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Guan L, Li B, Chen S, Ren G, Li K, Lin Y. Bioinspired Cu-based metal-organic framework mimicking SOD for superoxide anion sensing and scavenging. Talanta 2023; 265:124860. [PMID: 37429254 DOI: 10.1016/j.talanta.2023.124860] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/31/2023] [Accepted: 06/04/2023] [Indexed: 07/12/2023]
Abstract
Superoxide anion (O2•-) is typically produced in living cells and organisms, while excess O2•- may cause unexpected damage, so monitoring and scavenging the O2•- is of considerable significance to exploring physiological and pathological process. In this study, a Cu-based metal-organic framework (Cu-MOF) which comprise sequential Cu metal ion and conductive organic 2,5-dicarboxylic acid-3,4-ethylene dioxythiophene is synthesized to mimic superoxide dismutase (SOD), in which Cu is the essence of active site. On one hand, the Cu-MOF possesses excellent electrocatalytic activity to detect O2•- at -0.05 V, biased at which potential the electrode showed good linearity toward O2•- with detection limit of 0.283 μM and interference immunity for AA, DA, UA, 5-HT and H2O2. The Cu-MOF modified microelectrode was applied for measuring the O2•- released from living cells real time and monitoring O2•- generation in rat brain. On the other hand, this Cu-MOF has the catalytic activity to mimic the superoxide dismutase for scavenging O2•- in HeLa cells effectively. This work provides a methodology to design metal ion based enzyme mimetic for analyzing and scavenging O2•- in cells and in vivo.
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Affiliation(s)
- Lihao Guan
- Department of Chemistry, Capital Normal University, Beijing, 100048, China
| | - Bo Li
- Department of Chemistry, Henan Open University, Henan, 450046, China
| | - Shutong Chen
- Department of Chemistry, Capital Normal University, Beijing, 100048, China
| | - Guoyuan Ren
- Department of Chemistry, Capital Normal University, Beijing, 100048, China
| | - Kai Li
- Department of Chemistry, Capital Normal University, Beijing, 100048, China
| | - Yuqing Lin
- Department of Chemistry, Capital Normal University, Beijing, 100048, China.
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2
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Ling P, Cheng S, Chen N, Qian C, Gao F. Nanozyme-Modified Metal-Organic Frameworks with Multienzymes Activity as Biomimetic Catalysts and Electrocatalytic Interfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:17185-17192. [PMID: 32009380 DOI: 10.1021/acsami.9b23147] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Many metal-organic frameworks have been designed and synthesized for biosensors because of high surface area and porosity, suitable size, and good biocompatibility. Despite recent advances, however, most of them are only used as a nanocarrier. In this work, a new artificial nanozyme was constructed on a metalloporphyrinic metal-organic framework (PMOF(Fe)), which was formed by Fe porphyrin and Zr4+ ions. Then, ultrasmall Pt nanoparticles (Pt NPs) were loaded on the surface of PMOF(Fe) to form Pt@PMOF(Fe). Because of the high surface area and exposed Fe activity center, PMOF(Fe) works as a nanocarrier to hinder the Pt NP aggregation and exhibits high peroxidase-mimicking activity. Hence, Pt NPs decorated on the surface of PMOF(Fe) possessed high stability and exhibited high activity. Due to the synergistic effect between PMOF(Fe) and Pt NPs, Pt@PMOF(Fe) exhibits superior catalase- and peroxidase-like activities. Moreover, Pt@PMOF(Fe) possesses high electrocatalytic activity toward the reduction of H2O2 and the oxygen reduction reaction (ORR). This strategy may serve as a strong foundation to design MOF-based artificial nanozymes and develop an ideal platform for MOFs and nanozymes toward artificial enzymatic catalytic systems, fuel cells and new analytical applications.
