement. As a result, a range of complex patterns can be printed using PEG-Laponite bioinks. The 3D bioprinted structure has similar mechanical properties compared to the as-casted structure. In addition, encapsulated cells within the PEG-Laponite bioink show high viability after bioprinting. Overall, this study introduces a new class of PEG-Laponite colloidal inks for bioprinting and cell delivery.
Collapse
Affiliation(s)
- Charles W Peak
- Biomedical Engineering and ‡Material Science and Engineering, Dwight Look College of Engineering, and §Center for Remote Health Technologies and Systems, Texas A&M University , College Station, Texas 77843, United States
| | - Jean Stein
- Biomedical Engineering and ‡Material Science and Engineering, Dwight Look College of Engineering, and §Center for Remote Health Technologies and Systems, Texas A&M University , College Station, Texas 77843, United States
| | - Karli A Gold
- Biomedical Engineering and ‡Material Science and Engineering, Dwight Look College of Engineering, and §Center for Remote Health Technologies and Systems, Texas A&M University , College Station, Texas 77843, United States
| | - Akhilesh K Gaharwar
- Biomedical Engineering and ‡Material Science and Engineering, Dwight Look College of Engineering, and §Center for Remote Health Technologies and Systems, Texas A&M University , College Station, Texas 77843, United States
| |
Collapse
|
22
|
Bodratti AM, Sarkar B, Alexandridis P. Adsorption of poly(ethylene oxide)-containing amphiphilic polymers on solid-liquid interfaces: Fundamentals and applications. Adv Colloid Interface Sci 2017; 244:132-163. [PMID: 28069108 DOI: 10.1016/j.cis.2016.09.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 09/23/2016] [Accepted: 09/23/2016] [Indexed: 12/30/2022]
Abstract
The adsorption of amphiphilic molecules of varying size on solid-liquid interfaces modulates the properties of colloidal systems. Nonionic, poly(ethylene oxide) (PEO)-based amphiphilic molecules are particularly useful because of their graded hydrophobic-hydrophilic nature, which allows for adsorption on a wide array of solid surfaces. Their adsorption also results in other useful properties, such as responsiveness to external stimuli and solubilization of hydrophobic compounds. This review focuses on the adsorption properties of PEO-based amphiphiles, beginning with a discussion of fundamental concepts pertaining to the adsorption of macromolecules on solid-liquid interfaces, and more specifically the adsorption of PEO homopolymers. The main portion of the review highlights studies on factors affecting the adsorption and surface self-assembly of PEO-PPO-PEO block copolymers, where PPO is poly(propylene oxide). Block copolymers of this type are commercially available and of interest in several fields, due to their low toxicity and compatibility in aqueous systems. Examples of applications relevant to the interfacial behavior of PEO-PPO-PEO block copolymers are paints and coatings, detergents, filtration, and drug delivery. The methods discussed herein for manipulating the adsorption properties of PEO-PPO-PEO are emphasized for their ability to shed light on molecular interactions at interfaces. Knowledge of these interactions guides the formulation of novel materials with useful mesoscale organization and micro- and macrophase properties.
Collapse
|
23
|
|
24
|
Microstructure of colloid-polymer mixtures containing charged colloidal disks and weakly-adsorbing polymers. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.07.091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
25
|
Nojoomi A, Tamjid E, Simchi A, Bonakdar S, Stroeve P. Injectable polyethylene glycol-laponite composite hydrogels as articular cartilage scaffolds with superior mechanical and rheological properties. INT J POLYM MATER PO 2016. [DOI: 10.1080/00914037.2016.1182914] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
26
|
Flocculated Laponite–PEG/PEO dispersions with monovalent salt, a SAXS and simulation study. J Colloid Interface Sci 2016; 466:330-42. [DOI: 10.1016/j.jcis.2015.12.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 11/19/2022]
|
27
|
Kishore S, Chen Y, Ravindra P, Bhatia SR. The effect of particle-scale dynamics on the macroscopic properties of disk-shaped colloid–polymer systems. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.06.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
28
|
Lee JH, Kim C, Jung JH. Control of the rheological properties of clay nanosheet hydrogels with a guanidinium-attached calix[4]arene binder. Chem Commun (Camb) 2015; 51:15184-7. [DOI: 10.1039/c5cc06024a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The CNS hydrogels prepared by combining calix[4]arene1with dispersed CNS surrounded with ASSP showed an enhancement of mechanical properties such as viscosity and elasticity.
