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Smith D, Wilson JW, Shivkumar S, Rigneault H, Bartels RA. Low-Frequency Coherent Raman Imaging Robust to Optical Scattering. CHEMICAL & BIOMEDICAL IMAGING 2024; 2:584-591. [PMID: 39211790 PMCID: PMC11351428 DOI: 10.1021/cbmi.4c00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 06/11/2024] [Accepted: 06/14/2024] [Indexed: 09/04/2024]
Abstract
We demonstrate low-frequency interferometric impulsive stimulated Raman scattering (ISRS) imaging with high robustness to distortions by optical scattering. ISRS is a pump-probe coherent Raman spectroscopy that can capture Raman vibrational spectra. Recording of ISRS spectra requires isolation of a probe pulse from the pump pulse. While this separation is simple in nonscattering specimens, such as liquids, scattering leads to significant pump pulse contamination and prevents the extraction of a Raman spectrum. We introduce a robust method for ISRS microscopy that works in complex scattering samples. High signal-to-noise ISRS spectra are obtained even when the pump and probe pulses pass through many scattering layers.
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Affiliation(s)
- David
R. Smith
- Biomedical
Imaging, Morgridge Institute for Research, Madison, Wisconsin 53715, United States
| | - Jesse W. Wilson
- Department
of Electrical Engineering, Colorado State
University, Fort Collins, Colorado 80523, United States
- School
of Biomedical Engineering, Colorado State
University, Fort Collins, Colorado 80523, United States
| | - Siddarth Shivkumar
- Aix
Marseille University, CNRS, Centrale Med, Institut Fresnel, Marseille 13397, France
- Department
of Physics, University of Ottawa, Ottawa, Ontario K1N6N5, Canada
| | - Hervé Rigneault
- Aix
Marseille University, CNRS, Centrale Med, Institut Fresnel, Marseille 13397, France
| | - Randy A. Bartels
- Biomedical
Imaging, Morgridge Institute for Research, Madison, Wisconsin 53715, United States
- Department
of Biomedical Engineering, University of
Wisconsin, Madison, Wisconsin 53715, United States
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2
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Bergman MJ, Garting T, Schurtenberger P, Stradner A. Experimental Evidence for a Cluster Glass Transition in Concentrated Lysozyme Solutions. J Phys Chem B 2019; 123:2432-2438. [PMID: 30785749 PMCID: PMC6550439 DOI: 10.1021/acs.jpcb.8b11781] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Lysozyme
is known to form equilibrium clusters at pH ≈ 7.8
and at low ionic strength as a result of a mixed potential. While
this cluster formation and the related dynamic and static structure
factors have been extensively investigated, its consequences on the
macroscopic dynamic behavior expressed by the zero shear viscosity
η0 remain controversial. Here we present results
from a systematic investigation of η0 using two complementary
passive microrheology techniques, dynamic light scattering based tracer
microrheology, and multiple particle tracking using confocal microscopy.
The combination of these techniques with a simple but effective evaporation
approach allows for reaching concentrations close to and above the
arrest transition in a controlled and gentle way. We find a strong
increase of η0 with increasing volume fraction ϕ
with an apparent divergence at ϕ ≈ 0.35, and unambiguously
demonstrate that this is due to the existence of an arrest transition
where a cluster glass forms. These findings demonstrate the power
of tracer microrheology to investigate complex fluids, where weak
temporary bonds and limited sample volumes make measurements with
classical rheology challenging.
