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Watts Moore O, Lewis C, Ross T, Waigh TA, Korabel N, Mendoza C. Extreme heterogeneity in the microrheology of lamellar surfactant gels analyzed with neural networks. Phys Rev E 2024; 110:014603. [PMID: 39161018 DOI: 10.1103/physreve.110.014603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 05/22/2024] [Indexed: 08/21/2024]
Abstract
The heterogeneity of the viscoelasticity of a lamellar gel network based on cetyl-trimethylammonium chloride and cetostearyl alcohol was studied using particle-tracking microrheology. A recurrent neural network (RNN) architecture was used for estimating the Hurst exponent, H, on small sections of tracks of probe spheres moving with fractional Brownian motion. Thus, dynamic segmentation of tracks via neural networks was used in microrheology and it is significantly more accurate than using mean square displacements (MSDs). An ensemble of 414 particles produces a MSD that is subdiffusive in time, t, with a power law of the form t^{0.74±0.02}, indicating power law viscoelasticity. RNN analysis of the probability distributions of H, combined with detailed analysis of the time-averaged MSDs of individual tracks, revealed diverse diffusion processes belied by the simple scaling of the ensemble MSD, such as caging phenomena, which give rise to the complex viscoelasticity of lamellar gels.
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Phillies GDJ. Diffusing Wave Microrheology in Polymeric Fluids. Polymers (Basel) 2024; 16:1332. [PMID: 38794527 PMCID: PMC11125129 DOI: 10.3390/polym16101332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/07/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Recently, there has been interest in determining the viscoelastic properties of polymeric liquids and other complex fluids by means of Diffusing Wave Spectroscopy (DWS). In this technique, light-scattering spectroscopy is applied to highly turbid fluids containing optical probe particles. The DWS spectrum is used to infer the time-dependent mean-square displacement and time-dependent diffusion coefficient D of the probes. From D, values for the storage modulus G'(ω) and the loss modulus G''(ω) are obtained. This paper is primarily concerned with the inference of the mean-square displacement from a DWS spectrum. However, in much of the literature, central to the inference that is said to yield D is an invocation g(1)(t)=exp(-2q2X(t)2¯) of the Gaussian Approximation for the field correlation function g(1)(t) of the scattered light in terms of the mean-square displacement X(t)2¯ of a probe particle during time t. Experiment and simulation both show that the Gaussian approximation is invalid for probes in polymeric liquids and other complex fluids. In this paper, we obtain corrections to the Gaussian approximation that will assist in interpreting DWS spectra of probes in polymeric liquids. The corrections reveal that these DWS spectra receive contributions from higher moments X(t)2n¯, n>1, of the probe displacement distribution function.
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Nordenström M, Benselfelt T, Hollertz R, Wennmalm S, Larsson PA, Mehandzhiyski A, Rolland N, Zozoulenko I, Söderberg D, Wågberg L. The structure of cellulose nanofibril networks at low concentrations and their stabilizing action on colloidal particles. Carbohydr Polym 2022; 297:120046. [DOI: 10.1016/j.carbpol.2022.120046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/08/2022] [Accepted: 08/24/2022] [Indexed: 11/25/2022]
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Yaothak J, Simpson JC, Heffernan LF, Tsai YS, Lin CC. 2D-GolgiTrack-a semi-automated tracking system to quantify morphological changes and dynamics of the Golgi apparatus and Golgi-derived membrane tubules. Med Biol Eng Comput 2021; 60:151-169. [PMID: 34783979 DOI: 10.1007/s11517-021-02460-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 10/07/2021] [Indexed: 11/25/2022]
Abstract
The Golgi apparatus and membrane tubules derived from this organelle play essential roles in membrane trafficking in eukaryotic cells. High-resolution live cell imaging is one highly suitable method for studying the molecular mechanisms of dynamics of organelles during membrane trafficking events. Due to the complex morphological changes and dynamic movements of the Golgi apparatus and associated membrane tubules during membrane trafficking, it is challenging to accurately quantify them. In this study, a semi-automated 2D tracking system, 2D-GolgiTrack, has been established for quantifying morphological changes and movements of Golgi elements, specifically encompassing the Golgi apparatus and its associated tubules, the fission and fusion of Golgi tubules, and the kinetics of formation of Golgi tubules and redistribution of the Golgi-associated protein Rab6A to the endoplasmic reticulum. The Golgi apparatus and associated tubules are segmented by a combination of Otsu's method and adaptive local normalization thresholding. Curvilinear skeletons and tips of skeletons of segmented tubules are used for calculating tubule length by the Geodesic method. The k-nearest neighbor is applied to search the possible candidate objects in the next frame and link the correct objects of adjacent frames by a tracking algorithm to calculate changes in morphological features of each Golgi object or tubule, e.g., number, length, shape, branch point and position, and fission or fusion events. Tracked objects are classified into morphological subtypes, and the Track-Map function of morphological evolution visualizes events of fission and fusion. Our 2D-GolgiTrack not only provides tracking results with 95% accuracy, but also maps morphological evolution for fast visual interpretation of the fission and fusion events. Our tracking system is able to characterize key morphological and dynamic features of the Golgi apparatus and associated tubules, enabling biologists to gain a greater understanding of the molecular mechanisms of membrane traffic involving this essential organelle. Graphical Abstract Overview of the semi-automated 2D tracking system. There are two main parts to the system, namely detection and tracking. The workflow process requires a raw sequence of images (a), which is filtered by the Gaussian filter method (c), and threshold intensity (b) to segment elements of Golgi cisternae (d) and tubules (e). Post-processing outputs are binary images of the cisternae area and tubule skeletons. The tubules are classified into three lengths, namely short, medium, and long tubules (f). Outputs of segmentation are calculated as morphological features (g). The tracking processing starts by loading the segmented outputs (h) and key-inputs of direction reference (i; (DR)) and interval setting of the start ((S)) and end ((E)) frame numbers (j). A tubule of interest is selected by the user (k; (GTinterest, S) as the tubule input ((GTIN)) at the current frame ((i = S)). The tracking algorithm tracks and links the correct tubules at each subsequent frame ((i = i + 1)). The locations of tubule tips are determined for detecting tubule branches using the (DR) to identify the direction of tubule growth (l: (1); (GTtipBr, i); Golgi cisternae: white area; Golgi tubule: white skeleton; tubule tips: green dots; branched tubules: two branches due to the (DR) of growth of the simulated tubule moving from left-to-right away from the Golgi cisternae location). According to the position of the (GTIN), five candidates ((GTcandidates, i)) are searched using the k-nearest neighbor method (l: (2)). Matching of tubules between the (GTIN) and those (GTcandidates, i) uses the bounding box technique to check the amount of tubule-overlap based on the tracking conditions (l: (3)). If there is tubule-overlap, the system collects that tubule as the final output ((GTOUT, i)). By contrast, shape (see the Extent feature in Table reftab:1) and distance features are used to generate the tracked output, which has a priority of a minimum of both of these features ((MinDIST, EXTENT)); otherwise, it is from the minimum of the distance ((MinDIST)). Once a loop of the interval track to the last frame is finished ((i = E + 1)), a Track-Map is generated allowing visualization of the morphological pattern of tubule formation and movement, including identification of fission and fusion events (m). Dynamic features are calculated (n). Related outputs are saved, and all features obtained from the detection and tracking processing are exported as MS Excel files (o).
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Affiliation(s)
- Jindaporn Yaothak
- Department of Biomedical Engineering, Chung Yuan Christian University, Taoyuan, Taiwan
| | - Jeremy C Simpson
- Cell Screening Laboratory, School of Biology and Environmental Science, Science Centre West, University College Dublin, Dublin 4, Ireland
| | - Linda F Heffernan
- Cell Screening Laboratory, School of Biology and Environmental Science, Science Centre West, University College Dublin, Dublin 4, Ireland
| | - Yuh-Show Tsai
- Department of Biomedical Engineering, Chung Yuan Christian University, Taoyuan, Taiwan.
| | - Chung-Chih Lin
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.
- Biophotonics Interdisciplinary Research Center, National Yang-Ming University, Taipei, Taiwan.
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan.
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Chowdhury F, Huang B, Wang N. Cytoskeletal prestress: The cellular hallmark in mechanobiology and mechanomedicine. Cytoskeleton (Hoboken) 2021; 78:249-276. [PMID: 33754478 PMCID: PMC8518377 DOI: 10.1002/cm.21658] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 12/13/2022]
Abstract
Increasing evidence demonstrates that mechanical forces, in addition to soluble molecules, impact cell and tissue functions in physiology and diseases. How living cells integrate mechanical signals to perform appropriate biological functions is an area of intense investigation. Here, we review the evidence of the central role of cytoskeletal prestress in mechanotransduction and mechanobiology. Elevating cytoskeletal prestress increases cell stiffness and reinforces cell stiffening, facilitates long-range cytoplasmic mechanotransduction via integrins, enables direct chromatin stretching and rapid gene expression, spurs embryonic development and stem cell differentiation, and boosts immune cell activation and killing of tumor cells whereas lowering cytoskeletal prestress maintains embryonic stem cell pluripotency, promotes tumorigenesis and metastasis of stem cell-like malignant tumor-repopulating cells, and elevates drug delivery efficiency of soft-tumor-cell-derived microparticles. The overwhelming evidence suggests that the cytoskeletal prestress is the governing principle and the cellular hallmark in mechanobiology. The application of mechanobiology to medicine (mechanomedicine) is rapidly emerging and may help advance human health and improve diagnostics, treatment, and therapeutics of diseases.