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Affiliation(s)
- Pinghua Ling
- Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Shan Cheng
- Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Nuo Chen
- Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Caihua Qian
- Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
| | - Feng Gao
- Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China
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3
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Safinya CR, Chung PJ, Song C, Li Y, Miller HP, Choi MC, Raviv U, Ewert KK, Wilson L, Feinstein SC. Minireview - Microtubules and Tubulin Oligomers: Shape Transitions and Assembly by Intrinsically Disordered Protein Tau and Cationic Biomolecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15970-15978. [PMID: 31539262 PMCID: PMC6988848 DOI: 10.1021/acs.langmuir.9b02208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this minireview, which is part of a special issue in honor of Jacob N. Israelachvili's remarkable research career on intermolecular forces and interfacial science, we present studies of structures, phase behavior, and forces in reaction mixtures of microtubules (MTs) and tubulin oligomers with either intrinsically disordered protein (IDP) Tau, cationic vesicles, or the polyamine spermine (4+). Bare MTs consist of 13 protofilaments (PFs), on average, where each PF is made of a linear stack of αβ-tubulin dimers (i.e., tubulin oligomers). We begin with a series of experiments which demonstrate the flexibility of PFs toward shape changes in response to local environmental cues. First, studies show that MT-associated protein (MAP) Tau controls the diameter of microtubules upon binding to the outer surface, implying a shape change in the cross-sectional area of PFs forming the MT perimeter. The diameter of a MT may also be controlled by the charge density of a lipid bilayer membrane that coats the outer surface. We further describe an experimental study where it is unexpectedly found that the biologically relevant polyamine spermine (+4e) is able to depolymerize taxol-stabilized microtubules with efficiency that increases with decreasing temperature. This MT destabilization drives a dynamical structural transition where inside-out curving of PFs, during the depolymerization peeling process, is followed by reassembly of ring-like curved PF building blocks into an array of helical inverted tubulin tubules. We finally turn to a very recent study on pressure-distance measurements in bundles of MTs employing the small-angle X-ray scattering (SAXS)-osmotic pressure technique, which complements the surface-forces-apparatus technique developed by Jacob N. Israelachvili. These latter studies are among the very few which are beginning to shed light on the precise nature of the interactions between MTs mediated by MAP Tau in 37 °C reaction mixtures containing GTP and lacking taxol.
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Affiliation(s)
- Cyrus R. Safinya
- Materials Department, Physics Department, Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA
| | - Peter J. Chung
- James Franck Institute and Department of Chemistry, University of Chicago, Illinois 60637, USA
| | - Chaeyeon Song
- Amorepacific Corporation R&D Center, Yongin 17074, Republic of Korea
| | - Youli Li
- Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA
| | - Herbert P. Miller
- Neuroscience Research Institute and Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA
| | - Myung Chul Choi
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Uri Raviv
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Kai K. Ewert
- Materials Department, Physics Department, Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA
| | - Leslie Wilson
- Neuroscience Research Institute and Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA
| | - Stuart C. Feinstein
- Neuroscience Research Institute and Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, California 93106, USA
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4
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Ling P, Zhang Q, Cao T, Gao F. Versatile Three-Dimensional Porous Cu@Cu2
O Aerogel Networks as Electrocatalysts and Mimicking Peroxidases. Angew Chem Int Ed Engl 2018; 57:6819-6824. [DOI: 10.1002/anie.201801369] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/18/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Pinghua Ling
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
| | - Qiang Zhang
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
| | - Tingting Cao
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
| | - Feng Gao
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
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5
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Ling P, Zhang Q, Cao T, Gao F. Versatile Three-Dimensional Porous Cu@Cu2
O Aerogel Networks as Electrocatalysts and Mimicking Peroxidases. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201801369] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Pinghua Ling
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
| | - Qiang Zhang
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
| | - Tingting Cao
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
| | - Feng Gao
- Laboratory of Functionalized Molecular Solids; Ministry of Education; Anhui Key Laboratory of Chemo/Biosensing; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB); College of Chemistry and Materials Science; Anhui Normal University; Wuhu 241002 P. R. China
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6
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Fan W, Liu L, Zhao H. Co-assembly of Patchy Polymeric Micelles and Protein Molecules. Angew Chem Int Ed Engl 2017; 56:8844-8848. [PMID: 28561455 DOI: 10.1002/anie.201704955] [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: 05/14/2017] [Indexed: 11/05/2022]
Abstract
The development in the synthesis and self-assembly of patchy nanoparticles has resulted in the creation of complex hierarchical structures. Co-assembly of polymeric nanoparticles and protein molecules combines the advantages of polymeric materials and biomolecules, and will produce new functional materials. Co-assembly of positively charged patchy micelles and negatively charged bovine serum albumin (BSA) molecules is investigated. The patchy micelles, which were synthesized using block copolymer brushes as templates, leads to co-assembly with protein molecules into vesicular structures. The average size of the assembled structures can be controlled by the molar ratio of BSA to patchy micelles. The assembled structures are dissociated in the presence of trypsin. The protein-polymer hybrid vesicles could find potential applications in medicine.