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Affiliation(s)
- Maxime J Bergman
- Division of Physical Chemistry, Department of Chemistry , Lund University , PO Box 124, SE-22100 Lund , Sweden
| | - Tommy Garting
- Division of Physical Chemistry, Department of Chemistry , Lund University , PO Box 124, SE-22100 Lund , Sweden
| | - Peter Schurtenberger
- Division of Physical Chemistry, Department of Chemistry , Lund University , PO Box 124, SE-22100 Lund , Sweden.,LINXS - Lund Institute of advanced Neutron and X-ray Science , SE-22100 Lund , Sweden
| | - Anna Stradner
- Division of Physical Chemistry, Department of Chemistry , Lund University , PO Box 124, SE-22100 Lund , Sweden.,LINXS - Lund Institute of advanced Neutron and X-ray Science , SE-22100 Lund , Sweden
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3
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Kotula AP, Migler KB. Evaluating models for polycaprolactone crystallization via simultaneous rheology and Raman spectroscopy. JOURNAL OF RHEOLOGY 2018; 62:343-356. [PMID: 29628538 PMCID: PMC5885807 DOI: 10.1122/1.5008381] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The crystallization of a polymer melt is characterized by dramatic structural and mechanical changes that significantly impact the processing conditions used to generate industrially-relevant products. Relationships between crystallinity and rheology are necessary to simulate and monitor the effect of processing conditions on the properties of the final product. However, separate measurements of crystallinity and rheology are difficult to correlate due to differences in sample history, geometry, and temperature. Recently, we have developed a rheo-Raman microscope for simultaneous rheology, Raman spectroscopy, and polarized reflection-mode optical measurements of soft materials, which allows for quantitative crystallinity measurements through features in the Raman spectrum. In this work, we apply this technique to monitor the isothermal crystallization of polycaprolactone to probe the relationship between structure, crystallinity, and rheology. Both crystallinity and the shear modulus vary over comparable timescales, but the birefringence increases much earlier in the crystallization process. We directly plot rheological parameters as a function of crystallinity to probe a range of suspension-based and empirical models relating the complex modulus to crystallinity, and we find that the previously developed models cannot describe the crystallinity-modulus relationship over the crystallization process. By developing a suspension-based model we can fit the complex modulus over the crystallization range. The crystallization process is characterized by a critical percolation fraction and a single scaling exponent.
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4
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Sobisch T, Lerche D. Separation behaviour of particles in biopolymer solutions in dependence on centrifugal acceleration: Investigation of slow structuring processes in formulations. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2017.07.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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5
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Krajina BA, Tropini C, Zhu A, DiGiacomo P, Sonnenburg JL, Heilshorn SC, Spakowitz AJ. Dynamic Light Scattering Microrheology Reveals Multiscale Viscoelasticity of Polymer Gels and Precious Biological Materials. ACS CENTRAL SCIENCE 2017; 3:1294-1303. [PMID: 29296670 PMCID: PMC5746858 DOI: 10.1021/acscentsci.7b00449] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Indexed: 05/22/2023]
Abstract
The development of experimental techniques capable of probing the viscoelasticity of soft materials over a broad range of time scales is essential to uncovering the physics that governs their behavior. In this work, we develop a microrheology technique that requires only 12 μL of sample and is capable of resolving dynamic behavior ranging in time scales from 10-6 to 10 s. Our approach, based on dynamic light scattering in the single-scattering limit, enables the study of polymer gels and other soft materials over a vastly larger hierarchy of time scales than macrorheology measurements. Our technique captures the viscoelastic modulus of polymer hydrogels with a broad range of stiffnesses from 10 to 104 Pa. We harness these capabilities to capture hierarchical molecular relaxations in DNA and to study the rheology of precious biological materials that are impractical for macrorheology measurements, including decellularized extracellular matrices and intestinal mucus. The use of a commercially available benchtop setup that is already available to a variety of soft matter researchers renders microrheology measurements accessible to a broader range of users than existing techniques, with the potential to reveal the physics that underlies complex polymer hydrogels and biological materials.