Collapse
Affiliation(s)
- Ji Ha Lee
- Department of Chemistry and Research Institute of Natural Sciences Gyeongsang National University
- Jinju 660-701
- Korea
| | - Chaelin Kim
- Department of Chemistry and Research Institute of Natural Sciences Gyeongsang National University
- Jinju 660-701
- Korea
| | - Jong Hwa Jung
- Department of Chemistry and Research Institute of Natural Sciences Gyeongsang National University
- Jinju 660-701
- Korea
| |
Collapse
|
29
|
Ye L, Xie Y, Qiu D, Kan Y, Zhang ZD. Particle shape dependence of rheological behavior for colloid-polymer mixtures. CHINESE JOURNAL OF POLYMER SCIENCE 2014. [DOI: 10.1007/s10118-014-1538-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
30
|
Morariu S, Bercea M, Sacarescu L. Tailoring of Clay/Poly(ethylene oxide) Hydrogel Properties by Chitosan Incorporation. Ind Eng Chem Res 2014. [DOI: 10.1021/ie501891t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Simona Morariu
- “Petru Poni” Institute
of Macromolecular Chemistry, 41-A Grigore
Ghica Voda Alley, 700487 Iasi, Romania
| | - Maria Bercea
- “Petru Poni” Institute
of Macromolecular Chemistry, 41-A Grigore
Ghica Voda Alley, 700487 Iasi, Romania
| | - Liviu Sacarescu
- “Petru Poni” Institute
of Macromolecular Chemistry, 41-A Grigore
Ghica Voda Alley, 700487 Iasi, Romania
| |
Collapse
|
31
|
Zulian L, Augusto de Melo Marques F, Emilitri E, Ruocco G, Ruzicka B. Dual aging behaviour in a clay-polymer dispersion. SOFT MATTER 2014; 10:4513-4521. [PMID: 24817524 DOI: 10.1039/c4sm00172a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Clay-polymer compounds have recently attracted increasing attention due to their intriguing physical properties in colloidal science and their rheological non-trivial behaviour in technological applications. Aqueous solutions of Laponite clay spontaneously age from a liquid up to an arrested state of different nature (gel or glass) depending on the colloidal volume fraction and ionic strength. We have investigated, through dynamic light scattering, how the aging dynamics of Laponite dispersions at fixed clay concentration (Cw = 2.0%) is modified by the addition of various amounts of poly(ethylene oxide) (PEO) (CPEO = (0.05 ÷ 0.50) %) at two different molecular weights (Mw = 100 kg mol(-1) and Mw = 200 kg mol(-1)). A surprising and intriguing phenomenon has been observed: the existence of a critical polymer concentration C that discriminates between two different aging dynamics. With respect to pure Laponite systems the aging will be assisted (faster) or hindered (slower) for PEO concentrations respectively lower (CPEO < C) or higher (CPEO > C) than the critical concentration. In this way a control on the aging dynamics of PEO-Laponite systems is obtained. A possible explanation based on the balance of competitive mechanisms related to the progressive saturation of the clay surface by polymers is proposed. This study shows how a real control on the aging speed of the PEO-Laponite system is at hand and renders possible a real control of the complex interparticle interaction potential.
