1
|
Liu K, Wiendels M, Yuan H, Ruan C, Kouwer PH. Cell-matrix reciprocity in 3D culture models with nonlinear elasticity. Bioact Mater 2022; 9:316-331. [PMID: 34820573 PMCID: PMC8586441 DOI: 10.1016/j.bioactmat.2021.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 06/24/2021] [Accepted: 08/03/2021] [Indexed: 01/17/2023] Open
Abstract
Three-dimensional (3D) matrix models using hydrogels are powerful tools to understand and predict cell behavior. The interactions between the cell and its matrix, however is highly complex: the matrix has a profound effect on basic cell functions but simultaneously, cells are able to actively manipulate the matrix properties. This (mechano)reciprocity between cells and the extracellular matrix (ECM) is central in regulating tissue functions and it is fundamentally important to broadly consider the biomechanical properties of the in vivo ECM when designing in vitro matrix models. This manuscript discusses two commonly used biopolymer networks, i.e. collagen and fibrin gels, and one synthetic polymer network, polyisocyanide gel (PIC), which all possess the characteristic nonlinear mechanics in the biological stress regime. We start from the structure of the materials, then address the uses, advantages, and limitations of each material, to provide a guideline for tissue engineers and biophysicists in utilizing current materials and also designing new materials for 3D cell culture purposes.
Collapse
Affiliation(s)
- Kaizheng Liu
- Research Center for Human Tissue and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, PR China
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Maury Wiendels
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Hongbo Yuan
- Institute of Biophysics, Hebei University of Technology, Tianjin, 300401, PR China
- Molecular Imaging and Photonics, Chemistry Department, KU Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium
| | - Changshun Ruan
- Research Center for Human Tissue and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, PR China
| | - Paul H.J. Kouwer
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| |
Collapse
|
2
|
Liu N, Zhou L, Wu ZQ. Alkyne-Palladium(II)-Catalyzed Living Polymerization of Isocyanides: An Exploration of Diverse Structures and Functions. Acc Chem Res 2021; 54:3953-3967. [PMID: 34601864 DOI: 10.1021/acs.accounts.1c00489] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Inspired by the perfect helical structures and the resulting exquisite functions of biomacromolecules, helical polymers have attracted increasing attention in recent years. Polyisocyanide is well known for its distinctive rodlike helical structure and various applications in chiral recognition, enantiomer separation, circularly polarized luminescence, liquid crystallization, and other fields. Although various methods and catalysts for isocyanide polymerization have been reported, the precise synthesis of helical polyisocyanides with controlled molecular weight, low dispersity, and high tacticity remains a formidable challenge. Owing to a limited synthesis strategy, the controlled synthesis of topological polyisocyanides has barely been realized. This Accounts highlights our recent endeavors to explore novel catalysts for the living polymerization of isocyanides. Fortunately, we discovered that alkyne-Pd(II) catalysts could initiate the living polymerization of isocyanides, resulting in helical polyisocyanides with controlled structures, high tacticity, and tunable compositions. These catalysts are applicable to various isocyanide monomers, including alkyl isocyanides, aryl isocyanides, and diisocyanobenzene derivatives. Incorporating chiral bidentate phosphine ligands onto alkyne-Pd(II) complexes formed chiral Pd(II) catalysts, which promoted the asymmetric living polymerization of achiral isocyanide, yielding single left- and right-handed helices with highly optical activities.Using alkyne-Pd(II) catalysts, various topological polyisocyanides have been facilely prepared, including hybrid block copolymers, bottlebrush polymers, core cross-linked star polymers, and organic/inorganic nanoparticles. For instance, various hybrid block polyisocyanides were easily produced by coupling alkyne-Pd(II)-catalyzed living isocyanide polymerization with controlled radical polymerization and ring-opening polymerization (ROP). Combining the ring-opening metathesis polymerization (ROMP) of norbornene with Pd(II)-catalyzed isocyanide polymerization, bottlebrush polyisocyanides and core cross-linked star polymers were easily prepared. Pd(II)-catalyzed living polymerization of poly(lactic acid)s with isocyanide termini resulted in densely grafted bottlebrush polyisocyanides with closely packed side chains. Moreover, the surface-initiated living polymerization of isocyanides produced a family of polyisocyanide-grafted organic/inorganic hybrid nanoparticles using nanoparticles with alkyne-Pd(II) catalysts anchored on the surfaces. Surprisingly, the nanoparticles and star polymers with helical polyisocyanide arms performed exceptionally well in terms of chiral recognition and resolution. Incorporated organocatalysts such as proline and prolinol units onto the pendants of optically active helical polyisocyanides, a family of polymer-based chiral organocatalysts, were generated, which showed significantly improved stereoselectivity for the asymmetric Aldol reaction and Michael addition and can be easily recycled.Using a chiral alkyne-Pd(II) catalyst, single-handed helical polyisocyanides bearing naphthalene and pyrene probes were produced from achiral isocyanide monomers. These polymers showed excellent self-sorting properties as revealed using a fluorescence resonance energy transfer (FRET) investigation and were self-assembled into two-dimensional (2D) smectic nanostructures driven by both helicity and chain length. Incorporating helical poly(phenyl isocyanide) (PPI) onto semiconducting poly(3-hexylthiophene) (P3HT) induced the asymmetric assembly of the resulting P3HT-b-PPI copolymers into single-handed cylindrical micelles with controlled dimensions and tunable photoluminescence.