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Affiliation(s)
- Brad A. Krajina
- Department
of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Carolina Tropini
- Department
of Microbiology and Immunology, Stanford
University School of Medicine, Stanford, California 94305, United States
| | - Audrey Zhu
- Department
of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Philip DiGiacomo
- Department
of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - Justin L. Sonnenburg
- Department
of Microbiology and Immunology, Stanford
University School of Medicine, Stanford, California 94305, United States
| | - Sarah C. Heilshorn
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Andrew J. Spakowitz
- Department
of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
- Biophysics
Program, Stanford University, Stanford, California 94305, United States
- E-mail:
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6
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Abstract
Microrheology provides a technique to probe the local viscoelastic properties and dynamics of soft materials at the microscopic level by observing the motion of tracer particles embedded within them. It is divided into passive and active microrheology according to the force exerted on the embedded particles. Particles are driven by thermal fluctuations in passive microrheology, and the linear viscoelasticity of samples can be obtained on the basis of the generalized Stokes-Einstein equation. In active microrheology, tracer particles are controlled by external forces, and measurements can be extended to the nonlinear regime. Microrheology techniques have many advantages such as the need for only small sample amounts and a wider measurable frequency range. In particular, microrheology is able to examine the spatial heterogeneity of samples at the microlevel, which is not possible using traditional rheology. Therefore, microrheology has considerable potential for studying the local mechanical properties and dynamics of soft matter, particularly complex fluids, including solutions, dispersions, and other colloidal systems. Food products such as emulsions, foams, or gels are complex fluids with multiple ingredients and phases. Their macroscopic properties, such as stability and texture, are closely related to the structure and mechanical properties at the microlevel. In this article, the basic principles and methods of microrheology are reviewed, and the latest developments and achievements of microrheology in the field of food science are presented.
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Affiliation(s)
- Nan Yang
- Glyn O. Phillips Hydrocolloid Research Centre, School of Food and Biological Engineering, and Hubei Collaborative Innovation Centre for Industrial Fermentation, Hubei University of Technology, Wuhan 430068, China;
| | - Ruihe Lv
- Glyn O. Phillips Hydrocolloid Research Centre, School of Food and Biological Engineering, and Hubei Collaborative Innovation Centre for Industrial Fermentation, Hubei University of Technology, Wuhan 430068, China;
| | - Junji Jia
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Katsuyoshi Nishinari
- Glyn O. Phillips Hydrocolloid Research Centre, School of Food and Biological Engineering, and Hubei Collaborative Innovation Centre for Industrial Fermentation, Hubei University of Technology, Wuhan 430068, China;
| | - Yapeng Fang
- Glyn O. Phillips Hydrocolloid Research Centre, School of Food and Biological Engineering, and Hubei Collaborative Innovation Centre for Industrial Fermentation, Hubei University of Technology, Wuhan 430068, China;
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7
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Kotula AP, Meyer MW, De Vito F, Plog J, Hight Walker AR, Migler KB. The rheo-Raman microscope: Simultaneous chemical, conformational, mechanical, and microstructural measures of soft materials. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:105105. [PMID: 27802720 DOI: 10.1063/1.4963746] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The design and performance of an instrument capable of simultaneous Raman spectroscopy, rheology, and optical microscopy are described. The instrument couples a Raman spectrometer and optical microscope to a rotational rheometer through an optically transparent base, and the resulting simultaneous measurements are particularly advantageous in situations where flow properties vary due to either chemical or conformational changes in molecular structure, such as in crystallization, melting, gelation, or curing processes. Instrument performance is demonstrated on two material systems that show thermal transitions. First, we perform steady state rotational tests, Raman spectroscopy, and polarized reflection microscopy during a melting transition in a cosmetic emulsion. Second, we perform small amplitude oscillatory shear measurements along with Raman spectroscopy and polarized reflection microscopy during crystallization of a high density polyethylene. The instrument can be applied to study structure-property relationships in a variety of soft materials including thermoset resins, liquid crystalline materials, colloidal suspensions undergoing sol-gel processes, and biomacromolecules. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.