Collapse
Affiliation(s)
- Laura Zulian
- Dipartimento di Scienza dei Materiali, Università degli Studi Milano Bicocca, Via Roberto Cozzi, 53 20125 Milano, Italy.
| | | | | | | | | |
Collapse
|
32
|
Davis JW, Kahl MS, Golden TD. Mechanistic study of cationic dye interactions with clay-polymer dispersions via metachromatic effect, aggregation, and surface charge. J Appl Polym Sci 2014. [DOI: 10.1002/app.40141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- James W. Davis
- Department of Chemistry; University of North Texas; Denton Texas 76203
| | - Michael S. Kahl
- Department of Chemistry; University of North Texas; Denton Texas 76203
| | - Teresa D. Golden
- Department of Chemistry; University of North Texas; Denton Texas 76203
| |
Collapse
|
33
|
Chu CY, Chen MH, Wu ML, Chen HL, Chiu YT, Chen SM, Huang CH. Hierarchical structure and crystal orientation in poly(ethylene oxide)/clay nanocomposite films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2886-2895. [PMID: 24555858 DOI: 10.1021/la4042748] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Water-cast nanocomposite films formed by poly(ethylene oxide) (PEO) and Laponite clay were found to display three characteristic levels of structure with large-scale orientation. The first level with the length scale of ca. 30-50 nm was the clay lamellar bundles, which tended to stack perpendicularly to the film surface. The second level with the characteristic length of 1.8 nm was associated with the alternating stacking of the silicate layers and the PEO chains sandwiched between them. The preferred orientations of these two levels of structure were independent of clay content, solvent removal rate for the film preparation, and the crystallization temperature of the PEO chains situating outside the clay bundles. The third level of structure was characterized by the preferred orientation of the PEO crystalline stems with respect to the surface of the silicate layers. Perpendicular orientation always dominated in the nanocomposite films prepared by slow solvent removal irrespective of crystallization temperature. In the films prepared by fast solvent removal, however, parallel crystal orientation set in as the clay concentration exceeded ca. 33 wt %. The preferred crystal orientation was ascribed to the confinement effect imposed by the clay bundles to the crystallization of the PEO chains situating in the interbundle region. In the films cast by slow solvent removal, the weaker confinement associated with the larger interbundle distance led to perpendicular crystal orientation. When the interbundle distance was reduced to ca. 30 nm in the films prepared by rapid solvent evaporation, the strong confinement directed the crystals to form parallel orientation.
Collapse
Affiliation(s)
- Che-Yi Chu
- Department of Chemical Engineering and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University , Hsin-Chu 30013, Taiwan
| | | | | | | | | | | | | |
Collapse
|
34
|
Wu CJ, Wilker JJ, Schmidt G. Robust and Adhesive Hydrogels from Cross-Linked Poly(ethylene glycol) and Silicate for Biomedical Use. Macromol Biosci 2012; 13:59-66. [DOI: 10.1002/mabi.201200362] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Indexed: 11/06/2022]
|
35
|
Sanna R, Sanna D, Alzari V, Nuvoli D, Scognamillo S, Piccinini M, Lazzari M, Gioffredi E, Malucelli G, Mariani A. Synthesis and characterization of graphene-containing thermoresponsive nanocomposite hydrogels of poly(N
-vinylcaprolactam) prepared by frontal polymerization. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26215] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
36
|
Sun W, Yang Y, Wang T, Huang H, Liu X, Tong Z. Effect of adsorbed poly(ethylene glycol) on the gelation evolution of Laponite suspensions: Aging time-polymer concentration superposition. J Colloid Interface Sci 2012; 376:76-82. [DOI: 10.1016/j.jcis.2012.01.064] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/06/2011] [Accepted: 01/10/2012] [Indexed: 11/26/2022]
