1
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Dindo M, Bevilacqua A, Soligo G, Calabrese V, Monti A, Shen AQ, Rosti ME, Laurino P. Chemotactic Interactions Drive Migration of Membraneless Active Droplets. J Am Chem Soc 2024; 146:15965-15976. [PMID: 38620052 DOI: 10.1021/jacs.4c02823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
In nature, chemotactic interactions are ubiquitous and play a critical role in driving the collective behavior of living organisms. Reproducing these interactions in vitro is still a paramount challenge due to the complexity of mimicking and controlling cellular features, such as tangled metabolic networks, cytosolic macromolecular crowding, and cellular migration, on a microorganism size scale. Here, we generate enzymatically active cell-sized droplets able to move freely, and by following a chemical gradient, able to interact with the surrounding droplets in a collective manner. The enzyme within the droplets generates a pH gradient that extends outside the edge of the droplets. We discovered that the external pH gradient triggers droplet migration and controls its directionality, which is selectively toward the neighboring droplets. Hence, by changing the enzyme activity inside the droplet, we tuned the droplet migration speed. Furthermore, we showed that these cellular-like features can facilitate the reconstitution of a simple and linear protometabolic pathway and increase the final reaction product generation. Our work suggests that simple and stable membraneless droplets can reproduce complex biological phenomena, opening new perspectives as bioinspired materials and synthetic biology tools.
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Affiliation(s)
- Mirco Dindo
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Alessandro Bevilacqua
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Giovanni Soligo
- Complex Fluids and Flows Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Vincenzo Calabrese
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Alessandro Monti
- Complex Fluids and Flows Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Amy Q Shen
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Marco Edoardo Rosti
- Complex Fluids and Flows Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
| | - Paola Laurino
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0412, Japan
- Institute for Protein Research, Osaka University, Suita 565-0871, Japan
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2
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Testa A, Spanke HT, Jambon-Puillet E, Yasir M, Feng Y, Küffner AM, Arosio P, Dufresne ER, Style RW, Rebane AA. Surface Passivation Method for the Super-repellence of Aqueous Macromolecular Condensates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14626-14637. [PMID: 37797324 PMCID: PMC10586374 DOI: 10.1021/acs.langmuir.3c01886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/21/2023] [Indexed: 10/07/2023]
Abstract
Solutions of macromolecules can undergo liquid-liquid phase separation to form droplets with ultralow surface tension. Droplets with such low surface tension wet and spread over common surfaces such as test tubes and microscope slides, complicating in vitro experiments. The development of a universal super-repellent surface for macromolecular droplets has remained elusive because their ultralow surface tension requires low surface energies. Furthermore, the nonwetting of droplets containing proteins poses additional challenges because the surface must remain inert to a wide range of chemistries presented by the various amino acid side chains at the droplet surface. Here, we present a method to coat microscope slides with a thin transparent hydrogel that exhibits complete dewetting (contact angles θ ≈ 180°) and minimal pinning of phase-separated droplets in aqueous solution. The hydrogel is based on a swollen matrix of chemically cross-linked polyethylene glycol diacrylate of molecular weight 12 kDa (PEGDA), and can be prepared with basic chemistry laboratory equipment. The PEGDA hydrogel is a powerful tool for in vitro studies of weak interactions, dynamics, and the internal organization of phase-separated droplets in aqueous solutions.
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Affiliation(s)
- Andrea Testa
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Etienne Jambon-Puillet
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
- LadHyX,
CNRS, Ecole Polytechnique, Institut Polytechnique
de Paris, Palaiseau 91120, France
| | - Mohammad Yasir
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Yanxia Feng
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Andreas M. Küffner
- Department
of Chemistry and Applied Biosciences, Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Paolo Arosio
- Department
of Chemistry and Applied Biosciences, Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Robert W. Style
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Aleksander A. Rebane
- Department
of Materials, ETH Zürich, 8093 Zürich, Switzerland
- Life
Molecules and Materials Laboratory, Programs in Chemistry and in Physics, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
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3
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Thome C, Hoertdoerfer WS, Bendorf JR, Lee JG, Shields CW. Electrokinetic Active Particles for Motion-Based Biomolecule Detection. NANO LETTERS 2023; 23:2379-2387. [PMID: 36881680 PMCID: PMC10038089 DOI: 10.1021/acs.nanolett.3c00319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Detection of biomolecules is essential for patient diagnosis, disease management, and numerous other applications. Recently, nano- and microparticle-based detection has been explored for improving traditional assays by reducing required sample volumes and assay times as well as enhancing tunability. Among these approaches, active particle-based assays that couple particle motion to biomolecule concentration expand assay accessibility through simplified signal outputs. However, most of these approaches require secondary labeling, which complicates workflows and introduces additional points of error. Here, we show a proof-of-concept for a label-free, motion-based biomolecule detection system using electrokinetic active particles. We prepare induced-charge electrophoretic microsensors (ICEMs) for the capture of two model biomolecules, streptavidin and ovalbumin, and show that the specific capture of the biomolecules leads to direct signal transduction through ICEM speed suppression at concentrations as low as 0.1 nM. This work lays the foundation for a new paradigm of rapid, simple, and label-free biomolecule detection using active particles.