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Affiliation(s)
- Farhan Chowdhury
- Department of Mechanical Engineering and Energy ProcessesSouthern Illinois University CarbondaleCarbondaleIllinoisUSA
| | - Bo Huang
- Department of Immunology, Institute of Basic Medical Sciences & State Key Laboratory of Medical Molecular BiologyChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Ning Wang
- Department of Mechanical Science and EngineeringUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
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Dai Y, Zhang R, Sun W, Wang T, Chen Y, Tong Z. Dynamical heterogeneity in the gelation process of a polymer solution with a lower critical solution temperature. SOFT MATTER 2021; 17:3222-3233. [PMID: 33624665 DOI: 10.1039/d0sm02159h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The gelation of a hydrophobically modified hyaluronic acid aqueous solution which shows a lower critical solution temperature of about 25 °C was investigated by multi-particle tracking microrheology. The linear viscoelasticity of the gelling system is converted from the microrheological data. The critical gelling temperature Tgel = 36.3 °C was determined from the loss tangent by the Winter-Chambon criterion. The critical exponent n = 0.62 was determined from the shift factors of the time-cure superposition. The length scales of the dynamic heterogeneity of the gelling system were analyzed using a proposed framework where single-particle and multi-particle non-Gaussian parameters were compared. The length scale of the dynamic heterogeneous regions monotonically decreases during the gelation process, consistent with the nucleation-and-growth mechanism of phase separation. Distributions of local viscosity in the gelling system were extracted from the observed distributions of particle displacement as a time-dependent fingerprint of the dynamic heterogeneity of the gelling system. The results and analyzing methods proposed in the present work can be applied to other microrheological studies.
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Affiliation(s)
- Yingkang Dai
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
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Hafner J, Oelschlaeger C, Willenbacher N. Microrheology imaging of fiber suspensions - a case study for lyophilized collagen I in HCl solutions. SOFT MATTER 2020; 16:9014-9027. [PMID: 32821895 DOI: 10.1039/d0sm01096k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In fiber suspensions with low optical contrast, the in situ characterization of structural properties with conventional microscopy methods fails. However, overlaying subsequent images of multiple particle tracking (MPT) videos including short trajectories usually discarded in MPT analysis allowed for direct visualization of individual fibers and the network structure of lyophilized collagen I (Coll) distributed in hydrochloric acid solutions. MPT yielded a broad distribution of mean square displacements (MSDs). Freely diffusing tracer particles yielded viscosities indicating that, irrespective of concentration, a constant amount of Coll is dissolved in the aqueous phase. Particles found elastically trapped within fibrous Coll structures exhibited a broad range of time-independent MSDs and we propose a structure comprising multiple fiber bundles with dense regions inaccessible to tracers and elastic regions of different stiffness in between. Bulky aggregates inaccessible to the 0.2 μm tracers exist even at low Coll concentrations, a network of slender fibers evolves above the sol-gel transition and these fibers densify with increasing Coll concentration. This novel MPT-based imaging technique possesses great potential to characterize the fiber distribution in and structural properties of a broad range of biological and technical suspensions showing low contrast when imaged with conventional techniques. Thus, MPT imaging and microrheology will help to better understand the effect of fiber distribution and network structure on the viscoelastic properties of complex suspensions.
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Affiliation(s)
- Johanna Hafner
- Department of Mechanical Engineering and Mechanics, Applied Mechanics Group, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Claude Oelschlaeger
- Department of Mechanical Engineering and Mechanics, Applied Mechanics Group, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Norbert Willenbacher
- Department of Mechanical Engineering and Mechanics, Applied Mechanics Group, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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Prediction of the enhanced insulin absorption across a triple co-cultured intestinal model using mucus penetrating PLGA nanoparticles. Int J Pharm 2020; 585:119516. [DOI: 10.1016/j.ijpharm.2020.119516] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/25/2020] [Accepted: 06/05/2020] [Indexed: 01/26/2023]
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Schiller JL, Lai SK. Tuning Barrier Properties of Biological Hydrogels. ACS APPLIED BIO MATERIALS 2020; 3:2875-2890. [DOI: 10.1021/acsabm.0c00187] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Schiller JL, Fogle MM, Bussey O, Kissner WJ, Hill DB, Lai SK. Antibody-mediated trapping in biological hydrogels is governed by sugar-sugar hydrogen bonds. Acta Biomater 2020; 107:91-101. [PMID: 32147470 DOI: 10.1016/j.actbio.2020.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 02/08/2023]
Abstract
N-glycans on IgG and IgM antibodies (Ab) facilitate Ab-mediated crosslinking of viruses and nanoparticles to the major structural elements of mucus and basement membranes. Nevertheless, the chemical moieties in these biological hydrogel matrices to which Ab can bind remain poorly understood. To gain insights into the chemistries that support Ab-matrix interactions, we systematically evaluated IgG- and IgM-mediated trapping of nanoparticles in different polysaccharide-based biogels with unique chemical features. In agarose, composed of alternating d-galactose and 3,6-anhydro-l-galactopyranose (i.e. hydroxyl groups only), anti-PEG IgM but not anti-PEG IgG trapped PEGylated nanoparticles. In alginate, comprised of homopolymeric blocks of mannuronate and guluronate (i.e. both hydroxyl and carboxyl groups), both IgG and IgM trapped PEGylated nanoparticles. In contrast, chitosan, comprised primarily of glucosamine (i.e. both hydroxyl and primary amine groups), did not facilitate either IgG- or IgM-mediated trapping. IgG-mediated trapping in alginate was abrogated upon removal of IgG N-glycans, whereas IgM-mediated trapping was eliminated in agarose but not alginate upon desialylation. These results led us to propose a model in which hydrogen bonding between carboxyl and hydroxyl groups of glycans on both Ab and matrix facilitates Ab-mediated trapping of pathogens in biogels. Our work here offers a blueprint for designing de novo hydrogels that could harness Ab-matrix interactions for various biomedical and biological applications. STATEMENT OF SIGNIFICANCE: Here, we interrogated the molecular mechanism of antibody-mediated trapping to address what are the chemical moieties on biogels that are essential for facilitating trapping in biogels. We systematically evaluated the potencies of IgG and IgM to trap nanoparticles in different polysaccharide-based biogels with unique and highly defined chemical moieties: hydroxyl groups (agarose), amine groups (chitosan), and carboxyl groups (alginate). We discovered that only hydroxyl/carboxyl hydrogen bonds (and stronger) are sufficiently strong enough to facilitate antibody-mediated trapping; weaker hydroxyl/hydroxyl bonds or hydroxyl/amine bonds fail to adequately slow particles. Our findings presents the first blueprint for how to engineer de novo biogels that are capable of harnessing antibodies to immobilize foreign entities in the biogels, for applications ranging from infectious disease to contraception to purification processes.
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Chen Z, Zhong M, Luo Y, Deng L, Hu Z, Song Y. Determination of rheology and surface tension of airway surface liquid: a review of clinical relevance and measurement techniques. Respir Res 2019; 20:274. [PMID: 31801520 PMCID: PMC6894196 DOI: 10.1186/s12931-019-1229-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 11/01/2019] [Indexed: 12/11/2022] Open
Abstract
By airway surface liquid, we mean a thin fluid continuum consisting of the airway lining layer and the alveolar lining layer, which not only serves as a protective barrier against foreign particles but also contributes to maintaining normal respiratory mechanics. In recent years, measurements of the rheological properties of airway surface liquid have attracted considerable clinical attention due to new advances in microrheology instruments and methods. This article reviews the clinical relevance of measurements of airway surface liquid viscoelasticity and surface tension from four main aspects: maintaining the stability of the airways and alveoli, preventing ventilator-induced lung injury, optimizing surfactant replacement therapy for respiratory syndrome distress, and characterizing the barrier properties of airway mucus to improve drug and gene delivery. Primary measuring techniques and methods suitable for determining the viscoelasticity and surface tension of airway surface liquid are then introduced with respect to principles, advantages and limitations. Cone and plate viscometers and particle tracking microrheometers are the most commonly used instruments for measuring the bulk viscosity and microviscosity of airway surface liquid, respectively, and pendant drop methods are particularly suitable for the measurement of airway surface liquid surface tension in vitro. Currently, in vivo and in situ measurements of the viscoelasticity and surface tension of the airway surface liquid in humans still presents many challenges.