|
37
|
Lorthioir C, Khalil M, Wintgens V, Amiel C. Segmental motions of poly(ethylene glycol) chains adsorbed on Laponite platelets in clay-based hydrogels: a NMR investigation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:7859-7871. [PMID: 22512344 DOI: 10.1021/la3010757] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The segmental dynamics of poly(ethylene glycol) (PEG) chains adsorbed on the clay platelets within nanocomposite PEG/Laponite hydrogels was investigated over the tens of microseconds time scale, using combined solution and solid-state NMR approaches. In a first step, the time evolution of the molecular mobility displayed by the PEG chains following the addition to a Laponite aqueous dispersion was monitored during the aggregation of the clay disks and the hydrogel formation, by means of (1)H solution-state NMR. Part of the PEG repeat units were found to get strongly constrained during the gelation process. Comparisons between this time evolution of the PEG local dynamics in the PEG/Laponite/water systems and the increase of the macroscopic storage shear modulus, mainly governed by the assembling of the Laponite disks, indicate that the slowing down of the segmental motions arises from adsorbed PEG repeat units or chain portions strongly constrained between aggregated clay layers. In a second step, after completion of the gelation process, the molecular motions of the adsorbed PEG chains were probed by (1)H solid-state NMR spectroscopy. (1)H double-quantum experiments indicate that the adsorbed PEG repeat units, though reported to be frozen over a few tens of nanoseconds, still display significant reorientational motions over the tens of microseconds time scale. Using a comparison with a model system of amorphized PEG chains, the characteristic frequency of these segmental motions was found to range between 78.0 kHz and 100.7 MHz at 300 K. Interestingly, at this temperature, the level of reorientational motions detected for these adsorbed PEG chain portions was found to be as restricted as the one of bulk amorphous PEG chains, cooled at a slightly lower temperature (about 290 K).
Collapse
Affiliation(s)
- Cédric Lorthioir
- Equipe Systèmes Polymères Complexes, Institut de Chimie et des Matériaux Paris-Est ( UMR 7182 CNRS/Université Paris-Est Créteil ), 2-8 rue Henri Dunant, 94320 Thiais, France.
| | | | | | | |
Collapse
|
38
|
Gaharwar AK, Kishore V, Rivera C, Bullock W, Wu CJ, Akkus O, Schmidt G. Physically crosslinked nanocomposites from silicate-crosslinked PEO: mechanical properties and osteogenic differentiation of human mesenchymal stem cells. Macromol Biosci 2012; 12:779-93. [PMID: 22517665 DOI: 10.1002/mabi.201100508] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 01/30/2012] [Indexed: 01/21/2023]
Abstract
The mechanical and biological properties of silicate-crosslinked PEO nanocomposites are studied. A strong correlation is observed between silicate concentration and mechanical properties. In vitro cell culture studies reveal that an increase in silicate concentration enhances the attachment and proliferation of human mesenchymal stem cells significantly. An upregulation in the expression of osteocalcin on nanocomposites compared to the tissue culture polystyrene control is observed. Together, these results suggest that silicate-based nanocomposites are bioactive and have the potential to be used in a range of biotechnological and biomedical applications such as injectable matrices, biomedical coatings, drug delivery, and regenerative medicine.
Collapse
Affiliation(s)
- Akhilesh K Gaharwar
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-2032, USA.