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Affiliation(s)
- Cooper
P. Thome
- Department of Chemical and
Biological Engineering, University of Colorado
Boulder, Boulder, Colorado 80303, United States
| | - Wren S. Hoertdoerfer
- Department of Chemical and
Biological Engineering, University of Colorado
Boulder, Boulder, Colorado 80303, United States
| | - Julia R. Bendorf
- Department of Chemical and
Biological Engineering, University of Colorado
Boulder, Boulder, Colorado 80303, United States
| | - Jin Gyun Lee
- Department of Chemical and
Biological Engineering, University of Colorado
Boulder, Boulder, Colorado 80303, United States
| | - C. Wyatt Shields
- Department of Chemical and
Biological Engineering, University of Colorado
Boulder, Boulder, Colorado 80303, United States
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4
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Ezquerro CS, Aznar JMG, Laspalas M. Prediction of the structure and mechanical properties of polycaprolactone-silica nanocomposites and the interphase region by molecular dynamics simulations: the effect of PEGylation. SOFT MATTER 2022; 18:2800-2813. [PMID: 35319045 DOI: 10.1039/d1sm01794b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Polymer/silica (PS) nanocomposites are, among numerous combinations of inorganic/organic nanocomposites, one of the most important materials reported in the literature and have been employed in a wide variety of applications. Due to this great interest in the scientific and industry community, knowledge about their physiochemistry allows for a better understanding of their development and improvement. One area of interest found in biopolymers is silica, where silica nanoparticles can be used to increase their mechanical properties and give them higher opportunities to replace synthetic plastics. With this aim in mind, molecular dynamics (MD) simulations were used to predict the structure and mechanical properties of the interphase region and nanocomposite systems of polycaprolactone (PCL), a common poly(hydroxy acid) type biopolymer, reinforced with silica nanoparticles. Two types of nanoparticles were studied to assess the effect of PEGylation: hydroxyl (ungrafted) and polyethylene glycol (PEG) (grafted or PEGylated) functionalized silica. The interaction energy between the nanoparticle and the polymeric matrix was determined, showing an increase of the affinity between each component due to the PEGylation of the nanoparticle. Through the analysis of polymer density profiles, the structure and thickness of the interphase region were determined, and it was observed that PEGylation increased the interphase thickness from 10.80 Å to 13.04 Å while it decreased the peak and average polymer density of the interphase region. Using compressed and expanded molecular models of the neat PCL polymer, the mechanical properties of the interphase region were related to its density through an interpolation model, and mechanical property profiles were obtained, from which the average values of the Young's modulus, Poisson's ratio and shear modulus of the interphase region were calculated. Finally, the mechanical properties of the nanocomposites were determined by molecular mechanics simulations, showing that the silica nanoparticles increased the stiffness of the composite system to about 7-8% with respect to that of the neat polymer, having a 2.09% weight of bare silica or 2.82% weight of PEGylated silica. PEGylation did not show an additional effect on the overall mechanical properties. A mean field micromechanics model (Mori-Tanaka) corroborated the properties calculated for the interphase region using MD simulations. It was concluded that the PEGylation of the nanoparticle improved the affinity, and thus the dispersion, of the silica nanoparticles towards the PCL matrix, but with no further increase in the mechanical properties of the composite.
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Affiliation(s)
| | | | - Manuel Laspalas
- Aragon Institute of Technology ITAINNOVA, María de Luna 7-8, Zaragoza 50018, Spain.
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5
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Multimodal microwheel swarms for targeting in three-dimensional networks. Sci Rep 2022; 12:5078. [PMID: 35332242 PMCID: PMC8948265 DOI: 10.1038/s41598-022-09177-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/16/2022] [Indexed: 01/02/2023] Open
Abstract
Microscale bots intended for targeted drug delivery must move through three-dimensional (3D) environments that include bifurcations, inclined surfaces, and curvature. In previous studies, we have shown that magnetically actuated colloidal microwheels (µwheels) reversibly assembled from superparamagnetic beads can translate rapidly and be readily directed. Here we show that, at high concentrations, µwheels assemble into swarms that, depending on applied magnetic field actuation patterns, can be designed to transport cargo, climb steep inclines, spread over large areas, or provide mechanical action. We test the ability of these multimodal swarms to navigate through complex, inclined microenvironments by characterizing the translation and dispersion of individual µwheels and swarms of µwheels on steeply inclined and flat surfaces. Swarms are then studied within branching 3D vascular models with multiple turns where good targeting efficiencies are achieved over centimeter length scales. With this approach, we present a readily reconfigurable swarm platform capable of navigating through 3D microenvironments.
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6
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Reduction of dissolved carbon dioxide in aqueous solution by UV-LED/TiO2 process under periodic illumination. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.101283] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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7
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Ordonez C, Watanabe N, Kozaki T. Migration of polyethylene glycol coated gold nanoparticles in surrogate natural barriers. J NUCL SCI TECHNOL 2020. [DOI: 10.1080/00223131.2020.1727371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Carlos Ordonez
- Graduate School of Engineering, Hokkaido University, North 13 West 8, Sapporo, Japan
| | - Naoko Watanabe
- Division of Energy and Environmental Systems, Faculty of Engineering, Hokkaido University, North 13 West 8, Sapporo, Japan
| | - Tamotsu Kozaki
- Division of Energy and Environmental Systems, Faculty of Engineering, Hokkaido University, North 13 West 8, Sapporo, Japan
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8
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Rinaldin M, Verweij RW, Chakraborty I, Kraft DJ. Colloid supported lipid bilayers for self-assembly. SOFT MATTER 2019; 15:1345-1360. [PMID: 30565635 PMCID: PMC6371764 DOI: 10.1039/c8sm01661e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/23/2018] [Indexed: 05/10/2023]
Abstract
The use of colloid supported lipid bilayers (CSLBs) has recently been extended to create colloidal joints, that enable the assembly of structures with internal degrees of flexibility, and to study lipid membranes on curved and closed geometries. These novel applications of CSLBs rely on previously unappreciated properties: the simultaneous fluidity of the bilayer, lateral mobility of inserted (linker) molecules and colloidal stability. Here we characterize every step in the manufacturing of CSLBs in view of these requirements using confocal microscopy and fluorescence recovery after photobleaching (FRAP). Specifically, we have studied the influence of different particle properties (roughness, surface charge, chemical composition, polymer coating) on the quality and mobility of the supported bilayer. We find that the insertion of lipopolymers in the bilayer can affect its homogeneity and fluidity. We improve the colloidal stability by inserting lipopolymers or double-stranded inert DNA into the bilayer. We include surface-mobile DNA linkers and use FRAP to characterize their lateral mobility both in their freely diffusive and bonded state. Finally, we demonstrate the self-assembly of flexibly linked structures from the CSLBs modified with surface-mobile DNA linkers. Our work offers a collection of experimental tools for working with CSLBs in applications ranging from controlled bottom-up self-assembly to model membrane studies.
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Affiliation(s)
- Melissa Rinaldin
- Huygens-Kamerlingh Onnes Lab, Universiteit Leiden
,
P.O. Box 9504
, 2300 RA Leiden
, The Netherlands
.
- Instituut-Lorentz, Universiteit Leiden
,
P.O. Box 9506
, 2300 RA Leiden
, The Netherlands
| | - Ruben W. Verweij
- Huygens-Kamerlingh Onnes Lab, Universiteit Leiden
,
P.O. Box 9504
, 2300 RA Leiden
, The Netherlands
.
| | - Indrani Chakraborty
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University
,
Tel Aviv 69978
, Israel
| | - Daniela J. Kraft
- Huygens-Kamerlingh Onnes Lab, Universiteit Leiden
,
P.O. Box 9504
, 2300 RA Leiden
, The Netherlands
.