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Affiliation(s)
- Zhenglong Chen
- School of Medical Instrumentation, Shanghai University of Medicine & Health Sciences, 257 Tianxiong Road, Shanghai, 201318 China
| | - Ming Zhong
- Department of Intensive Care Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032 China
| | - Yuzhou Luo
- School of Medical Instrumentation, Shanghai University of Medicine & Health Sciences, 257 Tianxiong Road, Shanghai, 201318 China
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, 213164 Jiangsu China
| | - Zhaoyan Hu
- School of Medical Instrumentation, Shanghai University of Medicine & Health Sciences, 257 Tianxiong Road, Shanghai, 201318 China
| | - Yuanlin Song
- Department of Pulmonary Medicine, Zhongshan Hospital Fudan University, 180 Fenglin Road, Xuhui District, Shanghai, 200032 China
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Schiller JL, Marvin A, McCallen JD, Lai SK. Robust antigen-specific tuning of the nanoscale barrier properties of biogels using matrix-associating IgG and IgM antibodies. Acta Biomater 2019; 89:95-103. [PMID: 30878451 DOI: 10.1016/j.actbio.2019.03.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 03/11/2019] [Accepted: 03/12/2019] [Indexed: 12/19/2022]
Abstract
Biological hydrogels (biogels) are selective barriers that restrict passage of harmful substances yet allow the rapid movement of nutrients and select cells. Current methods to modulate the barrier properties of biogels typically involve bulk changes in order to restrict diffusion by either steric hindrance or direct high-affinity interactions with microstructural constituents. Here, we introduce a third mechanism, based on antibody-based third party anchors that bind specific foreign species but form only weak and transient bonds with biogel constituents. The weak affinity to biogel constituents allows antibody anchors to quickly accumulate on the surface of specific foreign species and facilitates immobilization via multiple crosslinks with the biogel matrix. Using the basement membrane Matrigel® and a mixture of laminin/entactin, we demonstrate that antigen-specific, but not control, IgG and IgM efficiently immobilize a variety of individual nanoparticles. The addition of Salmonella typhimurium-binding IgG to biogel markedly reduced the invasion of these highly motile bacteria. These results underscore a generalized strategy through which the barrier properties of biogels can be readily tuned with molecular specificity against a diverse array of particulates. STATEMENT OF SIGNIFICANCE: Biological hydrogels (biogels) are essential in living systems to control the movement of cells and unwanted substances. However, current methods to control transport within biogels rely on altering the microstructure of the biogel matrix at a gross level, either by reducing the pore size to restrict passage through steric hindrance or by chemically modifying the matrix itself. Both methods are either nonspecific or not scalable. Here, we offer a new approach, based on weakly adhesive third-party molecular anchors, that allow for a variety of foreign entities to be trapped within a biogel simultaneously with exceptional potency and molecular specificity, without perturbing the bulk properties of the biogel. This strategy greatly increases our ability to control the properties of biogels at the nanoscale, including those used for wound healing or tissue engineering applications.
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Affiliation(s)
- Jennifer L Schiller
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Allison Marvin
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Justin D McCallen
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Samuel K Lai
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
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Abdulkarim M, Sharma PK, Gumbleton M. Self-emulsifying drug delivery system: Mucus permeation and innovative quantification technologies. Adv Drug Deliv Rev 2019; 142:62-74. [PMID: 30974131 DOI: 10.1016/j.addr.2019.04.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 12/14/2022]
Abstract
Mucus is a dynamic barrier which covers and protects the underlying mucosal epithelial membrane against bacteria and foreign particles. This protection mechanism extends to include therapeutic macromolecules and nanoparticles (NPs) through trapping of these particles. Mucus is not only a physical barrier that limiting particles movements based on their sizes but it selectively binds with particles through both hydrophilic and lipophilic interactions. Therefore, nano-carriers for mucosal delivery should be designed to eliminate entrapment by the mucus barrier. For this reason, different strategies have been approached for both solid nano-carriers and liquid core nano-carriers to synthesise muco-diffusive nano-carrier. Among these nano-strategies, Self-Emulsifying Drug Delivery System (SEDDS) was recognised as very promising nano-carrier for mucus delivery. The system was introduced to enhance the dissolution and bioavailability of orally administered insoluble drugs. SEDDS has shown high stability against intestinal enzymatic activity and more importantly, relatively rapid permeation characteristics across mucus barrier. The high diffusivity of SEDDS has been tested using various in vitro measurement techniques including both bulk and individual measurement of droplets diffusion within mucus. The selection and processing of an optimum in vitro technique is of great importance to avoid misinterpretation of the diffusivity of SEDDS through mucus barrier. In conclusion, SEDDS is a system with high capacity to diffuse through intestinal mucus even though this system has not been studied to the same extent as solid nano-carriers.
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Affiliation(s)
- Muthanna Abdulkarim
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | - Peeyush Kumar Sharma
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK; Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Mark Gumbleton
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK.
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Geonzon LC, Matsukawa S. Accuracy improvement of centroid coordinates and particle identification in particle tracking technique. ACTA ACUST UNITED AC 2019. [DOI: 10.17106/jbr.33.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Lester C. Geonzon
- Graduate School of Food Science and Technology, Tokyo University of Marine Science and Technology
| | - Shingo Matsukawa
- Graduate School of Food Science and Technology, Tokyo University of Marine Science and Technology
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Gutiérrez-Sosa C, Merino-González A, Sánchez R, Kozina A, Díaz-Leyva P. Microscopic Viscoelasticity of Polymer Solutions and Gels Observed from Translation and Rotation of Anisotropic Colloid Probes. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carlos Gutiérrez-Sosa
- Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, 09340 Mexico City, Mexico
| | - Arturo Merino-González
- Instituto de Química, Universidad Nacional Autónoma de México, P.O.
Box 70-213, 04510 Mexico City, Mexico
| | - Rodrigo Sánchez
- Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, 09340 Mexico City, Mexico
| | - Anna Kozina
- Instituto de Química, Universidad Nacional Autónoma de México, P.O.
Box 70-213, 04510 Mexico City, Mexico
| | - Pedro Díaz-Leyva
- Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco 186, 09340 Mexico City, Mexico
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Schroeder HA, Nunn KL, Schaefer A, Henry CE, Lam F, Pauly MH, Whaley KJ, Zeitlin L, Humphrys MS, Ravel J, Lai SK. Herpes simplex virus-binding IgG traps HSV in human cervicovaginal mucus across the menstrual cycle and diverse vaginal microbial composition. Mucosal Immunol 2018; 11:1477-1486. [PMID: 29988116 PMCID: PMC6485947 DOI: 10.1038/s41385-018-0054-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 05/29/2018] [Accepted: 05/31/2018] [Indexed: 02/04/2023]
Abstract
IgG possesses an important yet little recognized effector function in mucus. IgG bound to viral surface can immobilize otherwise readily diffusive viruses to the mucin matrix, excluding them from contacting target cells and facilitating their elimination by natural mucus clearance mechanisms. Cervicovaginal mucus (CVM) is populated by a microbial community, and its viscoelastic and barrier properties can vary substantially not only across the menstrual cycle, but also in women with distinct microbiota. How these variations impact the "muco-trapping" effector function of IgGs remains poorly understood. Here we obtained multiple fresh, undiluted CVM specimens (n = 82 unique specimens) from six women over time, and employed high-resolution multiple particle tracking to quantify the mobility of fluorescent Herpes Simplex Viruses (HSV-1) in CVM treated with different HSV-1-binding IgG. The IgG trapping potency was then correlated to the menstrual cycle, and the vaginal microbial composition was determined by 16 s rRNA. In the specimens studied, both polyclonal and monoclonal HSV-1-binding IgG appeared to consistently and effectively trap HSV-1 in CVM obtained at different times of the menstrual cycle and containing a diverse spectrum of commensals, including G. vaginalis-dominant microbiota. Our findings underscore the potential broad utility of this "muco-trapping" effector function of IgG to reinforce the vaginal mucosal defense, and motivates further investigation of passive immunization of the vagina as a strategy to protect against vaginally transmitted infections.
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Affiliation(s)
- Holly A. Schroeder
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27519, USA
| | - Kenetta L. Nunn
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27519, USA.,UNC/NCSU Joint Department of Biomedical Engineering, Chapel Hill, NC, 27519, USA
| | - Alison Schaefer
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27519, USA
| | - Christine E. Henry
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27519, USA
| | - Felix Lam
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27519, USA
| | | | | | - Larry Zeitlin
- Mapp Biopharmaceutical Inc., San Diego, CA, 92121, USA
| | - Mike S. Humphrys
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jacques Ravel
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Samuel K. Lai
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27519, USA.,UNC/NCSU Joint Department of Biomedical Engineering, Chapel Hill, NC, 27519, USA
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18
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Yu M, Xu L, Tian F, Su Q, Zheng N, Yang Y, Wang J, Wang A, Zhu C, Guo S, Zhang X, Gan Y, Shi X, Gao H. Rapid transport of deformation-tuned nanoparticles across biological hydrogels and cellular barriers. Nat Commun 2018; 9:2607. [PMID: 29973592 PMCID: PMC6031689 DOI: 10.1038/s41467-018-05061-3] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 04/26/2018] [Indexed: 11/14/2022] Open
Abstract
To optimally penetrate biological hydrogels such as mucus and the tumor interstitial matrix, nanoparticles (NPs) require physicochemical properties that would typically preclude cellular uptake, resulting in inefficient drug delivery. Here, we demonstrate that (poly(lactic-co-glycolic acid) (PLGA) core)-(lipid shell) NPs with moderate rigidity display enhanced diffusivity through mucus compared with some synthetic mucus penetration particles (MPPs), achieving a mucosal and tumor penetrating capability superior to that of both their soft and hard counterparts. Orally administered semi-elastic NPs efficiently overcome multiple intestinal barriers, and result in increased bioavailability of doxorubicin (Dox) (up to 8 fold) compared to Dox solution. Molecular dynamics simulations and super-resolution microscopy reveal that the semi-elastic NPs deform into ellipsoids, which enables rotation-facilitated penetration. In contrast, rigid NPs cannot deform, and overly soft NPs are impeded by interactions with the hydrogel network. Modifying particle rigidity may improve the efficacy of NP-based drugs, and can be applicable to other barriers. Penetration of the mucus and tumor interstitial matrix is an important consideration for drug delivery devices. Here, the authors report on a study into the optimization of rigidity for the transport of nanoparticles through biological hydrogels using core-shell polymer-lipid nanoparticles.