| | | | | | | | | | | | | |
Collapse
|
39
|
Morariu S, Bercea M. Effect of Temperature and Aging Time on the Rheological Behavior of Aqueous Poly(ethylene glycol)/Laponite RD Dispersions. J Phys Chem B 2011; 116:48-54. [DOI: 10.1021/jp208136g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Simona Morariu
- Petru Poni Institute of Macromolecular Chemistry, 41-A Grigore Ghica Vodǎ Alley, 700487 Iasi, Romania
| | - Maria Bercea
- Petru Poni Institute of Macromolecular Chemistry, 41-A Grigore Ghica Vodǎ Alley, 700487 Iasi, Romania
| |
Collapse
|
40
|
Gaharwar AK, Rivera CP, Wu CJ, Schmidt G. Transparent, elastomeric and tough hydrogels from poly(ethylene glycol) and silicate nanoparticles. Acta Biomater 2011; 7:4139-48. [PMID: 21839864 DOI: 10.1016/j.actbio.2011.07.023] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 06/17/2011] [Accepted: 07/25/2011] [Indexed: 10/17/2022]
Abstract
The structures and mechanical properties of both physically and covalently cross-linked nanocomposite hydrogels made from poly(ethylene glycol) (PEG) and silicate nanoparticles (Laponite RD) are investigated. Injectable nanocomposite precursor solutions can be covalently cross-linked via photopolymerization. The resulting hydrogels are transparent and have interconnected pores, high elongation and toughness. These properties depend on the hydrogel composition, polymer-nanoparticle interactions and degree of cross-linking (both physical and covalent). Covalent cross-linking of polymer chains leads to the formation of an elastic network, whereas physical cross-linking between nanoparticles and polymer chains induces viscoelastic properties. At high deformations covalent bonds may be broken but physical bonds rebuild and to some extent self-heal the overall network structure. Addition of silicate also enhances the bioactivity and adhesiveness of the hydrogel as these materials stick to soft tissue as well as to hard surfaces. In addition, MC3T3-E1 mouse preosteoblast cells readily adhere and spread on nanocomposite hydrogel surfaces. Collectively, the combinations of properties such as elasticity, stiffness, interconnected network, adhesiveness to surfaces and bio-adhesion to cells provide inspiration and opportunities to engineer mechanically strong and elastic tissue matrixes for orthopedic, craniofacial and dental applications.
Collapse
|
41
|
Wu CJ, Gaharwar AK, Chan BK, Schmidt G. Mechanically Tough Pluronic F127/Laponite Nanocomposite Hydrogels from Covalently and Physically Cross-Linked Networks. Macromolecules 2011. [DOI: 10.1021/ma200562k] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Chia-Jung Wu
- Department of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana 47907-2032, United States
| | - Akhilesh K. Gaharwar
- Department of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana 47907-2032, United States
| | - Burke K. Chan
- Department of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana 47907-2032, United States
| | - Gudrun Schmidt
- Department of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana 47907-2032, United States
| |
Collapse
|
42
|
Anisotropic domain growth and complex coacervation in nanoclay-polyelectrolyte solutions. Adv Colloid Interface Sci 2011; 167:12-23. [PMID: 21763636 DOI: 10.1016/j.cis.2011.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 06/14/2011] [Accepted: 06/19/2011] [Indexed: 11/23/2022]
Abstract
In this review, the generalized domain growth in a coacervating solution is discussed. Associative electrostatic interaction between nanoclay (Laponite) and gelatin-A (a polyelectrolyte) is shown to drive complex coacervation at room temperature (25°C). Phase separation kinetics, leading to spontaneous coacervation transition occurring below spinodal temperature (315K) was studied by depolarized dynamic light scattering. Depolarization and axial ratio data clearly revealed that the domains formed of soluble complexes undergo time-dependent anisotropic growth during the initial period of phase separation (t<500s). The equatorial axis of these domains was observed to grow following a power-law behavior: a(t)~t(β) and β=0.25 ± 0.04 independent of quench depth that was not deep. In contrast, the polar axis shrunk with time following: b(t)~t(-δ) and δ=0.15 ± 0.05 independent of quench depth. These domains preferentially grew as oblate ellipsoids during this time. Effect of gravity on domain growth was not observed in our experiments. These results answer the basic issue of binding between discotic colloidal particles and polyelectrolytes in dispersion phase and the resultant phase separation kinetics.