Collapse
Affiliation(s)
- Na Liu
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei 230009, China
| | - Li Zhou
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei 230009, China
| | - Zong-Quan Wu
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, and Anhui Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, Hefei University of Technology, Hefei 230009, China
| |
Collapse
|
3
|
van Dam EP, Yuan H, Kouwer PHJ, Bakker HJ. Structure and Dynamics of a Temperature-Sensitive Hydrogel. J Phys Chem B 2021; 125:8219-8224. [PMID: 34279949 PMCID: PMC8327313 DOI: 10.1021/acs.jpcb.1c03121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Polyisocyanotripeptides
(TriPIC) are biomimetic polymers which
consist of a β-helical backbone stabilized by hydrogen bonds
between amide groups. Their oligoethylene glycol side chains give
aqueous TriPIC solutions a thermoresponsive behavior: at 50 °C
the solution becomes a hydrogel. In this paper we study the molecular
structure and water dynamics of TriPIC aqueous solutions while undergoing
gelation using FT-IR spectroscopy and polarization-resolved femtosecond
infrared spectroscopy (fs-IR). We find evidence that the oligoethylene
glycol side chains trap part of the water molecules upon gel formation,
and we propose that the interaction between the oligoethylene glycol
side chains and water plays an essential role in the bundling of the
polymers and thus in the formation of a hydrogel.
Collapse
Affiliation(s)
| | - Hongbo Yuan
- Institute of Biophysics, Hebei University of Technology, Tianjin 300401, P. R. China.,Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Paul H J Kouwer
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Huib J Bakker
- AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| |
Collapse
|
4
|
Gerrits L, Hammink R, Kouwer PHJ. Semiflexible polymer scaffolds: an overview of conjugation strategies. Polym Chem 2021. [DOI: 10.1039/d0py01662d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Semiflexible polymers are excellent scaffolds for the presentation of a wide variety of (bio)molecules. This manuscript reviews advantages and challenges of the most common conjugation strategies for the major classes of semiflexible polymers.
Collapse
Affiliation(s)
- Lotte Gerrits
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
| | - Roel Hammink
- Department of Tumor Immunology
- Radboud Institute for Molecular Life Sciences
- Radboud University Medical Center
- 6525 GA Nijmegen
- The Netherlands
| | - Paul H. J. Kouwer
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
| |
Collapse
|
5
|
Grad EM, Tunn I, Voerman D, de Léon AS, Hammink R, Blank KG. Influence of Network Topology on the Viscoelastic Properties of Dynamically Crosslinked Hydrogels. Front Chem 2020; 8:536. [PMID: 32719773 PMCID: PMC7349520 DOI: 10.3389/fchem.2020.00536] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 05/26/2020] [Indexed: 01/15/2023] Open
Abstract
Biological materials combine stress relaxation and self-healing with non-linear stress-strain responses. These characteristic features are a direct result of hierarchical self-assembly, which often results in fiber-like architectures. Even though structural knowledge is rapidly increasing, it has remained a challenge to establish relationships between microscopic and macroscopic structure and function. Here, we focus on understanding how network topology determines the viscoelastic properties, i.e., stress relaxation, of biomimetic hydrogels. We have dynamically crosslinked two different synthetic polymers with one and the same crosslink. The first polymer, a polyisocyanopeptide (PIC), self-assembles into semi-flexible, fiber-like bundles, and thus displays stress-stiffening, similar to many biopolymer networks. The second polymer, 4-arm poly(ethylene glycol) (starPEG), serves as a reference network with well-characterized structural and viscoelastic properties. Using one and the same coiled coil crosslink allows us to decouple the effects of crosslink kinetics and network topology on the stress relaxation behavior of the resulting hydrogel networks. We show that the fiber-containing PIC network displays a relaxation time approximately two orders of magnitude slower than the starPEG network. This reveals that crosslink kinetics is not the only determinant for stress relaxation. Instead, we propose that the different network topologies determine the ability of elastically active network chains to relax stress. In the starPEG network, each elastically active chain contains exactly one crosslink. In the absence of entanglements, crosslink dissociation thus relaxes the entire chain. In contrast, each polymer is crosslinked to the fiber bundle in multiple positions in the PIC hydrogel. The dissociation of a single crosslink is thus not sufficient for chain relaxation. This suggests that tuning the number of crosslinks per elastically active chain in combination with crosslink kinetics is a powerful design principle for tuning stress relaxation in polymeric materials. The presence of a higher number of crosslinks per elastically active chain thus yields materials with a slow macroscopic relaxation time but fast dynamics at the microscopic level. Using this principle for the design of synthetic cell culture matrices will yield materials with excellent long-term stability combined with the ability to locally reorganize, thus facilitating cell motility, spreading, and growth.