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Affiliation(s)
- Miaorong Yu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China
| | - Lu Xu
- School of Pharmacy, Shenyang Pharmaceutical University, 110016, Shenyang, China
| | - Falin Tian
- CAS Key Laboratory for Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, 100190, Beijing, China
| | - Qian Su
- University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China.,CAS Key Laboratory for Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, 100190, Beijing, China.,LNM, Institute of Mechanics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Nan Zheng
- School of Pharmacy, Shenyang Pharmaceutical University, 110016, Shenyang, China
| | - Yiwei Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China
| | - Jiuling Wang
- University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China.,CAS Key Laboratory for Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, 100190, Beijing, China.,LNM, Institute of Mechanics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Aohua Wang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.,University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China
| | - Chunliu Zhu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China
| | - Shiyan Guo
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China
| | - XinXin Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China
| | - Yong Gan
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China. .,University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China.
| | - Xinghua Shi
- University of Chinese Academy of Sciences, NO.19A Yuquan Road, 100049, Beijing, China. .,CAS Key Laboratory for Nanosystem and Hierarchy Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, 100190, Beijing, China.
| | - Huajian Gao
- School of Engineering, Brown University, Providence, RI, 02912, USA.
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19
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Song W, Yang Y, Yu M, Zhu Q, Damaneh MS, Zhong H, Gan Y. Enhanced digestion inhibition and mucus penetration of F127-modified self-nanoemulsions for improved oral delivery. Asian J Pharm Sci 2018; 13:326-335. [PMID: 32104406 PMCID: PMC7032245 DOI: 10.1016/j.ajps.2018.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/01/2018] [Accepted: 03/05/2018] [Indexed: 01/27/2023] Open
Abstract
Self-nanoemulsifying systems (SNEs) have excellent ability to improve the solubility of poorly water-soluble drugs (PWSD). However, SNEs are likely to be degraded in gastrointestinal (GIT) when their surface is recognized by lipase/co-lipase enzyme complex, resulting in rapid release and precipitation of encapsulated drugs. The precipitates are then captured and removed by intestinal mucus, reducing the delivery efficacy of SNEs. Herein, the amphiphilic polymer Pluronic® F127 was incorporated into long and short-chain triglycerides (LCT, SCT) based SNEs to diminish the recognition and therefore minimized their degradation by enzymes and clearance by mucus. The SNEs were characterized in terms of particle size, zeta potential and stability. Ex vivo multiple particles tracking studies were performed by adding particle solution into fresh rat mucus. Cellular uptake of SNEs were conducted by using E12 cells, the absorption and distribution in small intestine were also studied after oral administration in male Sprague-Dawley (SD) rats. The in vitro digestion rate of SNEs were found to be in following order SCT-SNE > SCT-F127-SNE > LCT-SNE > LCT-F127-SNE. Moreover, the LCT-F127-SNE was found to be most effective in enhancing cellular uptake, resulting in 3.5-fold, 2.1-fold and 1.7-fold higher than that of SCT-SNE, LCT-SNE and SCT-F127-SNE, respectively. After incubating the SNE with E12 cells, the LCT-F127-SNE exhibited the highest amount regarding both mucus penetration and cellular uptake, with an uptake amount number (via bicinchoninic acid (BCA) analysis) of 3.5-fold, 2.1-fold and 1.7-fold higher than that of SCT-SNE, LCT-SNE and SCT-F127-SNE, respectively. The in vivo results revealed that orally administered LCT-F127-SNE could significantly increase the bioavailability of Cyclosporine A (CsA), which was approximately 2.43-fold, 1.33-fold and 1.80-fold higher than that of SCT-SNE, SCT-F127-SNE and LCT-SNE, respectively. We address in this work that F127-modified SNEs have potentials to improve oral drug absorption by significantly reducing gastrointestinal enzymatic degradation and simultaneously enhancing mucus penetration.
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Affiliation(s)
- Wenyi Song
- Department of Pharmacy, Medical College of Nanchang University, 461 Bayi Road, Nanchang 330066, China.,Shanghai Institute of Materia Medica, Chinese Academy of Sciences, No. 501 Haike Road, Shanghai 201203, China
| | - Yuting Yang
- Department of Pharmacy, Medical College of Nanchang University, 461 Bayi Road, Nanchang 330066, China.,Shanghai Institute of Materia Medica, Chinese Academy of Sciences, No. 501 Haike Road, Shanghai 201203, China
| | - Miaorong Yu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, No. 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, NO.19A Yuquan Road, Beijing 100049, China
| | - Quanlei Zhu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, No. 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, NO.19A Yuquan Road, Beijing 100049, China
| | - Mohammadali Soleimani Damaneh
- University of Chinese Academy of Sciences, NO.19A Yuquan Road, Beijing 100049, China.,Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Haijun Zhong
- Department of Pharmacy, Medical College of Nanchang University, 461 Bayi Road, Nanchang 330066, China
| | - Yong Gan
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, No. 501 Haike Road, Shanghai 201203, China.,University of Chinese Academy of Sciences, NO.19A Yuquan Road, Beijing 100049, China
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20
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Struntz P, Weiss M. The hitchhiker's guide to quantitative diffusion measurements. Phys Chem Chem Phys 2018; 20:28910-28919. [DOI: 10.1039/c8cp06158k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Quantitative comparison of three widely used techniques for diffusion measurements, implemented on a light sheet microscope.
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Affiliation(s)
- Philipp Struntz
- Experimental Physics I
- University of Bayreuth
- D-95447 Bayreuth
- Germany
| | - Matthias Weiss
- Experimental Physics I
- University of Bayreuth
- D-95447 Bayreuth
- Germany
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21
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Clayton KN, Berglund GD, Linnes JC, Kinzer-Ursem TL, Wereley ST. DNA Microviscosity Characterization with Particle Diffusometry for Downstream DNA Detection Applications. Anal Chem 2017; 89:13334-13341. [PMID: 29148723 DOI: 10.1021/acs.analchem.7b03513] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Analytical characterization of DNA microviscosity provides critical biophysical insights into nuclear crowding, nucleic acid based pharmaceutical development, and nucleic acid based biosensor device design. However, most viscosity characterization methods require large sample volumes and destructive testing. In contrast, particle diffusometry permits in situ analysis of DNA microviscosity with short measurement times (8 s) using small volumes (<3 μL) which are compatible with DNA preparatory procedures. This unconventional biosensing approach involves measuring the change in sample viscosity using image processing and correlation-based algorithms. Particle diffusometry requires only a fluorescence microscope equipped with a charge-coupled device (CCD) camera and is a nondestructive measurement method. We use particle diffusometry to characterize the effect of DNA topology, length, and concentration on solution viscosity. In addition, we use particle diffusometry to detect the amplification of DNA from Staphylococcus aureus and Klebsiella pneumoniae, two pathogens commonly related to neonatal sepsis. Successful characterization of pathogen amplification with particle diffusometry provides a new opportunity to apply viscosity characterization toward downstream applications in nucleic acid based pathogen detection.
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Affiliation(s)
- Katherine N Clayton
- School of Mechanical Engineering, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47906, United States
| | - Gregory D Berglund
- School of Mechanical Engineering, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47906, United States
| | - Jacqueline C Linnes
- School of Mechanical Engineering, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47906, United States
| | - Tamara L Kinzer-Ursem
- School of Mechanical Engineering, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47906, United States
| | - Steven T Wereley
- School of Mechanical Engineering, and ‡Weldon School of Biomedical Engineering, Purdue University , West Lafayette, Indiana 47906, United States
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22
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Matsumoto Y, Shundo A, Ohno M, Tsuruzoe N, Goto M, Tanaka K. Evolution of heterogeneity accompanying sol-gel transitions in a supramolecular hydrogel. SOFT MATTER 2017; 13:7433-7440. [PMID: 28967654 DOI: 10.1039/c7sm01612c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
When a peptide amphiphile is dispersed in water, it self-assembles into a fibrous network, leading to a supramolecular hydrogel. When the gel is physically disrupted by shaking, it transforms into a sol state. After aging at room temperature for a while, it spontaneously returns to the gel state, called sol-gel transition. However, repeating the sol-gel transition often causes a change in the rheological properties of the gel. To gain a better understanding of the sol-gel transition and its reversibility, we herein examined the thermal motion of probe particles at different locations in a supramolecular hydrogel. The sol obtained by shaking the gel was heterogeneous in terms of the rheological properties and the extent decreased with increasing aging time. This time course of heterogeneity, or homogeneity, which corresponded to the sol-to-gel transition, was observed for the 1st cycle. However, this was not the case for the 2nd and 3rd cycles; the heterogeneity was preserved even after aging. Fourier-transform infrared spectroscopy, small-angle X-ray scattering, and atomic force and confocal laser scanning microscopies revealed that, although the molecular aggregation states of amphiphiles both in the gel and sol remained unchanged with the cycles, the fibril density diversified to high and low density regions even after aging. The tracking of particles with different sizes indicated that the partial mesh size in the high density region and the characteristic length scale of the density fluctuation were smaller than 50 nm and 6 μm, respectively.