Collapse
|
43
|
Sheibat‐Othman N, Cenacchi‐Pereira A, Santos AMD, Bourgeat‐Lami E. A kinetic investigation of surfactant‐free emulsion polymerization of styrene using laponite clay platelets as stabilizers. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pola.24924] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Nida Sheibat‐Othman
- Université de Lyon, Univ. Lyon 1, CPE Lyon, CNRS, UMR 5007, Laboratoire d'Automatique et de Génie des Procédés (LAGEP), 43, Boulevard du 11 Novembre 1918, F‐69616 Villeurbanne, France
| | - Ana‐Maria Cenacchi‐Pereira
- Université de Lyon, Univ. Lyon 1, CPE Lyon, CNRS, UMR 5265, Laboratoire de Chimie, Catalyse, Polymères et Procédés (C2P2), LCPP group, 43, Boulevard du 11 Novembre 1918, F‐69616, Villeurbanne, France
| | | | - Elodie Bourgeat‐Lami
- Université de Lyon, Univ. Lyon 1, CPE Lyon, CNRS, UMR 5265, Laboratoire de Chimie, Catalyse, Polymères et Procédés (C2P2), LCPP group, 43, Boulevard du 11 Novembre 1918, F‐69616, Villeurbanne, France
| |
Collapse
|
44
|
Schexnailder PJ, Gaharwar AK, Bartlett RL, Seal BL, Schmidt G. Tuning cell adhesion by incorporation of charged silicate nanoparticles as cross-linkers to polyethylene oxide. Macromol Biosci 2011; 10:1416-23. [PMID: 20602416 DOI: 10.1002/mabi.201000053] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Controlling cell adhesion on a biomaterial surface is associated with the long-term efficacy of an implanted material. Here we connect the material properties of nanocomposite films made from PEO physically cross-linked with layered silicate nanoparticles (Laponite) to cellular adhesion. Fibroblast cells do not adhere to pure PEO, but they attach to silicate containing nanocomposites. Under aqueous conditions, the films swell and the degree of swelling depends on the nanocomposite composition and film structure. Higher PEO compositions do not support cell proliferation due to little exposed silicate surfaces. Higher silicate compositions do allow significant cell proliferation and spreading. These bio-nanocomposites have potential for the development of biomedical materials that can control cellular adhesion.
Collapse
Affiliation(s)
- Patrick J Schexnailder
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | | | | | | | | |
Collapse
|
45
|
Sun W, Yang Y, Wang T, Liu X, Wang C, Tong Z. Large amplitude oscillatory shear rheology for nonlinear viscoelasticity in hectorite suspensions containing poly(ethylene glycol). POLYMER 2011. [DOI: 10.1016/j.polymer.2011.01.048] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
46
|
Morikubo S, Sekine Y, Ikeda-Fukazawa T. Structure and dynamics of water in mixed solutions including laponite and PEO. J Chem Phys 2011; 134:044905. [DOI: 10.1063/1.3533233] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
47
|
Boucenna I, Royon L, Colinart P, Guedeau-Boudeville MA, Mourchid A. Structure and thermorheology of concentrated pluronic copolymer micelles in the presence of laponite particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:14430-14436. [PMID: 20726609 DOI: 10.1021/la102744c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Small-angle neutron scattering and thermorheology techniques are used to investigate in detail the effect of laponite particles in aqueous solutions of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), PEO-PPO-PEO, block copolymers in the concentrated regime. At high polymer concentration or temperature, the micellar solutions exhibit a phase transition from fluid to crystal due to crowding of the micelles. The addition of laponite is found to disturb this phase transition. The adsorption of the copolymer unimers onto laponite in large amounts describes these findings. It is shown that the preferred adsorption of the copolymer chains results in a sufficient increase in free volume for the remaining micelles to yield the observed enhancement of the structural disorder.
Collapse
Affiliation(s)
- Imane Boucenna
- Matière et Systèmes Complexes, UMR 7057 CNRS and Université Paris Diderot, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France.
