51
|
Skoropata E, Nichols J, Ok JM, Chopdekar RV, Choi ES, Rastogi A, Sohn C, Gao X, Yoon S, Farmer T, Desautels RD, Choi Y, Haskel D, Freeland JW, Okamoto S, Brahlek M, Lee HN. Interfacial tuning of chiral magnetic interactions for large topological Hall effects in LaMnO 3/SrIrO 3 heterostructures. SCIENCE ADVANCES 2020; 6:eaaz3902. [PMID: 32923583 PMCID: PMC7455502 DOI: 10.1126/sciadv.aaz3902] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 05/22/2020] [Indexed: 05/23/2023]
Abstract
Chiral interactions in magnetic systems can give rise to rich physics manifested, for example, as nontrivial spin textures. The foremost interaction responsible for chiral magnetism is the Dzyaloshinskii-Moriya interaction (DMI), resulting from inversion symmetry breaking in the presence of strong spin-orbit coupling. However, the atomistic origin of DMIs and their relationship to emergent electrodynamic phenomena, such as topological Hall effect (THE), remain unclear. Here, we investigate the role of interfacial DMIs in 3d-5d transition metal-oxide-based LaMnO3/SrIrO3 superlattices on THE from a chiral spin texture. By additively engineering the interfacial inversion symmetry with atomic-scale precision, we directly link the competition between interfacial collinear ferromagnetic interactions and DMIs to an enhanced THE. The ability to control the DMI and resulting THE points to a pathway for harnessing interfacial structures to maximize the density of chiral spin textures useful for developing high-density information storage and quantum magnets for quantum information science.
Collapse
Affiliation(s)
- Elizabeth Skoropata
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - John Nichols
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jong Mok Ok
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Rajesh V. Chopdekar
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Eun Sang Choi
- National High Field Magnet Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Ankur Rastogi
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Changhee Sohn
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xiang Gao
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Sangmoon Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Thomas Farmer
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Ryan D. Desautels
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yongseong Choi
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Daniel Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - John W. Freeland
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Satoshi Okamoto
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Matthew Brahlek
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Ho Nyung Lee
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| |
Collapse
|
52
|
Esteban Florez FL, Trofimov AA, Ievlev A, Qian S, Rondinone AJ, Khajotia SS. Advanced characterization of surface-modified nanoparticles and nanofilled antibacterial dental adhesive resins. Sci Rep 2020; 10:9811. [PMID: 32555360 PMCID: PMC7299952 DOI: 10.1038/s41598-020-66819-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/21/2020] [Indexed: 11/30/2022] Open
Abstract
Nanotechnology can improve the performance of dental polymers. The objective of this study was to modify the surfaces of nanoparticles with silanes and proteins, characterize nanoparticles' agglomeration levels and interfaces between nanoparticles and the polymeric matrix. Undoped (n-TiO2), nitrogen-doped (N_TiO2) and nitrogen-fluorine co-doped titanium dioxide nanoparticles (NF_TiO2) were synthesized and subjected to surface modification procedures in preparation for Small-Angle X-Ray Scattering (SAXS) and Small-Angle Neutron Scattering (SANS) characterizations. Experimental adhesives were manually synthesized by incorporating 20% (v/v) of n-TiO2, N_TiO2 or NF_TiO2 (as-synthesized or surface-modified) into OptiBond Solo Plus (OPTB). Specimens (n = 15/group; d = 6.0 mm, t = 0.5 mm) of OPTB and experimental adhesives were characterized using Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), 2-D ToF-SIMS chemical imaging and SANS. SAXS results indicated that surface-modified nanoparticles displayed higher scattering intensities in a particle-size dependent manner. ToF-SIMS results demonstrated that nanoparticles' incorporation did not adversely impact the parental polymer. 2-D ToF-SIMS chemical imaging demonstrated the distribution of Ti+ and confirmed nitrogen-doping levels. SANS results confirmed nanoparticles' functionalization and revealed the interfaces between nanoparticles and the polymer matrix. Metaloxide nanoparticles were successfully fabricated, incorporated and covalently functionalized in a commercial dental adhesive resin, thereby supporting the utilization of nanotechnology in dentistry.