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Affiliation(s)
- Yuji Matsumoto
- Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan.
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23
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Newby J, Schiller JL, Wessler T, Edelstein J, Forest MG, Lai SK. A blueprint for robust crosslinking of mobile species in biogels with weakly adhesive molecular anchors. Nat Commun 2017; 8:833. [PMID: 29018239 PMCID: PMC5635012 DOI: 10.1038/s41467-017-00739-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 07/25/2017] [Indexed: 12/21/2022] Open
Abstract
Biopolymeric matrices can impede transport of nanoparticulates and pathogens by entropic or direct adhesive interactions, or by harnessing "third-party" molecular anchors to crosslink nanoparticulates to matrix constituents. The trapping potency of anchors is dictated by association rates and affinities to both nanoparticulates and matrix; the popular dogma is that long-lived, high-affinity bonds to both species facilitate optimal trapping. Here we present a contrasting paradigm combining experimental evidence (using IgG antibodies and Matrigel®), a theoretical framework (based on multiple timescale analysis), and computational modeling. Anchors that bind and unbind rapidly from matrix accumulate on nanoparticulates much more quickly than anchors that form high-affinity, long-lived bonds with matrix, leading to markedly greater trapping potency of multiple invading species without saturating matrix trapping capacity. Our results provide a blueprint for engineering molecular anchors with finely tuned affinities to effectively enhance the barrier properties of biogels against diverse nanoparticulate species.Biological polymeric matrices often use molecular anchors, such as antibodies, to trap nanoparticulates. Here, the authors find that anchor-matrix bonds that are weak and short-lived confer superior trapping potency, contrary to the prevailing belief that effective molecular anchors should form strong bonds to both the matrix and the nanoparticulates.
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Affiliation(s)
- Jay Newby
- Department of Mathematics, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.,Department of Applied Physical Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jennifer L Schiller
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Timothy Wessler
- Department of Mathematics, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.,Department of Applied Physical Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jasmine Edelstein
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA
| | - M Gregory Forest
- Department of Mathematics, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA. .,Department of Applied Physical Sciences, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA. .,UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Samuel K Lai
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA. .,UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA. .,Department of Microbiology & Immunology, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
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24
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Weigand WJ, Messmore A, Tu J, Morales-Sanz A, Blair DL, Deheyn DD, Urbach JS, Robertson-Anderson RM. Active microrheology determines scale-dependent material properties of Chaetopterus mucus. PLoS One 2017; 12:e0176732. [PMID: 28562662 PMCID: PMC5451080 DOI: 10.1371/journal.pone.0176732] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 04/15/2017] [Indexed: 12/24/2022] Open
Abstract
We characterize the lengthscale-dependent rheological properties of mucus from the ubiquitous Chaetopterus marine worm. We use optically trapped probes (2-10 μm) to induce microscopic strains and measure the stress response as a function of oscillation amplitude. Our results show that viscoelastic properties are highly dependent on strain scale (l), indicating three distinct lengthscale-dependent regimes at l1 ≤4 μm, l2≈4-10 μm, and l3≥10 μm. While mucus response is similar to water for l1, suggesting that probes rarely contact the mucus mesh, the response for l2 is distinctly more viscous and independent of probe size, indicative of continuum mechanics. Only for l3 does the response match the macroscopic elasticity, likely due to additional stiffer constraints that strongly resist probe displacement. Our results suggest that, rather than a single lengthscale governing crossover from viscous to elastic, mucus responds as a hierarchical network with a loose biopolymer mesh coupled to a larger scaffold responsible for macroscopic gel-like mechanics.
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Affiliation(s)
- W. J. Weigand
- Department of Physics and Biophysics, University of San Diego, San Diego, California, United States of America
| | - A. Messmore
- Department of Physics and Biophysics, University of San Diego, San Diego, California, United States of America
| | - J. Tu
- Marine Biology Research Division, Scripps Institution of Oceanography, La Jolla, California, United States of America
| | - A. Morales-Sanz
- Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington DC, United States of America
| | - D. L. Blair
- Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington DC, United States of America
| | - D. D. Deheyn
- Marine Biology Research Division, Scripps Institution of Oceanography, La Jolla, California, United States of America
| | - J. S. Urbach
- Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington DC, United States of America
| | - R. M. Robertson-Anderson
- Department of Physics and Biophysics, University of San Diego, San Diego, California, United States of America
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25
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Del Giudice F, Tassieri M, Oelschlaeger C, Shen AQ. When Microrheology, Bulk Rheology, and Microfluidics Meet: Broadband Rheology of Hydroxyethyl Cellulose Water Solutions. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02727] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Francesco Del Giudice
- Micro/Bio/Nanofluidics
Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495 Japan
| | - Manlio Tassieri
- Division
of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow G12 8LT, U.K
| | - Claude Oelschlaeger
- Institute
for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Gotthard-Franz-Strasse 3, 76131 Karlsruhe, Germany
| | - Amy Q. Shen
- Micro/Bio/Nanofluidics
Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495 Japan
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26
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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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27
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Koo PK, Mochrie SGJ. Systems-level approach to uncovering diffusive states and their transitions from single-particle trajectories. Phys Rev E 2016; 94:052412. [PMID: 27967069 DOI: 10.1103/physreve.94.052412] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Indexed: 06/06/2023]
Abstract
The stochastic motions of a diffusing particle contain information concerning the particle's interactions with binding partners and with its local environment. However, an accurate determination of the underlying diffusive properties, beyond normal diffusion, has remained challenging when analyzing particle trajectories on an individual basis. Here, we introduce the maximum-likelihood estimator (MLE) for confined diffusion and fractional Brownian motion. We demonstrate that this MLE yields improved estimation over traditional mean-square displacement analyses. We also introduce a model selection scheme (that we call mleBIC) that classifies individual trajectories to a given diffusion mode. We demonstrate the statistical limitations of classification via mleBIC using simulated data. To overcome these limitations, we introduce a version of perturbation expectation-maximization (pEMv2), which simultaneously analyzes a collection of particle trajectories to uncover the system of interactions that give rise to unique normal and/or non-normal diffusive states within the population. We test and evaluate the performance of pEMv2 on various sets of simulated particle trajectories, which transition among several modes of normal and non-normal diffusion, highlighting the key considerations for employing this analysis methodology.
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Affiliation(s)
- Peter K Koo
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
| | - Simon G J Mochrie
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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28
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Henry CE, Wang YY, Yang Q, Hoang T, Chattopadhyay S, Hoen T, Ensign LM, Nunn KL, Schroeder H, McCallen J, Moench T, Cone R, Roffler SR, Lai SK. Anti-PEG antibodies alter the mobility and biodistribution of densely PEGylated nanoparticles in mucus. Acta Biomater 2016; 43:61-70. [PMID: 27424083 DOI: 10.1016/j.actbio.2016.07.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/24/2016] [Accepted: 07/12/2016] [Indexed: 11/18/2022]
Abstract
UNLABELLED Antibodies that specifically bind polyethylene glycol (PEG) can lead to rapid elimination of PEGylated therapeutics from the systemic circulation. We have recently shown that virus-binding IgG can immobilize viruses in mucus via multiple low-affinity crosslinks between IgG and mucins. However, it remains unclear whether anti-PEG antibodies in mucus may also alter the penetration and consequently biodistribution of PEGylated nanoparticles delivered to mucosal surfaces. We found that both anti-PEG IgG and IgM can readily bind nanoparticles that were densely coated with PEG polymer to minimize adhesive interactions with mucus constituents. Addition of anti-PEG IgG and IgM into mouse cervicovaginal mucus resulted in extensive trapping of mucus-penetrating PEGylated nanoparticles, with the fraction of mobile particles reduced from over 95% to only 34% and 7% with anti-PEG IgG and IgM, respectively. Surprisingly, we did not observe significant agglutination induced by either antibody, suggesting that particle immobilization is caused by adhesive crosslinks between mucin fibers and IgG or IgM bound to individual nanoparticles. Importantly, addition of corresponding control antibodies did not slow the PEGylated nanoparticles, confirming anti-PEG antibodies specifically bound to and trapped the PEGylated nanoparticles. Finally, we showed that trapped PEGylated nanoparticles remained largely in the luminal mucus layer of the mouse vagina even when delivered in hypotonic formulations that caused untrapped particles to be drawn by the flow of water (advection) through mucus all the way to the epithelial surface. These results underscore the potential importance of elucidating mucosal anti-PEG immune responses for PEGylated therapeutics and biomaterials applied to mucosal surfaces. STATEMENT OF SIGNIFICANCE PEG, generally considered a 'stealth' polymer, is broadly used to improve the circulation times and therapeutic efficacy of nanomedicines. Nevertheless, there is increasing scientific evidence that demonstrates both animals and humans can generate PEG-specific antibodies. Here, we show that anti-PEG IgG and IgM can specifically immobilize otherwise freely diffusing PEG-coated nanoparticles in fresh vaginal mucus gel ex vivo by crosslinking nanoparticles to the mucin mesh, and consequently prevent PEG-coated nanoparticles from accessing the vaginal epithelium in vivo. Given the increasing use of PEG coatings to enhance nanoparticle penetration of mucosal barriers, our findings demonstrate that anti-PEG immunity may be a potential concern not only for systemic drug delivery but also for mucosal drug delivery.