Collapse
Affiliation(s)
- Emilia M. Grad
- Mechano(bio) Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - Isabell Tunn
- Mechano(bio) Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Dion Voerman
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
- Division of Immunotherapy, Oncode Institute, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alberto S. de Léon
- Mechano(bio) Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Roel Hammink
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
- Division of Immunotherapy, Oncode Institute, Radboud University Medical Center, Nijmegen, Netherlands
| | - Kerstin G. Blank
- Mechano(bio) Chemistry, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| |
Collapse
|
6
|
Halogen effects on phenylethynyl palladium(II) complexes for living polymerization of isocyanides: a combined experimental and computational investigation. Sci China Chem 2019. [DOI: 10.1007/s11426-018-9415-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
7
|
Cabello G, Nwoko KC, Mingarelli M, McLaughlin AC, Trembleau L, Feldmann J, Cuesta A, Smith TA. Physicochemical Tools: Toward a Detailed Understanding of the Architecture of Targeted Radiotherapy Nanoparticles. ACS APPLIED BIO MATERIALS 2018; 1:1639-1646. [DOI: 10.1021/acsabm.8b00476] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Gema Cabello
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Kenneth C. Nwoko
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Marco Mingarelli
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Abbie C. McLaughlin
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Laurent Trembleau
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Joerg Feldmann
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Angel Cuesta
- Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Tim A.D. Smith
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| |
Collapse
|
8
|
Kontturi E, Laaksonen P, Linder MB, Gröschel AH, Rojas OJ, Ikkala O. Advanced Materials through Assembly of Nanocelluloses. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1703779. [PMID: 29504161 DOI: 10.1002/adma.201703779] [Citation(s) in RCA: 333] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/06/2017] [Indexed: 05/20/2023]
Abstract
There is an emerging quest for lightweight materials with excellent mechanical properties and economic production, while still being sustainable and functionalizable. They could form the basis of the future bioeconomy for energy and material efficiency. Cellulose has long been recognized as an abundant polymer. Modified celluloses were, in fact, among the first polymers used in technical applications; however, they were later replaced by petroleum-based synthetic polymers. Currently, there is a resurgence of interest to utilize renewable resources, where cellulose is foreseen to make again a major impact, this time in the development of advanced materials. This is because of its availability and properties, as well as economic and sustainable production. Among cellulose-based structures, cellulose nanofibrils and nanocrystals display nanoscale lateral dimensions and lengths ranging from nanometers to micrometers. Their excellent mechanical properties are, in part, due to their crystalline assembly via hydrogen bonds. Owing to their abundant surface hydroxyl groups, they can be easily modified with nanoparticles, (bio)polymers, inorganics, or nanocarbons to form functional fibers, films, bulk matter, and porous aerogels and foams. Here, some of the recent progress in the development of advanced materials within this rapidly growing field is reviewed.