Collapse
Affiliation(s)
- Fernando Luis Esteban Florez
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, Oklahoma, 73117, USA.
| | - Artem A Trofimov
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Anton Ievlev
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Shuo Qian
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee, 37831, USA
| | - Adam Justin Rondinone
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Sharukh Soli Khajotia
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, Oklahoma, 73117, USA
| |
Collapse
|
53
|
Ade-Browne C, Mirzamani M, Dawn A, Qian S, Thompson RG, Glenn RW, Kumari H. Effect of ethoxylation and lauryl alcohol on the self-assembly of sodium laurylsulfate: Significant structural and rheological transformation. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
54
|
Astete CE, De Mel JU, Gupta S, Noh Y, Bleuel M, Schneider GJ, Sabliov CM. Lignin-Graft-Poly(lactic- co-glycolic) Acid Biopolymers for Polymeric Nanoparticle Synthesis. ACS OMEGA 2020; 5:9892-9902. [PMID: 32391476 PMCID: PMC7203963 DOI: 10.1021/acsomega.0c00168] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/09/2020] [Indexed: 05/13/2023]
Abstract
A lignin-graft-poly(lactic-co-glycolic) acid (PLGA) biopolymer was synthesized with two types of lignin (LGN), alkaline lignin (ALGN) and sodium lignosulfonate (SLGN), at different (A/S)LGN/PLGA ratios (1:2, 1:4, and 1:6 w/w). 1H NMR and Fourier-transform infrared spectroscopy (FT-IR) confirmed the conjugation of PLGA to LGN. The (A/S)LGN-graft-PLGA biopolymers were used to form nanodelivery systems suitable for entrapment and delivery of drugs for disease treatment. The LGN-graft-PLGA NPs were generally small (100-200 nm), increased in size with the amount of PLGA added, monodisperse, and negatively charged (-48 to -60 mV). Small-angle scattering data showed that particles feature a relatively smooth surface and a compact spherical structure with a distinct core and a shell. The core size and shell thickness varied with the LGN/PLGA ratio, and at a 1:6 ratio, the particles deviated from the core-shell structure to a complex internal structure. The newly developed (A/S)LGN-graft-PLGA NPs are proposed as a potential delivery system for applications in biopharmaceutical, food, and agricultural sectors.
Collapse
Affiliation(s)
- Carlos E. Astete
- Biological
& Agricultural Engineering Department, Louisiana State University and LSU Ag Center, 149 E. B. Doran Bldg., Baton Rouge, Louisiana 70803, United States
| | - Judith U. De Mel
- Department
of Chemistry, Louisiana State University, Baton Rouge, 331 Chemistry
and Materials Bldg, Louisiana 70803, United States
| | - Sudipta Gupta
- Department
of Chemistry, Louisiana State University, Baton Rouge, 331 Chemistry
and Materials Bldg, Louisiana 70803, United States
| | - YeRim Noh
- Department
of Chemistry, Louisiana State University, Baton Rouge, 331 Chemistry
and Materials Bldg, Louisiana 70803, United States
| | - Markus Bleuel
- A235
NIST Center for Neutron Research National Institute of Standards and
Technology, Gaithersburg, Maryland 20988-8562, United States
| | - Gerald J. Schneider
- Department
of Chemistry, Louisiana State University, Baton Rouge, 331 Chemistry
and Materials Bldg, Louisiana 70803, United States
| | - Cristina M. Sabliov
- Biological
& Agricultural Engineering Department, Louisiana State University and LSU Ag Center, 149 E. B. Doran Bldg., Baton Rouge, Louisiana 70803, United States
| |
Collapse
|
55
|
Colossal oxygen vacancy formation at a fluorite-bixbyite interface. Nat Commun 2020; 11:1371. [PMID: 32170073 PMCID: PMC7069997 DOI: 10.1038/s41467-020-15153-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 02/16/2020] [Indexed: 11/13/2022] Open
Abstract
Oxygen vacancies in complex oxides are indispensable for information and energy technologies. There are several means to create oxygen vacancies in bulk materials. However, the use of ionic interfaces to create oxygen vacancies has not been fully explored. Herein, we report an oxide nanobrush architecture designed to create high-density interfacial oxygen vacancies. An atomically well-defined (111) heterointerface between the fluorite CeO2 and the bixbyite Y2O3 is found to induce a charge modulation between Y3+ and Ce4+ ions enabled by the chemical valence mismatch between the two elements. Local structure and chemical analyses, along with theoretical calculations, suggest that more than 10% of oxygen atoms are spontaneously removed without deteriorating the lattice structure. Our fluorite–bixbyite nanobrush provides an excellent platform for the rational design of interfacial oxide architectures to precisely create, control, and transport oxygen vacancies critical for developing ionotronic and memristive devices for advanced energy and neuromorphic computing technologies. Oxygen vacancies can impart interesting properties in complex oxides, but specific architectures designed to create high-density oxygen vacancies are largely unknown. Here the authors report a fluorite-bixbyite nanobrush platform to tune interfacial oxygen and show that an atomically well-defined heterointerface can induce charge modulation.