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Affiliation(s)
- Anthony P Kotula
- Materials Science and Engineering Division, NIST, Gaithersburg, Maryland 20899, USA
| | | | | | - Jan Plog
- Thermo Fisher Scientific, Karlsruhe D-76227, Germany
| | | | - Kalman B Migler
- Materials Science and Engineering Division, NIST, Gaithersburg, Maryland 20899, USA
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8
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Barnett GV, Qi W, Amin S, Lewis EN, Razinkov VI, Kerwin BA, Liu Y, Roberts CJ. Structural Changes and Aggregation Mechanisms for Anti-Streptavidin IgG1 at Elevated Concentration. J Phys Chem B 2015; 119:15150-63. [PMID: 26563591 DOI: 10.1021/acs.jpcb.5b08748] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Non-native protein aggregation may occur during manufacturing and storage of protein therapeutics, and this may decrease drug efficacy or jeopardize patient safety. From a regulatory perspective, changes in higher order structure due to aggregation are of particular interest but can be difficult to monitor directly at elevated protein concentrations. The present report focuses on non-native aggregation of antistreptavidin (AS) IgG1 at 30 mg/mL under solution conditions that prior work at dilute concentrations (e.g., 1 mg/mL) indicated would result in different aggregation mechanisms. Time-dependent aggregation and structural changes were monitored in situ with dynamic light scattering, small-angle neutron scattering, and Raman scattering and ex situ with far-UV circular dichroism and second-derivative UV spectroscopy. The effects of adding 0.15 M (∼5 w/w %) sucrose were also assessed. The addition of sucrose decreased monomer loss rates but did not change protein-protein interactions, aggregation mechanism(s), or aggregate structure and morphology. Consistent with prior results, altering the pD or salt concentration had the primary effect of changing the aggregation mechanism. Overall, the results provide a comparison of aggregate structure and morphology created via different growth mechanisms using orthogonal techniques and show that the techniques agree at least qualitatively. Interestingly, AS-IgG1 aggregates created at pD 5.3 with no added salt formed the smallest aggregates but had the largest structural changes compared to other solution conditions. The observation that the larger aggregates were also those with less structural perturbation compared to folded AS-IgG1 might be expected to extend to other proteins if the same strong electrostatic repulsions that mediate aggregate growth also mediate structural changes of the constituent proteins within aggregates.
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Affiliation(s)
- Gregory V Barnett
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 19716, United States
| | - Wei Qi
- Malvern Biosciences Incorporated, Columbia, Maryland 21046, United States
| | - Samiul Amin
- Malvern Biosciences Incorporated, Columbia, Maryland 21046, United States
| | - E Neil Lewis
- Malvern Biosciences Incorporated, Columbia, Maryland 21046, United States
| | - Vladimir I Razinkov
- Drug Product Development, Amgen Incorporated, Seattle, Washington 98119, United States
| | - Bruce A Kerwin
- Drug Product Development, Amgen Incorporated, Seattle, Washington 98119, United States
| | - Yun Liu
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 19716, United States.,Center for Neutron Science, National Institutes of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Christopher J Roberts
- Department of Chemical and Biomolecular Engineering, University of Delaware , Newark, Delaware 19716, United States
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9
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Blake S, Amin S, Qi W, Majumdar M, Lewis EN. Colloidal Stability & Conformational Changes in β-Lactoglobulin: Unfolding to Self-Assembly. Int J Mol Sci 2015; 16:17719-33. [PMID: 26247930 PMCID: PMC4581217 DOI: 10.3390/ijms160817719] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 11/16/2022] Open
Abstract
A detailed understanding of the mechanism of unfolding, aggregation, and associated rheological changes is developed in this study for β-Lactoglobulin at different pH values through concomitant measurements utilizing dynamic light scattering (DLS), optical microrheology, Raman spectroscopy, and differential scanning calorimetry (DSC). The diffusion interaction parameter kD emerges as an accurate predictor of colloidal stability for this protein consistent with observed aggregation trends and rheology. Drastic aggregation and gelation were observed at pH 5.5. Under this condition, the protein's secondary and tertiary structures changed simultaneously. At higher pH (7.0 and 8.5), oligomerizaton with no gel formation occurred. For these solutions, tertiary structure and secondary structure transitions were sequential. The low frequency Raman data, which is a good indicator of hydrogen bonding and structuring in water, has been shown to exhibit a strong correlation with the rheological evolution with temperature. This study has, for the first time, demonstrated that this low frequency Raman data, in conjunction with the DSC endotherm, can be been utilized to deconvolve protein unfolding and aggregation/gelation. These findings can have important implications for the development of protein-based biotherapeutics, where the formulation viscosity, aggregation, and stability strongly affects efficacy or in foods where protein structuring is critical for functional and sensory performance.