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Affiliation(s)
- Weijing Fan
- Key Laboratory of Functional Polymer Materials, Ministry of Education, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Li Liu
- Key Laboratory of Functional Polymer Materials, Ministry of Education, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Hanying Zhao
- Key Laboratory of Functional Polymer Materials, Ministry of Education, College of Chemistry, Nankai University, Tianjin, 300071, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300071, China
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7
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Fan W, Liu L, Zhao H. Co-assembly of Patchy Polymeric Micelles and Protein Molecules. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704955] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Weijing Fan
- Key Laboratory of Functional Polymer Materials; Ministry of Education, College of Chemistry; Nankai University; Tianjin 300071 China
| | - Li Liu
- Key Laboratory of Functional Polymer Materials; Ministry of Education, College of Chemistry; Nankai University; Tianjin 300071 China
| | - Hanying Zhao
- Key Laboratory of Functional Polymer Materials; Ministry of Education, College of Chemistry; Nankai University; Tianjin 300071 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin 300071 China
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8
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Wen D, Liu W, Haubold D, Zhu C, Oschatz M, Holzschuh M, Wolf A, Simon F, Kaskel S, Eychmüller A. Gold Aerogels: Three-Dimensional Assembly of Nanoparticles and Their Use as Electrocatalytic Interfaces. ACS NANO 2016; 10:2559-67. [PMID: 26751502 PMCID: PMC4768295 DOI: 10.1021/acsnano.5b07505] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/11/2016] [Indexed: 05/19/2023]
Abstract
Three-dimensional (3D) porous metal nanostructures have been a long sought-after class of materials due to their collective properties and widespread applications. In this study, we report on a facile and versatile strategy for the formation of Au hydrogel networks involving the dopamine-induced 3D assembly of Au nanoparticles. Following supercritical drying, the resulting Au aerogels exhibit high surface areas and porosity. They are all composed of porous nanowire networks reflecting in their diameters those of the original particles (5-6 nm) via electron microscopy. Furthermore, electrocatalytic tests were carried out in the oxidation of some small molecules with Au aerogels tailored by different functional groups. The beta-cyclodextrin-modified Au aerogel, with a host-guest effect, represents a unique class of porous metal materials of considerable interest and promising applications for electrocatalysis.
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Affiliation(s)
- Dan Wen
- Physical
Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany
| | - Wei Liu
- Physical
Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany
| | - Danny Haubold
- Physical
Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany
| | - Chengzhou Zhu
- Physical
Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany
| | - Martin Oschatz
- Inorganic
Chemistry, TU Dresden, Bergstrasse 66, 01062 Dresden, Germany
| | - Matthias Holzschuh
- Leibniz
Institute of Polymer Research Dresden, Hohe Strasse 6, 01069 Dresden, Germany
| | - André Wolf
- Physical
Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany
| | - Frank Simon
- Leibniz
Institute of Polymer Research Dresden, Hohe Strasse 6, 01069 Dresden, Germany
| | - Stefan Kaskel
- Inorganic
Chemistry, TU Dresden, Bergstrasse 66, 01062 Dresden, Germany
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9
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Mao Z, Xu B, Ji X, Zhou K, Zhang X, Chen M, Han X, Tang Q, Wang X, Xia Y. Titanium dioxide nanoparticles alter cellular morphology via disturbing the microtubule dynamics. NANOSCALE 2015; 7:8466-75. [PMID: 25891938 DOI: 10.1039/c5nr01448d] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Titanium dioxide (TiO2) nanoparticles (NPs) have been widely used in our daily lives, for example, in the areas of sunscreens, cosmetics, toothpastes, food products, and nanomedical reagents. Recently, increasing concern has been raised about their neurotoxicity, but the mechanisms underlying such toxic effects are still unknown. In this work, we employed a human neuroblastoma cell line (SH-SY5Y) to study the effects of TiO2 NPs on neurological systems. Our results showed that TiO2 NPs did not affect cell viability but induced noticeable morphological changes until 100 μg ml(-1). Immunofluorescence detection showed disorder, disruption, retraction, and decreased intensity of the microtubules after TiO2 NPs treatment. Both α and β tubule expressions did not change in the TiO2 NP-treated group, but the percentage of soluble tubules was increased. A microtubule dynamic study in living cells indicated that TiO2 NPs caused a lower growth rate and a higher shortening rate of microtubules as well as shortened lifetimes of de novo microtubules. TiO2 NPs did not cause changes in the expression and phosphorylation state of tau proteins, but a tau-TiO2 NP interaction was observed. TiO2 NPs could interact with tubule heterodimers, microtubules and tau proteins, which led to the instability of microtubules, thus contributing to the neurotoxicity of TiO2 NPs.