Collapse
|
56
|
Archibald RK, Doucet M, Johnston T, Young SR, Yang E, Heller WT. Classifying and analyzing small-angle scattering data using weighted k nearest neighbors machine learning techniques. J Appl Crystallogr 2020. [DOI: 10.1107/s1600576720000552] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A consistent challenge for both new and expert practitioners of small-angle scattering (SAS) lies in determining how to analyze the data, given the limited information content of said data and the large number of models that can be employed. Machine learning (ML) methods are powerful tools for classifying data that have found diverse applications in many fields of science. Here, ML methods are applied to the problem of classifying SAS data for the most appropriate model to use for data analysis. The approach employed is built around the method of weighted k nearest neighbors (wKNN), and utilizes a subset of the models implemented in the SasView package (https://www.sasview.org/) for generating a well defined set of training and testing data. The prediction rate of the wKNN method implemented here using a subset of SasView models is reasonably good for many of the models, but has difficulty with others, notably those based on spherical structures. A novel expansion of the wKNN method was also developed, which uses Gaussian processes to produce local surrogate models for the classification, and this significantly improves the classification accuracy. Further, by integrating a stochastic gradient descent method during post-processing, it is possible to leverage the local surrogate model both to classify the SAS data with high accuracy and to predict the structural parameters that best describe the data. The linking of data classification and model fitting has the potential to facilitate the translation of measured data into results for both novice and expert practitioners of SAS.
Collapse
|
57
|
Single-chain heteropolymers transport protons selectively and rapidly. Nature 2020; 577:216-220. [PMID: 31915399 DOI: 10.1038/s41586-019-1881-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 10/01/2019] [Indexed: 01/09/2023]
Abstract
Precise protein sequencing and folding are believed to generate the structure and chemical diversity of natural channels1,2, both of which are essential to synthetically achieve proton transport performance comparable to that seen in natural systems. Geometrically defined channels have been fabricated using peptides, DNAs, carbon nanotubes, sequence-defined polymers and organic frameworks3-13. However, none of these channels rivals the performance observed in their natural counterparts. Here we show that without forming an atomically structured channel, four-monomer-based random heteropolymers (RHPs)14 can mimic membrane proteins and exhibit selective proton transport across lipid bilayers at a rate similar to those of natural proton channels. Statistical control over the monomer distribution in an RHP leads to segmental heterogeneity in hydrophobicity, which facilitates the insertion of single RHPs into the lipid bilayers. It also results in bilayer-spanning segments containing polar monomers that promote the formation of hydrogen-bonded chains15,16 for proton transport. Our study demonstrates the importance of the adaptability that is enabled by statistical similarity among RHP chains and of the modularity provided by the chemical diversity of monomers, to achieve uniform behaviour in heterogeneous systems. Our results also validate statistical randomness as an unexplored approach to realize protein-like behaviour at the single-polymer-chain level in a predictable manner.