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9
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Kirkness MWH, Korosec CS, Forde NR. Modified Pluronic F127 Surface for Bioconjugation and Blocking Nonspecific Adsorption of Microspheres and Biomacromolecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13550-13557. [PMID: 30303387 DOI: 10.1021/acs.langmuir.8b02877] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Many experiments and applications require the chemical coupling of target molecules to surfaces, during which the elimination of nonspecific interactions presents a difficult challenge. We report on a technologically accessible surface passivation and chemical conjugation method based on an NHS end-labeled F127 Pluronic block copolymer (F127-NHS). To quantify interactions between the F127-NHS surface and magnetic microspheres, we developed a simple assay: the microsphere adhesion by gravity, inversion, then counting, or "MAGIC" assay. To improve blocking of microspheres while maintaining the ability to chemically couple additional molecules, we implemented a pH-dependent two-step chemical modification process for amine microspheres. This process achieves an extremely high level of blocking nonspecific interactions (less than 2% nonspecific adhesion) for a variety of microsphere surface charges and chemical functionalities. We also demonstrate the ability to specifically tether magnetic microspheres to an F127-NHS surface, using single DNA molecules. Using the DNA microspheres, we establish the applicability of the surface for force spectroscopy (stable with an applied load >30 pN) via the massively parallel technique of centrifuge force microscopy. Finally, we demonstrate that the surface can be used in fluorescence studies with a fluorogenic peptide cleavage assay, with high levels of blocking achieved for both the fluorogenic peptide and trypsin. These results suggest applications including, but not limited to, single-molecule force spectroscopy and fluorescence, biosensors, medical implants, and anti-biofouling, which could make use of the F127-NHS surface.
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10
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Derr JB, Tamayo J, Espinoza EM, Clark JA, Vullev VI. Dipole-induced effects on charge transfer and charge transport. Why do molecular electrets matter? CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0389] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Charge transfer (CT) and charge transport (CTr) are at the core of life-sustaining biological processes and of processes that govern the performance of electronic and energy-conversion devices. Electric fields are invaluable for guiding charge movement. Therefore, as electrostatic analogues of magnets, electrets have unexplored potential for generating local electric fields for accelerating desired CT processes and suppressing undesired ones. The notion about dipole-generated local fields affecting CT has evolved since the middle of the 20th century. In the 1990s, the first reports demonstrating the dipole effects on the kinetics of long-range electron transfer appeared. Concurrently, the development of molecular-level designs of electric junctions has led the exploration of dipole effects on CTr. Biomimetic molecular electrets such as polypeptide helices are often the dipole sources in CT systems. Conversely, surface-charge electrets and self-assembled monolayers of small polar conjugates are the preferred sources for modifying interfacial electric fields for controlling CTr. The multifaceted complexity of such effects on CT and CTr testifies for the challenges and the wealth of this field that still remains largely unexplored. This review outlines the basic concepts about dipole effects on CT and CTr, discusses their evolution, and provides accounts for their future developments and impacts.
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Affiliation(s)
- James B. Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Jesse Tamayo
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Eli M. Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - John A. Clark
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Valentine I. Vullev
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
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11
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van der Wel C, Bossert N, Mank QJ, Winter MGT, Heinrich D, Kraft DJ. Surfactant-free Colloidal Particles with Specific Binding Affinity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:9803-9810. [PMID: 28847149 PMCID: PMC5618147 DOI: 10.1021/acs.langmuir.7b02065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Colloidal particles with specific binding affinity are essential for in vivo and in vitro biosensing, targeted drug delivery, and micrometer-scale self-assembly. Key to these techniques are surface functionalizations that provide high affinities to specific target molecules. For stabilization in physiological environments, current particle coating methods rely on adsorbed surfactants. However, spontaneous desorption of these surfactants typically has an undesirable influence on lipid membranes. To address this issue and create particles for targeting molecules in lipid membranes, we present here a surfactant-free coating method that combines high binding affinity with stability at physiological conditions. After activating charge-stabilized polystyrene microparticles with EDC/Sulfo-NHS, we first coat the particles with a specific protein and subsequently covalently attach a dense layer of poly(ethyelene) glycol. This polymer layer provides colloidal stability at physiological conditions as well as antiadhesive properties, while the protein coating provides the specific affinity to the targeted molecule. We show that NeutrAvidin-functionalized particles bind specifically to biotinylated membranes and that Concanavalin A-functionalized particles bind specifically to the glycocortex of Dictyostelium discoideum cells. The affinity of the particles changes with protein density, which can be tuned during the coating procedure. The generic and surfactant-free coating method reported here transfers the high affinity and specificity of a protein onto colloidal polystyrene microparticles.
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Affiliation(s)
- Casper van der Wel
- Biological
and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O.
Box 9504, 2300 RA Leiden, The Netherlands
| | - Nelli Bossert
- Biological
and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O.
Box 9504, 2300 RA Leiden, The Netherlands
| | - Quinten J. Mank
- Biological
and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O.
Box 9504, 2300 RA Leiden, The Netherlands
| | - Marcel G. T. Winter
- Biological
and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O.
Box 9504, 2300 RA Leiden, The Netherlands
| | - Doris Heinrich
- Biological
and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O.
Box 9504, 2300 RA Leiden, The Netherlands
- Fraunhofer
Institute for Silicate Research, Neunerplatz 2, 97082 Würzburg, Germany
| | - Daniela J. Kraft
- Biological
and Soft Matter Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O.
Box 9504, 2300 RA Leiden, The Netherlands
- E-mail:
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12
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Lipid membrane-mediated attraction between curvature inducing objects. Sci Rep 2016; 6:32825. [PMID: 27618764 PMCID: PMC5020653 DOI: 10.1038/srep32825] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/16/2016] [Indexed: 01/18/2023] Open
Abstract
The interplay of membrane proteins is vital for many biological processes, such as cellular transport, cell division, and signal transduction between nerve cells. Theoretical considerations have led to the idea that the membrane itself mediates protein self-organization in these processes through minimization of membrane curvature energy. Here, we present a combined experimental and numerical study in which we quantify these interactions directly for the first time. In our experimental model system we control the deformation of a lipid membrane by adhering colloidal particles. Using confocal microscopy, we establish that these membrane deformations cause an attractive interaction force leading to reversible binding. The attraction extends over 2.5 times the particle diameter and has a strength of three times the thermal energy (-3.3 kBT). Coarse-grained Monte-Carlo simulations of the system are in excellent agreement with the experimental results and prove that the measured interaction is independent of length scale. Our combined experimental and numerical results reveal membrane curvature as a common physical origin for interactions between any membrane-deforming objects, from nanometre-sized proteins to micrometre-sized particles.