Collapse
Affiliation(s)
- Eero Kontturi
- Department of Bioproducts and Biosystems, Aalto University, Espoo, FI-00076, Finland
| | - Päivi Laaksonen
- Department of Bioproducts and Biosystems, Aalto University, Espoo, FI-00076, Finland
- Center of Excellence Molecular Engineering of Biosynthetic Hybrid Materials Research, Aalto University and VTT, Espoo, FI-00076, Finland
| | - Markus B Linder
- Department of Bioproducts and Biosystems, Aalto University, Espoo, FI-00076, Finland
- Center of Excellence Molecular Engineering of Biosynthetic Hybrid Materials Research, Aalto University and VTT, Espoo, FI-00076, Finland
| | - André H Gröschel
- Physical Chemistry and Centre for Nanointegration (CENIDE), University of Duisburg-Essen, DE-45127, Essen, Germany
| | - Orlando J Rojas
- Department of Bioproducts and Biosystems, Aalto University, Espoo, FI-00076, Finland
- Center of Excellence Molecular Engineering of Biosynthetic Hybrid Materials Research, Aalto University and VTT, Espoo, FI-00076, Finland
- Department of Applied Physics, Aalto University, Espoo, FI-00076, Finland
| | - Olli Ikkala
- Department of Bioproducts and Biosystems, Aalto University, Espoo, FI-00076, Finland
- Center of Excellence Molecular Engineering of Biosynthetic Hybrid Materials Research, Aalto University and VTT, Espoo, FI-00076, Finland
- Department of Applied Physics, Aalto University, Espoo, FI-00076, Finland
| |
Collapse
|
9
|
Yuan H, Xu J, van Dam EP, Giubertoni G, Rezus YLA, Hammink R, Bakker HJ, Zhan Y, Rowan AE, Xing C, Kouwer PHJ. Strategies To Increase the Thermal Stability of Truly Biomimetic Hydrogels: Combining Hydrophobicity and Directed Hydrogen Bonding. Macromolecules 2017; 50:9058-9065. [PMID: 29213150 PMCID: PMC5707627 DOI: 10.1021/acs.macromol.7b01832] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/08/2017] [Indexed: 01/29/2023]
Abstract
Enhancing the thermal stability of proteins is an important task for protein engineering. There are several ways to increase the thermal stability of proteins in biology, such as greater hydrophobic interactions, increased helical content, decreased occurrence of thermolabile residues, or stable hydrogen bonds. Here, we describe a well-defined polymer based on β-helical polyisocyanotripeptides (TriPIC) that uses biological approaches, including hydrogen bonding and hydrophobic interactions for its exceptional thermal stability in aqueous solutions. The multiple hydrogen bonding arrays along the polymer backbone shield the hydrophobic core from water. Variable temperature CD and FTIR studies indicate that, on heating, a better packed polymer conformation further stiffens the backbone. Driven by hydrophobic interactions, TriPIC solutions give fully reversible hydrogels that can withstand high temperatures (80 °C) for extended times. Cryo-scanning electron microscopy (cryo-SEM), small-angle X-ray scattering (SAXS), and thorough rheological analysis show that the hydrogel has a bundled architecture, which gives rise to strain stiffening effects on deformation of the gel, analogous to many biological hydrogels.
Collapse
Affiliation(s)
- Hongbo Yuan
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300401, P. R. China.,Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| | - Jialiang Xu
- School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Tianjin 300350, P. R. China.,Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| | | | | | - Yves L A Rezus
- AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Roel Hammink
- Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| | - Huib J Bakker
- AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Yong Zhan
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Alan E Rowan
- Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands.,Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Chengfen Xing
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300401, P. R. China
| | - Paul H J Kouwer
- Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525AJ Nijmegen, The Netherlands
| |
Collapse
|
10
|
Deshpande SR, Hammink R, Nelissen FHT, Rowan AE, Heus HA. Biomimetic Stress Sensitive Hydrogel Controlled by DNA Nanoswitches. Biomacromolecules 2017; 18:3310-3317. [PMID: 28930451 PMCID: PMC5665546 DOI: 10.1021/acs.biomac.7b00964] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
One
of the most intriguing and important aspects of biological
supramolecular materials is its ability to adapt macroscopic properties
in response to environmental cues for controlling cellular processes.
Recently, bulk matrix stiffness, in particular, stress sensitivity,
has been established as a key mechanical cue in cellular function
and development. However, stress-stiffening capacity and the ability
to control and exploit this key characteristic is relatively new to
the field of biomimetic materials. In this work, DNA-responsive hydrogels,
composed of semiflexible PIC polymers equipped with DNA cross-linkers,
were engineered to create mimics of natural biopolymer networks that
capture these essential elastic properties and can be controlled by
external stimuli. We show that the elastic properties are governed
by the molecular structure of the cross-linker, which can be readily
varied providing access to a broad range of highly tunable soft hydrogels
with diverse stress-stiffening regimes. By using cross-linkers based
on DNA nanoswitches, responsive to pH or ligands, internal control
elements of mechanical properties are implemented that allow for dynamic
control of elastic properties with high specificity. The work broadens
the current knowledge necessary for the development of user defined
biomimetic materials with stress stiffening capacity.