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Affiliation(s)
- Steven Blake
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - Samiul Amin
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - Wei Qi
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - Madhabi Majumdar
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - E Neil Lewis
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
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10
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Barnett GV, Qi W, Amin S, Neil Lewis E, Roberts CJ. Aggregate structure, morphology and the effect of aggregation mechanisms on viscosity at elevated protein concentrations. Biophys Chem 2015; 207:21-9. [PMID: 26284891 DOI: 10.1016/j.bpc.2015.07.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/07/2015] [Accepted: 07/07/2015] [Indexed: 01/04/2023]
Abstract
Non-native aggregation is a common issue in a number of degenerative diseases and during manufacturing of protein-based therapeutics. There is a growing interest to monitor protein stability at intermediate to high protein concentrations, which are required for therapeutic dosing of subcutaneous injections. An understanding of the impact of protein structural changes and interactions on the protein aggregation mechanisms and resulting aggregate size and morphology may lead to improved strategies to reduce aggregation and solution viscosity. This report investigates non-native aggregation of a model protein, α-chymotrypsinogen, under accelerated conditions at elevated protein concentrations. Far-UV circular dichroism and Raman scattering show structural changes during aggregation. Size exclusion chromatography and laser light scattering are used to monitor the progression of aggregate growth and monomer loss. Monomer loss is concomitant with increased β-sheet structures as monomers are added to aggregates, which illustrate a transition from a native monomeric state to an aggregate state. Aggregates grow predominantly through monomer-addition, resulting in a semi-flexible polymer morphology. Analysis of aggregation growth kinetics shows that pH strongly affects the characteristic timescales for nucleation (τn) and growth (τg), while the initial protein concentration has only minor effects on τn or τg. Low-shear viscosity measurements follow a common scaling relationship between average aggregate molecular weight (Mw(agg)) and concentration (σ), which is consistent with semi-dilute polymer-solution theory. The results establish a link between aggregate growth mechanisms, which couple Mw(agg) and σ, to increases in solution viscosity even at these intermediate protein concentrations (less than 3w/v %).
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Affiliation(s)
- Gregory V Barnett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA
| | - Wei Qi
- Malvern Biosciences Inc., Columbia, MD 21046, USA
| | - Samiul Amin
- Malvern Biosciences Inc., Columbia, MD 21046, USA
| | - E Neil Lewis
- Malvern Biosciences Inc., Columbia, MD 21046, USA
| | - Christopher J Roberts
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA.
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11
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Amin S, Blake S, Kennel RC, Lewis EN. Revealing New Structural Insights from Surfactant Micelles through DLS, Microrheology and Raman Spectroscopy. MATERIALS 2015. [PMCID: PMC5455709 DOI: 10.3390/ma8063754] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The correlation between molecular changes and microstructural evolution of rheological properties has been demonstrated for the first time in a mixed anionic/zwitterionic surfactant-based wormlike micellar system. Utilizing a novel combination of DLS-microrheology and Raman Spectroscopy, the effect of electrostatic screening on these properties of anionic (SLES) and zwitterionic (CapB) surfactant mixtures was studied by modulating the NaCl concentration. As Raman Spectroscopy delivers information about the molecular structure and DLS-microrheology characterizes viscoelastic properties, the combination of data delivered allows for a deeper understanding of the molecular changes underlying the viscoelastic ones. The high frequency viscoelastic response obtained through DLS-microrheology has shown the persistence of the Maxwell fluid response for low viscosity solutions at high NaCl concentrations. The intensity of the Raman band at 170 cm−1 exhibits very strong correlation with the viscosity variation. As this Raman band is assigned to hydrogen bonding, its variation with NaCl concentration additionally indicates differences in water structuring due to potential microstructural differences at low and high NaCl concentrations. The microstructural differences at low and high NaCl concentrations are further corroborated by persistence of a slow mode at the higher NaCl concentrations as seen through DLS measurements. The study illustrates the utility of the combined DLS, DLS-optical microrheology and Raman Spectroscopy in providing new molecular structural insights into the self-assembly process in complex fluids.
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Affiliation(s)
- Samiul Amin
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA; E-Mails: (S.B.); (E.N.L.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-443-878-1325
| | - Steven Blake
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA; E-Mails: (S.B.); (E.N.L.)
| | - Rachel C. Kennel
- Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St., Newark, DE 19716, USA; E-Mail:
| | - E. Neil Lewis
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA; E-Mails: (S.B.); (E.N.L.)
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