Collapse
|
58
|
Kozlovskaya V, Liu F, Yang Y, Ingle K, Qian S, Halade GV, Urban VS, Kharlampieva E. Temperature-Responsive Polymersomes of Poly(3-methyl- N-vinylcaprolactam)- block-poly( N-vinylpyrrolidone) To Decrease Doxorubicin-Induced Cardiotoxicity. Biomacromolecules 2019; 20:3989-4000. [PMID: 31503464 DOI: 10.1021/acs.biomac.9b01026] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Despite being one of the most potent chemotherapeutics, doxorubicin (DOX) facilitates cardiac toxicity by irreversibly damaging the cardiac muscle as well as severely dysregulating the immune system and impairing the resolution of cardiac inflammation. Herein, we report synthesis and aqueous self-assembly of nanosized polymersomes from temperature-responsive poly(3-methyl-N-vinylcaprolactam)-block-poly(N-vinylpyrrolidone) (PMVC-PVPON) diblock copolymers and demonstrate their potential to minimize DOX cardiotoxicity compared to liposomal DOX. RAFT polymerization of vinylpyrrolidone and 3-methyl-N-vinylcaprolactam, which are structurally similar monomers but have drastically different hydrophobicity, allows decreasing the cloud point of PMVCm-PVPONn copolymers below 20 °C. The lower critical solution temperature (LCST) of the PMVC58-PVPONn copolymer varied from 19.2 to 18.6 and to 15.2 °C by decreasing the length of the hydrophilic PVPONn block from n = 98 to n = 65 and to n = 20, respectively. The copolymers assembled into stable vesicles at room temperature when PVPON polymerization degrees were 65 and 98. Anticancer drug DOX was entrapped with high efficiency into the aqueous PMVC58-PVPON65 polymersomal core surrounded by the hydrophobic temperature-sensitive PMVC shell and the hydrophilic PVPON corona. Unlike many liposomal, micellar, or synthetic drug delivery systems, these polymersomes exhibit an exceptionally high loading capacity of DOX (49%) and encapsulation efficiency (95%) due to spontaneous loading of the drug at room temperature from aqueous DOX solution. We also show that C57BL/6J mice injected with the lethal dose of DOX at 15 mg kg-1 did not survive the 14 day treatment, resulting in 100% mortality. The DOX-loaded PMVC58-PVPON65 polymersomes did not cause any mortality in mice indicating that they can be used for successful DOX encapsulation. The gravimetric analyses of the animal organs from mice treated with liposome-encapsulated DOX (Lipo-DOX) and PMVC58-PVPON65 polymersomes (Poly-DOX) revealed that the Lipo-DOX injection caused some toxicity manifesting as decreased body weight compared to Poly-DOX and saline control. Masses of the left ventricle of the heart, lung, and spleen reduced in the Lipo-DOX-treated mice compared to the nontoxic saline control, while no significant decrease of those masses was observed for the Poly-DOX-treated mice. Our results provide evidence for superior stability of synthetic polymersomes in vivo and show promise for the development of next-generation drug carriers with minimal side effects.
Collapse
Affiliation(s)
| | | | | | | | - Shuo Qian
- Neutron Scattering Division, Neutron Sciences Directorate , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | | | - Volker S Urban
- Neutron Scattering Division, Neutron Sciences Directorate , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | | |
Collapse
|
59
|
An ensemble of flexible conformations underlies mechanotransduction by the cadherin-catenin adhesion complex. Proc Natl Acad Sci U S A 2019; 116:21545-21555. [PMID: 31591245 PMCID: PMC6815173 DOI: 10.1073/pnas.1911489116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Adherens junctions are specialized cell–cell adhesion complexes found in epithelial, endothelial, and neuronal tissues of multicellular organism. The cadherin–catenin complex is the core component of the adherens junction and transmits mechanical stress from cell to cell. This study reveals that the cadherin–catenin complex displays a wide spectrum of flexible structures, which suggests a dynamic mechanism for this complex in mechanotransduction for cell–cell adhesion. The cadherin–catenin adhesion complex is the central component of the cell–cell adhesion adherens junctions that transmit mechanical stress from cell to cell. We have determined the nanoscale structure of the adherens junction complex formed by the α-catenin•β-catenin•epithelial cadherin cytoplasmic domain (ABE) using negative stain electron microscopy, small-angle X-ray scattering, and selective deuteration/small-angle neutron scattering. The ABE complex is highly pliable and displays a wide spectrum of flexible structures that are facilitated by protein-domain motions in α- and β-catenin. Moreover, the 107-residue intrinsically disordered N-terminal segment of β-catenin forms a flexible “tongue” that is inserted into α-catenin and participates in the assembly of the ABE complex. The unanticipated ensemble of flexible conformations of the ABE complex suggests a dynamic mechanism for sensitivity and reversibility when transducing mechanical signals, in addition to the catch/slip bond behavior displayed by the ABE complex under mechanical tension. Our results provide mechanistic insight into the structural dynamics for the cadherin–catenin adhesion complex in mechanotransduction.
Collapse
|
60
|
Zeng M, King D, Huang D, Do C, Wang L, Chen M, Lei S, Lin P, Chen Y, Cheng Z. Iridescence in nematics: Photonic liquid crystals of nanoplates in absence of long-range periodicity. Proc Natl Acad Sci U S A 2019; 116:18322-18327. [PMID: 31444300 PMCID: PMC6744873 DOI: 10.1073/pnas.1906511116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Photonic materials with positionally ordered structure can interact strongly with light to produce brilliant structural colors. Here, we found that the nonperiodic nematic liquid crystals of nanoplates can also display structural color with only significant orientational order. Owing to the loose stacking of the nematic nanodiscs, such colloidal dispersion is able to reflect a broad-spectrum wavelength, of which the reflection color can be further enhanced by adding carbon nanoparticles to reduce background scattering. Upon the addition of electrolytes, such vivid colors of nematic dispersion can be fine-tuned via electrostatic forces. Furthermore, we took advantage of the fluidity of the nematic structure to create a variety of colorful arts. It was expected that the concept of implanting nematic features in photonic structure of lyotropic nanoparticles may open opportunities for developing advanced photonic materials for display, sensing, and art applications.