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Affiliation(s)
- Christine E Henry
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Ying-Ying Wang
- Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Qi Yang
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Thuy Hoang
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
| | - Sumon Chattopadhyay
- Center for Nanomedicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
| | - Timothy Hoen
- Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Laura M Ensign
- Center for Nanomedicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
| | - Kenetta L Nunn
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Holly Schroeder
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Justin McCallen
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Thomas Moench
- ReProtect, Inc., 703 Stags Head Road, Baltimore, MD 21286, USA
| | - Richard Cone
- Department of Biophysics, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - Steve R Roffler
- Institute of Biomedical Sciences, Academia Sinica, No. 128, Section 2, Academia Road, Taipei 11529, Taiwan
| | - Samuel K Lai
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA; UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA; Department of Microbiology & Immunology, University of North Carolina - Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA.
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29
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Weis C, Oelschlaeger C, Dijkstra D, Ranft M, Willenbacher N. Microstructure, local dynamics, and flow behavior of colloidal suspensions with weak attractive interactions. Sci Rep 2016; 6:33498. [PMID: 27653975 PMCID: PMC5031965 DOI: 10.1038/srep33498] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/25/2016] [Indexed: 11/19/2022] Open
Abstract
We present a comprehensive micro- and macrorheological study of the effect of weak depletion attraction (Ψdep ≈ 1-10 kBT) on dense colloidal suspensions stabilized by short-range repulsive interactions. We used aqueous polymer dispersions as model system and demonstrated the unique capabilities of multiple particle tracking (MPT) to disclose structural changes in such technically important systems exhibiting many characteristic features of hard sphere systems. Below the hard sphere freezing point ϕc, viscosity increases monotonically with increasing Ψdep due to the transition from a fluid to a fluid/crystalline and finally to a gel state. Above ϕc, increasing attraction strength first results in a viscosity reduction corresponding to the formation of large, permeable crystals and then in a viscosity increase when a network of dense, small crystals forms. The fraction of the fluid and crystal phase, particle concentration in each phase as well as the modulus of the micro-crystals are obtained, the latter decreases with Ψdep. Above the colloidal glass transition strong heterogeneities and different local particle mobility in the repulsive and attractive arrested states are found. Particles are trapped in the cage of neighboring particles rather than in an attractive potential well. The intermediate ergodic state exhibits uniform tracer diffusivity.
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Affiliation(s)
- Clara Weis
- Karlsruhe Institute for Technology (KIT), Institute for Mechanical Process Engineering and Mechanics, Applied Mechanics, Karlsruhe, 76131, Germany
| | - Claude Oelschlaeger
- Karlsruhe Institute for Technology (KIT), Institute for Mechanical Process Engineering and Mechanics, Applied Mechanics, Karlsruhe, 76131, Germany
| | | | | | - Norbert Willenbacher
- Karlsruhe Institute for Technology (KIT), Institute for Mechanical Process Engineering and Mechanics, Applied Mechanics, Karlsruhe, 76131, Germany
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31
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Frith WJ. Self-assembly of small peptide amphiphiles, the structures formed and their applications. (A foods and home and personal care perspective). PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2015.0138. [PMID: 27298432 DOI: 10.1098/rsta.2015.0138] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/12/2016] [Indexed: 06/06/2023]
Abstract
In this opinion piece, some specific challenges in the field of peptide self-assembly and gel formation are discussed. One major hurdle to finding functional small peptides is that there are a huge number of compounds to explore, which increases exponentially with the peptide size. This in itself creates a barrier to the discovery and application of materials, both through the difficulty of finding the peptides, and because protecting inventions also becomes more difficult. Recent work has shown that computer simulations may provide us a route to explore such a huge compound space; this is discussed along with the prospect for future developments. At the microscopic scale, many fibril-forming peptides form gels, apparently through a process of lateral association of primary self-assembled filaments, which leads to a relatively coarse-grained structure of rigid interconnects. However, recent data obtained on Fmoc-tyrosine gels appear to indicate that the gel microstructure is both more flexible and finer grained than previously believed. As such, it is clear that there is a considerable amount that is still not understood regarding this class of gel.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.
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Affiliation(s)
- W J Frith
- Unilever R&D Colworth, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
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32
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Kuroda M, Murayama Y. Simple method to measure and analyze the fluctuations of a small particle in biopolymer solutions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:125105. [PMID: 26724071 DOI: 10.1063/1.4936879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We developed a simple method to investigate the motion of a small particle in biopolymer solutions. Using optical tweezers with low stiffness, a trapped probe particle fluctuates widely for a long time along the light axis, which reflects the rheological properties of the surrounding environment. We present a convenient technique for three-dimensional position tracking and the analysis focused on the distribution of particle positions and its variance in a given time interval. It allows us to obtain useful information about the dynamics of a small particle in a wide range from a free diffusive motion to a constrained motion with statistical significance. We applied this method to investigate the dynamics in collagen and DNA solutions; it was found that a collagen solution behaves as a simple viscous liquid and a DNA solution has apparent elasticity due to the slow relaxation of the configuration of molecules.
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Affiliation(s)
- Masafumi Kuroda
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Yoshihiro Murayama
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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33
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Rohrer J, Partenhauser A, Hauptstein S, Gallati CM, Matuszczak B, Abdulkarim M, Gumbleton M, Bernkop-Schnürch A. Mucus permeating thiolated self-emulsifying drug delivery systems. Eur J Pharm Biopharm 2015; 98:90-7. [PMID: 26598209 DOI: 10.1016/j.ejpb.2015.11.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/21/2015] [Accepted: 11/09/2015] [Indexed: 01/13/2023]
Abstract
CONTEXT Mucus represents a critical obstacle for self-emulsifying drug delivery systems (SEDDS) targeting the epithelial membrane site. OBJECTIVE The aim of the study was the development of a novel SEDDS to overcome the mucus barrier. MATERIALS AND METHODS Two novel conjugates N-dodecyl-4-mercaptobutanimidamide (thiobutylamidine-dodecylamine, TBA-D) and 2-mercapto-N-octylacetamide (thioglycolicacid-octylamine, TGA-O) were synthesized, incorporated into SEDDS and analyzed for stability, cytotoxicity and physico-chemical characteristics using dynamic light scattering. Mucus interaction studies were performed using in vitro assays based on multiple particle tracking, rotational silicone tubes and rheology. RESULTS AND DISCUSSION TBA-D was synthesized using dodecylamine and iminothiolane as thiol precursor (yield=55 ± 5%). TGA-O was obtained via crosslinking of octylamine with SATA ((2,5-dioxopyrrolidin-1-yl) 2-acetylsulfanylacetate) (yield=70 ± 6%). The chemical structure of target compounds was confirmed via NMR analysis. The thiol-conjugates were incorporated in an amount of 3% (m/m) into SEDDS (Cremophor EL 30%, Capmul MCM 30%, Captex 355 30% and propylene glycol 10%), namely thiolated SEDDS leading to a droplet size around 50 nm and zeta potential close to 0 mV. Thiolated SEDDS with an effective diffusion coefficient 〈Deff〉 of up to 0.871 ± 0.122 cm(2) s(-1) × 10(-9) were obtained. Rotational silicone studies show increased permeation of the thiolated SEDDS A in comparison with unthiolated control. Rheological studies confirmed the mucolytic activity of the thiol-conjugates which differed only by 3% from DTT (dithiothreitol) serving as positive control. CONCLUSION Low molecular weight thiol-conjugates were identified to improve the mucus permeation, leading to highly efficient mucus permeating SEDDS, which were superior to conventional SEDDS and might thus be a new carrier for lipophilic drug delivery.
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Affiliation(s)
- Julia Rohrer
- Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria
| | - Alexandra Partenhauser
- Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria
| | - Sabine Hauptstein
- Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria
| | - Caroline Marie Gallati
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria
| | - Barbara Matuszczak
- Department of Pharmaceutical Chemistry, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria
| | - Muthanna Abdulkarim
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK
| | - Mark Gumbleton
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3NB, UK
| | - Andreas Bernkop-Schnürch
- Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, Innsbruck, Austria.
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34
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Wang YY, Nunn KL, Harit D, McKinley SA, Lai SK. Minimizing biases associated with tracking analysis of submicron particles in heterogeneous biological fluids. J Control Release 2015; 220:37-43. [PMID: 26478013 DOI: 10.1016/j.jconrel.2015.10.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/31/2015] [Accepted: 10/13/2015] [Indexed: 10/22/2022]
Abstract
Tracking the dynamic motion of individual nanoparticles or viruses offers quantitative insights into their real-time behavior and fate in different biological environments. Indeed, particle tracking is a powerful tool that has facilitated the development of drug carriers with enhanced penetration of mucus, brain tissues and other extracellular matrices. Nevertheless, heterogeneity is a hallmark of nanoparticle diffusion in such complex environments: identical particles can exhibit strongly hindered or unobstructed diffusion within microns of each other. The common practice in 2D particle tracking, namely analyzing all trackable particle traces with equal weighting, naturally biases towards rapidly diffusing sub-populations at shorter time scales. This in turn results in misrepresentation of particle behavior and a systematic underestimate of the time necessary for a population of nanoparticles to diffuse specific distances. We show here via both computational simulation and experimental data that this bias can be rigorously corrected by weighing the contribution by each particle trace on a 'frame-by-frame' basis. We believe this methodology presents an important step towards objective and accurate assessment of the heterogeneous transport behavior of submicron drug carriers and pathogens in biological environments.