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13
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Ciftci Z, Kurc MA, Kaya AD, Saracoglu GV, Deniz M, Gultekin E. Do we really need to coat the novel silicone intranasal splints with antibiotics? Am J Otolaryngol 2016; 37:447-51. [PMID: 27105976 DOI: 10.1016/j.amjoto.2016.02.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 02/11/2016] [Accepted: 02/15/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE The novel silicone intranasal splints are suggested to resist biofilm formation due to their surface characteristics. We aimed to ascertain the necessity of coating these splints with antibiotics to prevent splint associated infections, in vitro. MATERIALS AND METHODS Pieces of Doyle II airway nasal splints made of medical grade silicone were divided into two test groups, treated with either (i) 0.2% nitrofurazone solution or (ii) 0.2% nitrofurazone containing ointment, and a control group, treated with (iii) 0.9% saline. Splint pieces were then incubated with Staphylococcus aureus solutions at 37°C for 48 and 96h. Following this, the splint pieces were incubated in 20ml Mueller Hinton agar and appearing colonies were counted. RESULTS Following 48and 96h of incubation, the colonization rates in the saline group were significantly higher than the nitrofurazone ointment group (p<0.001). The colonization rates in the liquid nitrofurazone group were significantly lower in comparison to the nitrofurazone ointment group (p<0.001 and p=0.019 respectively). CONCLUSIONS The method of coating the splints with antibiotic was superior to using uncoated splints in terms of preventing S. aureus colonization. The rather smooth surfaces of the splints were insufficient to block bacterial colonization and coating them with antibiotics seems to be beneficial for the prevention of infections.
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Affiliation(s)
- Zafer Ciftci
- Namik Kemal University, School of Medicine, Department of Otorhinolaryngology
| | - Mine Aydin Kurc
- Namik Kemal University, School of Medicine, Department of Microbiology
| | - Ayse Demet Kaya
- Okan University, School of Medicine, Department of Microbiology
| | | | - Mahmut Deniz
- Namik Kemal University, School of Medicine, Department of Otorhinolaryngology
| | - Erdogan Gultekin
- Namik Kemal University, School of Medicine, Department of Otorhinolaryngology.
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14
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Re-assembly behaviors of block copolymer micelles on substrates: effects of block length and interaction force. Colloid Polym Sci 2016. [DOI: 10.1007/s00396-015-3761-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Espinoza EM, Xia B, Darabedian N, Larsen JM, Nuñez V, Bao D, Mac JT, Botero F, Wurch M, Zhou F, Vullev VI. Nitropyrene Photoprobes: Making Them, and What Are They Good for? European J Org Chem 2015. [DOI: 10.1002/ejoc.201501339] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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16
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Yang W, Zhang Y, Hilke M, Reisner W. Dynamic imaging of Au-nanoparticles via scanning electron microscopy in a graphene wet cell. NANOTECHNOLOGY 2015; 26:315703. [PMID: 26177916 DOI: 10.1088/0957-4484/26/31/315703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
High resolution nanoscale imaging in liquid environments is crucial for studying molecular interactions in biological and chemical systems. In particular, electron microscopy is the gold-standard tool for nanoscale imaging, but its high-vacuum requirements make application to in-liquid samples extremely challenging. Here we present a new graphene based wet cell device where high resolution scanning electron microscope (SEM) and energy dispersive x-rays (EDX) analysis can be performed directly inside a liquid environment. Graphene is an ideal membrane material as its high transparancy, conductivity and mechanical strength can support the high vacuum and grounding requirements of a SEM while enabling maximal resolution and signal. In particular, we obtain high resolution ([Formula: see text] nm) SEM video images of nanoparticles undergoing Brownian motion inside the graphene wet cell and EDX analysis of nanoparticle composition in the liquid enviornment. Our obtained resolution surpasses current conventional silicon nitride devices imaged in both a SEM and transmission electron microscope under much higher electron doses.
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Affiliation(s)
- Wayne Yang
- Department of Physics and RQMP, McGill University, Montreal, Canada
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17
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Larsen JM, Espinoza EM, Hartman JD, Lin CK, Wurch M, Maheshwari P, Kaushal RK, Marsella MJ, Beran GJO, Vullev VI. Building blocks for bioinspired electrets: molecular-level approach to materials for energy and electronics. PURE APPL CHEM 2015. [DOI: 10.1515/pac-2015-0109] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AbstractIn biology, an immense diversity of protein structural and functional motifs originates from only 20 common proteinogenic native amino acids arranged in various sequences. Is it possible to attain the same diversity in electronic materials based on organic macromolecules composed of non-native residues with different characteristics? This publication describes the design, preparation and characterization of non-native aromatic β-amino acid residues, i.e. derivatives of anthranilic acid, for polyamides that can efficiently mediate hole transfer. Chemical derivatization with three types of substituents at two positions of the aromatic ring allows for adjusting the energy levels of the frontier orbitals of the anthranilamide residues over a range of about one electronvolt. Most importantly, the anthranilamide residues possess permanent electric dipoles, adding to the electronic properties of the bioinspired conjugates they compose, making them molecular electrets.