Collapse
Affiliation(s)
- Minxiang Zeng
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Daniel King
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Dali Huang
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843
| | - Changwoo Do
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - Ling Wang
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
- School of Materials Science and Engineering, Tianjin University, 300350 Tianjin, China
| | - Mingfeng Chen
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
- Guangdong Provincial Key Laboratory on Functional Soft Condensed Matter, School of Materials and Energy, Guangdong University of Technology, 510006 Guangzhou, China
| | - Shijun Lei
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Pengcheng Lin
- Guangdong Provincial Key Laboratory on Functional Soft Condensed Matter, School of Materials and Energy, Guangdong University of Technology, 510006 Guangzhou, China
| | - Ying Chen
- Guangdong Provincial Key Laboratory on Functional Soft Condensed Matter, School of Materials and Energy, Guangdong University of Technology, 510006 Guangzhou, China
| | - Zhengdong Cheng
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843;
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843
| |
Collapse
|
61
|
Yin X, Hewitt DRO, Preston AN, Heroux LA, Agamalian MM, Quah SP, Zheng B, Smith AJ, Laughlin ST, Grubbs RB, Bhatia SR. Hierarchical assembly in PLA-PEO-PLA hydrogels with crystalline domains and effect of block stereochemistry. Colloids Surf B Biointerfaces 2019; 180:102-109. [PMID: 31030021 DOI: 10.1016/j.colsurfb.2019.04.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/10/2019] [Accepted: 04/13/2019] [Indexed: 01/16/2023]
Abstract
Understanding the development of microstructure (e.g., structures with length scales roughly 0.5-500 μm) in hydrogels is crucial for their use in several biomedical applications. We utilize ultra-small-angle neutron scattering (USANS) and confocal microscopy to explore microstructure of poly(lactide)-poly(ethylene oxide)-poly(lactide) (PLA-PEO-PLA) triblock copolymer hydrogels with varying l/d-lactide ratio. We have previously found that these polymers self-assemble on the nanoscale into micelles. Here, we observe large-scale structures with diverse morphologies, including highly porous self-similar networks with characteristic sizes spanning approximately 120 nm-200 μm. These structural features give rise to power-law scattering indicative of fractal structures in USANS. Mass fractal and surface fractal structures are found for gels with l/d ratios of 80/20 and 50/50, respectively. Confocal microscopy shows microscale water-filled channels and pores that are more clearly evident in gels with a higher fraction of l-lactide in the PLA block as compared to the 50/50 hydrogels. Tuning block stereochemistry may provide a means of controlling the self-assembly and structural evolution at both the nanoscale and microscale, impacting application of these materials in tissue engineering and drug delivery.
Collapse
Affiliation(s)
- Xuechen Yin
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - David R O Hewitt
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Alyssa N Preston
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Luke A Heroux
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Michael M Agamalian
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Suan P Quah
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Bingqian Zheng
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Andrew J Smith
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Scott T Laughlin
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Robert B Grubbs
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Surita R Bhatia
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA.
| |
Collapse
|
62
|
Li F, Parnell SR, Dalgliesh R, Washington A, Plomp J, Pynn R. Data Correction of Intensity Modulated Small Angle Scattering. Sci Rep 2019; 9:8563. [PMID: 31189935 PMCID: PMC6561909 DOI: 10.1038/s41598-019-44493-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/25/2019] [Indexed: 11/29/2022] Open
Abstract
To investigate long length scale structures using neutron scattering, real space techniques have shown certain advantages over the conventional methods working in reciprocal space. As one of the real space measurement techniques, spin echo modulated small angle neutron scattering (SEMSANS) has attracted attention, due to its relaxed constraints on sample environment and the possibility to combine SEMSANS and a conventional small angle neutron scattering instrument. In this report, we present the first implementation of SEMSANS at a pulsed neutron source and discuss important corrections to the data due to the sample absorption. These corrections allow measurements made with different neutron wavelengths and SEMSANS configurations to be overlaid and give confidence that the measurements provide an accurate representation of the density correlations in the sample.