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Affiliation(s)
- Ying-Ying Wang
- Department of Biophysics, Johns Hopkins University, 3400 North Charles St, Baltimore, MD 21218, USA
| | - Kenetta L Nunn
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, 120 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Dimple Harit
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, 120 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Scott A McKinley
- Mathematics Department, University of Florida, 1400 Stadium Road, Gainesville, FL 32611, USA
| | - Samuel K Lai
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill, 120 Mason Farm Road, Chapel Hill, NC 27599, USA; Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina - Chapel Hill, 120 Mason Farm Road, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina School of Medicine, 125 Mason Farm Road, Chapel Hill, NC 27599, USA.
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Enhanced Trapping of HIV-1 by Human Cervicovaginal Mucus Is Associated with Lactobacillus crispatus-Dominant Microbiota. mBio 2015; 6:e01084-15. [PMID: 26443453 PMCID: PMC4611035 DOI: 10.1128/mbio.01084-15] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cervicovaginal mucus (CVM) can provide a barrier that precludes HIV and other sexually transmitted virions from reaching target cells in the vaginal epithelium, thereby preventing or reducing infections. However, the barrier properties of CVM differ from woman to woman, and the causes of these variations are not yet well understood. Using high-resolution particle tracking of fluorescent HIV-1 pseudoviruses, we found that neither pH nor Nugent scores nor total lactic acid levels correlated significantly with virus trapping in unmodified CVM from diverse donors. Surprisingly, HIV-1 was generally trapped in CVM with relatively high concentrations of d-lactic acid and a Lactobacillus crispatus-dominant microbiota. In contrast, a substantial fraction of HIV-1 virions diffused rapidly through CVM with low concentrations of d-lactic acid that had a Lactobacillus iners-dominant microbiota or significant amounts of Gardnerella vaginalis, a bacterium associated with bacterial vaginosis. Our results demonstrate that the vaginal microbiota, including specific species of Lactobacillus, can alter the diffusional barrier properties of CVM against HIV and likely other sexually transmitted viruses and that these microbiota-associated changes may account in part for the elevated risks of HIV acquisition linked to bacterial vaginosis or intermediate vaginal microbiota. Variations in the vaginal microbiota, especially shifts away from Lactobacillus-dominant microbiota, are associated with differential risks of acquiring HIV or other sexually transmitted infections. However, emerging evidence suggests that Lactobacillus iners frequently colonizes women with recurring bacterial vaginosis, raising the possibility that L. iners may not be as protective as other Lactobacillus species. Our study was designed to improve understanding of how the cervicovaginal mucus barrier against HIV may vary between women along with the vaginal microbiota and led to the finding that the vaginal microbiota, including specific species of Lactobacillus, can directly alter the diffusional barrier properties of cervicovaginal mucus. This work advances our understanding of the complex barrier properties of mucus and highlights the differential protective ability of different species of Lactobacillus, with Lactobacillus crispatus and possibly other species playing a key role in protection against HIV and other sexually transmitted infections. These findings could lead to the development of novel strategies to protect women against HIV.
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36
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Grießinger J, Dünnhaupt S, Cattoz B, Griffiths P, Oh S, Gómez SBI, Wilcox M, Pearson J, Gumbleton M, Abdulkarim M, Pereira de Sousa I, Bernkop-Schnürch A. Methods to determine the interactions of micro- and nanoparticles with mucus. Eur J Pharm Biopharm 2015; 96:464-76. [DOI: 10.1016/j.ejpb.2015.01.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 02/01/2023]
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37
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Smal I, Meijering E. Quantitative comparison of multiframe data association techniques for particle tracking in time-lapse fluorescence microscopy. Med Image Anal 2015; 24:163-189. [PMID: 26176413 DOI: 10.1016/j.media.2015.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 04/29/2015] [Accepted: 06/17/2015] [Indexed: 02/08/2023]
Abstract
Biological studies of intracellular dynamic processes commonly require motion analysis of large numbers of particles in live-cell time-lapse fluorescence microscopy imaging data. Many particle tracking methods have been developed in the past years as a first step toward fully automating this task and enabling high-throughput data processing. Two crucial aspects of any particle tracking method are the detection of relevant particles in the image frames and their linking or association from frame to frame to reconstruct the trajectories. The performance of detection techniques as well as specific combinations of detection and linking techniques for particle tracking have been extensively evaluated in recent studies. Comprehensive evaluations of linking techniques per se, on the other hand, are lacking in the literature. Here we present the results of a quantitative comparison of data association techniques for solving the linking problem in biological particle tracking applications. Nine multiframe and two more traditional two-frame techniques are evaluated as a function of the level of missing and spurious detections in various scenarios. The results indicate that linking techniques are generally more negatively affected by missing detections than by spurious detections. If misdetections can be avoided, there appears to be no need to use sophisticated multiframe linking techniques. However, in the practically likely case of imperfect detections, the latter are a safer choice. Our study provides users and developers with novel information to select the right linking technique for their applications, given a detection technique of known quality.
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Affiliation(s)
- Ihor Smal
- Biomedical Imaging Group Rotterdam, Erasmus MC-University Medical Center Rotterdam, Departments of Medical Informatics and Radiology, P.O. Box 2040, Rotterdam 3000 CA, The Netherlands.
| | - Erik Meijering
- Biomedical Imaging Group Rotterdam, Erasmus MC-University Medical Center Rotterdam, Departments of Medical Informatics and Radiology, P.O. Box 2040, Rotterdam 3000 CA, The Netherlands
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38
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Kowalczyk A, Oelschlaeger C, Willenbacher N. Visualization of micro-scale inhomogeneities in acrylic thickener solutions: A multiple particle tracking study. POLYMER 2015. [DOI: 10.1016/j.polymer.2014.12.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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39
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Phillies GDJ. In complex fluids the Gaussian Diffusion Approximation is generally invalid. SOFT MATTER 2015; 11:580-586. [PMID: 25427441 DOI: 10.1039/c4sm02506g] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The Gaussian Diffusion Approximation proposes that the distribution of displacements Δx for a particle diffusing through a complex fluid has a Gaussian dependence on Δx. We demonstrate from experimental evidence and computer simulations that this approximation is generally incorrect in complex fluids. As a result, experimental studies that have used the Gaussian Diffusion Approximation to interpret their findings will need to be reconsidered.
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40
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Wang YY, Kannan A, Nunn KL, Murphy MA, Subramani DB, Moench T, Cone R, Lai SK. IgG in cervicovaginal mucus traps HSV and prevents vaginal herpes infections. Mucosal Immunol 2014; 7:1036-44. [PMID: 24496316 PMCID: PMC4122653 DOI: 10.1038/mi.2013.120] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 12/04/2013] [Indexed: 02/07/2023]
Abstract
IgG is the predominant immunoglobulin in cervicovaginal mucus (CVM), yet how immunoglobulin G (IgG) in mucus can protect against infections is not fully understood. IgG diffuses rapidly through cervical mucus, slowed only slightly by transient adhesive interactions with mucins. We hypothesize that this almost unhindered diffusion allows IgG to accumulate rapidly on pathogen surfaces, and the resulting IgG array forms multiple weak adhesive crosslinks to mucus gel that effectively trap (immobilize) pathogens, preventing them from initiating infections. Here, we report that herpes simplex virus serotype 1 (HSV-1) readily penetrated fresh, pH-neutralized ex vivo samples of CVM with low or no detectable levels of anti-HSV-1 IgG but was trapped in samples with even modest levels of anti-HSV-1 IgG. In samples with little or no endogenous anti-HSV-1 IgG, addition of exogenous anti-HSV-1 IgG, affinity-purified from intravenous immunoglobulin, trapped virions at concentrations below those needed for neutralization and with similar potency as endogenous IgG. Deglycosylating purified anti-HSV-1 IgG, or removing its Fc component, markedly reduced trapping potency. Finally, a non-neutralizing IgG against HSV-gG significantly protected mice against vaginal infection, and removing vaginal mucus by gentle lavage abolished protection. These observations suggest that IgG-Fc has a glycan-dependent "muco-trapping" effector function that may provide exceptionally potent protection at mucosal surfaces.
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Affiliation(s)
- Ying-Ying Wang
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Arthi Kannan
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina – Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kenetta L. Nunn
- UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina – Chapel Hill, Chapel Hill, NC 27599, USA
| | - Michael A. Murphy
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina – Chapel Hill, Chapel Hill, NC 27599, USA
| | - Durai B. Subramani
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina – Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Richard Cone
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Samuel K. Lai
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina – Chapel Hill, Chapel Hill, NC 27599, USA,UNC/NCSU Joint Department of Biomedical Engineering, University of North Carolina – Chapel Hill, Chapel Hill, NC 27599, USA
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41
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Groo AC, Lagarce F. Mucus models to evaluate nanomedicines for diffusion. Drug Discov Today 2014; 19:1097-108. [DOI: 10.1016/j.drudis.2014.01.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/20/2013] [Accepted: 01/24/2014] [Indexed: 01/25/2023]
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42
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Galy O, Zrelli K, Latour-Lambert P, Kirwan L, Henry N. Remote magnetic actuation of micrometric probes for in situ 3D mapping of bacterial biofilm physical properties. J Vis Exp 2014. [PMID: 24837001 DOI: 10.3791/50857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in these structures are held together by physical interactions mediated by a network of extracellular polymeric substances. Bacterial biofilms impact many human activities and the understanding of their properties is crucial for a better control of their development - maintenance or eradication - depending on their adverse or beneficial outcome. This paper describes a novel methodology aiming to measure in situ the local physical properties of the biofilm that had been, until now, examined only from a macroscopic and homogeneous material perspective. The experiment described here involves introducing magnetic particles into a growing biofilm to seed local probes that can be remotely actuated without disturbing the structural properties of the biofilm. Dedicated magnetic tweezers were developed to exert a defined force on each particle embedded in the biofilm. The setup is mounted on the stage of a microscope to enable the recording of time-lapse images of the particle-pulling period. The particle trajectories are then extracted from the pulling sequence and the local viscoelastic parameters are derived from each particle displacement curve, thereby providing the 3D-spatial distribution of the parameters. Gaining insights into the biofilm mechanical profile is essential from an engineer's point of view for biofilm control purposes but also from a fundamental perspective to clarify the relationship between the architectural properties and the specific biology of these structures.