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Affiliation(s)
- Jillian M. Larsen
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Eli M. Espinoza
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
| | - Joshua D. Hartman
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
| | - Chung-Kuang Lin
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Michelle Wurch
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Payal Maheshwari
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Raman K. Kaushal
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Michael J. Marsella
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
| | - Gregory J. O. Beran
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
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18
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Upadhyayula S, Nuñez V, Espinoza EM, Larsen JM, Bao D, Shi D, Mac JT, Anvari B, Vullev VI. Photoinduced dynamics of a cyanine dye: parallel pathways of non-radiative deactivation involving multiple excited-state twisted transients. Chem Sci 2015; 6:2237-2251. [PMID: 29449923 PMCID: PMC5701728 DOI: 10.1039/c4sc02881c] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 02/09/2015] [Indexed: 12/11/2022] Open
Abstract
Cyanine dyes are broadly used for fluorescence imaging and other photonic applications. 3,3'-Diethylthiacyanine (THIA) is a cyanine dye composed of two identical aromatic heterocyclic moieties linked with a single methine, -CH[double bond, length as m-dash]. The torsional degrees of freedom around the methine bonds provide routes for non-radiative decay, responsible for the inherently low fluorescence quantum yields. Using transient absorption spectroscopy, we determined that upon photoexcitation, the excited state relaxes along two parallel pathways producing three excited-state transients that undergo internal conversion to the ground state. The media viscosity impedes the molecular modes of ring rotation and preferentially affects one of the pathways of non-radiative decay, exerting a dominant effect on the emission properties of THIA. Concurrently, the polarity affects the energy of the transients involved in the decay pathways and further modulates the kinetics of non-radiative deactivation.
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Affiliation(s)
- Srigokul Upadhyayula
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
- Department of Biochemistry , University of California , Riverside , CA 92521 , USA
| | - Vicente Nuñez
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
| | - Eli M Espinoza
- Department of Chemistry , University of California , Riverside , CA 92521 , USA
| | - Jillian M Larsen
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
| | - Duoduo Bao
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
| | - Dewen Shi
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
| | - Jenny T Mac
- Department of Biochemistry , University of California , Riverside , CA 92521 , USA
| | - Bahman Anvari
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
| | - Valentine I Vullev
- Department of Bioengineering , University of California , Riverside , CA 92521 , USA .
- Department of Biochemistry , University of California , Riverside , CA 92521 , USA
- Department of Chemistry , University of California , Riverside , CA 92521 , USA
- Materials Science and Engineering Program , University of California , Riverside , CA 92521 , USA
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19
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Huang Q, Yoon I, Villanueva J, Kim K, Sirbuly DJ. Quantitative mechanical analysis of thin compressible polymer monolayers on oxide surfaces. SOFT MATTER 2014; 10:8001-8010. [PMID: 25157609 DOI: 10.1039/c4sm01530d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A clear understanding of the mechanical behavior of nanometer thick films on nanostructures, as well as developing versatile approaches to characterize their mechanical properties, are of great importance and may serve as the foundation for understanding and controlling molecular interactions at the interface of nanostructures. Here we report on the synthesis of thin, compressible polyethylene glycol (PEG) monolayers with a wet thickness of <20 nm on tin dioxide (SnO2) nanofibers through silane-based chemistries. Nanomechanical properties of such thin PEG films were extensively investigated using atomic force microscopy (AFM). In addition, tip-sample interactions were carefully studied, with different AFM tip modifications (i.e., hydrophilic and hydrophobic) and in different ionic solutions. We find that the steric forces dominate the tip-sample interactions when the polymer film is immersed in solution with salt concentrations similar to biological media (e.g., 1x phosphate buffer solution), while van der Waals and electrostatic forces have minimal contributions. A Dimitriadis thin film polymer compression model shows that the linear elastic regime is reproducible in the initial 50% indentation of these films which have tunable Young's moduli ranging from 5 MPa for the low molecular weight films to 700 kPa for the high molecular weight PEG films. Results are compared with the same PEG films deposited on silicon substrates which helped quantify the structural properties and understand the relationship between the structural and the mechanical properties of PEG films on the SnO2 fibers.
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Affiliation(s)
- Qian Huang
- Department of NanoEngineering, University of California, La Jolla, San Diego, CA 92093, USA.
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20
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Ghezzi M, Thickett SC, Telford AM, Easton CD, Meagher L, Neto C. Protein micropatterns by PEG grafting on Dewetted PLGA films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11714-11722. [PMID: 25195610 DOI: 10.1021/la5018592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The ability to control protein and cell positioning on a microscopic scale is crucial in many biomedical applications, such as single cell studies. We have developed and investigated the grafting of poly(ethylene glycol) (PEG) brushes onto poly(d,l-lactide-co-glycolide) (PLGA) thin films, which can be micropatterned by exploiting their spontaneous dewetting on top of polystyrene (PS) films. Dense PEG brushes with excellent protein repellence were achieved on PLGA by using cloud point grafting conditions, and selective adsorption of proteins on the micropatterned substrates was achieved by exploiting the different affinity protein adsorption onto the PEG brushes and the PS holes. PEG-grafted PLGA films showed better resistance against spontaneous degradation in buffer than bare PLGA films, due to passivation by the thin PEG coating. The simplicity of dewetting and subsequent grafting approaches, coupled with the ability to coat and pattern nonplanar substrates give rise to possible applications of PEG-grafted PLGA films in single cell studies and cell cultures for tissue engineering.
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Affiliation(s)
- Manuel Ghezzi
- School of Chemistry, The University of Sydney , Sydney, NSW 2006, Australia
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21
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Jacobson DR, McIntosh DB, Saleh OA. The snakelike chain character of unstructured RNA. Biophys J 2014; 105:2569-76. [PMID: 24314087 DOI: 10.1016/j.bpj.2013.10.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/16/2013] [Accepted: 10/23/2013] [Indexed: 01/30/2023] Open
Abstract
In the absence of base-pairing and tertiary structure, ribonucleic acid (RNA) assumes a random-walk conformation, modulated by the electrostatic self-repulsion of the charged, flexible backbone. This behavior is often modeled as a Kratky-Porod "wormlike chain" (WLC) with a Barrat-Joanny scale-dependent persistence length. In this study we report measurements of the end-to-end extension of poly(U) RNA under 0.1 to 10 pN applied force and observe two distinct elastic-response regimes: a low-force, power-law regime characteristic of a chain of swollen blobs on long length scales and a high-force, salt-valence-dependent regime consistent with ion-stabilized crumpling on short length scales. This short-scale structure is additionally supported by force- and salt-dependent quantification of the RNA ion atmosphere composition, which shows that ions are liberated under stretching; the number of ions liberated increases with increasing bulk salt concentration. Both this result and the observation of two elastic-response regimes directly contradict the WLC model, which predicts a single elastic regime across all forces and, when accounting for scale-dependent persistence length, the opposite trend in ion release with salt concentration. We conclude that RNA is better described as a "snakelike chain," characterized by smooth bending on long length scales and ion-stabilized crumpling on short length scales. In monovalent salt, these two regimes are separated by a characteristic length that scales with the Debye screening length, highlighting the determining importance of electrostatics in RNA conformation.