Collapse
Affiliation(s)
- Fankang Li
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.
| | - Steven R Parnell
- Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, Delft, JB 2629, The Netherlands
| | - Robert Dalgliesh
- ISIS Pulsed Neutron and Muon Source, STFC, Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX, UK
| | - Adam Washington
- ISIS Pulsed Neutron and Muon Source, STFC, Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX, UK
| | - Jeroen Plomp
- Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, Delft, JB 2629, The Netherlands
| | - Roger Pynn
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA.,Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN, 47408, USA
| |
Collapse
|
63
|
He L, Li C, Hamilton WA, Hong T, Tong X, Winn BL, Crow L, Bailey K, Gallego NC. Anomalous neutron scattering `halo' observed in highly oriented pyrolytic graphite. J Appl Crystallogr 2019. [DOI: 10.1107/s1600576719001110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Highly oriented pyrolytic graphite (HOPG) has been used as monochromators, analyzers and filters at neutron and X-ray scattering facilities for more than half a century. Interesting questions remain. In this work, the first observation of anomalous neutron `halo' scattering of HOPG is reported. The scattering projects a ring onto the detector with a half-cone angle of 12.4°, which surprisingly persists to incident neutron wavelengths far beyond the Bragg cutoff for graphite (6.71 Å). At longer wavelengths the ring is clearly a doublet with a splitting roughly proportional to wavelength. Sample tilting leads to the shift of the ring, which is wavelength dependent with longer wavelengths providing a smaller difference between the ring shift and the sample tilting. The ring broadens and weakens with decreasing HOPG quality. The lattice dynamics of graphite play a role in causing the scattering ring, as shown by the fact that the ring vanishes once the sample is cooled to 30 K. A possible interpretation by multiple scattering including elastic and inelastic processes is proposed.
Collapse
|
64
|
Ade-Browne C, Dawn A, Mirzamani M, Qian S, Kumari H. Differential behavior of sodium laurylsulfate micelles in the presence of nonionic polymers. J Colloid Interface Sci 2019; 544:276-283. [PMID: 30852353 DOI: 10.1016/j.jcis.2019.02.081] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/22/2019] [Accepted: 02/23/2019] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS Theory and practice have proven that the cleansing properties and irritation potential of surfactants can be controlled with the addition of co-surfactants or polymers. The size of the surfactant-polymer nanoassembly, which differs from the pure surfactant micelle, has been postulated to be the cause of the differences in a surfactant system's ability to disrupt the skin barrier. However, a firm structure-function relationship connecting polymer and surfactant under a consumer relevant condition is yet to be established. It is therefore hypothesized that apart from the size, the shape and the chemical nature of the polymer might play crucial roles. EXPERIMENTS We used combined small-angle neutron scattering, nuclear magnetic resonance spectroscopy, tensiometry, and dye solubilization methods to investigate the shape, size, and intermolecular interactions involved in sodium laurylsulfate-based systems in the presence of two industrially important and chemically distinct polymers, polyethylene glycol and polyvinyl alcohol, adopting a consumer relevant protocol. FINDINGS Apart from size, shape and inter-micellar interactions fine-tuned by the presence of the polymers are found to be the important factors. Secondly, the physicochemical property of the polymer including chemical structure, conformation, hydrophilicity, presence of side groups, all can have crucial influence on polymer-surfactant interaction, micelle formation, and micelle stability.
Collapse
Affiliation(s)
- Chandra Ade-Browne
- James Winkle College of Pharmacy, 231 Albert Sabin Way, Cincinnati, OH 45267-0514, USA
| | - Arnab Dawn
- James Winkle College of Pharmacy, 231 Albert Sabin Way, Cincinnati, OH 45267-0514, USA
| | - Marzieh Mirzamani
- James Winkle College of Pharmacy, 231 Albert Sabin Way, Cincinnati, OH 45267-0514, USA
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Harshita Kumari
- James Winkle College of Pharmacy, 231 Albert Sabin Way, Cincinnati, OH 45267-0514, USA.