Collapse
Affiliation(s)
- Swapneel R Deshpande
- Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Roel Hammink
- Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Frank H T Nelissen
- Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Alan E Rowan
- Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hans A Heus
- Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| |
Collapse
|
11
|
Hammink R, Eggermont LJ, Zisis T, Tel J, Figdor CG, Rowan AE, Blank KG. Affinity-Based Purification of Polyisocyanopeptide Bioconjugates. Bioconjug Chem 2017; 28:2560-2568. [PMID: 28846388 DOI: 10.1021/acs.bioconjchem.7b00398] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Water-soluble polyisocyanopeptides (PICs) are a new class of synthetic polymers that mimic natural protein-based filaments. Their unique semiflexible properties combined with a length of several hundred nanometers have recently enabled a number of biomedical applications ranging from tissue engineering to cancer immunotherapy. One crucial step toward the further development of PICs for these applications is the efficient and controlled synthesis and purification of PIC-biomolecule conjugates. Considering the large size of PICs and the biomolecules to be conjugated, conjugation reactions do usually not proceed to completion due to steric effects. As a consequence, purification of the reaction mixture is necessary to separate the obtained bioconjugates from unreacted biomolecules. As a direct result of the semiflexible nature of PICs, standard polymer and protein purification methods based on molecular weight have not been successful. Here, we introduce a new affinity-based purification method utilizing biotin as an affinity tag. PICs decorated with a controlled and tunable density of biotin molecules (biotinPICs) were efficiently bound to and eluted from a monoavidin resin in buffered aqueous solution. Using these biotinPICs, two different protein conjugates were synthesized, one carrying the enzyme alkaline phosphatase (PhoA) and the other T-cell activating anti-CD3 antibodies. The resulting biotinPIC-protein conjugates were successfully obtained in high purity (>90%) and without any loss of protein activity. The high purity greatly simplifies the analysis of biotinPIC bioconjugates, such as the determination of the average number of biomolecules conjugated per biotinPIC chain. Most importantly, it allows for the direct and straightforward application of the obtained bioconjugates in the desired applications. The new method developed may further be adapted for the purification of other advanced bioconjugates that are difficult to obtain in high purity with the available standard methods.
Collapse
Affiliation(s)
- Roel Hammink
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands
| | - Loek J Eggermont
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands
| | - Themistoklis Zisis
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Jurjen Tel
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands.,Department of Biomedical Engineering and Institute for Complex Molecular Systems, Laboratory of Immunoengineering, Eindhoven University of Technology , De Zaale 15, 5612 AP Eindhoven, The Netherlands
| | - Carl G Figdor
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands
| | - Alan E Rowan
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Kerstin G Blank
- Department of Molecular Materials, Institute for Molecules and Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,Mechano(bio)chemistry, Max Planck Institute of Colloids and Interfaces , Potsdam-Golm Science Park, 14424 Potsdam, Germany
| |
Collapse
|
12
|
Jaspers M, Vaessen SL, van Schayik P, Voerman D, Rowan AE, Kouwer PHJ. Nonlinear mechanics of hybrid polymer networks that mimic the complex mechanical environment of cells. Nat Commun 2017; 8:15478. [PMID: 28541273 PMCID: PMC5458517 DOI: 10.1038/ncomms15478] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 04/03/2017] [Indexed: 12/20/2022] Open
Abstract
The mechanical properties of cells and the extracellular environment they reside in are governed by a complex interplay of biopolymers. These biopolymers, which possess a wide range of stiffnesses, self-assemble into fibrous composite networks such as the cytoskeleton and extracellular matrix. They interact with each other both physically and chemically to create a highly responsive and adaptive mechanical environment that stiffens when stressed or strained. Here we show that hybrid networks of a synthetic mimic of biological networks and either stiff, flexible and semi-flexible components, even very low concentrations of these added components, strongly affect the network stiffness and/or its strain-responsive character. The stiffness (persistence length) of the second network, its concentration and the interaction between the components are all parameters that can be used to tune the mechanics of the hybrids. The equivalence of these hybrids with biological composites is striking.
Collapse
Affiliation(s)
- Maarten Jaspers
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Sarah L. Vaessen
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Pim van Schayik
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Dion Voerman
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Alan E. Rowan
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, Brisbane, Queensland 4072, Australia
| | - Paul H. J. Kouwer
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| |
Collapse
|
13
|
Dennison M, Jaspers M, Kouwer PHJ, Storm C, Rowan AE, MacKintosh FC. Critical behaviour in the nonlinear elastic response of hydrogels. SOFT MATTER 2016; 12:6995-7004. [PMID: 27464595 DOI: 10.1039/c6sm01033d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper we study the elastic response of synthetic hydrogels to an applied shear stress. The hydrogels studied here have previously been shown to mimic the behaviour of biopolymer networks when they are sufficiently far above the gel point. We show that near the gel point they exhibit an elastic response that is consistent with the predicted critical behaviour of networks near or below the isostatic point of marginal stability. This point separates rigid and floppy states, distinguished by the presence or absence of finite linear elastic moduli. Recent theoretical work has also focused on the response of such networks to finite or large deformations, both near and below the isostatic point. Despite this interest, experimental evidence for the existence of criticality in such networks has been lacking. Using computer simulations, we identify critical signatures in the mechanical response of sub-isostatic networks as a function of applied shear stress. We also present experimental evidence consistent with these predictions. Furthermore, our results show the existence of two distinct critical regimes, one of which arises from the nonlinear stretch response of semi-flexible polymers.