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Affiliation(s)
- David R Jacobson
- Department of Physics, University of California, Santa Barbara, CA
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22
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Janissen R, Berghuis BA, Dulin D, Wink M, van Laar T, Dekker NH. Invincible DNA tethers: covalent DNA anchoring for enhanced temporal and force stability in magnetic tweezers experiments. Nucleic Acids Res 2014; 42:e137. [PMID: 25140010 PMCID: PMC4191378 DOI: 10.1093/nar/gku677] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Magnetic tweezers are a powerful single-molecule technique that allows real-time quantitative investigation of biomolecular processes under applied force. High pulling forces exceeding tens of picoNewtons may be required, e.g. to probe the force range of proteins that actively transcribe or package the genome. Frequently, however, the application of such forces decreases the sample lifetime, hindering data acquisition. To provide experimentally viable sample lifetimes in the face of high pulling forces, we have designed a novel anchoring strategy for DNA in magnetic tweezers. Our approach, which exploits covalent functionalization based on heterobifunctional poly(ethylene glycol) crosslinkers, allows us to strongly tether DNA while simultaneously suppressing undesirable non-specific adhesion. A complete force and lifetime characterization of these covalently anchored DNA-tethers demonstrates that, compared to more commonly employed anchoring strategies, they withstand 3-fold higher pulling forces (up to 150 pN) and exhibit up to 200-fold higher lifetimes (exceeding 24 h at a constant force of 150 pN). This advance makes it possible to apply the full range of biologically relevant force scales to biomolecular processes, and its straightforward implementation should extend its reach to a multitude of applications in the field of single-molecule force spectroscopy.
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Affiliation(s)
- Richard Janissen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Bojk A Berghuis
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - David Dulin
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Max Wink
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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23
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Kucerova J, Svobodova Z, Knotek P, Palarcik J, Vlcek M, Kincl M, Horak D, Autebert J, Viovy JL, Bilkova Z. PEGylation of magnetic poly(glycidyl methacrylate) microparticles for microfluidic bioassays. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 40:308-15. [DOI: 10.1016/j.msec.2014.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/15/2014] [Accepted: 04/03/2014] [Indexed: 11/25/2022]
Affiliation(s)
- Jana Kucerova
- Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice, Czech Republic
| | - Zuzana Svobodova
- Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice, Czech Republic
| | - Petr Knotek
- Joint Laboratory of Solid State Chemistry of IMC and University of Pardubice, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice, Czech Republic
| | - Jiri Palarcik
- Institute of Environmental and Chemical Engineering, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice, Czech Republic
| | - Milan Vlcek
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 16206 Prague 6, Czech Republic
| | - Miloslav Kincl
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 16206 Prague 6, Czech Republic
| | - Daniel Horak
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 16206 Prague 6, Czech Republic
| | - Julien Autebert
- Macromolecules and Microsystems in Biology and Medicine, Institute Curie, UMR 168, 26 Rue d'Ulm, 75005 Paris, France
| | - Jean-Louis Viovy
- Macromolecules and Microsystems in Biology and Medicine, Institute Curie, UMR 168, 26 Rue d'Ulm, 75005 Paris, France
| | - Zuzana Bilkova
- Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, 53210 Pardubice, Czech Republic.
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24
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Bahmani B, Guerrero Y, Bacon D, Kundra V, Vullev VI, Anvari B. Functionalized polymeric nanoparticles loaded with indocyanine green as theranostic materials for targeted molecular near infrared fluorescence imaging and photothermal destruction of ovarian cancer cells. Lasers Surg Med 2014; 46:582-92. [DOI: 10.1002/lsm.22269] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2014] [Indexed: 01/15/2023]
Affiliation(s)
- Baharak Bahmani
- Department of Bioengineering; University of California; Riverside California 92521
| | - Yadir Guerrero
- Department of Bioengineering; University of California; Riverside California 92521
| | - Danielle Bacon
- Department of Bioengineering; University of California; Riverside California 92521
| | - Vikas Kundra
- Department of Diagnostic Radiology; The University of Texas, MD Anderson Cancer Center; Houston Texas 77030
| | - Valentine I. Vullev
- Department of Bioengineering; University of California; Riverside California 92521
| | - Bahman Anvari
- Department of Bioengineering; University of California; Riverside California 92521
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25
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Chandradoss SD, Haagsma AC, Lee YK, Hwang JH, Nam JM, Joo C. Surface passivation for single-molecule protein studies. J Vis Exp 2014. [PMID: 24797261 PMCID: PMC4179479 DOI: 10.3791/50549] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Single-molecule fluorescence spectroscopy has proven to be instrumental in understanding a wide range of biological phenomena at the nanoscale. Important examples of what this technique can yield to biological sciences are the mechanistic insights on protein-protein and protein-nucleic acid interactions. When interactions of proteins are probed at the single-molecule level, the proteins or their substrates are often immobilized on a glass surface, which allows for a long-term observation. This immobilization scheme may introduce unwanted surface artifacts. Therefore, it is essential to passivate the glass surface to make it inert. Surface coating using polyethylene glycol (PEG) stands out for its high performance in preventing proteins from non-specifically interacting with a glass surface. However, the polymer coating procedure is difficult, due to the complication arising from a series of surface treatments and the stringent requirement that a surface needs to be free of any fluorescent molecules at the end of the procedure. Here, we provide a robust protocol with step-by-step instructions. It covers surface cleaning including piranha etching, surface functionalization with amine groups, and finally PEG coating. To obtain a high density of a PEG layer, we introduce a new strategy of treating the surface with PEG molecules over two rounds, which remarkably improves the quality of passivation. We provide representative results as well as practical advice for each critical step so that anyone can achieve the high quality surface passivation.