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Affiliation(s)
- Zhilei Mao
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 211100, China
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10
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Bannwarth MB, Utech S, Ebert S, Weitz DA, Crespy D, Landfester K. Colloidal polymers with controlled sequence and branching constructed from magnetic field assembled nanoparticles. ACS NANO 2015; 9:2720-8. [PMID: 25695858 DOI: 10.1021/nn5065327] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The assembly of nanoparticles into polymer-like architectures is challenging and usually requires highly defined colloidal building blocks. Here, we show that the broad size-distribution of a simple dispersion of magnetic nanocolloids can be exploited to obtain various polymer-like architectures. The particles are assembled under an external magnetic field and permanently linked by thermal sintering. The remarkable variety of polymer-analogue architectures that arises from this simple process ranges from statistical and block copolymer-like sequencing to branched chains and networks. This library of architectures can be realized by controlling the sequencing of the particles and the junction points via a size-dependent self-assembly of the single building blocks.
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Affiliation(s)
- Markus B Bannwarth
- †Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- §Graduate School of Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
- ∥Empa, Laboratory for Protection and Physiology, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland
| | - Stefanie Utech
- ‡Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sandro Ebert
- †Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - David A Weitz
- ‡Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Daniel Crespy
- †Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Katharina Landfester
- †Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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11
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Kurochkina NA, Iadarola MJ. Helical assemblies: structure determinants. J Theor Biol 2015; 369:80-84. [PMID: 25613414 DOI: 10.1016/j.jtbi.2015.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 01/12/2015] [Accepted: 01/14/2015] [Indexed: 11/30/2022]
Abstract
Protein structural motifs such as helical assemblies and α/β barrels combine secondary structure elements with various types of interactions. Helix-helix interfaces of assemblies - Ankyrin, ARM/HEAT, PUM, LRR, and TPR repeats - exhibit unique amino acid composition and patterns of interactions that correlate with curvature of solenoids, surface geometry and mutual orientation of the helical edges. Inner rows of ankyrin, ARM/HEAT, and PUM-HD repeats utilize edges (i-1, i) and (i+1, i+2) for the interaction of the given α-helix with preceding and following helices correspondingly, whereas outer rows of these proteins and LRR repeats invert this pattern and utilize edges (i-1, i) and (i-3, i-2). Arrangement of contacts observed in protein ligands that bind helical assemblies has to mimic the assembly pattern to provide the same curvature as a determinant of binding specificity. These characteristics are important for understanding fold recognition, specificity of protein-protein interactions, and design of new drugs and materials.
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Affiliation(s)
- Natalya A Kurochkina
- The School of Theoretical Modeling, 1629 K St NW s 300, Washington, DC 20006, United States.
| | - Michael J Iadarola
- Anesthesia Section, Department of Perioperative Medicine, Clinical Center, NIH, Building 10, Room 2C401, 10 Center Drive, MSC 1510, Bethesda, MD 20892, United States.
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Kolli HB, Frezza E, Cinacchi G, Ferrarini A, Giacometti A, Hudson TS, De Michele C, Sciortino F. Self-assembly of hard helices: a rich and unconventional polymorphism. SOFT MATTER 2014; 10:8171-8187. [PMID: 25164281 DOI: 10.1039/c4sm01305k] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hard helices can be regarded as a paradigmatic elementary model for a number of natural and synthetic soft matter systems, all featuring the helix as their basic structural unit, from natural polynucleotides and polypeptides to synthetic helical polymers, and from bacterial flagella to colloidal helices. Here we present an extensive investigation of the phase diagram of hard helices using a variety of methods. Isobaric Monte Carlo numerical simulations are used to trace the phase diagram; on going from the low-density isotropic to the high-density compact phases a rich polymorphism is observed, exhibiting a special chiral screw-like nematic phase and a number of chiral and/or polar smectic phases. We present full characterization of the latter, showing that they have unconventional features, ascribable to the helical shape of the constituent particles. Equal area construction is used to locate the isotropic-to-nematic phase transition, and the results are compared with those stemming from an Onsager-like theory. Density functional theory is also used to study the nematic-to-screw-nematic phase transition; within the simplifying assumption of perfectly parallel helices, we compare different levels of approximation, that is second- and third-virial expansions and a Parsons-Lee correction.
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Affiliation(s)
- Hima Bindu Kolli
- Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia, Italy.
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