Collapse
Affiliation(s)
- M Dennison
- Department of Physics and Astronomy, Vrije Universiteit, 1081-HV Amsterdam, The Netherlands and Department of Applied Physics and Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600-MB Eindhoven, The Netherlands
| | - M Jaspers
- Radboud University Nijmegen, Institute for Molecules and Materials, Department of Molecular Materials, 6525-AJ Nijmegen, The Netherlands
| | - P H J Kouwer
- Radboud University Nijmegen, Institute for Molecules and Materials, Department of Molecular Materials, 6525-AJ Nijmegen, The Netherlands
| | - C Storm
- Department of Applied Physics and Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600-MB Eindhoven, The Netherlands
| | - A E Rowan
- Radboud University Nijmegen, Institute for Molecules and Materials, Department of Molecular Materials, 6525-AJ Nijmegen, The Netherlands
| | - F C MacKintosh
- Department of Physics and Astronomy, Vrije Universiteit, 1081-HV Amsterdam, The Netherlands and Departments of Chemical and Biomolecular Engineering, Chemistry and Physics, Rice University, Houston, TX, USA
| |
Collapse
|
14
|
Polymorphism and electronic structure of polyimine and its potential significance for prebiotic chemistry on Titan. Proc Natl Acad Sci U S A 2016; 113:8121-6. [PMID: 27382167 DOI: 10.1073/pnas.1606634113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The chemistry of hydrogen cyanide (HCN) is believed to be central to the origin of life question. Contradictions between Cassini-Huygens mission measurements of the atmosphere and the surface of Saturn's moon Titan suggest that HCN-based polymers may have formed on the surface from products of atmospheric chemistry. This makes Titan a valuable "natural laboratory" for exploring potential nonterrestrial forms of prebiotic chemistry. We have used theoretical calculations to investigate the chain conformations of polyimine (pI), a polymer identified as one major component of polymerized HCN in laboratory experiments. Thanks to its flexible backbone, the polymer can exist in several different polymorphs, which are relatively close in energy. The electronic and structural variability among them is extraordinary. The band gap changes over a 3-eV range when moving from a planar sheet-like structure to increasingly coiled conformations. The primary photon absorption is predicted to occur in a window of relative transparency in Titan's atmosphere, indicating that pI could be photochemically active and drive chemistry on the surface. The thermodynamics for adding and removing HCN from pI under Titan conditions suggests that such dynamics is plausible, provided that catalysis or photochemistry is available to sufficiently lower reaction barriers. We speculate that the directionality of pI's intermolecular and intramolecular =N-H(…)N hydrogen bonds may drive the formation of partially ordered structures, some of which may synergize with photon absorption and act catalytically. Future detailed studies on proposed mechanisms and the solubility and density of the polymers will aid in the design of future missions to Titan.
Collapse
|
15
|
Beun LH, Albertazzi L, van der Zwaag D, de Vries R, Cohen Stuart MA. Unidirectional Living Growth of Self-Assembled Protein Nanofibrils Revealed by Super-resolution Microscopy. ACS NANO 2016; 10:4973-4980. [PMID: 27124596 DOI: 10.1021/acsnano.6b01017] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Protein-based nanofibrils are emerging as a promising class of materials that provide unique properties for applications such as biomedical and food engineering. Here, we use atomic force microscopy and stochastic optical reconstruction microscopy imaging to elucidate the growth dynamics, exchange kinetics, and polymerization mechanism for fibrils composed of a de novo designed recombinant triblock protein polymer. This macromolecule features a silk-inspired self-assembling central block composed of GAGAGAGH repeats, which are known to fold into a β roll with turns at each histidine and, once folded, to stack, forming a long, ribbon-like structure. We find several properties that allow the growth of patterned protein nanofibrils: the self-assembly takes place on only one side of the growing fibrils by the essentially irreversible addition of protein polymer subunits, and these fibril ends remain reactive indefinitely in the absence of monomer ("living ends"). Exploiting these characteristics, we can grow stable diblock protein nanofibrils by the sequential addition of differently labeled proteins. We establish control over the block length ratio by simply varying monomer feed conditions. Our results demonstrate the use of engineered protein polymers in creating precisely patterned protein nanofibrils and open perspectives for the hierarchical self-assembly of functional biomaterials.