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Affiliation(s)
- Olivier Galy
- Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC
| | - Kais Zrelli
- Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC
| | | | - Lyndsey Kirwan
- Laboratoire Jean Perrin, CNRS UMR 8237, Sorbonne Universités, UPMC
| | - Nelly Henry
- Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC; Laboratoire Jean Perrin, CNRS UMR 8237, Sorbonne Universités, UPMC;
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Aufderhorst-Roberts A, Frith WJ, Donald AM. A microrheological study of hydrogel kinetics and micro-heterogeneity. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2014; 37:44. [PMID: 24859279 DOI: 10.1140/epje/i2014-14044-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 01/31/2014] [Accepted: 03/20/2014] [Indexed: 05/03/2023]
Abstract
The real-time dynamic heterogeneity of the gelation process of the amino acid derivative Fmoc-tyrosine (Fmoc-Y) is studied using particle tracking microrheology. To trigger gelation, glucono-δ-lactone (GdL) is added, which gradually lowers the p H over several hours. The onset of self-assembly in the system is signified by a sharp drop in the mean-squared displacement of embedded particles, a phenomenon that is found to correlate with the p H of the system reaching the pK(a) of Fmoc-Y. The gel point is identified and found to be dependent on the GdL concentration. Analysis of embedded probe particle dynamics allows the heterogeneity of the sample to be quantified, using three metrics: the heterogeneity ratio (HR), the non-Gaussian parameter of the van Hove correlation function (N and the bin distribution of the mean-squared displacement (MSD) of single particles (f(z)). Results from the three techniques are found to be approximately comparable, with increases in heterogeneity observed in all samples for incubation times t(w) = 0-3 hours. The final heterogeneity in all samples is found to be remarkably low compared to other systems previously reported in the literature.
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Affiliation(s)
- Anders Aufderhorst-Roberts
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK,
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Varner VD, Nelson CM. Let's push things forward: disruptive technologies and the mechanics of tissue assembly. Integr Biol (Camb) 2014; 5:1162-73. [PMID: 23907401 DOI: 10.1039/c3ib40080h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Although many of the molecular mechanisms that regulate tissue assembly in the embryo have been delineated, the physical forces that couple these mechanisms to actual changes in tissue form remain unclear. Qualitative studies suggest that mechanical loads play a regulatory role in development, but clear quantitative evidence has been lacking. This is partly owing to the complex nature of these problems - embryonic tissues typically undergo large deformations and exhibit evolving, highly viscoelastic material properties. Still, despite these challenges, new disruptive technologies are enabling study of the mechanics of tissue assembly in unprecedented detail. Here, we present novel experimental techniques that enable the study of each component of these physical problems: kinematics, forces, and constitutive properties. Specifically, we detail advances in light sheet microscopy, optical coherence tomography, traction force microscopy, fluorescence force spectroscopy, microrheology and micropatterning. Taken together, these technologies are helping elucidate a more quantitative understanding of the mechanics of tissue assembly.
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Affiliation(s)
- Victor D Varner
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, USA
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Pawelzyk P, Mücke N, Herrmann H, Willenbacher N. Attractive interactions among intermediate filaments determine network mechanics in vitro. PLoS One 2014; 9:e93194. [PMID: 24690778 PMCID: PMC3972185 DOI: 10.1371/journal.pone.0093194] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 02/28/2014] [Indexed: 01/11/2023] Open
Abstract
Mechanical and structural properties of K8/K18 and vimentin intermediate filament (IF) networks have been investigated using bulk mechanical rheometry and optical microrheology including diffusing wave spectroscopy and multiple particle tracking. A high elastic modulus G0 at low protein concentration c, a weak concentration dependency of G0 (G0∼c0.5±0.1) and pronounced strain stiffening are found for these systems even without external crossbridgers. Strong attractive interactions among filaments are required to maintain these characteristic mechanical features, which have also been reported for various other IF networks. Filament assembly, the persistence length of the filaments and the network mesh size remain essentially unaffected when a nonionic surfactant is added, but strain stiffening is completely suppressed, G0 drops by orders of magnitude and exhibits a scaling G0∼c1.9±0.2 in agreement with microrheological measurements and as expected for entangled networks of semi-flexible polymers. Tailless K8Δ/K18ΔT and various other tailless filament networks do not exhibit strain stiffening, but still show high G0 values. Therefore, two binding sites are proposed to exist in IF networks. A weaker one mediated by hydrophobic amino acid clusters in the central rod prevents stretched filaments between adjacent cross-links from thermal equilibration and thus provides the high G0 values. Another strong one facilitating strain stiffening is located in the tail domain with its high fraction of hydrophobic amino acid sequences. Strain stiffening is less pronounced for vimentin than for K8/K18 due to electrostatic repulsion forces partly compensating the strong attraction at filament contact points.
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Affiliation(s)
- Paul Pawelzyk
- Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Norbert Mücke
- Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
| | - Norbert Willenbacher
- Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- * E-mail:
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Wang YY, Lai SK, Ensign LM, Zhong W, Cone R, Hanes J. The microstructure and bulk rheology of human cervicovaginal mucus are remarkably resistant to changes in pH. Biomacromolecules 2013; 14:4429-35. [PMID: 24266646 DOI: 10.1021/bm401356q] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The protective barrier, lubricant, and clearance functions of mucus are intimately coupled to its microstructure and bulk rheology. Mucus gels consist of a network of mucin biopolymers along with lipids, salts, and other proteins and exhibit similar biochemical and physical properties across diverse mucosal surfaces. Nevertheless, mucus is exposed to a broad range of pH values throughout the human body. Protein functions are typically sensitive to small changes in pH, and prior investigations using reconstituted, purified mucin gels suggested mucus undergoes a transition from a low-viscosity liquid at neutral pH to a highly viscoelastic solid at low pH. We sought to determine whether those observations hold for fresh, minimally perturbed human mucus ex vivo by using different-sized muco-inert nanoparticles to probe microstructure and cone-and-plate rheometry to measure bulk rheology. We demonstrate that both the microstructure and bulk rheology of fresh, undiluted, and minimally perturbed cervicovaginal mucus exhibit relatively minor changes from pH 1-2 to 8-9, in marked contrast with the pH sensitivity of purified mucin gels. Our work also suggests additional components in mucus secretions, typically eliminated during mucin purification and reconstitution, may play an important role in maintaining the protective properties of mucus.
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Affiliation(s)
- Ying-Ying Wang
- Center for Nanomedicine, ‡Department of Biomedical Engineering, and §Department of Ophthalmology, Johns Hopkins University School of Medicine , Baltimore, Maryland 21231, United States
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Lakkegowda Y, Ammannappa R, Ananthamurthy S. Investigations on rheological properties and gelation of tasar regenerated silk fibroin solution. J Appl Polym Sci 2013. [DOI: 10.1002/app.40104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yogesha Lakkegowda
- Department of Physics; Jnanabharathi, Bangalore University; Bengaluru 560056 Karnataka India
- Department of Physics; Government Science College; Hassan 573201 Karnataka India
| | - Raghu Ammannappa
- Department of Physics; Jnanabharathi, Bangalore University; Bengaluru 560056 Karnataka India
- Post Graduate Department of Physics; Government College (Autonomous); Mandya 571401 Karnataka India
| | - Sharath Ananthamurthy
- Department of Physics; Jnanabharathi, Bangalore University; Bengaluru 560056 Karnataka India
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Golde T, Schuldt C, Schnauß J, Strehle D, Glaser M, Käs J. Fluorescent beads disintegrate actin networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:044601. [PMID: 24229308 DOI: 10.1103/physreve.88.044601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Indexed: 06/02/2023]
Abstract
We studied the influence of fluorescent polystyrene beads on both entangled and cross-linked actin networks. Thermal bead fluctuations were observed via video particle tracking and analyzed with one-point microrheology. Illumination of fluorescent beads with their appropriate excitation wavelength leads to a drastic softening of actin gels. Other wavelengths and bright field microscopy do not increase thermal bead fluctuations. This effect cannot be significantly reduced by adding common oxygen scavengers. We conclude that the usage of fluorescent beads impairs results when studying the microrheology of actin networks.
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Affiliation(s)
- Tom Golde
- Soft Matter Physics, Institute for Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany
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Moschakis T. Microrheology and particle tracking in food gels and emulsions. Curr Opin Colloid Interface Sci 2013. [DOI: 10.1016/j.cocis.2013.04.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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