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Affiliation(s)
- Stanley D Chandradoss
- Kavli Institute of NanoScience, Department of BioNanoScience, Delft University of Technology
| | - Anna C Haagsma
- Kavli Institute of NanoScience, Department of BioNanoScience, Delft University of Technology
| | | | - Jae-Ho Hwang
- Department of Chemistry, Seoul National University
| | - Jwa-Min Nam
- Department of Chemistry, Seoul National University
| | - Chirlmin Joo
- Kavli Institute of NanoScience, Department of BioNanoScience, Delft University of Technology;
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26
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Pallarola D, Bochen A, Boehm H, Rechenmacher F, Sobahi TR, Spatz JP, Kessler H. Interface Immobilization Chemistry of cRGD-based Peptides Regulates Integrin Mediated Cell Adhesion. ADVANCED FUNCTIONAL MATERIALS 2014; 24:943-956. [PMID: 25810710 PMCID: PMC4368046 DOI: 10.1002/adfm.201302411] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/28/2013] [Indexed: 05/29/2023]
Abstract
The interaction of specific surface receptors of the integrin family with different extracellular matrix-based ligands is of utmost importance for the cellular adhesion process. A ligand consists of an integrin-binding group, here cyclic RGDfX, a spacer molecule that lifts the integrin-binding group from the surface and a surface anchoring group. c(-RGDfX-) peptides are bound to gold nanoparticle structured surfaces via polyproline, polyethylene glycol or aminohexanoic acid containing spacers of different lengths. Although keeping the integrin-binding c(-RGDfX-) peptides constant for all compounds, changes of the ligand's spacer chemistry and length reveal significant differences in cell adhesion activation and focal adhesion formation. Polyproline-based peptides demonstrate improved cell adhesion kinetics and focal adhesion formation compared with common aminohexanoic acid or polyethylene glycol spacers. Binding activity can additionally be improved by applying ligands with two head groups, inducing a multimeric effect. This study gives insights into spacer-based differences in integrin-driven cell adhesion processes and remarkably highlights the polyproline-based spacers as suitable ligand-presenting templates for surface functionalization.
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Affiliation(s)
- Diego Pallarola
- Department of New Materials and Biosystems, Max Planck Institute for intelligent Systems Heisenbergstr. 3, 70569, Stuttgart, Germany ; Department of Biophysical Chemistry, University of Heidelberg 69120, Heidelberg, Germany
| | - Alexander Bochen
- Institute for Advanced Study and Center for Integrated Protein Science Department Chemie, Technische Universität München Lichtenbergstr. 4, 85747, Garching, Germany
| | - Heike Boehm
- Department of New Materials and Biosystems, Max Planck Institute for intelligent Systems Heisenbergstr. 3, 70569, Stuttgart, Germany ; Department of Biophysical Chemistry, University of Heidelberg 69120, Heidelberg, Germany ; CSF Biomaterials and Cellular Biophysics, Max Planck Institute for Intelligent Systems Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - Florian Rechenmacher
- Institute for Advanced Study and Center for Integrated Protein Science Department Chemie, Technische Universität München Lichtenbergstr. 4, 85747, Garching, Germany
| | - Tariq R Sobahi
- Chemistry Department Faculty of Science, King Abdulaziz University P.O. Box 80203, Jeddah 21589, Saudi Arabia
| | - Joachim P Spatz
- Department of New Materials and Biosystems, Max Planck Institute for intelligent Systems Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - Horst Kessler
- Institute for Advanced Study and Center for Integrated Protein Science Department Chemie, Technische Universität München Lichtenbergstr. 4, 85747, Garching, Germany ; Chemistry Department Faculty of Science, King Abdulaziz University P.O. Box 80203, Jeddah 21589, Saudi Arabia
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27
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Liu Y, Hao X, Waddington LJ, Qiu J, Hughes TC. Surface Modification of Multiwalled Carbon Nanotubes with Engineered Self-Assembled RAFT Diblock Coatings. Aust J Chem 2014. [DOI: 10.1071/ch13401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A facile method to modify the surface of multiwalled carbon nanotubes (MWCNTs) via electrostatic interactions between polyelectrolytes and oxidized MWCNTs was developed. Diblock copolymers containing poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC), a positively charged block, and poly(ethylene glycol) methacrylate (PEGMA), a neutral block, with tailored molecular weights and low polydispersities were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. Acid treated-MWCNTs were coated with the RAFT diblock copolymers to improve their dispersibility in aqueous phosphate buffered saline (PBS) solution. The short positively charged PMETAC block was designed to attach the block copolymers to the surface of MWCNTs via electrostatic interactions, whereas the PEGMA block improved dispersibility of the MWCNTs in aqueous solutions. Extensive screening of the diblock copolymers with different degrees of polymerization (DP) showed that the dispersion stability of the polymer-coated MWCNTs in PBS was greatly improved with increasing chain length of the PEGMA block. In particular, the MWCNTs coated with a diblock copolymer containing PEGMA (DP = 118, the longest block investigated) showed superior dispersion stability in both water and PBS solution.
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28
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Perez-Toralla K, Champ J, Mohamadi MR, Braun O, Malaquin L, Viovy JL, Descroix S. New non-covalent strategies for stable surface treatment of thermoplastic chips. LAB ON A CHIP 2013; 13:4409-4418. [PMID: 24061577 DOI: 10.1039/c3lc50888a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In order to be more extensively used outside of research laboratories, lab-on-chip technologies must be mass-produced using low-cost materials such as thermoplastics. Thermoplastics, however, are generally hydrophobic in their native state, which makes them unsuitable for direct use with biological samples in aqueous solution, and thus require surface coating. This coating should be robust, inexpensive and simple to implement, in order not to hinder the industrial advantage of thermoplastic chips. Cyclic Olefin Copolymer (COC) is a particularly appealing polymer, but it is also difficult to functionalize due to its chemical inertness. Here we introduce and compare the performance of two new approaches for COC coating. One relies on the use of a commercial triblock copolymer, Pluronic® F127. The second approach uses new copolymers synthesized by radical polymerization, and consisting of a dimethylacrylamide (DMA) backbone carrying aliphatic side chains (C22). Two DMA-C22 copolymers were synthesized with various C22/DMA ratios: DMA-S at 0.175% and DMA-M at 0.35%. Different physicochemical properties of the polymers such as critical micellar concentration (CMC), water contact angle, electroosmosis were investigated. Coated COC chips were then tested for their ability to reduce the adsorption of proteins, microparticles, and for protein electrophoresis. For each application we found an optimal treatment protocol to considerably improve the performance of the thermoplastic chip. These treatments use physisorption in situ which requires no photografting or chemical reaction and can be performed by a simple incubation either after chip production, or just prior to use.
