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Chen J, Luo Y. Disodium Cromoglycate Templates Anisotropic Short-Chain PEG Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2024; 16:33223-33234. [PMID: 38885610 DOI: 10.1021/acsami.4c07181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Anisotropic hydrogels have found widespread applications in biomedical engineering, particularly as scaffolds for tissue engineering. However, it remains a challenge to produce them using conventional fabrication methods, without specialized synthesis or equipment, such as 3D printing and unidirectional stretching. In this study, we explore the self-assembly behaviors of polyethylene glycol diacrylate (PEGDA), using disodium cromoglycate (DSCG), a lyotropic chromonic liquid crystal, as a removable template. The affinity between short-chain PEGDA (Mn = 250) and DSCG allows polymerization to take place at the DSCG surface, thereby forming anisotropic hydrogel networks with fibrin-like morphologies. This process requires considerable finesse as the phase behaviors of DSCG depend on a multitude of factors, including the weight percentage of PEGDA and DSCG, the chain length of PEGDA, and the concentration of ionic species. The key to modulating the microstructures of the all-PEG hydrogel networks is through precise control of the DSCG concentration, resulting in anisotropic mechanical properties. Using these anisotropic hydrogel networks, we demonstrate that human dermal fibroblasts are particularly sensitive to the alignment order. We find that cells exhibit a density-dependent activation pattern of a Yes-associated protein, a mechanotransducer, corroborating its role in enabling cells to translate external mechanical and morphological patterns to specific behaviors. The flexibility of modulating microstructure, along with PEG hydrogels' biocompatibility and biodegradability, underscores their potential use for tissue engineering to create functional structures with physiological morphologies.
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Affiliation(s)
- Juan Chen
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
| | - Yimin Luo
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
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García Daza FA, Puertas AM, Cuetos A, Patti A. Insight into the Viscoelasticity of Self-Assembling Smectic Liquid Crystals of Colloidal Rods from Active Microrheology Simulations. J Chem Theory Comput 2024; 20:1579-1589. [PMID: 37390389 PMCID: PMC10902840 DOI: 10.1021/acs.jctc.3c00356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
The rheology of colloidal suspensions is of utmost importance in a wide variety of interdisciplinary applications in formulation technology, determining equally interesting questions in fundamental science. This is especially intriguing when colloids exhibit a degree of long-range positional or orientational ordering, as in liquid crystals (LCs) of elongated particles. Along with standard methods, microrheology (MR) has emerged in recent years as a tool to assess the mechanical properties of materials at the microscopic level. In particular, by active MR one can infer the viscoelastic response of a soft material from the dynamics of a tracer particle being dragged through it by external forces. Although considerable efforts have been made to study the diffusion of guest particles in LCs, little is known about the combined effect of tracer size and directionality of the dragging force on the system's viscoelastic response. By dynamic Monte Carlo simulations, we apply active MR to investigate the viscoelasticity of self-assembling smectic (Sm) LCs consisting of rodlike particles. In particular, we track the motion of a spherical tracer whose size is varied within a range of values matching the system's characteristic length scales and being dragged by constant forces that are parallel, perpendicular, or at 45° to the nematic director. Our results reveal a uniform value of the effective friction coefficient as probed by the tracer at small and large forces, whereas a nonlinear, force-thinning regime is observed at intermediate forces. However, at relatively weak forces the effective friction is strongly determined by correlations between the tracer size and the structure of the host fluid. Moreover, we also show that external forces forming an angle with the nematic director provide additional details that cannot be simply inferred from the mere analysis of parallel and perpendicular forces. Our results highlight the fundamental interplay between tracer size and force direction in assessing the MR of Sm LC fluids.
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Affiliation(s)
- Fabián A García Daza
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, 41013 Sevilla, Spain
- Department of Chemical Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Antonio M Puertas
- Department of Chemistry and Physics, University of Almeriá, 04120 Almería, Spain
| | - Alejandro Cuetos
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, 41013 Sevilla, Spain
| | - Alessandro Patti
- Department of Chemical Engineering, The University of Manchester, Manchester M13 9PL, United Kingdom
- Department of Applied Physics, University of Granada, Avenida Fuente Nueva s/n, 18071 Granada, Spain
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García Daza FA, Puertas AM, Cuetos A, Patti A. Microrheology of isotropic and liquid-crystalline phases of hard rods by dynamic Monte Carlo simulations. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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M MR, Pujala RK, Paladugu S, Dhara S. Interactions of charged microrods in chiral nematic liquid crystals. Phys Rev E 2021; 104:014706. [PMID: 34412267 DOI: 10.1103/physreve.104.014706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 07/02/2021] [Indexed: 11/07/2022]
Abstract
We study the pair interaction of charged silica microrods in chiral nematic liquid crystals and show that the microrods with homeotropic surface anchoring form a bound state due to the competing effect of electrostatic (Coulomb) and elastic interactions. The robustness of the bound state is demonstrated by applying external electrical and mechanical forces that perturbs their equilibrium position as well as orientation. In the bound state we have measured the correlated thermal fluctuations of the position, using two-particle cross-correlation spectroscopy that uncovers their hydrodynamic interaction. These findings reveal unexplored aspects of liquid-crystal dispersions which are important for understanding the assembly and dynamics of nano- and microparticles in chiral nematic liquid crystals.