| |
Collapse
|
65
|
Shah R, Huang S, Pingali SV, Sawada D, Pu Y, Rodriguez M, Ragauskas AJ, Kim SH, Evans BR, Davison BH, O'Neill H. Hemicellulose-Cellulose Composites Reveal Differences in Cellulose Organization after Dilute Acid Pretreatment. Biomacromolecules 2019; 20:893-903. [PMID: 30554514 DOI: 10.1021/acs.biomac.8b01511] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Model hemicellulose-cellulose composites that mimic plant cell wall polymer interactions were prepared by synthesizing deuterated bacterial cellulose in the presence of glucomannan or xyloglucan. Dilute acid pretreatment (DAP) of these materials was studied using small-angle neutron scattering, X-ray diffraction, and sum frequency generation spectroscopy. The macrofibril dimensions of the pretreated cellulose alone were smaller but with similar entanglement of macrofibrillar network as native cellulose. In addition, the crystallite size dimension along the (010) plane increased. Glucomannan-cellulose underwent similar changes to cellulose, except that the macrofibrillar network was more entangled after DAP. Conversely, in xyloglucan-cellulose the macrofibril dimensions and macrofibrillar network were relatively unchanged after pretreatment, but the cellulose Iβ content was increased. Our results point to a tight interaction of xyloglucan with microfibrils while glucomannan only interacts with macrofibril surfaces. This study provides insight into roles of different hemicellulose-cellulose interactions and may help in improving pretreatment processes or engineering plants with decreased recalcitrance.
Collapse
Affiliation(s)
- Riddhi Shah
- Bredesen Center for Interdisciplinary Research , University of Tennessee , Knoxville Tennessee 37996 , United States
| | - Shixin Huang
- Department of Chemical Engineering , Pennsylvania State University , State College , Pennsylvania 16802 , United States
| | | | | | | | | | | | - Seong H Kim
- Department of Chemical Engineering , Pennsylvania State University , State College , Pennsylvania 16802 , United States
| | | | | | | |
Collapse
|
66
|
Alaboalirat M, Qi L, Arrington KJ, Qian S, Keum JK, Mei H, Littrell KC, Sumpter BG, Carrillo JMY, Verduzco R, Matson JB. Amphiphilic Bottlebrush Block Copolymers: Analysis of Aqueous Self-Assembly by Small-Angle Neutron Scattering and Surface Tension Measurements. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b02366] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Mohammed Alaboalirat
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Luqing Qi
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - Kyle J. Arrington
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | | | | | - Hao Mei
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | | | | | | | - Rafael Verduzco
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
| | - John B. Matson
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| |
Collapse
|
67
|
Perera SMDC, Chawla U, Shrestha UR, Bhowmik D, Struts AV, Qian S, Chu XQ, Brown MF. Small-Angle Neutron Scattering Reveals Energy Landscape for Rhodopsin Photoactivation. J Phys Chem Lett 2018; 9:7064-7071. [PMID: 30489081 DOI: 10.1021/acs.jpclett.8b03048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Knowledge of the activation principles for G-protein-coupled receptors (GPCRs) is critical to development of new pharmaceuticals. Rhodopsin is the archetype for the largest GPCR family, yet the changes in protein dynamics that trigger signaling are not fully understood. Here we show that rhodopsin can be investigated by small-angle neutron scattering (SANS) in fully protiated detergent micelles under contrast matching to resolve light-induced changes in the protein structure. In SANS studies of membrane proteins, the zwitterionic detergent [(cholamidopropyl)dimethylammonio]-propanesulfonate (CHAPS) is advantageous because of the low contrast difference between the hydrophobic core and hydrophilic head groups as compared with alkyl glycoside detergents. Combining SANS results with quasielastic neutron scattering reveals how changes in volumetric protein shape are coupled (slaved) to the aqueous solvent. Upon light exposure, rhodopsin is swollen by the penetration of water into the protein core, allowing interactions with effector proteins in the visual signaling mechanism.