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Affiliation(s)
- Karla Perez-Toralla
- Macromolecules and Microsystems in Biology and Medicine, Institut Curie, Centre National de Recherche Scientifique, Université Pierre et Marie Curie, UMR 168, 75005 Paris, France
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29
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Rasi Ghaemi S, Harding F, Delalat B, Vasani R, Voelcker NH. Surface Engineering for Long-Term Culturing of Mesenchymal Stem Cell Microarrays. Biomacromolecules 2013; 14:2675-83. [DOI: 10.1021/bm400531n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Soraya Rasi Ghaemi
- Mawson Institute, University of South Australia, GPO Box 2471, SA 5095, Australia
| | - Frances Harding
- Mawson Institute, University of South Australia, GPO Box 2471, SA 5095, Australia
| | - Bahman Delalat
- Mawson Institute, University of South Australia, GPO Box 2471, SA 5095, Australia
| | - Roshan Vasani
- Mawson Institute, University of South Australia, GPO Box 2471, SA 5095, Australia
| | - Nicolas H. Voelcker
- Mawson Institute, University of South Australia, GPO Box 2471, SA 5095, Australia
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30
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Bahmani B, Lytle CY, Walker AM, Gupta S, Vullev VI, Anvari B. Effects of nanoencapsulation and PEGylation on biodistribution of indocyanine green in healthy mice: quantitative fluorescence imaging and analysis of organs. Int J Nanomedicine 2013; 8:1609-20. [PMID: 23637530 PMCID: PMC3635661 DOI: 10.2147/ijn.s42511] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Near-infrared nanoconstructs present a potentially effective platform for site-specific and deep tissue optical imaging and phototherapy. We have engineered a polymeric nanocapsule composed of polyallylamine hydrochloride (PAH) chains cross-linked with sodium phosphate and doped with indocyanine green (ICG) toward such endeavors. The ICG-doped nanocapsules were coated covalently with polyethylene glycol (5000 daltons) through reductive amination. We administrated the constructs by tail vein injection to healthy mice. To characterize the biodistribution of the constructs, we performed in vivo quantitative fluorescence imaging and subsequently analyzed the various extracted organs. Our results suggest that encapsulation of ICG in these PEGylated constructs is an effective approach to prolong the circulation time of ICG and delay its hepatic accumulation. Increased bioavailability of ICG, due to encapsulation, offers the potential of extending the clinical applications of ICG, which are currently limited due to rapid elimination of ICG from the vasculature. Our results also indicate that PAH and ICG-doped nanocapsules (ICG-NCs) are not cytotoxic at the levels used in this study.
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Affiliation(s)
- Baharak Bahmani
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
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31
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Nuñez V, Upadhyayula S, Millare B, Larsen JM, Hadian A, Shin S, Vandrangi P, Gupta S, Xu H, Lin AP, Georgiev GY, Vullev VI. Microfluidic Space-Domain Time-Resolved Emission Spectroscopy of Terbium(III) and Europium(III) Chelates with Pyridine-2,6-Dicarboxylate. Anal Chem 2013; 85:4567-77. [DOI: 10.1021/ac400200x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Vicente Nuñez
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Srigokul Upadhyayula
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
| | - Brent Millare
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Jillian M. Larsen
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Ali Hadian
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sanghoon Shin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Prashanthi Vandrangi
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sharad Gupta
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Hong Xu
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Adam P. Lin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Georgi Y. Georgiev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Valentine I. Vullev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
- Department
of Chemistry, University of California,
Riverside, California 92521,
United States
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32
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Gao Y, van Reenen A, Hulsen MA, de Jong AM, Prins MWJ, den Toonder JMJ. Disaggregation of microparticle clusters by induced magnetic dipole-dipole repulsion near a surface. LAB ON A CHIP 2013; 13:1394-1401. [PMID: 23400503 DOI: 10.1039/c3lc41229f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ensembles of magnetic particles are known to align and aggregate into multi-particle clusters in an applied magnetic field, and the physical laws governing these processes are well described in literature. However, it has been elusive how to achieve the opposite process, i.e. the disaggregation of particle clusters in a magnetic field. We report a novel method to disaggregate clusters of superparamagnetic microparticles using time-dependent magnetic fields. The disaggregating field is designed to generate repulsive dipole-dipole forces between the particles and to stabilize the disaggregated particles on a physical surface. We demonstrate the disaggregation of large clusters of several tens of particles, within about one minute, using fields generated by a multipole electromagnet. After the disaggregation process the particles are uniformly distributed over the surface and ready for further lab-on-chip processing. Our results represent a novel methodology to disaggregate magnetic particle clusters and thereby improve the effectiveness and reproducibility of biological assays based on magnetic microparticles.
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Affiliation(s)
- Yang Gao
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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33
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Xia B, Bao D, Upadhyayula S, Jones G, Vullev VI. Anthranilamides as bioinspired molecular electrets: experimental evidence for a permanent ground-state electric dipole moment. J Org Chem 2013; 78:1994-2004. [PMID: 23270467 DOI: 10.1021/jo301942g] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As electrostatic equivalents of magnets, organic electrets offer unparalleled properties for impacting energy conversion and electronic applications. While biological systems have evolved to efficiently utilize protein α-helices as molecular electrets, the synthetic counterparts of these conjugates still remain largely unexplored. This paper describes a study of the electronic properties of anthranilamide oligomers, which proved to be electrets based on their intrinsic dipole moments as evident from their spectral and dielectric properties. NMR studies provided the means for estimating the direction of the intrinsic electric dipoles of these conjugates. This study sets the foundation for the development of a class of organic materials that are de novo designed from biomolecular motifs and possess unexplored electronic properties.
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Affiliation(s)
- Bing Xia
- Department of Bioengineering, University of California, Riverside, California 92521, United States
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34
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Jacob A, van IJzendoorn LJ, de Jong AM, Prins MW. Quantification of Protein–Ligand Dissociation Kinetics in Heterogeneous Affinity Assays. Anal Chem 2012; 84:9287-94. [DOI: 10.1021/ac301894k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Asha Jacob
- Department
of Applied Physics, Eindhoven University of Technology, Eindhoven, The
Netherlands
| | - Leo J. van IJzendoorn
- Department
of Applied Physics, Eindhoven University of Technology, Eindhoven, The
Netherlands
| | - Arthur M. de Jong
- Department
of Applied Physics, Eindhoven University of Technology, Eindhoven, The
Netherlands
| | - Menno W.J. Prins
- Department
of Applied Physics, Eindhoven University of Technology, Eindhoven, The
Netherlands
- Philips Research,
Eindhoven,
The Netherlands
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