| | | | | | | | | |
Collapse
|
48
|
Hu X, Wang T, Xiong L, Wang C, Liu X, Tong Z. Preferential adsorption of poly(ethylene glycol) on hectorite clay and effects on poly(N-isopropylacrylamide)/hectorite nanocomposite hydrogels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:4233-4238. [PMID: 19994842 DOI: 10.1021/la903298n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Poly(N-isopropylacrylamide)/Laponite nanocomposite hydrogel (NC gel) was synthesized via in situ polymerization in the Laponite suspension containing PEG. The adsorption of PEG on Laponite platelets was characterized by zeta-potential, which decreased with the PEG adsorption. The tensile strength decreased and elongation at break increased with increasing PEG concentration. The effective network chain density of PNIPAm/Laponite NC gels determined from the equilibrium modulus G(e) decreased upon adsorption of PEG on the Laponite. All of these results revealed the preferential adsorption of PEG on the Laponite platelets occupying the active sites for the PNIPAm chain anchoring, which hindered their cross-linking effect in the NC gels. However, the temperature sensitive swelling behavior still remained in the PNIPAm/Laponite NC gels containing PEG with higher swelling volume below the LCST due to the lower cross-linker density. By adjusting the amount of added PEG, we can easily control the properties of the PNIPAm/Laponite NC gels.
Collapse
Affiliation(s)
- Xiaobo Hu
- Research Institute of Materials Science, South China University of Technology, Guangzhou 510640, China
| | | | | | | | | | | |
Collapse
|
49
|
Loizou E, Porcar L, Schexnailder P, Schmidt G, Butler P. Shear-Induced Nanometer and Micrometer Structural Responses in Nanocomposite Hydrogels. Macromolecules 2009. [DOI: 10.1021/ma9019448] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elena Loizou
- Louisiana State University, Baton Rouge, Louisiana 70803
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899
- University of Cyprus, Nicosia, Cyprus
| | - Lionel Porcar
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899
- University of Maryland, College Park, Maryland 20742
- Institue Laue Langevin, Grenoble, France
| | | | | | - Paul Butler
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899
| |
Collapse
|
50
|
De Lisi R, Lazzara G, Lombardo R, Milioto S, Muratore N, Turco Liveri ML. Adsorption of triblock copolymers and their homopolymers at laponite clay/solution interface. Role played by the copolymer nature. Phys Chem Chem Phys 2009; 7:3994-4001. [PMID: 19810330 DOI: 10.1039/b510891h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The adsorption thermodynamics of copolymers, based on ethylene oxide (EO) and propylene oxide (PO) units, at the laponite (RD) clay/liquid interface was determined at 298 K. The copolymer nature was tuned at molecular level by changing the hydrophilicity, the architecture and the molecular weight (Mw) keeping constant the EO/PO ratio. Polyethylene (PEGs) and polypropylene (PPGs) glycols with varying Mw and their mixture were also investigated to discriminate the role of the EO and the PO segments in the adsorption process. Enthalpies of transfer of RD, at fixed concentration, from water to the aqueous macromolecule solutions as functions of the macromolecule molality were determined. They were treated quantitatively by means of a model based on two equilibria: (1) one-to-one binding between the macromolecule and the site on the solid and (2) two-to-one binding following which one macromolecule interacts with another one adsorbed onto the solid. The good agreement between the equilibrium constants obtained from calorimetry and those determined from kinetic experiments confirmed the reliability of the experimental and theoretical approaches. Almost all of the systems investigated are highlighted by the one-to-one binding; the L35 and 10R5 systems present both equilibria. The insights provided by the thermodynamics of adsorption of their homopolymers onto RD were fruitful in obtaining detailed information on the nature of the forces involved between RD and the copolymers. The data obtained in the present work clearly evidenced that for comparable polymer Mw, PPG is more suitable in building up a steric barrier around the RD particles and, indeed, exhibits several advantages and no drawbacks. Moreover, the parent copolymers may properly functionalize the RD surface by exploiting both their high affinity to the solid surface and the ability to self-assemble onto it as L35 and 10R5 clearly showed.
Collapse
Affiliation(s)
- R De Lisi
- Dipartimento di Chimica Fisica "F. Accascina", Università degli Studi di Palermo, Viale delle Scienze, Parco D'Orleans II, 90128 Palermo, Italy
| | | | | | | | | | | |
Collapse
|