Collapse
Affiliation(s)
- Lennart H Beun
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
| | - Lorenzo Albertazzi
- Institute for Complex Molecular Systems, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Institute for Bioengineering of Catalonia Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Daan van der Zwaag
- Institute for Complex Molecular Systems, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Renko de Vries
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
| | - Martien A Cohen Stuart
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
| |
Collapse
|
16
|
Das RK, Gocheva V, Hammink R, Zouani OF, Rowan AE. Stress-stiffening-mediated stem-cell commitment switch in soft responsive hydrogels. NATURE MATERIALS 2016; 15:318-25. [PMID: 26618883 DOI: 10.1038/nmat4483] [Citation(s) in RCA: 250] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 10/20/2015] [Indexed: 05/22/2023]
Abstract
Bulk matrix stiffness has emerged as a key mechanical cue in stem cell differentiation. Here, we show that the commitment and differentiation of human mesenchymal stem cells encapsulated in physiologically soft (∼0.2-0.4 kPa), fully synthetic polyisocyanopeptide-based three-dimensional (3D) matrices that mimic the stiffness of adult stem cell niches and show biopolymer-like stress stiffening, can be readily switched from adipogenesis to osteogenesis by changing only the onset of stress stiffening. This mechanical behaviour can be tuned by simply altering the material's polymer length whilst maintaining stiffness and ligand density. Our findings introduce stress stiffening as an important parameter that governs stem cell fate in a 3D microenvironment, and reveal a correlation between the onset of stiffening and the expression of the microtubule-associated protein DCAMKL1, thus implicating DCAMKL1 in a stress-stiffening-mediated, mechanotransduction pathway that involves microtubule dynamics in stem cell osteogenesis.
Collapse
Affiliation(s)
- Rajat K Das
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Veronika Gocheva
- Histide, Chaltenbodenstrasse 8, 8834 Schindellegi, Switzerland
- Histide Lab, Accinov, 317, avenue Jean Jaurès, 69007 Lyon, France
| | - Roel Hammink
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Omar F Zouani
- Histide, Chaltenbodenstrasse 8, 8834 Schindellegi, Switzerland
- Histide Lab, Accinov, 317, avenue Jean Jaurès, 69007 Lyon, France
| | - Alan E Rowan
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| |
Collapse
|
17
|
Keshavarz M, Engelkamp H, Xu J, Braeken E, Otten MBJ, Uji-I H, Schwartz E, Koepf M, Vananroye A, Vermant J, Nolte RJM, De Schryver F, Maan JC, Hofkens J, Christianen PCM, Rowan AE. Nanoscale Study of Polymer Dynamics. ACS NANO 2016; 10:1434-1441. [PMID: 26688072 DOI: 10.1021/acsnano.5b06931] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The thermal motion of polymer chains in a crowded environment is anisotropic and highly confined. Whereas theoretical and experimental progress has been made, typically only indirect evidence of polymer dynamics is obtained either from scattering or mechanical response. Toward a complete understanding of the complicated polymer dynamics in crowded media such as biological cells, it is of great importance to unravel the role of heterogeneity and molecular individualism. In the present work, we investigate the dynamics of synthetic polymers and the tube-like motion of individual chains using time-resolved fluorescence microscopy. A single fluorescently labeled polymer molecule is observed in a sea of unlabeled polymers, giving access to not only the dynamics of the probe chain itself but also to that of the surrounding network. We demonstrate that it is possible to extract the characteristic time constants and length scales in one experiment, providing a detailed understanding of polymer dynamics at the single chain level. The quantitative agreement with bulk rheology measurements is promising for using local probes to study heterogeneity in complex, crowded systems.