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Affiliation(s)
- Muhammed Rasi M
- School of Physics, University of Hyderabad, Hyderabad 500046, India
| | - Ravi Kumar Pujala
- Department of Physics, Indian Institute of Science Education and Research, Tirupati, Andhra Pradesh 517507, India
| | - Sathyanarayana Paladugu
- Department of Physics, Indian Institute of Science Education and Research, Tirupati, Andhra Pradesh 517507, India
| | - Surajit Dhara
- School of Physics, University of Hyderabad, Hyderabad 500046, India
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Passive and active microrheology of a lyotropic chromonic nematic liquid crystal disodium cromoglycate. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Farokhirad S, Ramakrishnan N, Eckmann DM, Ayyaswamy PS, Radhakrishnan R. Nanofluid Dynamics of Flexible Polymeric Nanoparticles Under Wall Confinement. JOURNAL OF HEAT TRANSFER 2019; 141:0524011-524016. [PMID: 31186582 PMCID: PMC6528683 DOI: 10.1115/1.4043014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 02/22/2019] [Indexed: 05/12/2023]
Abstract
Describing the hydrodynamics of nanoparticles in fluid media poses interesting challenges due to the coupling between the Brownian and hydrodynamic forces at the nanoscale. We focus on multiscale formulations of Brownian motion and hydrodynamic interactions (HI) of a single flexible polymeric nanoparticle in confining flows using the Brownian Dynamics method. The nanoparticle is modeled as a self-avoiding freely jointed polymer chain that is subject to Brownian forces, hydrodynamics forces, and repulsive interactions with the confining wall. To accommodate the effect of the wall, the hydrodynamic lift due to the wall is included in the mobility of a bead of the polymer chain which depends on its proximity to the wall. Using the example of a flexible polymeric nanoparticle, we illustrate temporal dynamics pertaining to the colloidal scale as well as the nanoscale.
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Affiliation(s)
- Samaneh Farokhirad
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104 e-mail:
| | - N Ramakrishnan
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA 19104 e-mail:
| | - David M Eckmann
- Department of Anesthesiology and Critical Care, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 e-mail:
| | - Portonovo S Ayyaswamy
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104 e-mail:
| | - Ravi Radhakrishnan
- Department of Chemical and Biomolecular Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 e-mail:
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Microrheology, advances in methods and insights. Adv Colloid Interface Sci 2018; 257:71-85. [PMID: 29859615 DOI: 10.1016/j.cis.2018.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/23/2018] [Accepted: 04/14/2018] [Indexed: 01/19/2023]
Abstract
Microrheology is an emerging technique that probes mechanical response of soft material at micro-scale. Generally, microrheology technique can be divided into active and passive versions. During last two decades, extensive efforts have been paid to improve both the experiment techniques and data analysis methods, especially about how to link consequential particle positions into trajectories. We review the recent advances in microrheology, including improvements in labeling, imaging, data acquiring, data processing and data interpretation. Some of the recent insights in soft matter and living systems gained by using this technique are given. Before these, we also give a very brief description of the basic principles of both active and passive microrheology techniques, and some details about optical particle tracking and DWS.
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Ramakrishnan N, Wang Y, Eckmann DM, Ayyaswamy PS, Radhakrishnan R. Motion of a nano-spheroid in a cylindrical vessel flow: Brownian and hydrodynamic interactions. JOURNAL OF FLUID MECHANICS 2017; 821:117-152. [PMID: 29109590 PMCID: PMC5669124 DOI: 10.1017/jfm.2017.182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We study the motion of a buoyant or a nearly neutrally buoyant nano-sized spheroid in a fluid filled tube without or with an imposed pressure gradient (weak Poiseuille flow). The fluctuating hydrodynamics approach and the deterministic method are both employed. We ensure that the fluctuation-dissipation relation and the principle of thermal equipartition of energy are both satisfied. The major focus is on the effect of the confining boundary. Results for the velocity and the angular velocity autocorrelations (VACF and AVACF), the diffusivities and the drag and the lift forces as functions of the shape, the aspect ratio, the inclination angle and the proximity to the wall are presented. For the parameters considered, the boundary modifies the VACF and AVACF such that three distinct regimes are discernible - an initial exponential decay followed by an algebraic decay culminating in a second exponential decay. The first is due to the thermal noise, the algebraic regime is due both to the thermal noise and the hydrodynamic correlations, while the second exponential decay shows the effect of momentum reflection from the confining wall. Our predictions display excellent comparison with published results for the algebraic regime (the only regime for which earlier results exist). We also discuss the role of the off-diagonal elements of the mobility and the diffusivity tensors that enable the quantifications of the degree of lift and margination of the nanocarrier. Our study covers a range of parameters that are of wide applicability in nanotechnology, microrheology and in targeted drug delivery.
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Affiliation(s)
- N. Ramakrishnan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19204, USA
| | - Y. Wang
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19204, USA
| | - D. M. Eckmann
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19204, USA
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA 19204, USA
| | - P. S. Ayyaswamy
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19204, USA
| | - R. Radhakrishnan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19204, USA
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19204, USA
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19204, USA
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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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