Collapse
Affiliation(s)
- Suchithranga M D C Perera
- Department of Chemistry and Biochemistry , University of Arizona , Tucson , Arizona 85721 , United States
| | - Udeep Chawla
- Department of Chemistry and Biochemistry , University of Arizona , Tucson , Arizona 85721 , United States
| | - Utsab R Shrestha
- Department of Physics and Astronomy , Wayne State University , Detroit , Michigan 48201 , United States
| | - Debsindhu Bhowmik
- Department of Physics and Astronomy , Wayne State University , Detroit , Michigan 48201 , United States
| | - Andrey V Struts
- Department of Chemistry and Biochemistry , University of Arizona , Tucson , Arizona 85721 , United States
- Laboratory of Biomolecular NMR , St. Petersburg State University , St. Petersburg 199034 , Russia
| | - Shuo Qian
- Neutron Scattering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Xiang-Qiang Chu
- Graduate School of China Academy of Engineering Physics , Beijing 100193 , China
| | - Michael F Brown
- Department of Chemistry and Biochemistry , University of Arizona , Tucson , Arizona 85721 , United States
- Department of Physics , University of Arizona , Tucson , Arizona 85721 , United States
| |
Collapse
|
68
|
Qian S, Rai DK. Grazing-Angle Neutron Diffraction Study of the Water Distribution in Membrane Hemifusion: From the Lamellar to Rhombohedral Phase. J Phys Chem Lett 2018; 9:5778-5784. [PMID: 30111108 DOI: 10.1021/acs.jpclett.8b01602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The water distribution between lipid bilayers is important in understanding the role of the hydration force at different steps of the membrane fusion pathway. In this study, we used grazing-angle neutron diffraction to map out the water distribution in lipid bilayers transiting from a lamellar structure to the hemifusion "stalk" structure in a rhombohedral phase. Under osmotic pressure exerted by different levels of relative humidity, the lipid membrane sample was maintained in equilibrium at different lattices suitable for neutron diffraction. The D2O used to hydrate the lipid membrane sample stood out from the lipid in the reconstructed structure because of its much higher coherent neutron scattering length density. The density map indicates that water dissociated from the headgroup in the lamellar phase. In the rhombohedral phase, water was significantly reduced and was squeezed into pockets around the stalk. This study complements earlier structural studies by grazing-angle X-ray diffraction, which is sensitive to only the parts of the structure with high electron density (such as phosphors). The experiment also demonstrated that the recently developed time-of-flight small-angle neutron scattering beamline at the Spallation Neutron Source is suitable for grazing-angle neutron diffraction to provide the structures of large unit cells on the order of a few nanometers, such as biomembrane structures.
Collapse
|
69
|
Argyriou DN, Allen AJ. Foreword to the special issue on advanced neutron scattering instrumentation. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576718007987] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
|
70
|
Heuser BJ, Lin JL, Do C, He L. Small-angle neutron scattering measurements of δ-phase deuteride (hydride) precipitates in Zircaloy 4. J Appl Crystallogr 2018. [DOI: 10.1107/s160057671800479x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Small-angle neutron scattering (SANS) measurements have been performed under ambient conditions to characterize deuteride (hydride) particles in Zircaloy 4, a fuel cladding material used in pressurized light-water nuclear reactors. Hydrogen pickup by the cladding leads to a rim structure in which large circumferential hydride plate-like particles preferentially form on the cooler water-side region of the cladding. Deuterium substitution has been used to increase the coherent response and decrease the incoherent background of the SANS measurements. Four bulk deuterium concentrations were investigated, approximately 100, 400, 500 and 1000 parts per million by weight (w.p.p.m.) deuterium, as well as a zero-deuterium-concentration reference sample. The net SANS response from the deuteride phase was determined at all concentration values after subtraction of the reference SANS response, which effectively subtracted the strong scattering from second-phase particles in as-received Zircaloy. The net SANS response consisted of strong Porod scattering from deuteride particles over the entire measured Q range (0.005–0.4 Å−1). The net SANS response was anisotropic at concentrations greater than 100 w.p.p.m. and required elliptical averaging analysis. A significant sample orientation effect on the intensity of the SANS response was observed, due to preferential alignment of deuteride particles. The effect of ex situ applied stress at elevated temperature on deuteride phase dissolution and reprecipitation was investigated; a weak effect was observed with SANS that could not be confirmed by optical microscopy.
Collapse
|
71
|
Marquardt D, Frontzek MD, Zhao Y, Chakoumakos BC, Katsaras J. Neutron diffraction from aligned stacks of lipid bilayers using the WAND instrument. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576718001243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Neutron diffraction from aligned stacks of lipid bilayers is examined using the Wide-Angle Neutron Diffractometer (WAND), located at the High Flux Isotope Reactor, Oak Ridge, Tennessee, USA. Data were collected at different levels of hydration and neutron contrast by varying the relative humidity (RH) and H2O/D2O ratio from multi-bilayers of dioleoylphosphatidylcholine and sunflower phosphatidylcholine extract aligned on single-crystal silicon substrates. This work highlights the capabilites of a newly fabricated sample hydration cell, which allows the lipid bilayers to be hydrated with varying H/D ratios from the RH generated by saturated salt solutions, and also demonstrates WAND's capability as an instrument suitable for the study of aligned lipid multi-bilayers.
Collapse
|