Collapse
Affiliation(s)
- Masoumeh Keshavarz
- High Field Magnet Laboratory (HFML - EMFL), Radboud University , Toernooiveld 7, NL-6525 ED Nijmegen, The Netherlands
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hans Engelkamp
- High Field Magnet Laboratory (HFML - EMFL), Radboud University , Toernooiveld 7, NL-6525 ED Nijmegen, The Netherlands
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven , Celestijnenlaan 200 F, B-3001 Heverlee, Belgium
| | - Jialiang Xu
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Els Braeken
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven , Celestijnenlaan 200 F, B-3001 Heverlee, Belgium
| | - Matthijs B J Otten
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hiroshi Uji-I
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven , Celestijnenlaan 200 F, B-3001 Heverlee, Belgium
| | - Erik Schwartz
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Matthieu Koepf
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Anja Vananroye
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven , Celestijnenlaan 200 F, B-3001 Heverlee, Belgium
| | - Jan Vermant
- Department of Chemical Engineering, Katholieke Universiteit Leuven , de Croylaan 46, B-3001 Heverlee, Belgium
- Department of Materials - Hönggerberg, ETH Zürich , Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Roeland J M Nolte
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Frans De Schryver
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven , Celestijnenlaan 200 F, B-3001 Heverlee, Belgium
| | - Jan C Maan
- High Field Magnet Laboratory (HFML - EMFL), Radboud University , Toernooiveld 7, NL-6525 ED Nijmegen, The Netherlands
| | - Johan Hofkens
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven , Celestijnenlaan 200 F, B-3001 Heverlee, Belgium
- Nano-Science Center/Department of Chemistry, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Peter C M Christianen
- High Field Magnet Laboratory (HFML - EMFL), Radboud University , Toernooiveld 7, NL-6525 ED Nijmegen, The Netherlands
| | - Alan E Rowan
- Institute for Molecules and Materials, Department of Molecular Materials, Radboud University , Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| |
Collapse
|
18
|
Lin NT, Satyanarayana K, Chen CH, Tsai YF, Yu SSF, Chan SI, Luh TY. Controlling the Orientation of Pendants in Two-Dimensional Comb-Like Polymers by Varying Stiffness of Polymeric Backbones. Macromolecules 2014. [DOI: 10.1021/ma5007655] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Nai-Ti Lin
- Department
of Chemistry, National Taiwan University, Taipei, 106 Taiwan
| | | | - Chih-Hsien Chen
- Department
of Chemical Engineering, Feng Chia University, Taichung, 407 Taiwan
| | - Yi-Fang Tsai
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, 115 Taiwan
| | - Steve Sheng-Fa Yu
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, 115 Taiwan
| | - Sunney I. Chan
- Institute
of Chemistry, Academia Sinica, Nangang, Taipei, 115 Taiwan
| | - Tien-Yau Luh
- Department
of Chemistry, National Taiwan University, Taipei, 106 Taiwan
| |
Collapse
|
19
|
Lin YL, Chang HY, Sheng YJ, Tsao HK. The fusion mechanism of small polymersomes formed by rod-coil diblock copolymers. SOFT MATTER 2014; 10:1500-1511. [PMID: 24652278 DOI: 10.1039/c3sm52387j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The fusion mechanism of polymersomes self-assembled by rod-coil copolymers is intrinsically different from that of liposomes due to the effect of chain topology on conformational entropy and molecular packing. The influences of membrane tension, coil-block length, rod-block length, mutual compatibility between the solvent and the rod-coil block, and π-π interaction strength on the fusion pathway are explored by dissipative particle dynamics. The fusion process of spontaneously formed polymersomes generally consists of four stages. In the kissing stage, hopping of rod-blocks forms a connection between two vesicles of a one-legged rod-coil copolymer. In the adhesion stage, a stalk is developed by a few link-up rods and then a stretched diaphragm with rods lying parallel to the stretching direction is formed in the hemi-fusion stage. Eventually, a pore is developed and expanded in the fusion stage. If the membrane tension (τ) is adjusted by deflation/inflation of the polymersomes, the hemi-fusion diaphragm disappears. As τ is reduced, multiple stalks take shape and lead to the formation of inverted micelles, which is the rate-determining step and raises the fusion time substantially. As τ is elevated, a neck is developed after the stalk formation. The fusion process is significantly accelerated. τ of spontaneously formed vesicles varies with the coil-block length, rod-block length, solvent quality, and π-π interaction strength. There exists a critical value of τ below which the fusion process cannot be completed and a hemi-fused polymersome is formed. In addition to τ, the anisotropic steric interactions within the rod layers also resist hopping of longer rod-blocks. The coil layers develop a barrier impeding fusion between vesicles with longer coil-blocks. Consequently, lowering the solvent quality for the coil-block or rod-block facilities the fusion process due to the formation of a thinner coil layer.
Collapse
Affiliation(s)
- Yung-Lung Lin
- Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China.
| | | | | | | |
Collapse
|
20
|
Mandal S, Eksteen-Akeroyd ZH, Jacobs MJ, Hammink R, Koepf M, Lambeck AJA, van Hest JCM, Wilson CJ, Blank K, Figdor CG, Rowan AE. Therapeutic nanoworms: towards novel synthetic dendritic cells for immunotherapy. Chem Sci 2013. [DOI: 10.1039/c3sc51399h] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|